package repository

import (
	"context"
	"time"

	"carrot_bbs/internal/dto"
	"carrot_bbs/internal/model"

	"gorm.io/gorm"
)

// LoginLogRepository 登录日志仓储接口
type LoginLogRepository interface {
	CreateLoginLog(ctx context.Context, log *model.LoginLog) error
	BatchCreateLoginLogs(ctx context.Context, logs []*model.LoginLog) error
	GetLoginLogs(ctx context.Context, filters dto.LoginFilter, page, pageSize int) ([]*model.LoginLog, int64, error)
	GetLoginLogsByUser(ctx context.Context, userID string, page, pageSize int) ([]*model.LoginLog, int64, error)
	GetFailedLoginsByIP(ctx context.Context, ip string, timeWindow time.Duration) (int64, error)
	GetRecentSuccessLogins(ctx context.Context, userID string, limit int) ([]*model.LoginLog, error)
	DeleteOldLogs(ctx context.Context, beforeDate string) error
	GetStatistics(ctx context.Context, startTime, endTime string) (*LoginLogStatistics, error)
}

// loginLogRepository 登录日志仓储实现
type loginLogRepository struct {
	db *gorm.DB
}

// NewLoginLogRepository 创建登录日志仓储
func NewLoginLogRepository(db *gorm.DB) LoginLogRepository {
	return &loginLogRepository{db: db}
}

// CreateLoginLog 创建单条登录日志
func (r *loginLogRepository) CreateLoginLog(ctx context.Context, log *model.LoginLog) error {
	return r.db.WithContext(ctx).Create(log).Error
}

// BatchCreateLoginLogs 批量创建登录日志
func (r *loginLogRepository) BatchCreateLoginLogs(ctx context.Context, logs []*model.LoginLog) error {
	if len(logs) == 0 {
		return nil
	}
	return r.db.WithContext(ctx).Create(logs).Error
}

// GetLoginLogs 获取登录日志列表（分页）
func (r *loginLogRepository) GetLoginLogs(ctx context.Context, filters dto.LoginFilter, page, pageSize int) ([]*model.LoginLog, int64, error) {
	query := r.db.WithContext(ctx).Model(&model.LoginLog{})

	if filters.UserID != "" {
		query = query.Where("user_id = ?", filters.UserID)
	}
	if filters.Event != "" {
		query = query.Where("event = ?", filters.Event)
	}
	if filters.Result != "" {
		query = query.Where("result = ?", filters.Result)
	}
	if filters.FailReason != "" {
		query = query.Where("fail_reason = ?", filters.FailReason)
	}
	if filters.LoginType != "" {
		query = query.Where("login_type = ?", filters.LoginType)
	}
	if !filters.StartTime.IsZero() {
		query = query.Where("created_at >= ?", filters.StartTime)
	}
	if !filters.EndTime.IsZero() {
		query = query.Where("created_at <= ?", filters.EndTime)
	}
	if filters.IP != "" {
		query = query.Where("ip = ?", filters.IP)
	}

	var total int64
	if err := query.Count(&total).Error; err != nil {
		return nil, 0, err
	}

	var logs []*model.LoginLog
	offset := (page - 1) * pageSize
	if err := query.Order("created_at DESC").Offset(offset).Limit(pageSize).Find(&logs).Error; err != nil {
		return nil, 0, err
	}

	return logs, total, nil
}

// GetLoginLogsByUser 获取指定用户的登录日志
func (r *loginLogRepository) GetLoginLogsByUser(ctx context.Context, userID string, page, pageSize int) ([]*model.LoginLog, int64, error) {
	return r.GetLoginLogs(ctx, dto.LoginFilter{UserID: userID}, page, pageSize)
}

// GetFailedLoginsByIP 获取指定IP的失败登录记录（用于风控）
func (r *loginLogRepository) GetFailedLoginsByIP(ctx context.Context, ip string, timeWindow time.Duration) (int64, error) {
	startTime := time.Now().Add(-timeWindow)
	var count int64
	err := r.db.WithContext(ctx).
		Model(&model.LoginLog{}).
		Where("ip = ? AND result = ? AND created_at >= ?", ip, string(model.LoginResultFail), startTime).
		Count(&count).Error
	return count, err
}

// GetRecentSuccessLogins 获取最近成功的登录记录
func (r *loginLogRepository) GetRecentSuccessLogins(ctx context.Context, userID string, limit int) ([]*model.LoginLog, error) {
	var logs []*model.LoginLog
	err := r.db.WithContext(ctx).
		Where("user_id = ? AND result = ? AND event = ?", userID, string(model.LoginResultSuccess), string(model.LoginEventLogin)).
		Order("created_at DESC").
		Limit(limit).
		Find(&logs).Error
	return logs, err
}

// DeleteOldLogs 删除旧的登录日志（用于定时清理）
func (r *loginLogRepository) DeleteOldLogs(ctx context.Context, beforeDate string) error {
	return r.db.WithContext(ctx).Where("created_at < ?", beforeDate).Delete(&model.LoginLog{}).Error
}

// GetStatistics 获取登录日志统计（使用单次 GROUP BY 查询，避免多次 COUNT）
func (r *loginLogRepository) GetStatistics(ctx context.Context, startTime, endTime string) (*LoginLogStatistics, error) {
	stats := &LoginLogStatistics{}

	query := r.db.WithContext(ctx).Model(&model.LoginLog{})
	if startTime != "" {
		query = query.Where("created_at >= ?", startTime)
	}
	if endTime != "" {
		query = query.Where("created_at <= ?", endTime)
	}

	// 使用单次 GROUP BY 查询获取 result 计数
	type resultCount struct {
		Result string
		Count  int64
	}
	var results []resultCount
	err := query.Select("result, count(*) as count").Group("result").Scan(&results).Error
	if err != nil {
		return nil, err
	}

	// 汇总结果
	for _, r := range results {
		stats.TotalCount += r.Count
		if r.Result == string(model.LoginResultSuccess) {
			stats.SuccessCount = r.Count
		} else if r.Result == string(model.LoginResultFail) {
			stats.FailCount = r.Count
		}
	}

	// 单独查询登录次数
	if startTime != "" || endTime != "" {
		loginQuery := r.db.WithContext(ctx).Model(&model.LoginLog{})
		if startTime != "" {
			loginQuery = loginQuery.Where("created_at >= ?", startTime)
		}
		if endTime != "" {
			loginQuery = loginQuery.Where("created_at <= ?", endTime)
		}
		loginQuery.Where("event = ?", string(model.LoginEventLogin)).Count(&stats.LoginCount)
	}

	return stats, nil
}

// LoginLogStatistics 登录日志统计
type LoginLogStatistics struct {
	TotalCount   int64
	SuccessCount int64
	FailCount    int64
	LoginCount   int64
}