added logging for unknown dispenser status positions

bootstrap/bootstrap.go

@@ -0,0 +1,18 @@
+// internal/bootstrap/db.go
+package bootstrap
+
+import (
+	"database/sql"
+
+	"gitea.futuresens.co.uk/futuresens/hardlink/config"
+	"gitea.futuresens.co.uk/futuresens/hardlink/db"
+)
+
+func OpenDB(cfg *config.ConfigRec) (*sql.DB, error) {
+	return db.InitMSSQL(
+		cfg.Dbport,
+		cfg.Dbuser,
+		cfg.Dbpassword,
+		cfg.Dbname,
+	)
+}

config/config.go

@@ -0,0 +1,93 @@
+package config
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	"gitea.futuresens.co.uk/futuresens/hardlink/errorhandlers"
+	log "github.com/sirupsen/logrus"
+	yaml "gopkg.in/yaml.v3"
+)
+
+// configRec holds values from config.yml.
+type ConfigRec struct {
+	Port           int    `yaml:"port"`
+	LockserverUrl  string `yaml:"lockservUrl"`
+	LockType       string `yaml:"lockType"`
+	EncoderAddress string `yaml:"encoderAddr"`
+	Cert           string `yaml:"cert"`
+	DispenserPort  string `yaml:"dispensPort"`
+	DispenserAdrr  string `yaml:"dispensAddr"`
+	PrinterName    string `yaml:"printerName"`
+	LogDir         string `yaml:"logdir"`
+	Dbport         int    `yaml:"dbport"`     // Port for the database connection
+	Dbname         string `yaml:"dbname"`     // Database name for the connection
+	Dbuser         string `yaml:"dbuser"`     // User for the database connection
+	Dbpassword     string `yaml:"dbpassword"` // Password for the database connection
+	IsPayment      bool   `yaml:"isPayment"`
+	TestMode       bool   `yaml:"testMode"`
+}
+
+// ReadConfig reads config.yml and applies defaults.
+func ReadHardlinkConfig() ConfigRec {
+	var cfg ConfigRec
+	const configName = "config.yml"
+	defaultPort := 9091
+	sep := string(os.PathSeparator)
+
+	data, err := os.ReadFile(configName)
+	if err != nil {
+		log.Warnf("ReadConfig %s: %v", configName, err)
+	} else if err := yaml.Unmarshal(data, &cfg); err != nil {
+		log.Warnf("Unmarshal config: %v", err)
+	}
+
+	if cfg.Port == 0 {
+		cfg.Port = defaultPort
+	}
+
+	if cfg.LockType == "" {
+		err = fmt.Errorf("LockType is required in %s", configName)
+		errorhandlers.FatalError(err)
+	}
+	cfg.LockType = strings.ToLower(cfg.LockType)
+
+	if cfg.LogDir == "" {
+		cfg.LogDir = "./logs" + sep
+	} else if !strings.HasSuffix(cfg.LogDir, sep) {
+		cfg.LogDir += sep
+	}
+
+	if cfg.Dbport <= 0 || cfg.Dbuser == "" || cfg.Dbname == "" || cfg.Dbpassword == "" {
+		err = fmt.Errorf("Database config (dbport, dbuser, dbname, dbpassword) are required in %s", configName)
+		log.Warnf(err.Error())
+	}
+
+	return cfg
+}
+
+func ReadPreauthReleaserConfig() ConfigRec {
+	var cfg ConfigRec
+	const configName = "config.yml"
+	sep := string(os.PathSeparator)
+
+	data, err := os.ReadFile(configName)
+	if err != nil {
+		log.Warnf("ReadConfig %s: %v", configName, err)
+	} else if err := yaml.Unmarshal(data, &cfg); err != nil {
+		log.Warnf("Unmarshal config: %v", err)
+	}
+
+	if cfg.Dbport <= 0 || cfg.Dbuser == "" || cfg.Dbname == "" || cfg.Dbpassword == "" {
+		err = fmt.Errorf("Database config (dbport, dbuser, dbname, dbpassword) are required in %s", configName)
+		errorhandlers.FatalError(err)
+	}
+
+	if cfg.LogDir == "" {
+		cfg.LogDir = "./logs" + sep
+	} else if !strings.HasSuffix(cfg.LogDir, sep) {
+		cfg.LogDir += sep
+	}
+	return cfg
+}

db/db.go

@@ -0,0 +1,201 @@
+package db
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"fmt"
+	"strconv"
+	"strings"
+	"time"
+
+	mssqldb "github.com/denisenkom/go-mssqldb" // for error inspection
+	log "github.com/sirupsen/logrus"
+
+	"gitea.futuresens.co.uk/futuresens/hardlink/types"
+)
+
+// InitMSSQL opens and pings the SQL Server instance (keeps your original behaviour)
+func InitMSSQL(port int, user, password, database string) (*sql.DB, error) {
+	if port <= 0 || user == "" || database == "" {
+		return nil, errors.New("incomplete database configuration")
+	}
+
+	dsn := fmt.Sprintf(
+		"sqlserver://%s:%s@%s:%d?database=%s&encrypt=disable",
+		user, password, "localhost", port, database,
+	)
+
+	db, err := sql.Open("sqlserver", dsn)
+	if err != nil {
+		return nil, err
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	if err := db.PingContext(ctx); err != nil {
+		db.Close()
+		return nil, err
+	}
+
+	if err := db.QueryRowContext(ctx, "SELECT 1").Scan(new(int)); err != nil {
+		db.Close()
+		return nil, err
+	}
+	log.Info("Database connection established")
+	return db, nil
+}
+
+func parseDateOnly(s string) (time.Time, error) {
+	parsed, err := time.Parse(types.CustomLayout, s)
+	if err == nil {
+		// construct midnight in local timezone, then convert to UTC for storage consistency
+		localMidnight := time.Date(parsed.Year(), parsed.Month(), parsed.Day(), 0, 0, 0, 0, time.Local)
+		return localMidnight.UTC(), nil
+	}
+	return time.Time{}, fmt.Errorf("parseDateOnly error: parsing %q: %w", s, err)
+}
+
+// InsertPreauth stores a preauthorization record. It is idempotent: duplicate TxnReference is ignored.
+func InsertPreauth(ctx context.Context, db *sql.DB, m map[string]string, checkoutDate string) error {
+	const funcName = "InsertPreauth"
+
+	totalMinorUnits := m[types.TotalAmount]
+	txnReference := m[types.Reference]
+	if txnReference == "" {
+		return fmt.Errorf("%s: missing REFERENCE", funcName)
+	}
+	if totalMinorUnits == "" {
+		return fmt.Errorf("%s: missing TotalAmount", funcName)
+	}
+
+	// parse minor units, fallback to 0 on parse error but report it
+	amountInt, err := strconv.ParseInt(totalMinorUnits, 10, 64)
+	if err != nil {
+		log.WithFields(log.Fields{
+			"func":  funcName,
+			"value": totalMinorUnits,
+			"error": err,
+		}).Warnf("parsing TotalAmount, defaulting to 0")
+		amountInt = 0
+	}
+	totalAmount := float64(amountInt) / 100.0
+
+	txnTime := time.Now().UTC()
+
+	// parse departure / checkout date and compute release date (48h after departure)
+	checkOutDate, err := parseDateOnly(checkoutDate)
+	if err != nil {
+		return fmt.Errorf("InsertPreauth: parsing checkoutDate %q: %w", checkoutDate, err)
+	}
+	releaseDate := checkOutDate.Add(48 * time.Hour)
+
+	const stmt = `
+INSERT INTO dbo.Preauthorizations
+    (TxnReference, TotalMinorUnits, TotalAmount, TxnDateTime, DepartureDate, ReleaseDate)
+VALUES
+    (@TxnReference, @TotalMinorUnits, @TotalAmount, @TxnDateTime, @DepartureDate, @ReleaseDate);
+`
+	_, err = db.ExecContext(ctx, stmt,
+		sql.Named("TxnReference", txnReference),
+		sql.Named("TotalMinorUnits", totalMinorUnits),
+		sql.Named("TotalAmount", totalAmount),
+		sql.Named("TxnDateTime", txnTime),
+		sql.Named("DepartureDate", checkOutDate),
+		sql.Named("ReleaseDate", releaseDate),
+	)
+	if err != nil {
+		// handle duplicate-key (unique constraint) gracefully: SQL Server error numbers 2601/2627
+		var sqlErr mssqldb.Error
+		if errors.As(err, &sqlErr) {
+			if sqlErr.Number == 2627 || sqlErr.Number == 2601 {
+				log.Infof("InsertPreauth: preauth %s already exists (duplicate key) - ignoring", txnReference)
+				return nil
+			}
+		}
+		return fmt.Errorf("InsertPreauth exec: %w", err)
+	}
+
+	log.Infof("Inserted preauth %s amount=%s minorUnits release=%s", txnReference, totalMinorUnits, releaseDate.Format(time.RFC3339))
+	return nil
+}
+
+// GetDuePreauths returns preauths with ReleaseDate <= now where Released = 0.
+// If limit > 0, the query uses TOP(limit) to bound results at DB level.
+func GetDuePreauths(ctx context.Context, db *sql.DB, now time.Time, limit int) ([]types.PreauthRec, error) {
+	baseQuery := `
+SELECT Id, TxnReference, TotalMinorUnits, TotalAmount, TxnDateTime, DepartureDate, ReleaseDate, Released, ReleasedAt
+FROM dbo.Preauthorizations
+WHERE Released = 0 AND ReleaseDate <= @Now
+ORDER BY ReleaseDate ASC
+`
+	query := baseQuery
+	if limit > 0 {
+		// embed TOP to keep DB from returning everything; limit is controlled by the caller.
+		query = strings.Replace(baseQuery, "SELECT", fmt.Sprintf("SELECT TOP (%d)", limit), 1)
+	}
+
+	rows, err := db.QueryContext(ctx, query, sql.Named("Now", now))
+	if err != nil {
+		return nil, fmt.Errorf("GetDuePreauths query: %w", err)
+	}
+	defer rows.Close()
+
+	var out []types.PreauthRec
+	for rows.Next() {
+		var r types.PreauthRec
+		var departure sql.NullTime
+		var releasedAt sql.NullTime
+		// Note: adjust scanning targets if types.PreauthRec fields differ
+		if err := rows.Scan(
+			&r.Id,
+			&r.TxnReference,
+			&r.TotalMinorUnits,
+			&r.TotalAmount,
+			&r.TxnDateTime,
+			&departure,
+			&r.ReleaseDate,
+			&r.Released,
+			&releasedAt,
+		); err != nil {
+			return nil, fmt.Errorf("GetDuePreauths scan: %w", err)
+		}
+
+		if departure.Valid {
+			r.DepartureDate = departure.Time
+		} else {
+			r.DepartureDate = time.Time{}
+		}
+		r.ReleasedAt = releasedAt
+
+		out = append(out, r)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, fmt.Errorf("GetDuePreauths rows: %w", err)
+	}
+	return out, nil
+}
+
+// MarkPreauthReleased sets Released=1 and stores the timestamp. Returns error if no rows updated.
+func MarkPreauthReleased(ctx context.Context, db *sql.DB, txnReference string, releasedAt time.Time) error {
+	const stmt = `
+UPDATE dbo.Preauthorizations
+SET Released = 1, ReleasedAt = @ReleasedAt
+WHERE TxnReference = @TxnReference AND Released = 0;
+`
+	res, err := db.ExecContext(ctx, stmt, sql.Named("ReleasedAt", releasedAt), sql.Named("TxnReference", txnReference))
+	if err != nil {
+		return fmt.Errorf("MarkPreauthReleased exec: %w", err)
+	}
+	n, err := res.RowsAffected()
+	if err != nil {
+		return fmt.Errorf("MarkPreauthReleased RowsAffected: %w", err)
+	}
+	if n == 0 {
+		return fmt.Errorf("no rows updated for %s (maybe already released)", txnReference)
+	}
+	log.Infof("Marked preauth %s released at %s", txnReference, releasedAt.Format(time.RFC3339))
+	return nil
+}
+

dispenser/dispenser.go

@@ -1,9 +1,8 @@
 package dispenser
 
 import (
-	// "encoding/hex"
 	"fmt"
-	// "log"
+	"strings"
 	"time"
 
 	log "github.com/sirupsen/logrus"
@@ -20,29 +19,25 @@ const (
 	space    = 0x00                   // Space character
 	baudRate = 9600                   // Baud rate for serial communication
 	delay    = 500 * time.Millisecond // Delay for processing commands
-)
 
