package main

import (
	"context"
	"fmt"
	"net/http"
	"os"
	"os/signal"
	"strings"
	"syscall"
	"time"

	"github.com/gin-gonic/gin"
	"go.uber.org/zap"
	pgdriver "gorm.io/driver/postgres"
	"gorm.io/gorm"
	gormlogger "gorm.io/gorm/logger"

	appservice "github.com/genex/trading-service/internal/application/service"
	"github.com/genex/trading-service/internal/infrastructure/kafka"
	"github.com/genex/trading-service/internal/infrastructure/postgres"
	"github.com/genex/trading-service/internal/interface/http/handler"
	"github.com/genex/trading-service/internal/interface/http/middleware"
)

func main() {
	logger, _ := zap.NewProduction()
	defer logger.Sync()

	port := os.Getenv("PORT")
	if port == "" {
		port = "3003"
	}

	// ── Infrastructure Layer ────────────────────────────────────────────
	db := mustInitDB(logger)

	orderRepo := postgres.NewPostgresOrderRepository(db)
	tradeRepo := postgres.NewPostgresTradeRepository(db)

	eventPublisher := mustInitKafka(logger)
	defer eventPublisher.Close()

	// ── Application Layer ───────────────────────────────────────────────
	matchingService := appservice.NewMatchingService(eventPublisher)
	tradeService := appservice.NewTradeService(orderRepo, tradeRepo, matchingService, eventPublisher)

	// ── Interface Layer (HTTP) ──────────────────────────────────────────
	r := gin.New()
	r.Use(gin.Recovery())

	// Health endpoints
	r.GET("/health", func(c *gin.Context) {
		c.JSON(200, gin.H{"status": "ok", "service": "trading-service", "timestamp": time.Now().UTC().Format(time.RFC3339)})
	})
	r.GET("/health/ready", func(c *gin.Context) { c.JSON(200, gin.H{"status": "ready"}) })
	r.GET("/health/live", func(c *gin.Context) { c.JSON(200, gin.H{"status": "alive"}) })

	// API routes
	api := r.Group("/api/v1")

	// User-facing trade handler
	tradeHandler := handler.NewTradeHandler(tradeService)

	trades := api.Group("/trades")
	trades.Use(middleware.JWTAuth())
	{
		trades.POST("/orders", tradeHandler.PlaceOrder)
		trades.DELETE("/orders/:id", tradeHandler.CancelOrder)
		trades.GET("/my/orders", tradeHandler.MyOrders)
		trades.POST("/coupons/:id/transfer", tradeHandler.TransferCoupon)
	}

	// Public orderbook
	api.GET("/trades/orderbook/:couponId", tradeHandler.GetOrderBook)

	// Admin routes (require JWT + admin role)
	adminTradeHandler := handler.NewAdminTradeHandler(tradeService)
	adminMMHandler := handler.NewAdminMMHandler(tradeService)

	admin := api.Group("/admin")
	admin.Use(middleware.JWTAuth(), middleware.RequireAdmin())
	{
		// Trade administration
		adminTrades := admin.Group("/trades")
		adminTrades.GET("/stats", adminTradeHandler.GetTradingStats)
		adminTrades.GET("/orders", adminTradeHandler.ListOrders)
		adminTrades.GET("/volume-trend", adminTradeHandler.GetVolumeTrend)
		adminTrades.POST("/orders/:id/investigate", adminTradeHandler.InvestigateOrder)

		// Market maker administration
		mm := admin.Group("/mm")
		mm.GET("/list", adminMMHandler.ListMarketMakers)
		mm.GET("/:id/details", adminMMHandler.GetMarketMakerDetails)
		mm.POST("/:id/suspend", adminMMHandler.SuspendMarketMaker)
		mm.POST("/:id/resume", adminMMHandler.ResumeMarketMaker)
		mm.GET("/liquidity-pools", adminMMHandler.GetLiquidityPools)
		mm.GET("/order-book-depth", adminMMHandler.GetOrderBookDepth)
		mm.GET("/health-indicators", adminMMHandler.GetHealthIndicators)
	}

	server := &http.Server{
		Addr:         ":" + port,
		Handler:      r,
		ReadTimeout:  15 * time.Second,
		WriteTimeout: 15 * time.Second,
		IdleTimeout:  60 * time.Second,
	}

	go func() {
		logger.Info("Trading Service starting", zap.String("port", port))
		if err := server.ListenAndServe(); err != nil && err != http.ErrServerClosed {
			logger.Fatal("Server failed", zap.Error(err))
		}
	}()

	quit := make(chan os.Signal, 1)
	signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM)
	<-quit

	logger.Info("Shutting down gracefully...")
	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()

	if err := server.Shutdown(ctx); err != nil {
		logger.Fatal("Server forced to shutdown", zap.Error(err))
	}
	logger.Info("Trading Service stopped")
}

func mustInitDB(logger *zap.Logger) *gorm.DB {
	host := getEnv("DB_HOST", "localhost")
	dbPort := getEnv("DB_PORT", "5432")
	user := getEnv("DB_USERNAME", "genex")
	pass := getEnv("DB_PASSWORD", "genex_dev_password")
	name := getEnv("DB_NAME", "genex")

	dsn := fmt.Sprintf("host=%s port=%s user=%s password=%s dbname=%s sslmode=disable",
		host, dbPort, user, pass, name)

	db, err := gorm.Open(pgdriver.Open(dsn), &gorm.Config{
		Logger: gormlogger.Default.LogMode(gormlogger.Warn),
	})
	if err != nil {
		logger.Fatal("Failed to connect to PostgreSQL", zap.Error(err))
	}

	sqlDB, _ := db.DB()
	sqlDB.SetMaxOpenConns(20)
	sqlDB.SetMaxIdleConns(5)
	sqlDB.SetConnMaxLifetime(30 * time.Minute)

	logger.Info("PostgreSQL connected", zap.String("host", host), zap.String("db", name))
	return db
}

func mustInitKafka(logger *zap.Logger) *kafka.KafkaEventPublisher {
	brokersEnv := getEnv("KAFKA_BROKERS", "localhost:9092")
	brokers := strings.Split(brokersEnv, ",")

	publisher, err := kafka.NewKafkaEventPublisher(brokers)
	if err != nil {
		logger.Fatal("Failed to connect to Kafka", zap.Error(err))
	}

	logger.Info("Kafka producer connected", zap.Strings("brokers", brokers))
	return publisher
}

func getEnv(key, fallback string) string {
	if v := os.Getenv(key); v != "" {
		return v
	}
	return fallback
}