package middleware

import (
	"net/http"
	"strings"

	"github.com/gin-gonic/gin"
	"github.com/rss2/backend/internal/auth"
	"github.com/rss2/backend/internal/config"
)

func AuthRequired() gin.HandlerFunc {
	return func(c *gin.Context) {
		authHeader := c.GetHeader("Authorization")
		if authHeader == "" {
			c.JSON(http.StatusUnauthorized, gin.H{"error": "Authorization header required"})
			c.Abort()
			return
		}

		tokenString := strings.TrimPrefix(authHeader, "Bearer ")
		if tokenString == authHeader {
			c.JSON(http.StatusUnauthorized, gin.H{"error": "Bearer token required"})
			c.Abort()
			return
		}

		claims, err := auth.ValidateToken(tokenString)
		if err != nil {
			c.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid token"})
			c.Abort()
			return
		}

		c.Set("user", claims)
		c.Next()
	}
}

func AdminRequired() gin.HandlerFunc {
	return func(c *gin.Context) {
		userVal, exists := c.Get("user")
		if !exists {
			c.JSON(http.StatusUnauthorized, gin.H{"error": "Not authenticated"})
			c.Abort()
			return
		}

		claims := userVal.(*auth.Claims)
		if !claims.IsAdmin {
			c.JSON(http.StatusForbidden, gin.H{"error": "Admin access required"})
			c.Abort()
			return
		}

		c.Next()
	}
}

func CORSMiddleware() gin.HandlerFunc {
	cfg := config.Load()
	allowedOrigins := strings.Split(cfg.AllowedOrigins, ",")

	return func(c *gin.Context) {
		origin := c.Request.Header.Get("Origin")
		
		allowed := false
		for _, o := range allowedOrigins {
			o = strings.TrimSpace(o)
			if o == "*" || o == origin {
				allowed = true
				break
			}
		}

		if allowed {
			if cfg.AllowedOrigins == "*" {
				c.Writer.Header().Set("Access-Control-Allow-Origin", "*")
			} else {
				c.Writer.Header().Set("Access-Control-Allow-Origin", origin)
				c.Writer.Header().Set("Access-Control-Allow-Credentials", "true")
			}
		}

		c.Writer.Header().Set("Access-Control-Allow-Headers", "Content-Type, Content-Length, Accept-Encoding, X-CSRF-Token, Authorization, accept, origin, Cache-Control, X-Requested-With")
		c.Writer.Header().Set("Access-Control-Allow-Methods", "POST, OPTIONS, GET, PUT, DELETE, PATCH")

		if c.Request.Method == "OPTIONS" {
			c.AbortWithStatus(204)
			return
		}

		c.Next()
	}
}

func LoggerMiddleware() gin.HandlerFunc {
	return func(c *gin.Context) {
		c.Next()

		status := c.Writer.Status()
		if status >= 400 {
			// Log error responses
		}
	}
}

func RateLimitMiddleware(requestsPerMinute int) gin.HandlerFunc {
	return func(c *gin.Context) {
		c.Next()
	}
}