package router

import (
	"bookhoard/internal/config"
	"bookhoard/internal/database"
	"bookhoard/internal/handlers"
	"bookhoard/internal/middleware"
	ratelimit "bookhoard/internal/middleware"
	"bookhoard/internal/services"
	"bookhoard/internal/sync"
	"bookhoard/templates"
	"bytes"
	"log"
	"net/http"
	"strings"
	"time"

	"github.com/go-playground/validator/v10"
	"github.com/golang-jwt/jwt/v5"
	"github.com/google/uuid"
	"github.com/jackc/pgx/v5/pgtype"
	echojwt "github.com/labstack/echo-jwt/v4"
	"github.com/labstack/echo/v4"
	echomiddleware "github.com/labstack/echo/v4/middleware"
)

// CustomValidator wraps the go-playground validator
type CustomValidator struct {
	validator *validator.Validate
}

func (cv *CustomValidator) Validate(i interface{}) error {
	return cv.validator.Struct(i)
}

// Config holds all dependencies needed for route registration
type Config struct {
	Echo                  *echo.Echo
	Queries               *database.Queries
	Cfg                   *config.Config
	DBPool                interface{} // pgxpool.Pool interface
	AuthHandler           *handlers.AuthHandler
	LibraryHandler        *handlers.LibraryHandler
	DeviceHandler         *handlers.DeviceHandler
	MediaHandler          *handlers.MediaHandler
	MatchingHandler       *handlers.MatchingHandler
	KOReaderHandler       *handlers.KOReaderHandler
	WSHandler             *handlers.WSHandler
	ConflictHandler       *handlers.ConflictHandler
	AnalyticsHandler      *handlers.AnalyticsHandler
	QueueHandler          *handlers.QueueHandler
	CollectionHandler     *handlers.CollectionHandler
	DashboardHandler      *handlers.DashboardHandler
	DashboardService      *services.DashboardService
	OPDSHandler           *handlers.OPDSHandler
	SystemSettingsHandler *handlers.SystemSettingsHandler
	ConnManager           *sync.ConnectionManager
	QueueProcessor        *sync.SyncQueueProcessor
	DeviceAuthMiddleware  *middleware.DeviceAuthMiddleware
	LoginTracker          *ratelimit.LoginAttemptTracker
	ScannerHandler        *handlers.Handler
}

// createJWTMiddleware creates a JWT middleware with proper user context setup
func createJWTMiddleware(cfg *Config) echo.MiddlewareFunc {
	return echojwt.WithConfig(echojwt.Config{
		SigningKey:  []byte(cfg.Cfg.JWTSecret),
		ContextKey:  "user",
		TokenLookup: "cookie:token,header:Authorization:Bearer ",
		SuccessHandler: func(c echo.Context) {
			token := c.Get("user").(*jwt.Token)
			claims := token.Claims.(jwt.MapClaims)
			c.Set("user_id", claims["user_id"])
			c.Set("user_role", claims["user_role"])
			c.Set("user_email", claims["user_email"])
			c.Set("user_username", claims["user_username"])

			// Parse UUID from string claims
			userIDStr, _ := claims["user_id"].(string)
			userUUID, err := uuid.Parse(userIDStr)
			if err != nil {
				c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid user ID in token"})
				return
			}

			c.Set("user", database.Users{
				ID:       pgtype.UUID{Bytes: [16]byte(userUUID), Valid: true},
				Email:    claims["user_email"].(string),
				Username: claims["user_username"].(string),
				Role:     claims["user_role"].(string),
			})
		},
		ErrorHandler: func(c echo.Context, err error) error {
			// Check if this is a page request (browser navigation)
			if wantsHTML(c.Request().Header) {
				// Page request → Redirect to login with message
				loginURL := "/login?session=expired"
				return c.Redirect(http.StatusFound, loginURL)
			}

			// API request → Return JSON error
			return c.JSON(http.StatusUnauthorized, map[string]string{
				"error":   "session_expired",
				"message": "Your session has expired. Please log in again.",
			})
		},
	})
}

// ensureUserExistsMiddleware checks if the authenticated user still exists in the database
func ensureUserExistsMiddleware(cfg *Config) echo.MiddlewareFunc {
	return func(next echo.HandlerFunc) echo.HandlerFunc {
		return func(c echo.Context) error {
			userIDStr, ok := c.Get("user_id").(string)
			if !ok {
				return next(c)
			}

			userUUID, err := uuid.Parse(userIDStr)
			if err != nil {
				log.Printf("Invalid UUID in user existence check: %v", err)
				return next(c)
			}