-// type (
+	// cache freshness for "continuous status" reads (tune as you wish)
-// 	configRec struct {
+	defaultStatusTTL = 1500 * time.Millisecond
-// 		SerialPort string `yaml:"port"`
+)
-// 		Address    string `yaml:"addr"`
-// 	}
-// )
 
 var (
 	SerialPort string
 	Address    []byte
-	commandFC7 = []byte{ETX, 0x46, 0x43, 0x37} // "FC7" command dispense card at read card position
+
-	commandFC0 = []byte{ETX, 0x46, 0x43, 0x30} // "FC0" command dispense card out of card mouth command
+	commandFC7 = []byte{ETX, 0x46, 0x43, 0x37} // "FC7"
+	commandFC0 = []byte{ETX, 0x46, 0x43, 0x30} // "FC0"
 
 	statusPos0 = map[byte]string{
 		0x38: "Keep",
 		0x34: "Command cannot execute",
 		0x32: "Preparing card fails",
 		0x31: "Preparing card",
-		0x30: "Normal", // Default if none of the above
+		0x30: "Normal",
 	}
-
 	statusPos1 = map[byte]string{
 		0x38: "Dispensing card",
 		0x34: "Capturing card",
@@ -50,7 +45,6 @@ var (
 		0x31: "Capture card error",
 		0x30: "Normal",
 	}
-
 	statusPos2 = map[byte]string{
 		0x38: "No captured card",
 		0x34: "Card overlapped",
@@ -58,7 +52,6 @@ var (
 		0x31: "Card pre-empty",
 		0x30: "Normal",
 	}
-
 	statusPos3 = map[byte]string{
 		0x38: "Card empty",
 		0x34: "Card ready position",
@@ -69,10 +62,16 @@ var (
 	}
 )
 
-func checkStatus(statusResp []byte) (string, error) {
+// --------------------
-	if len(statusResp) > 3 {
+// Status helpers
-		statusBytes := statusResp[7:11] // Extract the relevant bytes from the response
+// --------------------
-		// For each position, get the ASCII character, hex value, and mapped meaning.
+
+func logStatus(statusBytes []byte) {
+	if len(statusBytes) < 4 {
+		log.Infof("Dispenser status: <invalid len=%d>", len(statusBytes))
+		return
+	}
+
 	posStatus := []struct {
 		pos    int
 		value  byte
@@ -84,33 +83,56 @@ func checkStatus(statusResp []byte) (string, error) {
 		{pos: 4, value: statusBytes[3], mapper: statusPos3},
 	}
 
-		result := ""
+	var result strings.Builder
 	for _, p := range posStatus {
 		statusMsg, exists := p.mapper[p.value]
 		if !exists {
-				statusMsg = "Unknown status"
+			statusMsg = fmt.Sprintf("Unknown status 0x%X at position %d", p.value, p.pos)
 		}
 		if p.value != 0x30 {
-				result += fmt.Sprintf("Status: %s; ", statusMsg)
+			result.WriteString(statusMsg + "; ")
-			}
-			if p.pos == 4 && p.value == 0x38 {
-				return result, fmt.Errorf("Card well empty")
-			}
-		}
-		return result, nil
-
-	} else {
-		if len(statusResp) == 3 && statusResp[0] == ACK && statusResp[1] == Address[0] && statusResp[2] == Address[1] {
-			return "active;", nil
-		} else if len(statusResp) > 0 && statusResp[0] == NAK {
-			return "", fmt.Errorf("negative response from dispenser")
-		} else {
-			return "", fmt.Errorf("unexpected response status: % X", statusResp)
 		}
 	}
+	log.Infof("Dispenser status: %s", result.String())
 }
 
-// calculateBCC computes the Block Check Character (BCC) as the XOR of all bytes from STX to ETX.
+func isAtEncoderPosition(statusBytes []byte) bool {
+	return len(statusBytes) >= 4 && statusBytes[3] == 0x33
+}
+
+func stockTake(statusBytes []byte) string {
+	if len(statusBytes) < 4 {
+		return ""
+	}
+	status := ""
+	if statusBytes[2] != 0x30 {
+		status = statusPos2[statusBytes[2]]
+	}
+	if statusBytes[3] == 0x38 {
+		status = statusPos3[statusBytes[3]]
+	}
+	return status
+}
+
+func isCardWellEmpty(statusBytes []byte) bool {
+	return len(statusBytes) >= 4 && statusBytes[3] == 0x38
+}
+
+func checkACK(statusResp []byte) error {
+	if len(statusResp) == 3 &&
+		statusResp[0] == ACK &&
+		len(Address) >= 2 &&
+		statusResp[1] == Address[0] &&
+		statusResp[2] == Address[1] {
+		return nil
+	}
+	if len(statusResp) > 0 && statusResp[0] == NAK {
+		return fmt.Errorf("negative response from dispenser")
+	}
+	return fmt.Errorf("unexpected response status: % X", statusResp)
+}
+
+// calculateBCC computes BCC as XOR of all bytes from STX to ETX.
 func calculateBCC(data []byte) byte {
 	var bcc byte
 	for _, b := range data {
@@ -121,8 +143,8 @@ func calculateBCC(data []byte) byte {
 
 func createPacket(address []byte, command []byte) []byte {
 	packet := []byte{STX}
-	packet = append(packet, address...) // Address bytes
+	packet = append(packet, address...)
-	packet = append(packet, space)      // Space character
+	packet = append(packet, space)
 	packet = append(packet, command...)
 	packet = append(packet, ETX)
 	bcc := calculateBCC(packet)
@@ -130,165 +152,134 @@ func createPacket(address []byte, command []byte) []byte {
 	return packet
 }
 
-func buildCheckRF(address []byte) []byte {
+func buildCheckAP(address []byte) []byte { return createPacket(address, []byte{STX, 0x41, 0x50}) }
-	return createPacket(address, []byte{STX, 0x52, 0x46})
-}
-
-func buildCheckAP(address []byte) []byte {
-	return createPacket(address, []byte{STX, 0x41, 0x50})
-}
 
 func sendAndReceive(port *serial.Port, packet []byte, delay time.Duration) ([]byte, error) {
-	n, err := port.Write(packet)
+	_, err := port.Write(packet)
 	if err != nil {
 		return nil, fmt.Errorf("error writing to port: %w", err)
 	}
-	// log.Printf("TX %d bytes: % X", n, packet[:n])
 
-	time.Sleep(delay) // Wait for the dispenser to process the command
+	time.Sleep(delay)
 
 	buf := make([]byte, 128)
-	n, err = port.Read(buf)
+	n, err := port.Read(buf)
 	if err != nil {
 		return nil, fmt.Errorf("error reading from port: %w", err)
 	}
-	resp := buf[:n]
+	return buf[:n], nil
-	// log.Printf("RX %d bytes: % X", n, buf[:n])
-	return resp, nil
 }
 
+// --------------------
+// Serial init (3 attempts)
+// --------------------
+
 func InitializeDispenser() (*serial.Port, error) {
-	const funcName = "initializeDispenser"
+	const (
+		funcName   = "InitializeDispenser"
+		maxRetries = 3
+		retryDelay = 2 * time.Second
+	)
+
+	if SerialPort == "" {
+		return nil, fmt.Errorf("%s: SerialPort is empty", funcName)
+	}
+	if len(Address) < 2 {
+		return nil, fmt.Errorf("%s: Address must be at least 2 bytes", funcName)
+	}
+
 	serialConfig := &serial.Config{
 		Name:        SerialPort,
 		Baud:        baudRate,
-		ReadTimeout: time.Second * 2,
+		ReadTimeout: 2 * time.Second,
 	}
+
+	var lastErr error
+	for attempt := 1; attempt <= maxRetries; attempt++ {
 		port, err := serial.OpenPort(serialConfig)
-	if err != nil {
+		if err == nil {
-		return nil, fmt.Errorf("error opening dispenser COM port: %w", err)
+			log.Infof("%s: dispenser opened on %s (attempt %d/%d)", funcName, SerialPort, attempt, maxRetries)
-	}
 			return port, nil
 		}
 
-func DispenserSequence(port *serial.Port) (string, error) {
+		lastErr = err
-	const funcName = "dispenserSequence"
+		log.Warnf("%s: failed to open dispenser on %s (attempt %d/%d): %v", funcName, SerialPort, attempt, maxRetries, err)
-	var result string
+		if attempt < maxRetries {
-
+			time.Sleep(retryDelay)
-	// Check dispenser status
-	status, err := CheckDispenserStatus(port)
-	if err != nil {
-		return status, fmt.Errorf("[%s] error checking dispenser status: %v", funcName, err)
 		}
-	result += status
-
-	// Send card to encoder position
-	status, err = CardToEncoderPosition(port)
-	if err != nil {
-		return status, fmt.Errorf("[%s] error sending card to encoder position: %v", funcName, err)
-	}
-	result += "; " + status
-
-	return result, nil
 	}
 
-// if dispenser is not responding, I should repeat the command
+	return nil, fmt.Errorf("%s: failed to open dispenser on %s after %d attempts: %w", funcName, SerialPort, maxRetries, lastErr)
-func CheckDispenserStatus(port *serial.Port) (string, error) {
+}
-	const funcName = "checkDispenserStatus"
+
-	var result string
+// --------------------
+// Internal (port-owner only) operations
+// --------------------
+
+// checkDispenserStatus talks to the device and returns the 4 status bytes [pos0..pos3].
+func checkDispenserStatus(port *serial.Port) ([]byte, error) {
 	checkCmd := buildCheckAP(Address)
 	enq := append([]byte{ENQ}, Address...)
 
-	// Send check command (AP)
 	statusResp, err := sendAndReceive(port, checkCmd, delay)
 	if err != nil {
-		return "", fmt.Errorf("error sending check command: %v", err)
+		return nil, fmt.Errorf("error sending check command: %w", err)
 	}
 	if len(statusResp) == 0 {
-		return "", fmt.Errorf("no response from dispenser")
+		return nil, fmt.Errorf("no response from dispenser")
 	}
-	status, err := checkStatus(statusResp)
+	if err := checkACK(statusResp); err != nil {
-	if err != nil {
+		return nil, err
-		return status, err
 	}
-	result += "; " + status
 
-	// Send ENQ+ADDR to prompt device to execute the command.
 	statusResp, err = sendAndReceive(port, enq, delay)
 	if err != nil {
-		log.Errorf("error sending ENQ: %v", err)
+		return nil, fmt.Errorf("error sending ENQ: %w", err)
 	}
-	if len(statusResp) == 0 {
+	if len(statusResp) < 13 {
-		return "", fmt.Errorf("no response from dispenser")
+		return nil, fmt.Errorf("incomplete status response from dispenser: % X", statusResp)
 	}
-	status, err = checkStatus(statusResp)
+	return statusResp[7:11], nil
-	if err != nil {
-		return status, err
-	}
-	result += status
-	return result, nil
 }
 
-func CardToEncoderPosition(port *serial.Port) (string, error) {
+func cardToEncoderPosition(port *serial.Port) error {
-	const funcName = "cartToEncoderPosition"
 	enq := append([]byte{ENQ}, Address...)
 
-	//Send Dispense card to encoder position (FC7) ---
 	dispenseCmd := createPacket(Address, commandFC7)
 	log.Println("Send card to encoder position")
+
 	statusResp, err := sendAndReceive(port, dispenseCmd, delay)
 	if err != nil {
-		return "", fmt.Errorf("error sending card to encoder position: %v", err)
+		return fmt.Errorf("error sending card to encoder position: %w", err)
 	}
-	_, err = checkStatus(statusResp)
+	if err := checkACK(statusResp); err != nil {
-	if err != nil {
+		return err
-		return "", err
 	}
 
-	//Send ENQ to prompt device ---
 	_, err = port.Write(enq)
 	if err != nil {
-		return "", fmt.Errorf("error sending ENQ to prompt device: %v", err)
+		return fmt.Errorf("error sending ENQ to prompt device: %w", err)
+	}
+	return nil
 }
 
-	time.Sleep(delay)
+func cardOutOfMouth(port *serial.Port) error {
-
-	//Check card position status
-	status, err := CheckDispenserStatus(port)
-	if err != nil {
-		return "", err
-	}
-	return status, nil
-}
-
-func CardOutOfMouth(port *serial.Port) (string, error) {
-	const funcName = "CardOutOfMouth"
 	enq := append([]byte{ENQ}, Address...)
 
