package main

import (
	"bytes"
	"encoding/json"
	"encoding/xml"
	"fmt"
	"io"
	"net/http"
	"os"
	"os/exec"
	"os/signal"
	"strings"
	"syscall"
	"time"

	"github.com/tarm/serial"

	log "github.com/sirupsen/logrus"
	yaml "gopkg.in/yaml.v3"

	"gitea.futuresens.co.uk/futuresens/hardlink/dispenser"
	"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/cmstypes"
	"gitea.futuresens.co.uk/futuresens/logging"
)

const (
	buildVersion   = "1.0.18"
	serviceName    = "hardlink"
	customLayout   = "2006-01-02 15:04:05 -0700"
	transactionUrl = "http://127.0.0.1:18181/start-transaction/"
)

// 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"`
}

// App holds shared resources.
type App struct {
	configRec  configRec
	dispPort   *serial.Port
	lockserver lockserver.LockServer
}

func newApp(dispPort *serial.Port, config configRec) *App {
	return &App{
		configRec:  config,
		dispPort:   dispPort,
		lockserver: lockserver.NewLockServer(config.LockType, config.EncoderAddress, fatalError),
	}
}

func main() {
	// Load config
	config := readConfig()
	printer.Layout = readTicketLayout()
	printer.PrinterName = config.PrinterName
	lockserver.Cert = config.Cert
	lockserver.LockServerURL = config.LockserverUrl

	// Setup logging and get file handle
	logFile, err := setupLogging(config.LogDir)
	if err != nil {
		log.Printf("Failed to set up logging: %v\n", err)
	}
	defer logFile.Close()

	// Initialize dispenser
	dispenser.SerialPort = config.DispenserPort
	dispenser.Address = []byte(config.DispenserAdrr)
	dispHandle, err := dispenser.InitializeDispenser()
	if err != nil {
		fatalError(err)
	}
	defer dispHandle.Close()

	status, err := dispenser.CheckDispenserStatus(dispHandle)
	if err != nil {
		if len(status) == 0 {
			err = fmt.Errorf("%s; wrong dispenser address: %s", err, config.DispenserAdrr)
			fatalError(err)
		} else {
			fmt.Println(status)
			fmt.Println(err.Error())
		}
	}
	log.Infof("Dispenser initialized on port %s, %s", config.DispenserPort, status)

	// Test lock-server connection
	switch strings.ToLower(config.LockType) {
	case lockserver.TLJ:

	default:
		lockConn, err := lockserver.InitializeServerConnection(config.LockserverUrl)
		if err != nil {
			fatalError(err)
		}
		log.Infof("Connectting to lock server at %s", config.LockserverUrl)
		lockConn.Close()
	}

	if config.IsPayment {
		startClient := func() (*exec.Cmd, error) {
			cmd := exec.Command("./ChipDNAClient/ChipDnaClient.exe")
			err := cmd.Start()
			if err != nil {
				return nil, fmt.Errorf("failed to start ChipDnaClient: %v", err)
			}
			log.Infof("ChipDnaClient started with PID %d", cmd.Process.Pid)
			return cmd, nil
		}

		cmd, err := startClient()
		if err != nil {
			fatalError(err)
		}

		// Restart loop
		go func() {
			for {
				err := cmd.Wait()
				if err != nil {
					log.Errorf("ChipDnaClient exited unexpectedly: %v", err)
					time.Sleep(2 * time.Second)
					cmd, err = startClient()
					if err != nil {
						log.Errorf("Restart failed: %v", err)
						return
					}
					log.Info("ChipDnaClient restarted successfully")
				}
			}
		}()

		// Handle shutdown signals
		sigs := make(chan os.Signal, 1)
		signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
		go func() {
			<-sigs
			log.Info("Shutting down...")
			if cmd.Process != nil {
				log.Info("Sending SIGTERM to ChipDnaClient...")
				_ = cmd.Process.Signal(syscall.SIGTERM)
				// wait up to 5s for graceful shutdown
				done := make(chan error, 1)
				go func() { done <- cmd.Wait() }()
				select {
				case <-time.After(5 * time.Second):
					log.Warn("ChipDnaClient did not exit in time, killing...")
					_ = cmd.Process.Kill()
				case err := <-done:
					log.Infof("ChipDnaClient exited cleanly: %v", err)
				}
			}
			os.Exit(0)
		}()
	}

	// Create App and wire routes
	// dispHandle := &serial.Port{} // Placeholder, replace with actual dispenser handle
	app := newApp(dispHandle, config)

	mux := http.NewServeMux()
	setUpRoutes(app, mux)

	addr := fmt.Sprintf(":%d", config.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 {
		fatalError(err)
	}
}

func setUpRoutes(app *App, mux *http.ServeMux) {
	mux.HandleFunc("/issuedoorcard", app.issueDoorCard)
	mux.HandleFunc("/printroomticket", app.printRoomTicket)
	mux.HandleFunc("/starttransaction", app.startTransaction)
}

func fatalError(err error) {
	fmt.Println(err.Error())
	log.Errorf(err.Error())
	fmt.Println(". Press Enter to exit...")
	fmt.Scanln()
	os.Exit(1)
}

