package middleware

import (
	"net/http"
	"strings"

	"goblog/handlers"

	"github.com/gin-gonic/gin"
	"github.com/golang-jwt/jwt/v5"
)

// tokenFromContext 统一从 Cookie 或 Authorization 头提取 JWT token
// 优先读 Cookie（服务端渲染 + 同域 AJAX 自动携带），回退到 Authorization 头
func tokenFromContext(c *gin.Context) string {
	if tokenString, err := c.Cookie("token"); err == nil && tokenString != "" {
		return tokenString
	}
	authHeader := c.GetHeader("Authorization")
	if authHeader != "" {
		parts := strings.SplitN(authHeader, " ", 2)
		if len(parts) == 2 && parts[0] == "Bearer" {
			return parts[1]
		}
	}
	return ""
}

// JWT 认证中间件
func JWTAuth() gin.HandlerFunc {
	return func(c *gin.Context) {
		tokenString := tokenFromContext(c)
		if tokenString == "" {
			c.JSON(http.StatusUnauthorized, gin.H{"error": "缺少认证令牌"})
			c.Abort()
			return
		}

		claims := &handlers.Claims{}

		token, err := jwt.ParseWithClaims(tokenString, claims, func(token *jwt.Token) (interface{}, error) {
			return handlers.JWTSecret(), nil
		})

		if err != nil || !token.Valid {
			c.JSON(http.StatusUnauthorized, gin.H{"error": "无效的令牌"})
			c.Abort()
			return
		}

		c.Set("userID", claims.UserID)
		c.Set("username", claims.Username)
		c.Set("role", claims.Role)
		c.Next()
	}
}

// 管理员权限中间件
func AdminRequired() gin.HandlerFunc {
	return func(c *gin.Context) {
		role, exists := c.Get("role")
		if !exists || role != "admin" {
			c.JSON(http.StatusForbidden, gin.H{"error": "需要管理员权限"})
			c.Abort()
			return
		}
		c.Next()
	}
}

// OptionalAuth 可选认证中间件（用于某些既支持游客又支持登录用户的接口/页面）
func OptionalAuth() gin.HandlerFunc {
	return func(c *gin.Context) {
		tokenString := tokenFromContext(c)
		if tokenString == "" {
			c.Next()
			return
		}

		claims := &handlers.Claims{}

		token, err := jwt.ParseWithClaims(tokenString, claims, func(token *jwt.Token) (interface{}, error) {
			return handlers.JWTSecret(), nil
		})

		if err == nil && token.Valid {
			c.Set("userID", claims.UserID)
			c.Set("username", claims.Username)
			c.Set("role", claims.Role)
		}

		c.Next()
	}
}