package service

import (
	"carrotskin/internal/model"
	"carrotskin/internal/repository"
	"context"
	"errors"
	"fmt"
	"strconv"
	"time"

	"github.com/google/uuid"
	"github.com/jackc/pgx/v5"
	"go.uber.org/zap"
)

// tokenServiceImpl TokenService的实现
type tokenServiceImpl struct {
	tokenRepo   repository.TokenRepository
	profileRepo repository.ProfileRepository
	logger      *zap.Logger
}

// NewTokenService 创建TokenService实例
func NewTokenService(
	tokenRepo repository.TokenRepository,
	profileRepo repository.ProfileRepository,
	logger *zap.Logger,
) TokenService {
	return &tokenServiceImpl{
		tokenRepo:   tokenRepo,
		profileRepo: profileRepo,
		logger:      logger,
	}
}

const (
	tokenExtendedTimeout = 10 * time.Second
	tokensMaxCount       = 10
)

func (s *tokenServiceImpl) Create(userID int64, UUID string, clientToken string) (*model.Profile, []*model.Profile, string, string, error) {
	var (
		selectedProfileID *model.Profile
		availableProfiles []*model.Profile
	)

	// 设置超时上下文
	_, cancel := context.WithTimeout(context.Background(), DefaultTimeout)
	defer cancel()

	// 验证用户存在
	if UUID != "" {
		_, err := s.profileRepo.FindByUUID(UUID)
		if err != nil {
			return selectedProfileID, availableProfiles, "", "", fmt.Errorf("获取用户信息失败: %w", err)
		}
	}

	// 生成令牌
	if clientToken == "" {
		clientToken = uuid.New().String()
	}

	accessToken := uuid.New().String()
	token := model.Token{
		AccessToken: accessToken,
		ClientToken: clientToken,
		UserID:      userID,
		Usable:      true,
		IssueDate:   time.Now(),
	}

	// 获取用户配置文件
	profiles, err := s.profileRepo.FindByUserID(userID)
	if err != nil {
		return selectedProfileID, availableProfiles, "", "", fmt.Errorf("获取用户配置文件失败: %w", err)
	}

	// 如果用户只有一个配置文件，自动选择
	if len(profiles) == 1 {
		selectedProfileID = profiles[0]
		token.ProfileId = selectedProfileID.UUID
	}
	availableProfiles = profiles

	// 插入令牌
	err = s.tokenRepo.Create(&token)
	if err != nil {
		return selectedProfileID, availableProfiles, "", "", fmt.Errorf("创建Token失败: %w", err)
	}

	// 清理多余的令牌
	go s.checkAndCleanupExcessTokens(userID)

	return selectedProfileID, availableProfiles, accessToken, clientToken, nil
}

func (s *tokenServiceImpl) Validate(accessToken, clientToken string) bool {
	if accessToken == "" {
		return false
	}

	token, err := s.tokenRepo.FindByAccessToken(accessToken)
	if err != nil {
		return false
	}

	if !token.Usable {
		return false
	}

	if clientToken == "" {
		return true
	}

	return token.ClientToken == clientToken
}

func (s *tokenServiceImpl) Refresh(accessToken, clientToken, selectedProfileID string) (string, string, error) {
	if accessToken == "" {
		return "", "", errors.New("accessToken不能为空")
	}

	// 查找旧令牌
	oldToken, err := s.tokenRepo.FindByAccessToken(accessToken)
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return "", "", errors.New("accessToken无效")
		}
		s.logger.Error("查询Token失败", zap.Error(err), zap.String("accessToken", accessToken))
		return "", "", fmt.Errorf("查询令牌失败: %w", err)
	}

	// 验证profile
	if selectedProfileID != "" {
		valid, validErr := s.validateProfileByUserID(oldToken.UserID, selectedProfileID)
		if validErr != nil {
			s.logger.Error("验证Profile失败",
				zap.Error(err),
				zap.Int64("userId", oldToken.UserID),
				zap.String("profileId", selectedProfileID),
			)
			return "", "", fmt.Errorf("验证角色失败: %w", err)
		}
		if !valid {
			return "", "", errors.New("角色与用户不匹配")
		}
	}

	// 检查 clientToken 是否有效
	if clientToken != "" && clientToken != oldToken.ClientToken {
		return "", "", errors.New("clientToken无效")
	}