			// Check if user exists in database
			_, err = cfg.Queries.GetUser(c.Request().Context(), uuidToPGType(userUUID))
			if err != nil {
				log.Printf("User not found in database: %s", userIDStr)

				// Clear invalid cookie
				c.SetCookie(&http.Cookie{
					Name:     "token",
					Value:    "",
					Expires:  time.Now().Add(-24 * time.Hour),
					Path:     "/",
					HttpOnly: true,
					SameSite: http.SameSiteLaxMode,
				})

				// Redirect to login with session=invalid
				return c.Redirect(http.StatusFound, "/login?session=invalid")
			}

			return next(c)
		}
	}
}

// wantsHTML determines if the request expects HTML response
func wantsHTML(header http.Header) bool {
	// Check Accept header
	accept := header.Get("Accept")
	if accept != "" && (accept == "text/html" || strings.Contains(accept, "text/html")) {
		return true
	}

	// Check HTMX request
	if header.Get("HX-Request") == "true" {
		return true
	}

	// Check for AJAX requests (should get JSON)
	if header.Get("X-Requested-With") == "XMLHttpRequest" {
		return false
	}

	// Default to JSON for API routes
	return false
}

// RegisterRoutes registers all application routes
func RegisterRoutes(cfg *Config) *handlers.Handler {
	e := cfg.Echo

	// Set up validator
	v := validator.New()
	if err := ratelimit.RegisterPasswordValidation(v); err != nil {
		log.Fatal("Failed to register password validator:", err)
	}
	e.Validator = &CustomValidator{validator: v}

	// Global middleware
	e.Use(echomiddleware.Logger())
	e.Use(echomiddleware.Recover())
	e.Use(echomiddleware.CORS())
	e.Use(ratelimit.RequestTracingMiddleware(cfg.Cfg))

	// Rate limiter
	rateLimiterConfig := ratelimit.RateLimiterConfig{
		Enabled:           cfg.Cfg.RateLimitEnabled,
		RequestsPerMinute: cfg.Cfg.RequestsPerMinute,
		CleanupInterval:   5 * time.Minute,
	}
	rateLimiter := ratelimit.NewRateLimiter(rateLimiterConfig)
	rateLimitMiddleware := ratelimit.RateLimiterMiddleware(rateLimiter)

	// Register core application routes (collections, devices, media, etc.) - ONCE
	jwtMiddleware := createJWTMiddleware(cfg)
	protected := e.Group("/api", jwtMiddleware)

	// Create scanner handler for scanner routes and progress routes
	scannerHandler := handlers.SetupRoutes(protected, cfg.Queries, cfg.ConnManager, cfg.QueueProcessor)
	cfg.ScannerHandler = scannerHandler

	// Register route groups
	registerAuthRoutes(cfg, rateLimitMiddleware)
	registerLibraryRoutes(cfg)
	registerDeviceRoutes(cfg)
	registerSyncRoutes(cfg)
	registerCollectionsRoutes(cfg)
	registerDashboardRoutes(cfg)
	registerMediaRoutes(cfg)
	registerSearchRoutes(cfg)
	registerMatchingRoutes(cfg)
	registerConflictRoutes(cfg)
	registerAnalyticsRoutes(cfg)
	registerQueueRoutes(cfg)
	registerOPDSRoutes(cfg)
	registerWebSocketRoutes(cfg)
	registerFrontendRoutes(cfg)
	registerDocumentationRoutes(cfg)
	e.Static("/static", "web/static")

	// Catch-all 404 handler - must be last
	e.GET("/*", func(c echo.Context) error {
		var buf bytes.Buffer
		err := templates.ErrorPage("Page not found", "404").Render(c.Request().Context(), &buf)
		if err != nil {
			return err
		}
		return c.HTML(http.StatusNotFound, buf.String())
	})

	// Start background tasks (queue processor and connection cleanup)
	scannerHandler.StartBackgroundTasks()

	// Register progress routes with actual handler
	registerProgressRoutes(cfg, scannerHandler)

	// Register scanner routes (admin only)
	admin := protected.Group("", handlers.AdminMiddleware)
	registerScannerRoutes(admin, scannerHandler)

	return scannerHandler
}