-	// Send  card out of card mouth (FC0) ---
 	dispenseCmd := createPacket(Address, commandFC0)
 	log.Println("Send card to out mouth position")
+
 	statusResp, err := sendAndReceive(port, dispenseCmd, delay)
 	if err != nil {
-		return "", fmt.Errorf("error sending out of mouth command: %v", err)
+		return fmt.Errorf("error sending out of mouth command: %w", err)
 	}
-	_, err = checkStatus(statusResp)
+	if err := checkACK(statusResp); err != nil {
-	if err != nil {
+		return err
-		return "", err
 	}
 
-	//Send ENQ to prompt device ---
 	_, err = port.Write(enq)
 	if err != nil {
-		return "", fmt.Errorf("error sending ENQ to prompt device: %v", err)
+		return fmt.Errorf("error sending ENQ to prompt device: %w", err)
 	}
-
+	return nil
-	time.Sleep(delay)
-
-	//Check card position status
-	status, err := CheckDispenserStatus(port)
-	if err != nil {
-		return "", err
-	}
-	return status, nil
 }

dispenser/dispenserclient.go

@@ -0,0 +1,341 @@
+// --------------------
+// Queue-based client (single owner of port)
+// --------------------
+package dispenser
+
+import (
+	"context"
+	"fmt"
+	"sync"
+	"time"
+
+	log "github.com/sirupsen/logrus"
+	"github.com/tarm/serial"
+)
+
+type cmdType int
+
+const (
+	cmdStatus cmdType = iota
+	cmdToEncoder
+	cmdOutOfMouth
+)
+
+type cmdReq struct {
+	typ    cmdType
+	ctx    context.Context
+	respCh chan cmdResp
+}
+
+type cmdResp struct {
+	status []byte
+	err    error
+}
+
+type Client struct {
+	port *serial.Port
+
+	reqCh chan cmdReq
+	done  chan struct{}
+
+	// status cache
+	mu          sync.RWMutex
+	lastStatus  []byte
+	lastStatusT time.Time
+	statusTTL   time.Duration
+
+	// published "stock/cardwell" cache + callback
+	lastStockMu sync.RWMutex
+	lastStock   string
+	onStock     func(string)
+}
+
+// NewClient starts the worker that owns the serial port.
+func NewClient(port *serial.Port, queueSize int) *Client {
+	if queueSize <= 0 {
+		queueSize = 16
+	}
+	c := &Client{
+		port:      port,
+		reqCh:     make(chan cmdReq, queueSize),
+		done:      make(chan struct{}),
+		statusTTL: defaultStatusTTL,
+	}
+	go c.loop()
+	return c
+}
+
+func (c *Client) Close() {
+	select {
+	case <-c.done:
+		return
+	default:
+		close(c.done)
+	}
+}
+
+// Optional: tune cache TTL (how "fresh" cached status must be)
+func (c *Client) SetStatusTTL(d time.Duration) {
+	c.mu.Lock()
+	c.statusTTL = d
+	c.mu.Unlock()
+}
+
+// OnStockUpdate registers a callback called whenever polling (or status reads) produce a stock status string.
+func (c *Client) OnStockUpdate(fn func(string)) {
+	c.lastStockMu.Lock()
+	c.onStock = fn
+	c.lastStockMu.Unlock()
+}
+
+// LastStock returns the most recently computed stock/card-well status string.
+func (c *Client) LastStock() string {
+	c.lastStockMu.RLock()
+	defer c.lastStockMu.RUnlock()
+	return c.lastStock
+}
+
+func (c *Client) setStock(statusBytes []byte) {
+	stock := stockTake(statusBytes)
+
+	c.lastStockMu.Lock()
+	c.lastStock = stock
+	fn := c.onStock
+	c.lastStockMu.Unlock()
+
+	// call outside lock
+	if fn != nil {
+		fn(stock)
+	}
+}
+
+// StartPolling performs a periodic status refresh.
+// It will NOT interrupt commands: it enqueues only when queue is idle.
+func (c *Client) StartPolling(interval time.Duration) {
+	if interval <= 0 {
+		return
+	}
+	go func() {
+		t := time.NewTicker(interval)
+		defer t.Stop()
+
+		for {
+			select {
+			case <-c.done:
+				return
+			case <-t.C:
+				// enqueue only if idle to avoid delaying real commands
+				if len(c.reqCh) != 0 {
+					continue
+				}
+				ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+				_, err := c.CheckStatus(ctx)
+				if err != nil {
+					log.Debugf("dispenser polling: %v", err)
+				}
+				cancel()
+			}
+		}
+	}()
+}
+
+func (c *Client) loop() {
+	for {
+		select {
+		case <-c.done:
+			return
+		case req := <-c.reqCh:
+			c.handle(req)
+		}
+	}
+}
+
+func (c *Client) handle(req cmdReq) {
+	select {
+	case <-req.ctx.Done():
+		req.respCh <- cmdResp{err: req.ctx.Err()}
+		return
+	default:
+	}
+
+	switch req.typ {
+	case cmdStatus:
+		st, err := checkDispenserStatus(c.port)
+		if err == nil && len(st) == 4 {
+			c.mu.Lock()
+			c.lastStatus = append([]byte(nil), st...)
+			c.lastStatusT = time.Now()
+			c.mu.Unlock()
+
+			// publish stock/cardwell
+			c.setStock(st)
+		}
+		req.respCh <- cmdResp{status: st, err: err}
+
+	case cmdToEncoder:
+		err := cardToEncoderPosition(c.port)
+		req.respCh <- cmdResp{err: err}
+
+	case cmdOutOfMouth:
+		err := cardOutOfMouth(c.port)
+		req.respCh <- cmdResp{err: err}
+
+	default:
+		req.respCh <- cmdResp{err: fmt.Errorf("unknown command")}
+	}
+}
+
+func (c *Client) do(ctx context.Context, typ cmdType) ([]byte, error) {
+	rch := make(chan cmdResp, 1)
+	req := cmdReq{typ: typ, ctx: ctx, respCh: rch}
+
+	select {
+	case c.reqCh <- req:
+	case <-ctx.Done():
+		return nil, ctx.Err()
+	}
+
+	select {
+	case r := <-rch:
+		return r.status, r.err
+	case <-ctx.Done():
+		return nil, ctx.Err()
+	}
+}
+
+// CheckStatus returns cached status if fresh, otherwise enqueues a device status read.
+func (c *Client) CheckStatus(ctx context.Context) ([]byte, error) {
+	c.mu.RLock()
+	ttl := c.statusTTL
+	st := append([]byte(nil), c.lastStatus...)
+	ts := c.lastStatusT
+	c.mu.RUnlock()
+
+	if len(st) == 4 && time.Since(ts) <= ttl {
+		// even when returning cached, keep stock in sync
+		c.setStock(st)
+		return st, nil
+	}
+	return c.do(ctx, cmdStatus)
+}
+
+func (c *Client) ToEncoder(ctx context.Context) error {
+	_, err := c.do(ctx, cmdToEncoder)
+	return err
+}
+
+func (c *Client) OutOfMouth(ctx context.Context) error {
+	_, err := c.do(ctx, cmdOutOfMouth)
+	return err
+}
+
+// --------------------
+// Public sequences updated to use Client (queue)
+// --------------------
+
+// DispenserPrepare: check status; if empty => ok; else ensure at encoder.
+func (c *Client) DispenserPrepare(ctx context.Context) (string, error) {
+	const funcName = "DispenserPrepare"
+	stockStatus := ""
+
+	status, err := c.CheckStatus(ctx)
+	if err != nil {
+		return stockStatus, fmt.Errorf("[%s] check status: %w", funcName, err)
+	}
+
+	logStatus(status)
+	stockStatus = stockTake(status)
+	c.setStock(status)
+
+	if isCardWellEmpty(status) {
+		return stockStatus, nil
+	}
+	if isAtEncoderPosition(status) {
+		return stockStatus, nil
+	}
+
+	if err := c.ToEncoder(ctx); err != nil {
+		return stockStatus, fmt.Errorf("[%s] to encoder: %w", funcName, err)
+	}
+
+	time.Sleep(delay)
+	status, err = c.CheckStatus(ctx)
+	if err != nil {
+		return stockStatus, fmt.Errorf("[%s] re-check status: %w", funcName, err)
+	}
+	logStatus(status)
+	stockStatus = stockTake(status)
+	c.setStock(status)
+
+	return stockStatus, nil
+}
+
+func (c *Client) DispenserStart(ctx context.Context) (string, error) {
+	const funcName = "DispenserStart"
+	stockStatus := ""
+
+	status, err := c.CheckStatus(ctx)
+	if err != nil {
+		return stockStatus, fmt.Errorf("[%s] check status: %w", funcName, err)
+	}
+
+	logStatus(status)
+	stockStatus = stockTake(status)
+	c.setStock(status)
+
+	if isCardWellEmpty(status) {
+		return stockStatus, fmt.Errorf(stockStatus)
+	}
+	if isAtEncoderPosition(status) {
+		return stockStatus, nil
+	}
+
+	if err := c.ToEncoder(ctx); err != nil {
+		return stockStatus, fmt.Errorf("[%s] to encoder: %w", funcName, err)
+	}
+
+	time.Sleep(delay)
+	status, err = c.CheckStatus(ctx)
+	if err != nil {
+		return stockStatus, fmt.Errorf("[%s] re-check status: %w", funcName, err)
+	}
+	logStatus(status)
+	stockStatus = stockTake(status)
+	c.setStock(status)
+
+	return stockStatus, nil
+}
+
+func (c *Client) DispenserFinal(ctx context.Context) (string, error) {
+	const funcName = "DispenserFinal"
+	stockStatus := ""
+
+	if err := c.OutOfMouth(ctx); err != nil {
+		return stockStatus, fmt.Errorf("[%s] out of mouth: %w", funcName, err)
+	}
+
+	time.Sleep(delay)
+	status, err := c.CheckStatus(ctx)
+	if err != nil {
+		return stockStatus, fmt.Errorf("[%s] check status: %w", funcName, err)
+	}
+	logStatus(status)
+	stockStatus = stockTake(status)
+	c.setStock(status)
+
+	time.Sleep(delay)
+	if err := c.ToEncoder(ctx); err != nil {
+		return stockStatus, fmt.Errorf("[%s] to encoder: %w", funcName, err)
+	}
+
+	time.Sleep(delay)
+	status, err = c.CheckStatus(ctx)
+	if err != nil {
+		return stockStatus, fmt.Errorf("[%s] re-check status: %w", funcName, err)
+	}
+	logStatus(status)
+	stockStatus = stockTake(status)
+	c.setStock(status)
+
+	return stockStatus, nil
+}

errorhandlers/errorhandlers.go

@@ -0,0 +1,32 @@
+package errorhandlers
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"os"
+
+	"gitea.futuresens.co.uk/futuresens/cmstypes"
+	log "github.com/sirupsen/logrus"
+)
+
+const serviceName = "hardlink"
+
+// writeError is a helper to send a JSON error and HTTP status in one go.
+func WriteError(w http.ResponseWriter, status int, msg string) {
+	theResponse := cmstypes.StatusRec{
+		Code:    status,
+		Message: msg,
+	}
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	json.NewEncoder(w).Encode(theResponse)
+}
+
+func FatalError(err error) {
+	fmt.Println(err.Error())
+	log.Errorf(err.Error())
+	fmt.Println(". Press Enter to exit...")
+	fmt.Scanln()
+	os.Exit(1)
+}

go.mod

@@ -3,7 +3,7 @@ module gitea.futuresens.co.uk/futuresens/hardlink
 go 1.23.2
 
 require (
-	gitea.futuresens.co.uk/futuresens/cmstypes v1.0.179
+	gitea.futuresens.co.uk/futuresens/cmstypes v1.0.190
 	gitea.futuresens.co.uk/futuresens/logging v1.0.9
 	github.com/alexbrainman/printer v0.0.0-20200912035444-f40f26f0bdeb
 	github.com/denisenkom/go-mssqldb v0.12.3

go.sum

@@ -1,5 +1,5 @@
-gitea.futuresens.co.uk/futuresens/cmstypes v1.0.179 h1:3OLzX6jJ2dwfZ9Fcijk5z6/GUdTl5FUNw3eWuRkDhZw=
+gitea.futuresens.co.uk/futuresens/cmstypes v1.0.190 h1:OxP911wT8HQqBJ20KIZcBxi898rsYHhhCkne2u45p1A=
-gitea.futuresens.co.uk/futuresens/cmstypes v1.0.179/go.mod h1:ABMUkdm+3VGrkuoCJsXMfPPud9GHDOwBb1NiifFqxes=
+gitea.futuresens.co.uk/futuresens/cmstypes v1.0.190/go.mod h1:ABMUkdm+3VGrkuoCJsXMfPPud9GHDOwBb1NiifFqxes=
 gitea.futuresens.co.uk/futuresens/fscrypto v0.0.0-20221125125050-9acaffd21362 h1:MnhYo7XtsECCU+5yVMo3tZZOOSOKGkl7NpOvTAieBTo=
 gitea.futuresens.co.uk/futuresens/fscrypto v0.0.0-20221125125050-9acaffd21362/go.mod h1:p95ouVfK4qyC20D3/k9QLsWSxD2pdweWiY6vcYi9hpM=
 gitea.futuresens.co.uk/futuresens/logging v1.0.9 h1:uvCQq/plecB0z/bUWOhFhwyYUWGPkTBZHsYNL+3RFvI=

