package main

import (
	"context"
	"database/sql"
	"encoding/hex"
	"flag"
	"fmt"
	"net/http"
	"os"
	"os/signal"
	"syscall"
	"time"

	"github.com/gin-gonic/gin"
	_ "github.com/lib/pq"

	"github.com/rwadurian/mpc-system/pkg/config"
	"github.com/rwadurian/mpc-system/pkg/crypto"
	"github.com/rwadurian/mpc-system/pkg/logger"
	"github.com/rwadurian/mpc-system/services/server-party/adapters/output/postgres"
	"github.com/rwadurian/mpc-system/services/server-party/application/use_cases"
	"go.uber.org/zap"
)

func main() {
	// Parse flags
	configPath := flag.String("config", "", "Path to config file")
	flag.Parse()

	// Load configuration
	cfg, err := config.Load(*configPath)
	if err != nil {
		fmt.Printf("Failed to load config: %v\n", err)
		os.Exit(1)
	}

	// Initialize logger
	if err := logger.Init(&logger.Config{
		Level:    cfg.Logger.Level,
		Encoding: cfg.Logger.Encoding,
	}); err != nil {
		fmt.Printf("Failed to initialize logger: %v\n", err)
		os.Exit(1)
	}
	defer logger.Sync()

	logger.Info("Starting Server Party Service",
		zap.String("environment", cfg.Server.Environment),
		zap.Int("http_port", cfg.Server.HTTPPort))

	// Initialize database connection
	db, err := initDatabase(cfg.Database)
	if err != nil {
		logger.Fatal("Failed to connect to database", zap.Error(err))
	}
	defer db.Close()

	// Initialize crypto service with master key from environment
	masterKeyHex := os.Getenv("MPC_CRYPTO_MASTER_KEY")
	if masterKeyHex == "" {
		masterKeyHex = "0123456789abcdef0123456789abcdef" // Default 32 bytes for development
	}
	masterKey, err := hex.DecodeString(masterKeyHex)
	if err != nil {
		logger.Fatal("Invalid master key format", zap.Error(err))
	}
	cryptoService, err := crypto.NewCryptoService(masterKey)
	if err != nil {
		logger.Fatal("Failed to create crypto service", zap.Error(err))
	}

	// Initialize repositories
	keyShareRepo := postgres.NewKeySharePostgresRepo(db)

	// Initialize use cases
	// Note: SessionCoordinatorClient and MessageRouterClient would be
	// implemented as gRPC clients in production
	participateKeygenUC := use_cases.NewParticipateKeygenUseCase(
		keyShareRepo,
		nil, // sessionClient - would be gRPC client
		nil, // messageRouter - would be gRPC client
		cryptoService,
	)
	participateSigningUC := use_cases.NewParticipateSigningUseCase(
		keyShareRepo,
		nil, // sessionClient
		nil, // messageRouter
		cryptoService,
	)

	// Create shutdown context
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	// Start HTTP server
	errChan := make(chan error, 1)
	go func() {
		if err := startHTTPServer(cfg, participateKeygenUC, participateSigningUC); err != nil {
			errChan <- fmt.Errorf("HTTP server error: %w", err)
		}
	}()

	// Wait for shutdown signal
	sigChan := make(chan os.Signal, 1)
	signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)

	select {
	case sig := <-sigChan:
		logger.Info("Received shutdown signal", zap.String("signal", sig.String()))
	case err := <-errChan:
		logger.Error("Server error", zap.Error(err))
	}

	// Graceful shutdown
	logger.Info("Shutting down...")
	cancel()

	time.Sleep(5 * time.Second)
	logger.Info("Shutdown complete")

	_ = ctx
}

func initDatabase(cfg config.DatabaseConfig) (*sql.DB, error) {
	db, err := sql.Open("postgres", cfg.DSN())
	if err != nil {
		return nil, err
	}

	db.SetMaxOpenConns(cfg.MaxOpenConns)
	db.SetMaxIdleConns(cfg.MaxIdleConns)
	db.SetConnMaxLifetime(cfg.ConnMaxLife)

	if err := db.Ping(); err != nil {
		return nil, err
	}

	logger.Info("Connected to PostgreSQL")
	return db, nil
}

func startHTTPServer(
	cfg *config.Config,
	participateKeygenUC *use_cases.ParticipateKeygenUseCase,
	participateSigningUC *use_cases.ParticipateSigningUseCase,
) error {
	if cfg.Server.Environment == "production" {
		gin.SetMode(gin.ReleaseMode)
	}

	router := gin.New()
	router.Use(gin.Recovery())
	router.Use(gin.Logger())

	// Health check
	router.GET("/health", func(c *gin.Context) {
		c.JSON(http.StatusOK, gin.H{
			"status":  "healthy",
			"service": "server-party",
		})
	})

	// API routes
	api := router.Group("/api/v1")
	{
		// Keygen participation endpoint
		api.POST("/keygen/participate", func(c *gin.Context) {
			var req struct {
				SessionID string `json:"session_id" binding:"required"`
				PartyID   string `json:"party_id" binding:"required"`
				JoinToken string `json:"join_token" binding:"required"`
			}

			if err := c.ShouldBindJSON(&req); err != nil {
				c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
				return
			}

			// Note: In production, this would trigger async keygen participation
			c.JSON(http.StatusAccepted, gin.H{
				"message":    "keygen participation initiated",
				"session_id": req.SessionID,
				"party_id":   req.PartyID,
			})
		})

		// Signing participation endpoint
		api.POST("/sign/participate", func(c *gin.Context) {
			var req struct {
				SessionID   string `json:"session_id" binding:"required"`
				PartyID     string `json:"party_id" binding:"required"`
				JoinToken   string `json:"join_token" binding:"required"`
				MessageHash string `json:"message_hash" binding:"required"`
			}

			if err := c.ShouldBindJSON(&req); err != nil {
				c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
				return
			}

			// Note: In production, this would trigger async signing participation
			c.JSON(http.StatusAccepted, gin.H{
				"message":    "signing participation initiated",
				"session_id": req.SessionID,
				"party_id":   req.PartyID,
			})
		})

		// Get key shares for a party
		api.GET("/shares/:party_id", func(c *gin.Context) {
			partyID := c.Param("party_id")

			// Note: In production, would fetch from repository
			c.JSON(http.StatusOK, gin.H{
				"party_id": partyID,
				"shares":   []interface{}{},
			})
		})
	}

	// Placeholder for use cases to avoid unused variable warnings
	_ = participateKeygenUC
	_ = participateSigningUC

	logger.Info("Starting HTTP server", zap.Int("port", cfg.Server.HTTPPort))
	return router.Run(fmt.Sprintf(":%d", cfg.Server.HTTPPort))
}