	// 检查 selectedProfileID 的逻辑
	if selectedProfileID != "" {
		if oldToken.ProfileId != "" && oldToken.ProfileId != selectedProfileID {
			return "", "", errors.New("原令牌已绑定角色，无法选择新角色")
		}
	} else {
		selectedProfileID = oldToken.ProfileId
	}

	// 生成新令牌
	newAccessToken := uuid.New().String()
	newToken := model.Token{
		AccessToken: newAccessToken,
		ClientToken: oldToken.ClientToken,
		UserID:      oldToken.UserID,
		Usable:      true,
		ProfileId:   selectedProfileID,
		IssueDate:   time.Now(),
	}

	// 先插入新令牌，再删除旧令牌
	err = s.tokenRepo.Create(&newToken)
	if err != nil {
		s.logger.Error("创建新Token失败", zap.Error(err), zap.String("accessToken", accessToken))
		return "", "", fmt.Errorf("创建新Token失败: %w", err)
	}

	err = s.tokenRepo.DeleteByAccessToken(accessToken)
	if err != nil {
		s.logger.Warn("删除旧Token失败，但新Token已创建",
			zap.Error(err),
			zap.String("oldToken", oldToken.AccessToken),
			zap.String("newToken", newAccessToken),
		)
	}

	s.logger.Info("成功刷新Token", zap.Int64("userId", oldToken.UserID), zap.String("accessToken", newAccessToken))
	return newAccessToken, oldToken.ClientToken, nil
}

func (s *tokenServiceImpl) Invalidate(accessToken string) {
	if accessToken == "" {
		return
	}

	err := s.tokenRepo.DeleteByAccessToken(accessToken)
	if err != nil {
		s.logger.Error("删除Token失败", zap.Error(err), zap.String("accessToken", accessToken))
		return
	}
	s.logger.Info("成功删除Token", zap.String("token", accessToken))
}

func (s *tokenServiceImpl) InvalidateUserTokens(userID int64) {
	if userID == 0 {
		return
	}

	err := s.tokenRepo.DeleteByUserID(userID)
	if err != nil {
		s.logger.Error("删除用户Token失败", zap.Error(err), zap.Int64("userId", userID))
		return
	}

	s.logger.Info("成功删除用户Token", zap.Int64("userId", userID))
}

func (s *tokenServiceImpl) GetUUIDByAccessToken(accessToken string) (string, error) {
	return s.tokenRepo.GetUUIDByAccessToken(accessToken)
}

func (s *tokenServiceImpl) GetUserIDByAccessToken(accessToken string) (int64, error) {
	return s.tokenRepo.GetUserIDByAccessToken(accessToken)
}

// 私有辅助方法

func (s *tokenServiceImpl) checkAndCleanupExcessTokens(userID int64) {
	if userID == 0 {
		return
	}

	tokens, err := s.tokenRepo.GetByUserID(userID)
	if err != nil {
		s.logger.Error("获取用户Token失败", zap.Error(err), zap.String("userId", strconv.FormatInt(userID, 10)))
		return
	}

	if len(tokens) <= tokensMaxCount {
		return
	}

	tokensToDelete := make([]string, 0, len(tokens)-tokensMaxCount)
	for i := tokensMaxCount; i < len(tokens); i++ {
		tokensToDelete = append(tokensToDelete, tokens[i].AccessToken)
	}

	deletedCount, err := s.tokenRepo.BatchDelete(tokensToDelete)
	if err != nil {
		s.logger.Error("清理用户多余Token失败", zap.Error(err), zap.String("userId", strconv.FormatInt(userID, 10)))
		return
	}

	if deletedCount > 0 {
		s.logger.Info("成功清理用户多余Token", zap.Int64("userId", userID), zap.Int64("count", deletedCount))
	}
}

func (s *tokenServiceImpl) validateProfileByUserID(userID int64, UUID string) (bool, error) {
	if userID == 0 || UUID == "" {
		return false, errors.New("用户ID或配置文件ID不能为空")
	}

	profile, err := s.profileRepo.FindByUUID(UUID)
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return false, errors.New("配置文件不存在")
		}
		return false, fmt.Errorf("验证配置文件失败: %w", err)
	}
	return profile.UserID == userID, nil
}