handlers/db_helpers.go

@@ -0,0 +1,206 @@
+package handlers
+
+import (
+	"bufio"
+	"context"
+	"database/sql"
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
+	"time"
+
+	"gitea.futuresens.co.uk/futuresens/hardlink/db"
+	log "github.com/sirupsen/logrus"
+)
+
+type preauthSpoolRecord struct {
+	CreatedAt    time.Time         `json:"createdAt"`
+	CheckoutDate string            `json:"checkoutDate"` // keep as received
+	Fields       map[string]string `json:"fields"`       // ChipDNA result.Fields
+}
+
+func (app *App) getDB(ctx context.Context) (*sql.DB, error) {
+	app.dbMu.Lock()
+	defer app.dbMu.Unlock()
+
+	// Fast path: db exists and is alive
+	if app.db != nil {
+		pingCtx, cancel := context.WithTimeout(ctx, 1*time.Second)
+		defer cancel()
+
+		if err := app.db.PingContext(pingCtx); err == nil {
+			return app.db, nil
+		}
+
+		// stale handle
+		_ = app.db.Close()
+		app.db = nil
+	}
+
+	// Reconnect once, bounded
+	dialCtx, cancel := context.WithTimeout(ctx, 3*time.Second)
+	defer cancel()
+
+	dbConn, err := db.InitMSSQL(
+		app.cfg.Dbport,
+		app.cfg.Dbuser,
+		app.cfg.Dbpassword,
+		app.cfg.Dbname,
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	pingCtx, cancel2 := context.WithTimeout(dialCtx, 1*time.Second)
+	defer cancel2()
+
+	if err := dbConn.PingContext(pingCtx); err != nil {
+		_ = dbConn.Close()
+		return nil, err
+	}
+
+	app.db = dbConn
+	return app.db, nil
+}
+
+func (app *App) spoolPath() string {
+	// keep it near logs; adjust if you prefer a dedicated dir
+	// ensure LogDir ends with separator in your config loader
+	return filepath.Join(app.cfg.LogDir, "preauth_spool.ndjson")
+}
+
+// persistPreauth tries DB first; if DB is down or insert fails, it spools to file.
+// It never returns an error to the caller (so your HTTP flow stays simple),
+// but it logs failures.
+func (app *App) persistPreauth(ctx context.Context, fields map[string]string, checkoutDate string) {
+	// First, try DB (with your reconnect logic inside getDB)
+	dbConn, err := app.getDB(ctx)
+	if err == nil && dbConn != nil {
+		if err := db.InsertPreauth(ctx, dbConn, fields, checkoutDate); err == nil {
+			// opportunistic drain once DB is alive
+			go app.drainPreauthSpool(context.Background())
+			return
+		} else {
+			log.WithError(err).Warn("DB insert failed; will spool preauth")
+		}
+	} else {
+		log.WithError(err).Warn("DB unavailable; will spool preauth")
+	}
+
+	// Fallback: spool to file
+	rec := preauthSpoolRecord{
+		CreatedAt:    time.Now().UTC(),
+		CheckoutDate: checkoutDate,
+		Fields:       fields,
+	}
+	if spErr := app.spoolPreauth(rec); spErr != nil {
+		log.WithError(spErr).Error("failed to spool preauth")
+	}
+}
+
+// append one line JSON (NDJSON)
+func (app *App) spoolPreauth(rec preauthSpoolRecord) error {
+	p := app.spoolPath()
+
+	f, err := os.OpenFile(p, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666)
+	if err != nil {
+		return fmt.Errorf("open spool file: %w", err)
+	}
+	defer f.Close()
+
+	b, err := json.Marshal(rec)
+	if err != nil {
+		return fmt.Errorf("marshal spool record: %w", err)
+	}
+
+	if _, err := f.Write(append(b, '\n')); err != nil {
+		return fmt.Errorf("write spool record: %w", err)
+	}
+
+	return f.Sync() // ensure it's on disk
+}
+
+// Drain spool into DB.
+// Strategy: read all lines, insert each; keep failures in a temp file; then replace original.
+func (app *App) drainPreauthSpool(ctx context.Context) {
+	dbConn, err := app.getDB(ctx)
+	if err != nil {
+		return // still down, nothing to do
+	}
+
+	spool := app.spoolPath()
+	in, err := os.Open(spool)
+	if err != nil {
+		// no spool is fine
+		return
+	}
+	defer in.Close()
+
+	tmp := spool + ".tmp"
+	out, err := os.OpenFile(tmp, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0666)
+	if err != nil {
+		log.WithError(err).Warn("drain spool: open tmp failed")
+		return
+	}
+	defer out.Close()
+
+	sc := bufio.NewScanner(in)
+	// allow long lines if receipts ever sneak in (shouldn't, but safe)
+	buf := make([]byte, 0, 64*1024)
+	sc.Buffer(buf, 2*1024*1024)
+
+	var (
+		okCount   int
+		failCount int
+	)
+
+	for sc.Scan() {
+		line := sc.Bytes()
+		if len(line) == 0 {
+			continue
+		}
+
+		var rec preauthSpoolRecord
+		if err := json.Unmarshal(line, &rec); err != nil {
+			// malformed line: keep it so we don't lose evidence
+			_, _ = out.Write(append(line, '\n'))
+			failCount++
+			continue
+		}
+
+		// attempt insert
+		if err := db.InsertPreauth(ctx, dbConn, rec.Fields, rec.CheckoutDate); err != nil {
+			// DB still flaky or data issue: keep it for later retry
+			_, _ = out.Write(append(line, '\n'))
+			failCount++
+			continue
+		}
+
+		okCount++
+	}
+
+	if err := sc.Err(); err != nil {
+		log.WithError(err).Warn("drain spool: scanner error")
+		// best effort; do not replace spool
+		return
+	}
+
+	_ = out.Sync()
+
+	// Replace original spool with temp (atomic on Windows is best-effort; still OK here)
+	_ = in.Close()
+	_ = out.Close()
+
+	if err := os.Rename(tmp, spool); err != nil {
+		log.WithError(err).Warn("drain spool: rename failed")
+		return
+	}
+
+	if okCount > 0 || failCount > 0 {
+		log.WithFields(log.Fields{
+			"inserted":  okCount,
+			"remaining": failCount,
+		}).Info("preauth spool drained")
+	}
+}

handlers/handlers.go

@@ -2,56 +2,67 @@ package handlers
 
 import (
 	"bytes"
+	"context"
+	"database/sql"
 	"encoding/json"
 	"encoding/xml"
 	"io"
 	"net/http"
 	"strings"
+	"sync"
 	"time"
 
-	"github.com/tarm/serial"
-
 	"gitea.futuresens.co.uk/futuresens/cmstypes"
+	"gitea.futuresens.co.uk/futuresens/hardlink/config"
 	"gitea.futuresens.co.uk/futuresens/hardlink/dispenser"
+	"gitea.futuresens.co.uk/futuresens/hardlink/errorhandlers"
 	"gitea.futuresens.co.uk/futuresens/hardlink/lockserver"
 	"gitea.futuresens.co.uk/futuresens/hardlink/payment"
 	"gitea.futuresens.co.uk/futuresens/hardlink/printer"
+	"gitea.futuresens.co.uk/futuresens/hardlink/types"
 	"gitea.futuresens.co.uk/futuresens/logging"
 	log "github.com/sirupsen/logrus"
 )
 
-const (
-	customLayout   = "2006-01-02 15:04:05 -0700"
-	transactionUrl = "http://127.0.0.1:18181/start-transaction/"
-)
-
 type App struct {
-	dispPort   *serial.Port
+	disp           *dispenser.Client
 	lockserver     lockserver.LockServer
 	isPayment      bool
+	db             *sql.DB
+	cfg            *config.ConfigRec
+	dbMu           sync.Mutex
+	cardWellMu     sync.RWMutex
+	cardWellStatus string
 }
 
-func NewApp(dispPort *serial.Port, lockType, encoderAddress string, isPayment bool) *App {
+func NewApp(disp *dispenser.Client, lockType, encoderAddress, cardWellStatus string, db *sql.DB, cfg *config.ConfigRec) *App {
-	return &App{
+	app := &App{
-		isPayment:  isPayment,
+		isPayment:  cfg.IsPayment,
-		dispPort:   dispPort,
+		disp:       disp,
-		lockserver: lockserver.NewLockServer(lockType, encoderAddress, FatalError),
+		lockserver: lockserver.NewLockServer(lockType, encoderAddress, errorhandlers.FatalError),
+		db:         db,
+		cfg:        cfg,
 	}
+	app.SetCardWellStatus(cardWellStatus)
+	return app
 }
 
 func (app *App) RegisterRoutes(mux *http.ServeMux) {
 	mux.HandleFunc("/issuedoorcard", app.issueDoorCard)
 	mux.HandleFunc("/printroomticket", app.printRoomTicket)
-	mux.HandleFunc("/starttransaction", app.startTransaction)
+	mux.HandleFunc("/takepreauth", app.takePreauthorization)
+	mux.HandleFunc("/takepayment", app.takePayment)
+	mux.HandleFunc("/dispenserstatus", app.reportDispenserStatus)
 }
 
-func (app *App) startTransaction(w http.ResponseWriter, r *http.Request) {
+func (app *App) takePreauthorization(w http.ResponseWriter, r *http.Request) {
-	const op = logging.Op("startTransaction")
+	const op = logging.Op("takePreauthorization")
 	var (
 		theResponse cmstypes.ResponseRec
-		cardholderReceipt string
 		theRequest  cmstypes.TransactionRec
 		trResult    payment.TransactionResultXML
+		result      payment.PaymentResult
+		save        bool
 	)
 
 	theResponse.Status.Code = http.StatusInternalServerError
@@ -63,7 +74,7 @@ func (app *App) startTransaction(w http.ResponseWriter, r *http.Request) {
 	w.Header().Set("Content-Type", "application/json")
 
 	if !app.isPayment {
-		theResponse.Data = payment.BuildFailureURL(payment.ResultError, "Payment processing is disabled")
+		theResponse.Data = payment.BuildFailureURL(types.ResultError, "Payment processing is disabled")
 		writeTransactionResult(w, http.StatusServiceUnavailable, theResponse)
 		return
 	}
@@ -73,16 +84,16 @@ func (app *App) startTransaction(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	log.Println("startTransaction called")
+	log.Println("takePreauthorization called")
 	if r.Method != http.MethodPost {
-		theResponse.Data = payment.BuildFailureURL(payment.ResultError, "Method not allowed; use POST")
+		theResponse.Data = payment.BuildFailureURL(types.ResultError, "Method not allowed; use POST")
 		writeTransactionResult(w, http.StatusMethodNotAllowed, theResponse)
 		return
 	}
 	defer r.Body.Close()
 
 	if ct := r.Header.Get("Content-Type"); ct != "text/xml" {
-		theResponse.Data = payment.BuildFailureURL(payment.ResultError, "Content-Type must be text/xml")
+		theResponse.Data = payment.BuildFailureURL(types.ResultError, "Content-Type must be text/xml")
 		writeTransactionResult(w, http.StatusUnsupportedMediaType, theResponse)
 		return
 	}
@@ -91,17 +102,17 @@ func (app *App) startTransaction(w http.ResponseWriter, r *http.Request) {
 	err := xml.Unmarshal(body, &theRequest)
 	if err != nil {
 		logging.Error(serviceName, err.Error(), "ReadXML", string(op), "", "", 0)
-		theResponse.Data = payment.BuildFailureURL(payment.ResultError, "Invalid XML payload")
+		theResponse.Data = payment.BuildFailureURL(types.ResultError, "Invalid XML payload")
 		writeTransactionResult(w, http.StatusBadRequest, theResponse)
 		return
 	}
-	log.Printf("Start trnasaction payload: Amount=%s, Type=%s", theRequest.AmountMinorUnits, theRequest.TransactionType)
+	log.Printf("Transaction payload: Amount=%s, Type=%s", theRequest.AmountMinorUnits, theRequest.TransactionType)
 
 	client := &http.Client{Timeout: 300 * time.Second}
-	response, err := client.Post(transactionUrl, "text/xml", bytes.NewBuffer(body))
+	response, err := client.Post(types.LinkTakePreauthorization, "text/xml", bytes.NewBuffer(body))
 	if err != nil {
 		logging.Error(serviceName, err.Error(), "Payment processing error", string(op), "", "", 0)
-		theResponse.Data = payment.BuildFailureURL(payment.ResultError, "No response from payment processor")
+		theResponse.Data = payment.BuildFailureURL(types.ResultError, "No response from payment processor")
 		writeTransactionResult(w, http.StatusBadGateway, theResponse)
 		return
 	}
@@ -110,7 +121,7 @@ func (app *App) startTransaction(w http.ResponseWriter, r *http.Request) {
 	body, err = io.ReadAll(response.Body)
 	if err != nil {
 		logging.Error(serviceName, err.Error(), "Read response body error", string(op), "", "", 0)
-		theResponse.Data = payment.BuildFailureURL(payment.ResultError, "Failed to read response body")
+		theResponse.Data = payment.BuildFailureURL(types.ResultError, "Failed to read response body")
 		writeTransactionResult(w, http.StatusInternalServerError, theResponse)
 		return
 	}
@@ -120,27 +131,104 @@ func (app *App) startTransaction(w http.ResponseWriter, r *http.Request) {
 	}
 
 	// Compose JSON from responseEntries
-	result := make(map[string]string)
+	result.FillFromTransactionResult(trResult)
-	for _, e := range trResult.Entries {
-		switch e.Key {
-		case payment.ReceiptData, payment.ReceiptDataMerchant:
-			// ignore these
-		case payment.ReceiptDataCardholder:
-			cardholderReceipt = e.Value
-		case payment.TransactionResult:
-			theResponse.Status.Message = e.Value
-			theResponse.Status.Code = http.StatusOK
-			result[e.Key] = e.Value
-		default:
-			result[e.Key] = e.Value
-		}
-	}
 
-	if err := printer.PrintCardholderReceipt(cardholderReceipt); err != nil {
+	if err := printer.PrintCardholderReceipt(result.CardholderReceipt); err != nil {
 		log.Errorf("PrintCardholderReceipt error: %v", err)
 	}
 
