package middleware

import (
	"context"
	"fmt"
	"strings"

	"dubbo.apache.org/dubbo-go/v3/common/constant"
	"github.com/topfans/backend/pkg/jwt"
	"github.com/topfans/backend/pkg/logger"
	"go.uber.org/zap"
	"google.golang.org/grpc/metadata"
)

// Context Key 类型
type contextKey string

const (
	UserIDKey contextKey = "user_id"
	StarIDKey contextKey = "star_id"
)

// min 返回两个整数中的较小值
func min(a, b int) int {
	if a < b {
		return a
	}
	return b
}

// extractTokenFromMetadata 从 gRPC metadata 或 Dubbo attachments 中提取 Token
// 支持两种格式：
// 1. Authorization: Bearer <token>
// 2. authorization: <token>
func extractTokenFromMetadata(ctx context.Context) (string, error) {
	// 方案1: 尝试从 Dubbo attachments 中获取
	if attachments := ctx.Value(constant.AttachmentKey); attachments != nil {
		if attMap, ok := attachments.(map[string]interface{}); ok {
			logger.Logger.Debug("Found Dubbo attachments",
				zap.Any("attachments", attMap),
			)

			// 尝试获取 authorization（可能是字符串或字符串数组）
			if authValue, ok := attMap["authorization"]; ok && authValue != nil {
				var token string

				// 处理字符串类型
				if tokenStr, ok := authValue.(string); ok && tokenStr != "" {
					token = tokenStr
				} else if tokenArr, ok := authValue.([]string); ok && len(tokenArr) > 0 {
					// 处理字符串数组类型
					token = tokenArr[0]
				} else if tokenArrInterface, ok := authValue.([]interface{}); ok && len(tokenArrInterface) > 0 {
					// 处理 []interface{} 类型
					if tokenStr, ok := tokenArrInterface[0].(string); ok {
						token = tokenStr
					}
				}

				if token != "" {
					logger.Logger.Debug("Found token in Dubbo attachments (authorization)",
						zap.String("token_prefix", token[:min(20, len(token))]+"..."),
					)
					// 支持 "Bearer <token>" 格式
					if strings.HasPrefix(token, "Bearer ") {
						return strings.TrimPrefix(token, "Bearer "), nil
					}
					return token, nil
				}
			}

			// 尝试获取 Authorization（大写）
			if authValue, ok := attMap["Authorization"]; ok && authValue != nil {
				var token string

				if tokenStr, ok := authValue.(string); ok && tokenStr != "" {
					token = tokenStr
				} else if tokenArr, ok := authValue.([]string); ok && len(tokenArr) > 0 {
					token = tokenArr[0]
				} else if tokenArrInterface, ok := authValue.([]interface{}); ok && len(tokenArrInterface) > 0 {
					if tokenStr, ok := tokenArrInterface[0].(string); ok {
						token = tokenStr
					}
				}

				if token != "" {
					logger.Logger.Debug("Found token in Dubbo attachments (Authorization)",
						zap.String("token_prefix", token[:min(20, len(token))]+"..."),
					)
					if strings.HasPrefix(token, "Bearer ") {
						return strings.TrimPrefix(token, "Bearer "), nil
					}
					return token, nil
				}
			}
		}
	}

	// 方案2: 尝试从 gRPC metadata 中获取
	md, ok := metadata.FromIncomingContext(ctx)
	if ok {
		logger.Logger.Debug("Found gRPC metadata",
			zap.Any("keys", md),
		)

		// 尝试从 "authorization" 字段获取
		authHeaders := md.Get("authorization")
		if len(authHeaders) == 0 {
			// 尝试从 "Authorization" 字段获取（大写）
			authHeaders = md.Get("Authorization")
		}

		if len(authHeaders) > 0 {
			authHeader := authHeaders[0]
			logger.Logger.Debug("Found token in gRPC metadata",
				zap.String("token_prefix", authHeader[:20]+"..."),
			)

			// 支持 "Bearer <token>" 格式
			if strings.HasPrefix(authHeader, "Bearer ") {
				return strings.TrimPrefix(authHeader, "Bearer "), nil
			}

			// 直接返回 token
			return authHeader, nil
		}
	}

	logger.Logger.Warn("Token not found in context",
		zap.Bool("has_metadata", ok),
		zap.Any("attachments", ctx.Value(constant.AttachmentKey)),
	)
	return "", fmt.Errorf("authorization token not found in context")
}

// ExtractUserIDFromContext 从 Context 中提取 user_id
func ExtractUserIDFromContext(ctx context.Context) (int64, error) {
	userID, ok := ctx.Value(UserIDKey).(int64)
	if !ok {
		return 0, fmt.Errorf("user_id not found in context")
	}
	return userID, nil
}

// ExtractStarIDFromContext 从 Context 中提取 star_id
func ExtractStarIDFromContext(ctx context.Context) (int64, error) {
	starID, ok := ctx.Value(StarIDKey).(int64)
	if !ok {
		return 0, fmt.Errorf("star_id not found in context")
	}
	return starID, nil
}

// ExtractUserInfoFromContext 从 Context 中提取 user_id 和 star_id
func ExtractUserInfoFromContext(ctx context.Context) (int64, int64, error) {
	userID, err := ExtractUserIDFromContext(ctx)
	if err != nil {
		return 0, 0, err
	}

	starID, err := ExtractStarIDFromContext(ctx)
	if err != nil {
		return 0, 0, err
	}

	return userID, starID, nil
}

// ValidateTokenAndExtractClaims 验证 Token 并提取用户信息到 Context
// 这是一个辅助函数，用于在 Provider 方法中手动验证 Token
func ValidateTokenAndExtractClaims(ctx context.Context) (context.Context, error) {
	// 从 metadata 中提取 Token
	token, err := extractTokenFromMetadata(ctx)
	if err != nil {
		logger.Logger.Warn("Failed to extract token from metadata",
			zap.Error(err),
		)
		return ctx, fmt.Errorf("missing or invalid authorization token")
	}

	// 验证 Token 并提取用户信息
	claims, err := jwt.ParseToken(token)
	if err != nil {
		logger.Logger.Warn("Failed to parse token",
			zap.Error(err),
		)
		return ctx, fmt.Errorf("invalid token")
	}

	// 将用户信息注入到 Context
	ctx = context.WithValue(ctx, UserIDKey, claims.UserID)
	ctx = context.WithValue(ctx, StarIDKey, claims.StarID)

	logger.Logger.Debug("Token validated successfully",
		zap.Int64("user_id", claims.UserID),
		zap.Int64("star_id", claims.StarID),
	)

	return ctx, nil
}