package main

import (
	"context"
	"database/sql"
	"fmt"
	"log"
	"net/http"
	"os"
	"os/signal"
	"syscall"
	"time"

	"github.com/gin-gonic/gin"
	_ "github.com/go-sql-driver/mysql"

	"git.piskot.si/SeminarM2/lambdaiot-core/internal/config"
	"git.piskot.si/SeminarM2/lambdaiot-core/internal/devicecheck"
	"git.piskot.si/SeminarM2/lambdaiot-core/internal/handler"
	"git.piskot.si/SeminarM2/lambdaiot-core/internal/middleware"
	mqttclient "git.piskot.si/SeminarM2/lambdaiot-core/internal/mqtt"
)

func main() {
	// load configuration (look for ./config.toml by default)
	cfg, err := config.Load("")
	if err != nil {
		log.Fatalf("failed to load config: %v", err)
	}

	// connect to MySQL database
	dsn := fmt.Sprintf("%s:%s@tcp(%s:%d)/%s?parseTime=true", cfg.Database.User, cfg.Database.Password, cfg.Database.Host, cfg.Database.Port, cfg.Database.Name)
	sqlDB, err := sql.Open("mysql", dsn)
	if err != nil {
		log.Fatalf("failed to connect to database: %v", err)
	}
	defer sqlDB.Close()

	// test connection
	if err := sqlDB.Ping(); err != nil {
		log.Fatalf("failed to ping database: %v", err)
	}
	log.Println("connected to database")

	// determine address
	addr := cfg.Server.Address
	if addr == "" {
		addr = ":8080"
	}
	if cfg.Server.Port != 0 {
		addr = fmt.Sprintf(":%d", cfg.Server.Port)
	}

	h := &handler.Handler{DB: sqlDB, JWTSecret: cfg.Server.JWTSecret, MQTTTopic: cfg.MQTT.Topic}

	// connect to MQTT broker (best-effort)
	var mq *mqttclient.Client
	var checker *devicecheck.Checker
	var checkCtx context.Context
	var checkCancel context.CancelFunc
	if cfg.MQTT.Broker != "" {
		mqc, err := mqttclient.Connect(cfg.MQTT)
		if err != nil {
			log.Printf("warning: mqtt connect failed: %v", err)
		} else {
			mq = mqc
			mqttclient.SetDefault(mqc)

			// start device state checker when MQTT is available
			checkCtx, checkCancel = context.WithCancel(context.Background())
			checker = devicecheck.New(sqlDB, mq, cfg.MQTT.Topic, 0, 0)
			checker.Start(checkCtx)

			// subscribe to the configured topic and log incoming messages
			if cfg.MQTT.Topic != "" {
				handlerFn := func(t string, p []byte) {
					log.Printf("mqtt recv on %s: %s", t, string(p))
					if checker != nil {
						checker.HandleMessage(p)
					}
					if handled, err := h.ProcessSensorReadingMessage(p); handled && err != nil {
						log.Printf("sensor reading message error: %v", err)
					}
				}
				if err := mq.Subscribe(cfg.MQTT.Topic, handlerFn); err != nil {
					log.Printf("warning: mqtt subscribe failed: %v", err)
				}
			}

			// subscribe to discovery topic
			discoveryTopic := cfg.MQTT.Topic + "/discovery"
			discoveryHandler := func(t string, p []byte) {
				log.Printf("device discovery on %s", t)
				if err := h.ProcessDiscoveryMessage(p); err != nil {
					log.Printf("error processing discovery message: %v", err)
				}
			}
			if err := mq.Subscribe(discoveryTopic, discoveryHandler); err != nil {
				log.Printf("warning: mqtt subscribe to discovery failed: %v", err)
			}

			// publish a startup message (non-blocking)
			go func() {
				msg := fmt.Sprintf("lambdaiot-core started on %s", addr)
				if err := mq.Publish(cfg.MQTT.Topic, []byte(msg)); err != nil {
					log.Printf("mqtt publish failed: %v", err)
				}
			}()
		}
	}

	// mqttping endpoint will be added after router initialization

	// Gin setup
	r := gin.New()
	r.Use(gin.Recovery())
	r.Use(middleware.CORS())
	r.Use(middleware.GinLogger())

	// Public routes
	r.GET("/health", h.Health)
	r.GET("/hello", h.Hello)
	r.POST("/login", h.Login)
	r.GET("/devices", h.GetDevices)

	// mqttping endpoint handled by internal/handler (protected)

	// Protected routes
	auth := r.Group("/")
	auth.POST("/register", h.Register)
	auth.Use(middleware.AuthMiddleware(cfg.Server.JWTSecret))
	auth.GET("/protected", h.Protected)
	auth.GET("/mqttping", h.MQTTPing)
	auth.GET("/sensors", h.GetSensors)
	auth.GET("/sensors/:id", h.GetSensor)
	auth.POST("/sensors/:id/trigger", h.TriggerSensor)
	auth.POST("/sensors", h.CreateSensor)
	auth.PUT("/sensors/:id", h.UpdateSensor)
	auth.DELETE("/sensors/:id", h.DeleteSensor)

	auth.GET("/actors", h.GetActors)
	auth.GET("/actors/:id", h.GetActor)
	auth.POST("/actors/:id/write", h.WriteActor)
	auth.POST("/actors", h.CreateActor)
	auth.PUT("/actors/:id", h.UpdateActor)
	auth.DELETE("/actors/:id", h.DeleteActor)

	auth.GET("/sensor-readings", h.GetSensorReadings)
	auth.GET("/sensor-readings/:id", h.GetSensorReading)
	auth.POST("/sensor-readings", h.CreateSensorReading)
	auth.PUT("/sensor-readings/:id", h.UpdateSensorReading)
	auth.DELETE("/sensor-readings/:id", h.DeleteSensorReading)

	// Device CRUD routes
	auth.POST("/devices", h.CreateDevice)
	auth.GET("/devices/:id", h.GetDevice)
	auth.PUT("/devices/:id", h.UpdateDevice)
	auth.DELETE("/devices/:id", h.DeleteDevice)

	srv := &http.Server{
		Addr:    addr,
		Handler: r,
	}

	go func() {
		log.Printf("starting server on %s", addr)
		if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
			log.Fatalf("listen: %v", err)
		}
	}()

	quit := make(chan os.Signal, 1)
	signal.Notify(quit, os.Interrupt, syscall.SIGTERM)
	<-quit
	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()
	if err := srv.Shutdown(ctx); err != nil {
		log.Fatalf("server forced to shutdown: %v", err)
	}
	if mq != nil {
		mq.Close()
	}
	if checkCancel != nil {
		checkCancel()
	}
	log.Println("server exiting")
}

// removed unused getJWTSecret helper; configuration provides JWTSecret