package middleware

import (
	"errors"
	"log"
	"strings"

	"github.com/Wei-Shaw/sub2api/internal/config"
	"github.com/Wei-Shaw/sub2api/internal/service"

	"github.com/gin-gonic/gin"
)

// NewAPIKeyAuthMiddleware 创建 API Key 认证中间件
func NewAPIKeyAuthMiddleware(apiKeyService *service.APIKeyService, subscriptionService *service.SubscriptionService, cfg *config.Config, opsService *service.OpsService) APIKeyAuthMiddleware {
	return APIKeyAuthMiddleware(apiKeyAuthWithSubscription(apiKeyService, subscriptionService, cfg, opsService))
}

// apiKeyAuthWithSubscription API Key认证中间件（支持订阅验证）
func apiKeyAuthWithSubscription(apiKeyService *service.APIKeyService, subscriptionService *service.SubscriptionService, cfg *config.Config, opsService *service.OpsService) gin.HandlerFunc {
	return func(c *gin.Context) {
		// 尝试从Authorization header中提取API key (Bearer scheme)
		authHeader := c.GetHeader("Authorization")
		var apiKeyString string

		if authHeader != "" {
			// 验证Bearer scheme
			parts := strings.SplitN(authHeader, " ", 2)
			if len(parts) == 2 && parts[0] == "Bearer" {
				apiKeyString = parts[1]
			}
		}

		// 如果Authorization header中没有，尝试从x-api-key header中提取
		if apiKeyString == "" {
			apiKeyString = c.GetHeader("x-api-key")
		}

		// 如果x-api-key header中没有，尝试从x-goog-api-key header中提取（Gemini CLI兼容）
		if apiKeyString == "" {
			apiKeyString = c.GetHeader("x-goog-api-key")
		}

		// 如果header中没有，尝试从query参数中提取（Google API key风格）
		if apiKeyString == "" {
			apiKeyString = c.Query("key")
		}

		// 兼容常见别名
		if apiKeyString == "" {
			apiKeyString = c.Query("api_key")
		}

		// 如果所有header都没有API key
		if apiKeyString == "" {
			recordOpsAuthError(c, opsService, nil, 401, "API key is required in Authorization header (Bearer scheme), x-api-key header, x-goog-api-key header, or key/api_key query parameter")
			AbortWithError(c, 401, "API_KEY_REQUIRED", "API key is required in Authorization header (Bearer scheme), x-api-key header, x-goog-api-key header, or key/api_key query parameter")
			return
		}

		// 从数据库验证API key
		apiKey, err := apiKeyService.GetByKey(c.Request.Context(), apiKeyString)
		if err != nil {
			if errors.Is(err, service.ErrAPIKeyNotFound) {
				recordOpsAuthError(c, opsService, nil, 401, "Invalid API key")
				AbortWithError(c, 401, "INVALID_API_KEY", "Invalid API key")
				return
			}
			recordOpsAuthError(c, opsService, nil, 500, "Failed to validate API key")
			AbortWithError(c, 500, "INTERNAL_ERROR", "Failed to validate API key")
			return
		}

		// 检查API key是否激活
		if !apiKey.IsActive() {
			recordOpsAuthError(c, opsService, apiKey, 401, "API key is disabled")
			AbortWithError(c, 401, "API_KEY_DISABLED", "API key is disabled")
			return
		}

		// 检查关联的用户
		if apiKey.User == nil {
			recordOpsAuthError(c, opsService, apiKey, 401, "User associated with API key not found")
			AbortWithError(c, 401, "USER_NOT_FOUND", "User associated with API key not found")
			return
		}

		// 检查用户状态
		if !apiKey.User.IsActive() {
			recordOpsAuthError(c, opsService, apiKey, 401, "User account is not active")
			AbortWithError(c, 401, "USER_INACTIVE", "User account is not active")
			return
		}

		if cfg.RunMode == config.RunModeSimple {
			// 简易模式：跳过余额和订阅检查，但仍需设置必要的上下文
			c.Set(string(ContextKeyAPIKey), apiKey)
			c.Set(string(ContextKeyUser), AuthSubject{
				UserID:      apiKey.User.ID,
				Concurrency: apiKey.User.Concurrency,
			})
			c.Set(string(ContextKeyUserRole), apiKey.User.Role)
			c.Next()
			return
		}