-	theResponse.Data = payment.BuildRedirectURL(result)
+	theResponse.Status = result.Status
+	theResponse.Data, save = payment.BuildPreauthRedirectURL(result.Fields)
+	if save {
+		go app.persistPreauth(context.Background(), result.Fields, theRequest.CheckoutDate)
+	}
+
+	writeTransactionResult(w, http.StatusOK, theResponse)
+}
+
+func (app *App) takePayment(w http.ResponseWriter, r *http.Request) {
+	const op = logging.Op("takePayment")
+	var (
+		theResponse cmstypes.ResponseRec
+		theRequest  cmstypes.TransactionRec
+		trResult    payment.TransactionResultXML
+		result      payment.PaymentResult
+	)
+
+	theResponse.Status.Code = http.StatusInternalServerError
+	theResponse.Status.Message = "500 Internal server error"
+
+	w.Header().Set("Access-Control-Allow-Origin", "*")
+	w.Header().Set("Access-Control-Allow-Methods", "POST, OPTIONS")
+	w.Header().Set("Access-Control-Allow-Headers", "Content-Type")
+	w.Header().Set("Content-Type", "application/json")
+
+	if !app.isPayment {
+		theResponse.Data = payment.BuildFailureURL(types.ResultError, "Payment processing is disabled")
+		writeTransactionResult(w, http.StatusServiceUnavailable, theResponse)
+		return
+	}
+
+	if r.Method == http.MethodOptions {
+		w.WriteHeader(http.StatusNoContent)
+		return
+	}
+
+	log.Println("takePayment called")
+	if r.Method != http.MethodPost {
+		theResponse.Data = payment.BuildFailureURL(types.ResultError, "Method not allowed; use POST")
+		writeTransactionResult(w, http.StatusMethodNotAllowed, theResponse)
+		return
+	}
+	defer r.Body.Close()
+
+	if ct := r.Header.Get("Content-Type"); ct != "text/xml" {
+		theResponse.Data = payment.BuildFailureURL(types.ResultError, "Content-Type must be text/xml")
+		writeTransactionResult(w, http.StatusUnsupportedMediaType, theResponse)
+		return
+	}
+
+	body, _ := io.ReadAll(r.Body)
+	err := xml.Unmarshal(body, &theRequest)
+	if err != nil {
+		logging.Error(serviceName, err.Error(), "ReadXML", string(op), "", "", 0)
+		theResponse.Data = payment.BuildFailureURL(types.ResultError, "Invalid XML payload")
+		writeTransactionResult(w, http.StatusBadRequest, theResponse)
+		return
+	}
+	log.Printf("Transaction payload: Amount=%s, Type=%s", theRequest.AmountMinorUnits, theRequest.TransactionType)
+
+	client := &http.Client{Timeout: 300 * time.Second}
+	response, err := client.Post(types.LinkTakePayment, "text/xml", bytes.NewBuffer(body))
+	if err != nil {
+		logging.Error(serviceName, err.Error(), "Payment processing error", string(op), "", "", 0)
+		theResponse.Data = payment.BuildFailureURL(types.ResultError, "No response from payment processor")
+		writeTransactionResult(w, http.StatusBadGateway, theResponse)
+		return
+	}
+	defer response.Body.Close()
+
+	body, err = io.ReadAll(response.Body)
+	if err != nil {
+		logging.Error(serviceName, err.Error(), "Read response body error", string(op), "", "", 0)
+		theResponse.Data = payment.BuildFailureURL(types.ResultError, "Failed to read response body")
+		writeTransactionResult(w, http.StatusInternalServerError, theResponse)
+		return
+	}
+
+	if err := trResult.ParseTransactionResult(body); err != nil {
+		logging.Error(serviceName, err.Error(), "Parse transaction result error", string(op), "", "", 0)
+	}
+
+	// Compose JSON from responseEntries
+	result.FillFromTransactionResult(trResult)
+
+	if err := printer.PrintCardholderReceipt(result.CardholderReceipt); err != nil {
+		log.Errorf("PrintCardholderReceipt error: %v", err)
+	}
+
+	theResponse.Status = result.Status
+	theResponse.Data = payment.BuildPaymentRedirectURL(result.Fields)
 	writeTransactionResult(w, http.StatusOK, theResponse)
 }
 
@@ -163,77 +251,81 @@ func (app *App) issueDoorCard(w http.ResponseWriter, r *http.Request) {
 
 	log.Println("issueDoorCard called")
 	if r.Method != http.MethodPost {
-		writeError(w, http.StatusMethodNotAllowed, "Method not allowed; use POST")
+		errorhandlers.WriteError(w, http.StatusMethodNotAllowed, "Method not allowed; use POST")
 		return
 	}
 	defer r.Body.Close()
 
 	if ct := r.Header.Get("Content-Type"); ct != "application/json" {
-		writeError(w, http.StatusUnsupportedMediaType, "Content-Type must be application/json")
+		errorhandlers.WriteError(w, http.StatusUnsupportedMediaType, "Content-Type must be application/json")
 		return
 	}
 
 	if err := json.NewDecoder(r.Body).Decode(&doorReq); err != nil {
 		logging.Error(serviceName, err.Error(), "ReadJSON", string(op), "", "", 0)
-		writeError(w, http.StatusBadRequest, "Invalid JSON payload: "+err.Error())
+		errorhandlers.WriteError(w, http.StatusBadRequest, "Invalid JSON payload: "+err.Error())
 		return
 	}
 
 	// parse times
-	checkIn, err := time.Parse(customLayout, doorReq.CheckinTime)
+	checkIn, err := time.Parse(types.CustomLayout, doorReq.CheckinTime)
 	if err != nil {
 		logging.Error(serviceName, err.Error(), "Invalid checkinTime format", string(op), "", "", 0)
-		writeError(w, http.StatusBadRequest, "Invalid checkinTime format: "+err.Error())
+		errorhandlers.WriteError(w, http.StatusBadRequest, "Invalid checkinTime format: "+err.Error())
 		return
 	}
-	checkOut, err := time.Parse(customLayout, doorReq.CheckoutTime)
+	checkOut, err := time.Parse(types.CustomLayout, doorReq.CheckoutTime)
 	if err != nil {
 		logging.Error(serviceName, err.Error(), "Invalid checkoutTime format", string(op), "", "", 0)
-		writeError(w, http.StatusBadRequest, "Invalid checkoutTime format: "+err.Error())
+		errorhandlers.WriteError(w, http.StatusBadRequest, "Invalid checkoutTime format: "+err.Error())
 		return
 	}
 
-	// dispenser sequence
+	// Ensure dispenser ready (card at encoder) BEFORE we attempt encoding.
-	if status, err := dispenser.DispenserSequence(app.dispPort); err != nil {
+	// With queued dispenser ops, this will not clash with polling.
-		if status != "" {
+	status, err := app.disp.DispenserStart(r.Context())
-			logging.Error(serviceName, status, "Dispense error", string(op), "", "", 0)
+	app.SetCardWellStatus(status)
-			writeError(w, http.StatusServiceUnavailable, "Dispense error: "+err.Error())
+	if err != nil {
-		} else {
 		logging.Error(serviceName, err.Error(), "Dispense error", string(op), "", "", 0)
-			writeError(w, http.StatusServiceUnavailable, "Dispense error: "+err.Error()+"; check card stock")
+		errorhandlers.WriteError(w, http.StatusServiceUnavailable, "Dispense error: "+err.Error())
-		}
 		return
-	} else {
+	}
-		log.Info(status)
+
+	// Always attempt to finalize after we have moved a card / started an issuance flow.
+	// This guarantees we eject and prepare the next card even on lock failures.
+	finalize := func() {
+		if app.disp == nil {
+			return
+		}
+		ctx, cancel := context.WithTimeout(context.Background(), 20*time.Second)
+		defer cancel()
+
+		status, ferr := app.disp.DispenserFinal(ctx)
+		if ferr != nil {
+			logging.Error(serviceName, ferr.Error(), "Dispenser final error", string(op), "", "", 0)
+			return
+		}
+		app.SetCardWellStatus(status)
 	}
 
 	// build lock server command
 	app.lockserver.BuildCommand(doorReq, checkIn, checkOut)
 
 	// lock server sequence
-	err = app.lockserver.LockSequence()
+	if err := app.lockserver.LockSequence(); err != nil {
-	if err != nil {
 		logging.Error(serviceName, err.Error(), "Key encoding", string(op), "", "", 0)
-		writeError(w, http.StatusBadGateway, err.Error())
+		finalize()
-		dispenser.CardOutOfMouth(app.dispPort)
+		errorhandlers.WriteError(w, http.StatusBadGateway, err.Error())
 		return
 	}
 
 	// final dispenser steps
-	if status, err := dispenser.CardOutOfMouth(app.dispPort); err != nil {
+	finalize()
-		logging.Error(serviceName, err.Error(), "Dispenser eject error", string(op), "", "", 0)
-		writeError(w, http.StatusServiceUnavailable, "Dispenser eject error: "+err.Error())
-		return
-	} else {
-		log.Info(status)
-	}
 
 	theResponse.Code = http.StatusOK
 	theResponse.Message = "Card issued successfully"
-	// success! return 200 and any data you like
-	w.Header().Set("Content-Type", "application/json")
 	w.WriteHeader(http.StatusOK)
-	json.NewEncoder(w).Encode(theResponse)
+	_ = json.NewEncoder(w).Encode(theResponse)
 }
 
 func (app *App) printRoomTicket(w http.ResponseWriter, r *http.Request) {
@@ -250,32 +342,32 @@ func (app *App) printRoomTicket(w http.ResponseWriter, r *http.Request) {
 	}
 	log.Println("printRoomTicket called")
 	if r.Method != http.MethodPost {
-		writeError(w, http.StatusMethodNotAllowed, "Method not allowed; use POST")
+		errorhandlers.WriteError(w, http.StatusMethodNotAllowed, "Method not allowed; use POST")
 		return
 	}
 	if ct := r.Header.Get("Content-Type"); !strings.Contains(ct, "xml") {
-		writeError(w, http.StatusUnsupportedMediaType, "Content-Type must be application/xml")
+		errorhandlers.WriteError(w, http.StatusUnsupportedMediaType, "Content-Type must be application/xml")
 		return
 	}
 
 	defer r.Body.Close()
 	if err := xml.NewDecoder(r.Body).Decode(&roomDetails); err != nil {
 		logging.Error(serviceName, err.Error(), "ReadXML", string(op), "", "", 0)
-		writeError(w, http.StatusBadRequest, "Invalid XML payload: "+err.Error())
+		errorhandlers.WriteError(w, http.StatusBadRequest, "Invalid XML payload: "+err.Error())
 		return
 	}
 
 	data, err := printer.BuildRoomTicket(roomDetails)
 	if err != nil {
 		logging.Error(serviceName, err.Error(), "BuildRoomTicket", string(op), "", "", 0)
-		writeError(w, http.StatusInternalServerError, "BuildRoomTicket failed: "+err.Error())
+		errorhandlers.WriteError(w, http.StatusInternalServerError, "BuildRoomTicket failed: "+err.Error())
 		return
 	}
 
 	// Send to the Windows Epson TM-T82II via the printer package
 	if err := printer.SendToPrinter(data); err != nil {
 		logging.Error(serviceName, err.Error(), "printRoomTicket", "printRoomTicket", "", "", 0)
-		writeError(w, http.StatusInternalServerError, "Print failed: "+err.Error())
+		errorhandlers.WriteError(w, http.StatusInternalServerError, "Print failed: "+err.Error())
 		return
 	}
 
@@ -287,3 +379,24 @@ func (app *App) printRoomTicket(w http.ResponseWriter, r *http.Request) {
 		Message: "Print job sent successfully",
 	})
 }
+
+func (app *App) reportDispenserStatus(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(http.StatusOK)
+	_ = json.NewEncoder(w).Encode(cmstypes.StatusRec{
+		Code:    http.StatusOK,
+		Message: app.CardWellStatus(),
+	})
+}
+
+func (app *App) SetCardWellStatus(s string) {
+	app.cardWellMu.Lock()
+	app.cardWellStatus = s
+	app.cardWellMu.Unlock()
+}
+
+func (app *App) CardWellStatus() string {
+	app.cardWellMu.RLock()
+	defer app.cardWellMu.RUnlock()
+	return app.cardWellStatus
+}

handlers/http_helpers.go

@@ -2,28 +2,14 @@ package handlers
 
 import (
 	"encoding/json"
-	"fmt"
 	"net/http"
-	"os"
 
 	"gitea.futuresens.co.uk/futuresens/cmstypes"
 	"gitea.futuresens.co.uk/futuresens/logging"
-	log "github.com/sirupsen/logrus"
 )
 
 const serviceName = "hardlink"
 
-// writeError is a helper to send a JSON error and HTTP status in one go.
-func writeError(w http.ResponseWriter, status int, msg string) {
-	theResponse := cmstypes.StatusRec{
-		Code:    status,
-		Message: msg,
-	}
-	w.Header().Set("Content-Type", "application/json")
-	w.WriteHeader(status)
-	json.NewEncoder(w).Encode(theResponse)
-}
-
 func writeTransactionResult(w http.ResponseWriter, status int, theResponse cmstypes.ResponseRec) {
 	w.Header().Set("Content-Type", "application/json")
 	w.WriteHeader(status)
@@ -32,10 +18,3 @@ func writeTransactionResult(w http.ResponseWriter, status int, theResponse cmsty
 	}
 }
 