// 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
}

// 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)
	if err := json.NewEncoder(w).Encode(theResponse); err != nil {
		logging.Error(serviceName, err.Error(), "JSON encode error", "startTransaction", "", "", 0)
	}
}

func (app *App) startTransaction(w http.ResponseWriter, r *http.Request) {
	const op = logging.Op("startTransaction")
	var (
		theResponse       cmstypes.ResponseRec
		cardholderReceipt string
		theRequest        cmstypes.TransactionRec
	)

	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.configRec.IsPayment {
		theResponse.Data = payment.BuildFailureURL(payment.ResultError, "Payment processing is disabled")
		writeTransactionResult(w, http.StatusServiceUnavailable, theResponse)
		return
	}

	if r.Method == http.MethodOptions {
		w.WriteHeader(http.StatusNoContent)
		return
	}

	log.Println("startTransaction called")
	if r.Method != http.MethodPost {
		theResponse.Data = payment.BuildFailureURL(payment.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")
		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(payment.ResultError, "Invalid XML payload")
		writeTransactionResult(w, http.StatusBadRequest, theResponse)
		return
	}
	log.Printf("Start trnasaction 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))
	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")
		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(payment.ResultError, "Failed to read response body")
		writeTransactionResult(w, http.StatusInternalServerError, theResponse)
		return
	}

	responseEntries, _ := payment.ParseTransactionResult(body)

	// Compose JSON from responseEntries
	result := make(map[string]string)
	for _, e := range responseEntries {
		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 {
		log.Errorf("PrintCardholderReceipt error: %v", err)
	}

	theResponse.Data = payment.BuildRedirectURL(result)
	writeTransactionResult(w, http.StatusOK, theResponse)
}

func (app *App) issueDoorCard(w http.ResponseWriter, r *http.Request) {
	const op = logging.Op("issueDoorCard")
	var (
		doorReq     lockserver.DoorCardRequest
		theResponse cmstypes.StatusRec
	)

	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 r.Method == http.MethodOptions {
		w.WriteHeader(http.StatusNoContent)
		return
	}

	log.Println("issueDoorCard called")
	if r.Method != http.MethodPost {
		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")
		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())
		return
	}

	// parse times
	checkIn, err := time.Parse(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())
		return
	}
	checkOut, err := time.Parse(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())
		return
	}

	// dispenser sequence
	if status, err := dispenser.DispenserSequence(app.dispPort); err != nil {
		if status != "" {
			logging.Error(serviceName, status, "Dispense error", string(op), "", "", 0)
			writeError(w, http.StatusServiceUnavailable, "Dispense error: "+err.Error())
		} else {
			logging.Error(serviceName, err.Error(), "Dispense error", string(op), "", "", 0)
			writeError(w, http.StatusServiceUnavailable, "Dispense error: "+err.Error()+"; check card stock")
		}
		return
	} else {
		log.Info(status)
	}

	// build lock server command
	app.lockserver.BuildCommand(doorReq, checkIn, checkOut)

	// lock server sequence
	err = app.lockserver.LockSequence()
	if err != nil {
		logging.Error(serviceName, err.Error(), "Key encoding", string(op), "", "", 0)
		writeError(w, http.StatusBadGateway, err.Error())
		dispenser.CardOutOfMouth(app.dispPort)
		return
	}

	// final dispenser steps
	if status, err := dispenser.CardOutOfMouth(app.dispPort); err != nil {
		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)
}

func (app *App) printRoomTicket(w http.ResponseWriter, r *http.Request) {
	const op = logging.Op("printRoomTicket")
	var roomDetails printer.RoomDetailsRec
	// Allow CORS preflight if needed
	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")

	if r.Method == http.MethodOptions {
		w.WriteHeader(http.StatusNoContent)
		return
	}
	log.Println("printRoomTicket called")
	if r.Method != http.MethodPost {
		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")
		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())
		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())
		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())
		return
	}

	// Success
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(cmstypes.StatusRec{
		Code:    http.StatusOK,
		Message: "Print job sent successfully",
	})
}

// 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)
		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

	// 1) Read the file
	data, err := os.ReadFile(layoutName)
	if err != nil {
		fatalError(fmt.Errorf("failed to read %s: %v", layoutName, err))
	}

	// 2) Unmarshal into your struct
	if err := xml.Unmarshal(data, &layout); err != nil {
		fatalError(fmt.Errorf("failed to parse %s: %v", layoutName, err))
	}

	return layout
}