		// 判断计费方式：订阅模式 vs 余额模式
		isSubscriptionType := apiKey.Group != nil && apiKey.Group.IsSubscriptionType()

		if isSubscriptionType && subscriptionService != nil {
			// 订阅模式：验证订阅
			subscription, err := subscriptionService.GetActiveSubscription(
				c.Request.Context(),
				apiKey.User.ID,
				apiKey.Group.ID,
			)
			if err != nil {
				recordOpsAuthError(c, opsService, apiKey, 403, "No active subscription found for this group")
				AbortWithError(c, 403, "SUBSCRIPTION_NOT_FOUND", "No active subscription found for this group")
				return
			}

			// 验证订阅状态（是否过期、暂停等）
			if err := subscriptionService.ValidateSubscription(c.Request.Context(), subscription); err != nil {
				recordOpsAuthError(c, opsService, apiKey, 403, err.Error())
				AbortWithError(c, 403, "SUBSCRIPTION_INVALID", err.Error())
				return
			}

			// 激活滑动窗口（首次使用时）
			if err := subscriptionService.CheckAndActivateWindow(c.Request.Context(), subscription); err != nil {
				log.Printf("Failed to activate subscription windows: %v", err)
			}

			// 检查并重置过期窗口
			if err := subscriptionService.CheckAndResetWindows(c.Request.Context(), subscription); err != nil {
				log.Printf("Failed to reset subscription windows: %v", err)
			}

			// 预检查用量限制（使用0作为额外费用进行预检查）
			if err := subscriptionService.CheckUsageLimits(c.Request.Context(), subscription, apiKey.Group, 0); err != nil {
				recordOpsAuthError(c, opsService, apiKey, 429, err.Error())
				AbortWithError(c, 429, "USAGE_LIMIT_EXCEEDED", err.Error())
				return
			}

			// 将订阅信息存入上下文
			c.Set(string(ContextKeySubscription), subscription)
		} else {
			// 余额模式：检查用户余额
			if apiKey.User.Balance <= 0 {
				recordOpsAuthError(c, opsService, apiKey, 403, "Insufficient account balance")
				AbortWithError(c, 403, "INSUFFICIENT_BALANCE", "Insufficient account balance")
				return
			}
		}

		// 将API key和用户信息存入上下文
		c.Set(string(ContextKeyAPIKey), apiKey)
		c.Set(string(ContextKeyUser), AuthSubject{
			UserID:      apiKey.User.ID,
			Concurrency: apiKey.User.Concurrency,
		})
		c.Set(string(ContextKeyUserRole), apiKey.User.Role)

		c.Next()
	}
}

func recordOpsAuthError(c *gin.Context, opsService *service.OpsService, apiKey *service.APIKey, status int, message string) {
	if opsService == nil || c == nil {
		return
	}

	errType := "authentication_error"
	phase := "auth"
	severity := "P3"
	switch status {
	case 403:
		errType = "billing_error"
		phase = "billing"
	case 429:
		errType = "rate_limit_error"
		phase = "billing"
		severity = "P2"
	case 500:
		errType = "api_error"
		phase = "internal"
		severity = "P1"
	}

	logEntry := &service.OpsErrorLog{
		Phase:      phase,
		Type:       errType,
		Severity:   severity,
		StatusCode: status,
		Message:    message,
		ClientIP:   c.ClientIP(),
		RequestPath: func() string {
			if c.Request != nil && c.Request.URL != nil {
				return c.Request.URL.Path
			}
			return ""
		}(),
	}

	if apiKey != nil {
		logEntry.APIKeyID = &apiKey.ID
		if apiKey.User != nil {
			logEntry.UserID = &apiKey.User.ID
		}
		if apiKey.GroupID != nil {
			logEntry.GroupID = apiKey.GroupID
		}
		if apiKey.Group != nil {
			logEntry.Platform = apiKey.Group.Platform
		}
	}

	enqueueOpsAuthErrorLog(opsService, logEntry)
}

// GetAPIKeyFromContext 从上下文中获取API key
func GetAPIKeyFromContext(c *gin.Context) (*service.APIKey, bool) {
	value, exists := c.Get(string(ContextKeyAPIKey))
	if !exists {
		return nil, false
	}
	apiKey, ok := value.(*service.APIKey)
	return apiKey, ok
}

// GetSubscriptionFromContext 从上下文中获取订阅信息
func GetSubscriptionFromContext(c *gin.Context) (*service.UserSubscription, bool) {
	value, exists := c.Get(string(ContextKeySubscription))
	if !exists {
		return nil, false
	}
	subscription, ok := value.(*service.UserSubscription)
	return subscription, ok
}
