package middleware

import (
	"net/http"
	"strings"
	"github.com/gin-gonic/gin"
	"photography-backend/internal/service/auth"
	"photography-backend/internal/model/entity"
)

// AuthMiddleware 认证中间件
type AuthMiddleware struct {
	jwtService *auth.JWTService
}

// NewAuthMiddleware 创建认证中间件
func NewAuthMiddleware(jwtService *auth.JWTService) *AuthMiddleware {
	return &AuthMiddleware{
		jwtService: jwtService,
	}
}

// RequireAuth 需要认证的中间件
func (m *AuthMiddleware) RequireAuth() gin.HandlerFunc {
	return func(c *gin.Context) {
		// 从Header中获取Authorization
		authHeader := c.GetHeader("Authorization")
		if authHeader == "" {
			c.JSON(http.StatusUnauthorized, gin.H{
				"error": "Authorization header is required",
			})
			c.Abort()
			return
		}
		
		// 检查Bearer前缀
		if !strings.HasPrefix(authHeader, "Bearer ") {
			c.JSON(http.StatusUnauthorized, gin.H{
				"error": "Invalid authorization header format",
			})
			c.Abort()
			return
		}
		
		// 提取token
		token := strings.TrimPrefix(authHeader, "Bearer ")
		
		// 验证token
		claims, err := m.jwtService.ValidateToken(token)
		if err != nil {
			c.JSON(http.StatusUnauthorized, gin.H{
				"error": "Invalid or expired token",
			})
			c.Abort()
			return
		}
		
		// 将用户信息存入上下文
		c.Set("user_id", claims.UserID)
		c.Set("username", claims.Username)
		c.Set("user_role", claims.Role)
		
		c.Next()
	}
}

// RequireRole 需要特定角色的中间件
func (m *AuthMiddleware) RequireRole(requiredRole string) gin.HandlerFunc {
	return func(c *gin.Context) {
		userRole, exists := c.Get("user_role")
		if !exists {
			c.JSON(http.StatusUnauthorized, gin.H{
				"error": "User role not found in context",
			})
			c.Abort()
			return
		}
		
		roleStr, ok := userRole.(string)
		if !ok {
			c.JSON(http.StatusUnauthorized, gin.H{
				"error": "Invalid user role",
			})
			c.Abort()
			return
		}
		
		// 检查角色权限
		if !m.hasPermission(roleStr, requiredRole) {
			c.JSON(http.StatusForbidden, gin.H{
				"error": "Insufficient permissions",
			})
			c.Abort()
			return
		}
		
		c.Next()
	}
}

// RequireAdmin 需要管理员权限的中间件
func (m *AuthMiddleware) RequireAdmin() gin.HandlerFunc {
	return m.RequireRole(string(entity.UserRoleAdmin))
}

// RequirePhotographer 需要摄影师权限的中间件
func (m *AuthMiddleware) RequirePhotographer() gin.HandlerFunc {
	return m.RequireRole(string(entity.UserRolePhotographer))
}

// OptionalAuth 可选认证中间件
func (m *AuthMiddleware) OptionalAuth() gin.HandlerFunc {
	return func(c *gin.Context) {
		authHeader := c.GetHeader("Authorization")
		if authHeader == "" {
			c.Next()
			return
		}
		
		if !strings.HasPrefix(authHeader, "Bearer ") {
			c.Next()
			return
		}
		
		token := strings.TrimPrefix(authHeader, "Bearer ")
		claims, err := m.jwtService.ValidateToken(token)
		if err != nil {
			c.Next()
			return
		}
		
		// 将用户信息存入上下文
		c.Set("user_id", claims.UserID)
		c.Set("username", claims.Username)
		c.Set("user_role", claims.Role)
		
		c.Next()
	}
}

// GetCurrentUser 获取当前用户ID
func GetCurrentUser(c *gin.Context) (uint, bool) {
	userID, exists := c.Get("user_id")
	if !exists {
		return 0, false
	}
	
	id, ok := userID.(uint)
	return id, ok
}

// GetCurrentUserRole 获取当前用户角色
func GetCurrentUserRole(c *gin.Context) (string, bool) {
	userRole, exists := c.Get("user_role")
	if !exists {
		return "", false
	}
	
	role, ok := userRole.(string)
	return role, ok
}

// GetCurrentUsername 获取当前用户名
func GetCurrentUsername(c *gin.Context) (string, bool) {
	username, exists := c.Get("username")
	if !exists {
		return "", false
	}
	
	name, ok := username.(string)
	return name, ok
}

// IsAuthenticated 检查是否已认证
func IsAuthenticated(c *gin.Context) bool {
	_, exists := c.Get("user_id")
	return exists
}

// IsAdmin 检查是否为管理员
func IsAdmin(c *gin.Context) bool {
	role, exists := GetCurrentUserRole(c)
	if !exists {
		return false
	}
	return role == string(entity.UserRoleAdmin)
}

// IsPhotographer 检查是否为摄影师或以上
func IsPhotographer(c *gin.Context) bool {
	role, exists := GetCurrentUserRole(c)
	if !exists {
		return false
	}
	return role == string(entity.UserRolePhotographer) || role == string(entity.UserRoleAdmin)
}

// hasPermission 检查权限
func (m *AuthMiddleware) hasPermission(userRole, requiredRole string) bool {
	roleLevel := map[string]int{
		string(entity.UserRoleUser):         1,
		string(entity.UserRolePhotographer): 2,
		string(entity.UserRoleAdmin):        3,
	}
	
	userLevel, exists := roleLevel[userRole]
	if !exists {
		return false
	}
	
	requiredLevel, exists := roleLevel[requiredRole]
	if !exists {
		return false
	}
	
	return userLevel >= requiredLevel
}