package api

import (
	"net/http"
	"strconv"
	"strings"

	"github.com/gin-gonic/gin"

	"hightube/internal/db"
	"hightube/internal/model"
	"hightube/internal/monitor"
	"hightube/internal/utils"
)

// AuthMiddleware intercepts requests, validates JWT, and injects user_id into context
func AuthMiddleware() gin.HandlerFunc {
	return func(c *gin.Context) {
		authHeader := c.GetHeader("Authorization")
		if authHeader == "" {
			c.JSON(http.StatusUnauthorized, gin.H{"error": "Authorization header is required"})
			c.Abort()
			return
		}

		parts := strings.Split(authHeader, " ")
		if len(parts) != 2 || parts[0] != "Bearer" {
			c.JSON(http.StatusUnauthorized, gin.H{"error": "Authorization header format must be Bearer {token}"})
			c.Abort()
			return
		}

		tokenStr := parts[1]
		claims, err := utils.ParseToken(tokenStr)
		if err != nil {
			c.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid or expired token"})
			c.Abort()
			return
		}

		userID, _ := strconv.ParseUint(claims.Subject, 10, 32)

		var user model.User
		if err := db.DB.First(&user, uint(userID)).Error; err != nil {
			c.JSON(http.StatusUnauthorized, gin.H{"error": "User not found"})
			c.Abort()
			return
		}

		if !user.Enabled {
			c.JSON(http.StatusForbidden, gin.H{"error": "Account is disabled"})
			c.Abort()
			return
		}

		c.Set("user_id", uint(userID))
		c.Set("username", user.Username)
		c.Set("role", user.Role)
		c.Next()
	}
}

func AdminMiddleware() gin.HandlerFunc {
	return func(c *gin.Context) {
		role, ok := c.Get("role")
		if !ok || role != "admin" {
			c.JSON(http.StatusForbidden, gin.H{"error": "admin access required"})
			c.Abort()
			return
		}
		c.Next()
	}
}

func RequestMetricsMiddleware() gin.HandlerFunc {
	return func(c *gin.Context) {
		monitor.IncrementRequestCount()
		c.Next()
		if c.Writer.Status() >= http.StatusBadRequest {
			monitor.IncrementErrorCount()
		}
	}
}

// CORSMiddleware handles cross-origin requests from web clients
func CORSMiddleware() gin.HandlerFunc {
	return func(c *gin.Context) {
		c.Writer.Header().Set("Access-Control-Allow-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")

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

		c.Next()
	}
}