-func FatalError(err error) {
-	fmt.Println(err.Error())
-	log.Errorf(err.Error())
-	fmt.Println(". Press Enter to exit...")
-	fmt.Scanln()
-	os.Exit(1)
-}

hardlink-preauth-release/main.go

@@ -0,0 +1,49 @@
+// cmd/hardlink-preauth-release/main.go
+package main
+
+import (
+	"fmt"
+	"os"
+	"time"
+
+	"gitea.futuresens.co.uk/futuresens/hardlink/bootstrap"
+	"gitea.futuresens.co.uk/futuresens/hardlink/config"
+	"gitea.futuresens.co.uk/futuresens/hardlink/logging"
+	"gitea.futuresens.co.uk/futuresens/hardlink/payment"
+	log "github.com/sirupsen/logrus"
+)
+
+const (
+	buildVersion = "1.0.2"
+	serviceName  = "preauth-release"
+)
+
+func main() {
+	config := config.ReadPreauthReleaserConfig()
+	// Setup logging and get file handle
+	logFile, err := logging.SetupLogging(config.LogDir, serviceName, buildVersion)
+	if err != nil {
+		log.Printf("Failed to set up logging: %v\n", err)
+	}
+	defer logFile.Close()
+	database, err := bootstrap.OpenDB(&config)
+	if err != nil {
+		log.WithError(err).Fatal("DB init failed")
+	}
+	defer database.Close()
+
+	if err := payment.ReleasePreauthorizations(database); err != nil {
+		log.Error(err)
+		fmt.Println(err)
+	} else {
+		log.Info("Task completed successfully")
+		fmt.Println("Task completed successfully")
+	}
+
+	for i := 20; i > 0; i-- {
+		fmt.Printf("\rExiting in %2d seconds...   ", i)
+		time.Sleep(time.Second)
+	}
+	fmt.Println("\rExiting now.            ")
+	os.Exit(0)
+}

lockserver/saltolockserver.go

@@ -155,7 +155,7 @@ func (lock *SaltoLockServer) LockSequence() error {
 	reader := bufio.NewReader(conn)
 
 	// 1. Send ENQ
-	log.Infof("Sending ENQ")
+	log.Infof("LockSequence: sending ENQ")
 	if _, e := conn.Write([]byte{ENQ}); e != nil {
 		return fmt.Errorf("failed to send ENQ: %w", e)
 	}
@@ -166,7 +166,7 @@ func (lock *SaltoLockServer) LockSequence() error {
 	}
 
 	// 3. Send command frame
-	log.Infof("Sending encoding command: %q", string(lock.command))
+	log.Infof("LockSequence: sending encoding command: %q", string(lock.command))
 	if _, e := conn.Write(lock.command); e != nil {
 		return fmt.Errorf("failed to send command frame: %w", e)
 	}

logging/logging.go

@@ -0,0 +1,31 @@
+package logging
+
+import (
+	"fmt"
+	"os"
+	"time"
+
+	log "github.com/sirupsen/logrus"
+)
+
+// setupLogging ensures log directory, opens log file, and configures logrus.
+// Returns the *os.File so caller can defer its Close().
+func SetupLogging(logDir, serviceName, buildVersion string) (*os.File, error) {
+	fileName := logDir + serviceName + ".log"
+	f, err := os.OpenFile(fileName, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0666)
+	if err != nil {
+		return nil, fmt.Errorf("open log file: %w", err)
+	}
+
+	log.SetOutput(f)
+	log.SetFormatter(&log.JSONFormatter{
+		TimestampFormat: time.RFC3339,
+	})
+	log.SetLevel(log.InfoLevel)
+
+	log.WithFields(log.Fields{
+		"buildVersion": buildVersion,
+	}).Info("Logging initialized")
+
+	return f, nil
+}

main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"context"
 	"encoding/xml"
 	"fmt"
 	"net/http"
@@ -14,90 +15,94 @@ import (
 	"github.com/tarm/serial"
 
 	log "github.com/sirupsen/logrus"
-	yaml "gopkg.in/yaml.v3"
 
+	"gitea.futuresens.co.uk/futuresens/hardlink/bootstrap"
+	"gitea.futuresens.co.uk/futuresens/hardlink/config"
 	"gitea.futuresens.co.uk/futuresens/hardlink/dispenser"
+	"gitea.futuresens.co.uk/futuresens/hardlink/errorhandlers"
 	"gitea.futuresens.co.uk/futuresens/hardlink/handlers"
 	"gitea.futuresens.co.uk/futuresens/hardlink/lockserver"
+	"gitea.futuresens.co.uk/futuresens/hardlink/logging"
 	"gitea.futuresens.co.uk/futuresens/hardlink/printer"
 )
 
 const (
-	buildVersion = "1.0.24"
+	buildVersion     = "1.1.2"
 	serviceName      = "hardlink"
+	pollingFrequency = 8 * time.Second
 )
 
-// configRec holds values from config.yml.
-type configRec struct {
-	Port           int    `yaml:"port"`
-	LockserverUrl  string `yaml:"lockservUrl"`
-	LockType       string `yaml:"lockType"`
-	EncoderAddress string `yaml:"encoderAddr"`
-	Cert           string `yaml:"cert"`
-	DispenserPort  string `yaml:"dispensPort"`
-	DispenserAdrr  string `yaml:"dispensAddr"`
-	PrinterName    string `yaml:"printerName"`
-	LogDir         string `yaml:"logdir"`
-	IsPayment      bool   `yaml:"isPayment"`
-	TestMode       bool   `yaml:"testMode"`
-}
-
 func main() {
 	// Load config
-	config := readConfig()
+	cfg := config.ReadHardlinkConfig()
 	printer.Layout = readTicketLayout()
-	printer.PrinterName = config.PrinterName
+	printer.PrinterName = cfg.PrinterName
-	lockserver.Cert = config.Cert
+	lockserver.Cert = cfg.Cert
-	lockserver.LockServerURL = config.LockserverUrl
+	lockserver.LockServerURL = cfg.LockserverUrl
-	dispHandle := &serial.Port{}
+
+	var (
+		dispPort       *serial.Port
+		disp           *dispenser.Client
+		cardWellStatus string
+	)
 
 	// Setup logging and get file handle
-	logFile, err := setupLogging(config.LogDir)
+	logFile, err := logging.SetupLogging(cfg.LogDir, serviceName, buildVersion)
 	if err != nil {
 		log.Printf("Failed to set up logging: %v\n", err)
 	}
 	defer logFile.Close()
 
 	// Initialize dispenser
-	if !config.TestMode {
+	if !cfg.TestMode {
-		dispenser.SerialPort = config.DispenserPort
+		dispenser.SerialPort = cfg.DispenserPort
-		dispenser.Address = []byte(config.DispenserAdrr)
+		dispenser.Address = []byte(cfg.DispenserAdrr)
-		dispHandle, err = dispenser.InitializeDispenser()
-		if err != nil {
-			handlers.FatalError(err)
-		}
-		defer dispHandle.Close()
 
-		status, err := dispenser.CheckDispenserStatus(dispHandle)
+		dispPort, err = dispenser.InitializeDispenser()
 		if err != nil {
-			if len(status) == 0 {
+			errorhandlers.FatalError(err)
-				err = fmt.Errorf("%s; wrong dispenser address: %s", err, config.DispenserAdrr)
-				handlers.FatalError(err)
-			} else {
-				fmt.Println(status)
-				fmt.Println(err.Error())
 		}
+		defer dispPort.Close()
+
+		// Start queued dispenser client (single goroutine owns the serial port)
+		disp = dispenser.NewClient(dispPort, 32)
+		defer disp.Close()
+
+		// Prepare dispenser (ensures card at encoder position unless empty)
+		ctx, cancel := context.WithTimeout(context.Background(), 20*time.Second)
+		defer cancel()
+
+		cardWellStatus, err = disp.DispenserPrepare(ctx)
+		if err != nil {
+			err = fmt.Errorf("%s; wrong dispenser address: %s", err, cfg.DispenserAdrr)
+			errorhandlers.FatalError(err)
 		}
-		log.Infof("Dispenser initialized on port %s, %s", config.DispenserPort, status)
+		fmt.Println(cardWellStatus)
 	}
 
 	// Test lock-server connection
-	switch strings.ToLower(config.LockType) {
+	switch strings.ToLower(cfg.LockType) {
 	case lockserver.TLJ:
-
+		// TLJ uses HTTP - skip TCP probe here (as you did before)
 	default:
-		lockConn, err := lockserver.InitializeServerConnection(config.LockserverUrl)
+		lockConn, err := lockserver.InitializeServerConnection(cfg.LockserverUrl)
 		if err != nil {
 			fmt.Println(err.Error())
 			log.Errorf(err.Error())
 		} else {
-			fmt.Printf("Connected to the lock server successfuly at %s\n", config.LockserverUrl)
+			fmt.Printf("Connected to the lock server successfuly at %s\n", cfg.LockserverUrl)
-			log.Infof("Connected to the lock server successfuly at %s", config.LockserverUrl)
+			log.Infof("Connected to the lock server successfuly at %s", cfg.LockserverUrl)
 			lockConn.Close()
 		}
 	}
 
-	if config.IsPayment {
+	database, err := bootstrap.OpenDB(&cfg)
+	if err != nil {
+		log.Warnf("DB init failed: %v", err)
+	}
+	defer database.Close()
+
+	if cfg.IsPayment {
 		fmt.Println("Payment processing is enabled")
 		log.Info("Payment processing is enabled")
 		startChipDnaClient()
@@ -107,73 +112,35 @@ func main() {
 	}
 
 	// Create App and wire routes
-	app := handlers.NewApp(dispHandle, config.LockType, config.EncoderAddress, config.IsPayment)
+	// NOTE: change handlers.NewApp signature to accept *dispenser.Client instead of *serial.Port
+	app := handlers.NewApp(disp, cfg.LockType, cfg.EncoderAddress, cardWellStatus, database, &cfg)
+
+	// Update cardWellStatus when dispenser status changes
+	if !cfg.TestMode {
+		// Set initial cardWellStatus
+		app.SetCardWellStatus(cardWellStatus)
+
+		// Set up callback to update cardWellStatus when dispenser status changes
+		disp.OnStockUpdate(func(stock string) {
+			app.SetCardWellStatus(stock)
+		})
+
+		// Start polling for dispenser status every 10 seconds
+		disp.StartPolling(pollingFrequency)
+	}
 
 	mux := http.NewServeMux()
 	app.RegisterRoutes(mux)
 
-	addr := fmt.Sprintf(":%d", config.Port)
+	addr := fmt.Sprintf(":%d", cfg.Port)
 	log.Infof("Starting HTTP server on http://localhost%s", addr)
 	fmt.Printf("Starting HTTP server on http://localhost%s", addr)
+
 	if err := http.ListenAndServe(addr, mux); err != nil {
-		handlers.FatalError(err)
+		errorhandlers.FatalError(err)
 	}
 }
 
-// setupLogging ensures log directory, opens log file, and configures logrus.
-// Returns the *os.File so caller can defer its Close().
-func setupLogging(logDir string) (*os.File, error) {
-	fileName := logDir + serviceName + ".log"
-	f, err := os.OpenFile(fileName, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0666)
-	if err != nil {
-		return nil, fmt.Errorf("open log file: %w", err)
-	}
-
-	log.SetOutput(f)
-	log.SetFormatter(&log.JSONFormatter{
-		TimestampFormat: time.RFC3339,
-	})
-	log.SetLevel(log.InfoLevel)
-
-	log.WithFields(log.Fields{
-		"buildVersion": buildVersion,
-	}).Info("Logging initialized")
-
-	return f, nil
-}
-
-// readConfig reads config.yml and applies defaults.
-func readConfig() configRec {
-	var cfg configRec
-	const configName = "config.yml"
-	defaultPort := 9091
-	sep := string(os.PathSeparator)
-
-	data, err := os.ReadFile(configName)
-	if err != nil {
-		log.Warnf("ReadConfig %s: %v", configName, err)
-	} else if err := yaml.Unmarshal(data, &cfg); err != nil {
-		log.Warnf("Unmarshal config: %v", err)
-	}
-
-	if cfg.Port == 0 {
-		cfg.Port = defaultPort
-	}
-
-	if cfg.LockType == "" {
-		err = fmt.Errorf("LockType is required in %s", configName)
-		handlers.FatalError(err)
-	}
-	cfg.LockType = strings.ToLower(cfg.LockType)
-
-	if cfg.LogDir == "" {
-		cfg.LogDir = "./logs" + sep
-	} else if !strings.HasSuffix(cfg.LogDir, sep) {
-		cfg.LogDir += sep
-	}
-	return cfg
-}
-
 func readTicketLayout() printer.LayoutOptions {
 	const layoutName = "TicketLayout.xml"
 	var layout printer.LayoutOptions
@@ -181,12 +148,12 @@ func readTicketLayout() printer.LayoutOptions {
 	// 1) Read the file
 	data, err := os.ReadFile(layoutName)
 	if err != nil {
-		handlers.FatalError(fmt.Errorf("failed to read %s: %v", layoutName, err))
+		errorhandlers.FatalError(fmt.Errorf("failed to read %s: %v", layoutName, err))
 	}
 
 	// 2) Unmarshal into your struct
 	if err := xml.Unmarshal(data, &layout); err != nil {
-		handlers.FatalError(fmt.Errorf("failed to parse %s: %v", layoutName, err))
+		errorhandlers.FatalError(fmt.Errorf("failed to parse %s: %v", layoutName, err))
 	}
 
 	return layout
@@ -205,7 +172,7 @@ func startChipDnaClient() {
 
 	cmd, err := startClient()
 	if err != nil {
-		handlers.FatalError(err)
+		errorhandlers.FatalError(err)
 	}
 
 	// Restart loop

payment/creditcall.go

@@ -1,53 +1,19 @@
 package payment
 
 import (
-	"context"
-	"database/sql"
 	"encoding/hex"
 	"encoding/xml"
 	"fmt"
+	"net/http"
 	"net/url"
-	"strconv"
 	"strings"
-	"time"
 
+	"gitea.futuresens.co.uk/futuresens/cmstypes"
+	"gitea.futuresens.co.uk/futuresens/hardlink/types"
 	_ "github.com/denisenkom/go-mssqldb"
 	log "github.com/sirupsen/logrus"
 )
 
-const (
-	// Transaction types
-	SaleTransactionType     = "sale"
-	AccountVerificationType = "account verification"
-
-	// Transaction results
-	ResultApproved              = "approved"
-	ResultDeclined              = "declined"
-	ResultCancelled             = "cancelled"
-	ResultPending               = "pending"
-	ResultError                 = "error"
-	CheckinSuccessfulEndpoint   = "/successful" // Endpoint to send guest to after successful payment
-	CheckinUnsuccessfulEndpoint = "/unsuccessful"
-
-	// Response map keys
-	CardReference         = "CARD_REFERENCE"
-	CardHash              = "CARD_HASH"
-	Errors                = "ERRORS"
-	ReceiptData           = "RECEIPT_DATA"
-	ReceiptDataMerchant   = "RECEIPT_DATA_MERCHANT"
-	ReceiptDataCardholder = "RECEIPT_DATA_CARDHOLDER"
-	Reference             = "REFERENCE"
-	TransactionResult     = "TRANSACTION_RESULT"
-	TransactionType       = "TRANSACTION_TYPE"
-	ConfirmResult         = "CONFIRM_RESULT"
-	ConfirmErrors         = "CONFIRM_ERRORS"
-
-	// Log field keys
-	LogFieldError       = "error"
-	LogFieldDescription = "description"
-	LogResult           = "transactionResult"
-)
-
 // XML parsing structs
 type (
 	TransactionRec struct {
@@ -73,6 +39,17 @@ type (
 		ErrorDescription      string   `xml:"ErrorDescription"`
 		ReceiptDataCardholder string   `xml:"ReceiptDataCardholder"`
 	}
+
+	PaymentResult struct {
+		Fields            map[string]string
+		CardholderReceipt string
+		Status            cmstypes.StatusRec
+	}
+
+	TransactionInfo struct {
+		transactionRes   string
+		transactionState string
+	}
 )
 
 // ParseTransactionResult parses the XML into entries.
@@ -83,214 +60,104 @@ func (tr *TransactionResultXML) ParseTransactionResult(data []byte) error {
 	return nil
 }
 
-// initMSSQL opens and pings the SQL Server instance localhost\SQLEXPRESS
+func (ti *TransactionInfo) FillFromTransactionResult(trResult TransactionResultXML) {
-// using user=Kiosk, password=Gr33nfarm, database=TransactionDatabase.
+	for _, e := range trResult.Entries {
-func InitMSSQL(port int, user, password, database string) (*sql.DB, error) {
+		switch e.Key {
-	const server = "localhost"
+		case types.TransactionResult:
-
+			ti.transactionRes = e.Value
-	// Use TCP; drop the \SQLEXPRESS instance name
+		case types.TransactionState:
-	connString := fmt.Sprintf(
+			ti.transactionState = e.Value
-		"sqlserver://%s:%s@%s:%d?database=%s&encrypt=disable",
-		user, password, server, port, database,
-	)
-
-	db, err := sql.Open("sqlserver", connString)
-	if err != nil {
-		return nil, fmt.Errorf("opening DB: %w", err)
 		}
-
-	// Verify connectivity
-	if err := db.PingContext(context.Background()); err != nil {
-		db.Close()
-		return nil, fmt.Errorf("pinging DB: %w", err)
-	}
-
-	return db, nil
-}
-
-// insertTransactionRecord inserts one row into TransactionRecords.
-// m is the map from keys to string values as returned by ChipDNA.
-func InsertTransactionRecord(ctx context.Context, db *sql.DB, m map[string]string) error {
-	// Extract fields with defaults or NULL handling.
-
-	// 1. TxnReference <- REFERENCE
-	ref, ok := m["REFERENCE"]
-	if !ok || ref == "" {
-		return fmt.Errorf("missing REFERENCE in result map")
-	}
-
-	// 2. TxnDateTime <- parse AUTH_DATE_TIME (layout "20060102150405"), else use now
-	var txnTime time.Time
-	if s, ok := m["AUTH_DATE_TIME"]; ok && s != "" {
-		t, err := time.ParseInLocation("20060102150405", s, time.UTC)
-		if err != nil {
-			// fallback: use now
-			txnTime = time.Now().UTC()
-		} else {
-			txnTime = t
-		}
-	} else {
-		txnTime = time.Now().UTC()
-	}
-
-	// 3. TotalAmount <- parse TOTAL_AMOUNT minor units into float (divide by 100)
-	var totalAmount sql.NullFloat64
-	if s, ok := m["TOTAL_AMOUNT"]; ok && s != "" {
-		if iv, err := strconv.ParseInt(s, 10, 64); err == nil {
-			// convert minor units to major (e.g. 150 -> 1.50)
-			totalAmount.Float64 = float64(iv) / 100.0
-			totalAmount.Valid = true
 	}
 }
 
-	// 4. MerchantId <- MERCHANT_ID_MASKED
+func (r *PaymentResult) FillFromTransactionResult(trResult TransactionResultXML) {
-	merchantId := sql.NullString{String: m["MERCHANT_ID_MASKED"], Valid: m["MERCHANT_ID_MASKED"] != ""}
+	if r.Fields == nil {
-
+		r.Fields = make(map[string]string)
-	// 5. TerminalId <- TERMINAL_ID_MASKED
-	terminalId := sql.NullString{String: m["TERMINAL_ID_MASKED"], Valid: m["TERMINAL_ID_MASKED"] != ""}
-
-	// 6. CardSchemeName <- CARD_SCHEME
-	cardScheme := sql.NullString{String: m["CARD_SCHEME"], Valid: m["CARD_SCHEME"] != ""}
-
-	// 7. ExpiryDate <- EXPIRY_DATE
-	expiryDate := sql.NullString{String: m["EXPIRY_DATE"], Valid: m["EXPIRY_DATE"] != ""}
-
-	// 8. RecordReference <- CARD_REFERENCE
-	recordRef := sql.NullString{String: m["CARD_REFERENCE"], Valid: m["CARD_REFERENCE"] != ""}
-
-	// 9. Token1 <- CARD_HASH
-	token1 := sql.NullString{String: m["CARD_HASH"], Valid: m["CARD_HASH"] != ""}
-
-	// 10. Token2 <- CARDEASE_REFERENCE
-	token2 := sql.NullString{String: m["CARDEASE_REFERENCE"], Valid: m["CARDEASE_REFERENCE"] != ""}
-
-	// 11. PanMasked <- PAN_MASKED
-	panMasked := sql.NullString{String: m["PAN_MASKED"], Valid: m["PAN_MASKED"] != ""}
-
-	// 12. AuthCode <- AUTH_CODE
-	authCode := sql.NullString{String: m["AUTH_CODE"], Valid: m["AUTH_CODE"] != ""}
-
-	// 13. TransactionResult <- TRANSACTION_RESULT
-	txnResult := sql.NullString{String: m["TRANSACTION_RESULT"], Valid: m["TRANSACTION_RESULT"] != ""}
-
-	// Build INSERT statement with named parameters.
-	// Assuming your table is [TransactionDatabase].[dbo].[TransactionRecords].
-	const stmt = `
-INSERT INTO [TransactionDatabase].[dbo].[TransactionRecords]
-(
-    [TxnReference],
-    [TxnDateTime],
-    [TotalAmount],
-    [MerchantId],
-    [TerminalId],
-    [CardSchemeName],
-    [ExpiryDate],
-    [RecordReference],
-    [Token1],
-    [Token2],
-    [PanMasked],
-    [AuthCode],
-    [TransactionResult]
-)
-VALUES
-(
-    @TxnReference,
-    @TxnDateTime,
-    @TotalAmount,
-    @MerchantId,
-    @TerminalId,
-    @CardSchemeName,
-    @ExpiryDate,
-    @RecordReference,
-    @Token1,
-    @Token2,
-    @PanMasked,
-    @AuthCode,
-    @TransactionResult
-);
-`
-	// Execute with sql.Named parameters:
-	_, err := db.ExecContext(ctx, stmt,
-		sql.Named("TxnReference", ref),
-		sql.Named("TxnDateTime", txnTime),
-		sql.Named("TotalAmount", nullableFloatArg(totalAmount)),
-		sql.Named("MerchantId", nullableStringArg(merchantId)),
-		sql.Named("TerminalId", nullableStringArg(terminalId)),
-		sql.Named("CardSchemeName", nullableStringArg(cardScheme)),
-		sql.Named("ExpiryDate", nullableStringArg(expiryDate)),
-		sql.Named("RecordReference", nullableStringArg(recordRef)),
-		sql.Named("Token1", nullableStringArg(token1)),
-		sql.Named("Token2", nullableStringArg(token2)),
-		sql.Named("PanMasked", nullableStringArg(panMasked)),
-		sql.Named("AuthCode", nullableStringArg(authCode)),
-		sql.Named("TransactionResult", nullableStringArg(txnResult)),
-	)
-	if err != nil {
-		return fmt.Errorf("insert TransactionRecords: %w", err)
-	}
-	// Successfully inserted
-	log.Infof("Inserted transaction record for reference %s", ref)
-	return nil
 	}
 
-// Helpers to pass NULL when appropriate:
+	for _, e := range trResult.Entries {
-func nullableStringArg(ns sql.NullString) interface{} {
+		switch e.Key {
-	if ns.Valid {
+
-		return ns.String
+		case types.ReceiptData, types.ReceiptDataMerchant:
+			// intentionally ignored
+
+		case types.ReceiptDataCardholder:
+			r.CardholderReceipt = e.Value
+
+		case types.TransactionResult:
+			r.Status.Message = e.Value
+			r.Status.Code = http.StatusOK
+			r.Fields[e.Key] = e.Value
+
+		default:
+			r.Fields[e.Key] = e.Value
 		}
-	return nil
 	}
-func nullableFloatArg(nf sql.NullFloat64) interface{} {
-	if nf.Valid {
-		return nf.Float64
-	}
-	return nil
 }
 
 // BuildRedirectURL builds the redirect URL to send the guest to after payment.
-func BuildRedirectURL(result map[string]string) string {
+func BuildPaymentRedirectURL(result map[string]string) string {
-	res := result[TransactionResult]
+	res := result[types.TransactionResult]
-	tType := result[TransactionType]
 
 	// Transaction approved?
-	if strings.EqualFold(res, ResultApproved) {
+	if strings.EqualFold(res, types.ResultApproved) {
-		switch {
-		// Transaction type AccountVerification?
-		case strings.EqualFold(tType, AccountVerificationType):
-			log.WithField(LogResult, result[TransactionResult]).
-				Info("Account verification approved")
-
-			return buildSuccessURL(result)
-
-		// Transaction type Sale?
-		case strings.EqualFold(tType, SaleTransactionType):
 		// Transaction confirmed?
-			if strings.EqualFold(result[ConfirmResult], ResultApproved) {
+		if strings.EqualFold(result[types.ConfirmResult], types.ResultApproved) {
-				log.WithField(LogResult, result[ConfirmResult]).
+			log.WithField(types.LogResult, result[types.ConfirmResult]).
 				Info("Transaction approved and confirmed")
 
 			return buildSuccessURL(result)
 		}
 
 		// Not confirmed
-			log.WithFields(log.Fields{LogFieldError: result[ConfirmResult], LogFieldDescription: result[ConfirmErrors]}).
+		log.WithFields(log.Fields{types.LogFieldError: result[types.ConfirmResult], types.LogFieldDescription: result[types.ConfirmErrors]}).
 			Error("Transaction approved but not confirmed")
 
-			return BuildFailureURL(result[ConfirmResult], result[ConfirmErrors])
+		return BuildFailureURL(result[types.ConfirmResult], result[types.ConfirmErrors])
+	}
+
+	// Not approved
+	return BuildFailureURL(res, result[types.Errors])
+}
+
+func BuildPreauthRedirectURL(result map[string]string) (string, bool) {
+	res := result[types.TransactionResult]
+	tType := result[types.TransactionType]
+
+	// Transaction approved?
+	if strings.EqualFold(res, types.ResultApproved) {
+		switch {
+		// Transaction type AccountVerification?
+		case strings.EqualFold(tType, types.AccountVerificationType):
+			log.WithField(types.LogResult, result[types.TransactionResult]).
+				Info("Account verification approved")
+
+			return buildSuccessURL(result), false
+
+		// Transaction type Sale?
+		case strings.EqualFold(tType, types.SaleTransactionType):
+			// Transaction confirmed?
+			log.WithField(types.LogResult, result[types.ConfirmResult]).
+				Info("Amount preauthorized successfully")
+
+			return buildSuccessURL(result), true
 		}
 	}
 
 	// Not approved
-	return BuildFailureURL(res, result[Errors])
+	return BuildFailureURL(res, result[types.Errors]), false
 }
 
 func buildSuccessURL(result map[string]string) string {
 	q := url.Values{}
-	q.Set("TxnReference", result[Reference])
+	q.Set("CardNumber", hex.EncodeToString([]byte(result[types.PAN_MASKED])))
-	q.Set("CardHash", hex.EncodeToString([]byte(result[CardHash])))
+	q.Set("ExpiryDate", hex.EncodeToString([]byte(result[types.EXPIRY_DATE])))
-	q.Set("CardReference", hex.EncodeToString([]byte(result[CardReference])))
+	q.Set("TxnReference", result[types.Reference])
+	q.Set("CardHash", hex.EncodeToString([]byte(result[types.CardHash])))
+	q.Set("CardReference", hex.EncodeToString([]byte(result[types.CardReference])))
 	return (&url.URL{
-		Path:     CheckinSuccessfulEndpoint,
+		Path:     types.CheckinSuccessfulEndpoint,
 		RawQuery: q.Encode(),
 	}).String()
 }
@@ -301,16 +168,16 @@ func BuildFailureURL(msgType, description string) string {
 		description = fmt.Sprintf("Transaction %s", strings.ToLower(msgType))
 	}
 	if description != "" {
-		msgType = ResultError
+		msgType = types.ResultError
 	}
 
-	log.WithFields(log.Fields{LogFieldError: msgType, LogFieldDescription: description}).
+	log.WithFields(log.Fields{types.LogFieldError: msgType, types.LogFieldDescription: description}).
 		Error("Transaction failed")
 
 	q.Set("MsgType", msgType)
 	q.Set("Description", description)
 	return (&url.URL{
-		Path:     CheckinUnsuccessfulEndpoint,
+		Path:     types.CheckinUnsuccessfulEndpoint,
 		RawQuery: q.Encode(),
 	}).String()
 }

payment/preauthReleaser.go

@@ -0,0 +1,237 @@
+package payment
+
+import (
+	"bytes"
+	"context"
+	"database/sql"
+	"encoding/xml"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+	"time"
+
+	"gitea.futuresens.co.uk/futuresens/hardlink/db"
+	"gitea.futuresens.co.uk/futuresens/hardlink/types"
+	log "github.com/sirupsen/logrus"
+)
+
+const (
+	httpTimeout = 120 * time.Second
+)
+
+/* ==============================
+   Public Entry Point
+   ============================== */
+
+func ReleasePreauthorizations(database *sql.DB) error {
+	ctx := context.Background()
+	now := time.Now().UTC()
+	client := &http.Client{Timeout: httpTimeout}
+
+	preauths, err := fetchDuePreauths(ctx, database, now)
+	if err != nil {
+		return err
+	}
+
+	if len(preauths) == 0 {
+		log.Info("No preauthorizations due for release")
+		return nil
+	} else {
+		log.Infof("%d preauthorizations due for release", len(preauths))
+	}
+
+	var failed []string
+	var completed int
+	for _, p := range preauths {
+		if err := handlePreauthRelease(ctx, database, client, p, now); err != nil {
+			log.Errorf("Preauth %s failed: %v", p.TxnReference, err)
+			failed = append(failed, p.TxnReference)
+		}
+		completed++
+	}
+	log.Infof("Preauth release completed: %d processed, %d failed", completed, len(failed))
+
+	if len(failed) > 0 {
+		return fmt.Errorf("preauth release incomplete, failed refs: %s", strings.Join(failed, ", "))
+	}
+
+	return nil
+}
+
+/* ==============================
+   Core Business Logic
+   ============================== */
+
+func handlePreauthRelease(
+	ctx context.Context,
+	dbConn *sql.DB,
+	client *http.Client,
+	preauth types.PreauthRec,
+	now time.Time,
+) error {
+
+	ref := preauth.TxnReference
+	log.Infof("Evaluating preauth %s", ref)
+
+	info, err := fetchTransactionInfo(ctx, client, ref)
+	if err != nil {
+		return err
+	}
+	log.Infof("res=%s state=%s", info.transactionRes, info.transactionState)
+
+	// If already voided or declined → mark released
+	if isAlreadyReleased(info) {
+		return markReleased(ctx, dbConn, ref, now)
+	}
+
+	// Only void approved + uncommitted
+	if !isVoidable(info) {
+		log.Infof("Preauth %s not eligible for void (res=%s state=%s)", ref, info.transactionRes, info.transactionState)
+		return nil
+	}
+
+	// Void transaction
+	if err := voidPreauth(ctx, client, ref); err != nil {
+		return err
+	}
+
+	// Verify final state
+	finalInfo, err := fetchTransactionInfo(ctx, client, ref)
+	if err != nil {
+		return err
+	}
+
+	if !isSuccessfullyVoided(finalInfo) {
+		return fmt.Errorf("unexpected final state res=%s state=%s",
+			finalInfo.transactionRes, finalInfo.transactionState)
+	}
+
+	log.Infof("Preauth %s successfully voided", ref)
+	return markReleased(ctx, dbConn, ref, now)
+}
+
+/* ==============================
+   State Evaluation Helpers
+   ============================== */
+
+func isVoidable(info TransactionInfo) bool {
+	return strings.EqualFold(info.transactionRes, types.ResultApproved) &&
+		strings.EqualFold(info.transactionState, types.ResultStateUncommitted)
+}
+
+func isAlreadyReleased(info TransactionInfo) bool {
+	return strings.EqualFold(info.transactionState, types.ResultStateVoided) ||
+		strings.EqualFold(info.transactionRes, types.ResultDeclined)
+}
+
+func isSuccessfullyVoided(info TransactionInfo) bool {
+	return strings.EqualFold(info.transactionRes, types.ResultDeclined) &&
+		strings.EqualFold(info.transactionState, types.ResultStateVoided)
+}
+
+/* ==============================
+   External Operations
+   ============================== */
+
+func fetchDuePreauths(
+	ctx context.Context,
+	dbConn *sql.DB,
+	now time.Time,
+) ([]types.PreauthRec, error) {
+
+	return db.GetDuePreauths(ctx, dbConn, now, 0)
+}
+
+func markReleased(
+	ctx context.Context,
+	dbConn *sql.DB,
+	ref string,
+	now time.Time,
+) error {
+
+	return db.MarkPreauthReleased(ctx, dbConn, ref, now)
+}
+
+func fetchTransactionInfo(
+	ctx context.Context,
+	client *http.Client,
+	ref string,
+) (TransactionInfo, error) {
+
+	var tr TransactionResultXML
+	var info TransactionInfo
+
+	payload, _ := xml.Marshal(types.TransactionReferenceRequest{
+		TransactionReference: ref,
+	})
+
+	body, err := postXML(ctx, client, types.LinkTransactionInformation, payload)
+	if err != nil {
+		return info, err
+	}
+
+	if err := tr.ParseTransactionResult(body); err != nil {
+		return info, err
+	}
+
+	info.FillFromTransactionResult(tr)
+	return info, nil
+}
+
+func voidPreauth(
+	ctx context.Context,
+	client *http.Client,
+	ref string,
+) error {
+
+	var tr TransactionResultXML
+	var info TransactionInfo
+
+	payload, _ := xml.Marshal(types.TransactionReferenceRequest{
+		TransactionReference: ref,
+	})
+
+	body, err := postXML(ctx, client, types.LinkVoidTransaction, payload)
+	if err != nil {
+		return err
+	}
+
+	if err := tr.ParseTransactionResult(body); err != nil {
+		return err
+	}
+
+	info.FillFromTransactionResult(tr)
+
+	if !strings.EqualFold(info.transactionRes, types.ResultApproved) {
+		return fmt.Errorf("void rejected: %s", info.transactionRes)
+	}
+
+	return nil
+}
+
+/* ==============================
+   Low-level HTTP
+   ============================== */
+
+func postXML(
+	ctx context.Context,
+	client *http.Client,
+	url string,
+	payload []byte,
+) ([]byte, error) {
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, url, bytes.NewReader(payload))
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("Content-Type", "text/xml")
+
+	resp, err := client.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	return io.ReadAll(resp.Body)
+}

release notes.md

@@ -2,6 +2,40 @@
 
 builtVersion is a const in main.go
 
+#### 1.1.2 - 02 February 2026
+added logging for unknown dispenser status positions
+
+#### 1.1.1 - 02 February 2026
+added contionuous polling of the dispenser status every 8 seconds to update the card well status
+
+#### 1.1.0 - 26 January 2026
+divided `/starttransaction` endpoint into two separate endpoints:
+  `/takepreauth` to request preauthorization payment
+  `/takepayment` to request taking payment
+added preauth releaser functionality to release preauthorization payments after a defined time period
+added db connection check before adding a transaction to the database
+and reconnection functionality if the connection to the database is lost
+added `/dispenserstatus` endpoint
+key card always stays at encoder position
+
+#### 1.0.30 - 09 January 2026
+improved logging for preauth releaser
+
+#### 1.0.29 - 08 January 2026
+added count down before exiting the preauth releaser 20 seconds
+
+#### 1.0.28 - 10 December 2025
+added preauth releaser
+
+#### 1.0.27 - 10 December 2025
+updated handling AmountTooSmall response from creditcall
+
+#### 1.0.26 - 10 December 2025
+added route for taking preauthorization payment
+
+#### 1.0.25 - 08 December 2025
+return masked card number and expiry date in the payment success URL
+
 #### 1.0.24 - 13 November 2025
 improved logging for creditcall payment processing
 

types/types.go

@@ -0,0 +1,71 @@
+package types
+
+import (
+	"database/sql"
+	"encoding/xml"
+	"time"
+)
+
+const (
+	DateOnly                   = "2006-01-02"
+	CustomLayout               = "2006-01-02 15:04:05 -0700"
+	LinkTakePreauthorization   = "http://127.0.0.1:18181/start-transaction/"
+	LinkTakePayment            = "http://127.0.0.1:18181/start-and-confirm-transaction/"
+	LinkTransactionInformation = "http://127.0.0.1:18181/transaction-information/"
+	LinkVoidTransaction        = "http://127.0.0.1:18181/void-transaction/"
+	// Transaction types
+	SaleTransactionType     = "sale"
+	AccountVerificationType = "account verification"
+
+	// Transaction results
+	ResultApproved              = "approved"
+	ResultDeclined              = "declined"
+	ResultCancelled             = "cancelled"
+	ResultPending               = "pending"
+	ResultStateUncommitted      = "uncommitted"
+	ResultStateVoided           = "voided"
+	ResultError                 = "error"
+	CheckinSuccessfulEndpoint   = "/successful" // Endpoint to send guest to after successful payment
+	CheckinUnsuccessfulEndpoint = "/unsuccessful"
+
+	// Response map keys
+	CardReference         = "CARD_REFERENCE"
+	CardHash              = "CARD_HASH"
+	Errors                = "ERRORS"
+	ReceiptData           = "RECEIPT_DATA"
+	ReceiptDataMerchant   = "RECEIPT_DATA_MERCHANT"
+	ReceiptDataCardholder = "RECEIPT_DATA_CARDHOLDER"
+	Reference             = "REFERENCE"
+	PAN_MASKED            = "PAN_MASKED"
+	EXPIRY_DATE           = "EXPIRY_DATE"
+	TransactionResult     = "TRANSACTION_RESULT"
+	TransactionType       = "TRANSACTION_TYPE"
+	TransactionState      = "TRANSACTION_STATE"
+	ConfirmResult         = "CONFIRM_RESULT"
+	ConfirmErrors         = "CONFIRM_ERRORS"
+	TotalAmount           = "TOTAL_AMOUNT"
+
+	// Log field keys
+	LogFieldError       = "error"
+	LogFieldDescription = "description"
+	LogResult           = "transactionResult"
+)
+
+type (
+	TransactionReferenceRequest struct {
+		XMLName              xml.Name `xml:"TransactionReferenceRequest"`
+		TransactionReference string   `xml:"TransactionReference"`
+	}
+
+	PreauthRec struct {
+		Id              int64
+		TxnReference    string
+		TotalMinorUnits int64
+		TotalAmount     float64
+		TxnDateTime     time.Time
+		DepartureDate   time.Time // date-only (00:00)
+		ReleaseDate     time.Time
+		Released        bool
+		ReleasedAt      sql.NullTime
+	}
+)