package dao

import (
	"time"

	"gorm.io/datatypes"
	"gorm.io/gorm"
	"gorm.io/gorm/clause"
)

// AnalyticsEvent 数据埋点事件表
type AnalyticsEvent struct {
	ID         int64          `gorm:"bigint;primaryKey;autoIncrement;column:id;comment:主键ID" json:"id"`
	UserID     int64          `gorm:"column:user_id;not null;index:idx_user_id;comment:用户ID" json:"user_id"`
	EventName  string         `gorm:"column:event_name;varchar(128);not null;index:idx_event_name;comment:事件名称" json:"event_name"`
	Properties datatypes.JSON `gorm:"column:properties;type:json;comment:事件属性(JSON)" json:"properties"`
	DeviceInfo datatypes.JSON `gorm:"column:device_info;type:json;comment:设备信息(JSON)" json:"device_info"`
	MetaData   datatypes.JSON `gorm:"column:meta_data;type:json;comment:元数据(JSON，包含task_id等)" json:"meta_data"`
	CreatedAt  time.Time      `gorm:"column:created_at;comment:创建时间;not null;default:current_timestamp;index:idx_created_at" json:"created_at"`
}

func (e *AnalyticsEvent) TableName() string {
	return "analytics_events"
}

// AnalyticsEventDao 数据埋点事件DAO
type AnalyticsEventDao struct{}

func NewAnalyticsEventDao() *AnalyticsEventDao {
	return &AnalyticsEventDao{}
}

// Create 创建事件记录
func (dao *AnalyticsEventDao) Create(tx *gorm.DB, event *AnalyticsEvent) error {
	return tx.Create(event).Error
}

// BatchCreate 批量创建事件记录
func (dao *AnalyticsEventDao) BatchCreate(tx *gorm.DB, events []*AnalyticsEvent) error {
	if len(events) == 0 {
		return nil
	}
	return tx.CreateInBatches(events, 100).Error
}

// GetByID 根据ID获取事件
func (dao *AnalyticsEventDao) GetByID(tx *gorm.DB, id int64) (*AnalyticsEvent, error) {
	event := &AnalyticsEvent{}
	err := tx.Where("id = ?", id).First(event).Error
	if err != nil {
		if err == gorm.ErrRecordNotFound {
			return nil, nil
		}
		return nil, err
	}
	return event, nil
}

// GetUserEvents 获取用户的事件列表
func (dao *AnalyticsEventDao) GetUserEvents(tx *gorm.DB, userID int64, page, pageSize int) ([]*AnalyticsEvent, int64, error) {
	var events []*AnalyticsEvent
	var total int64

	offset := (page - 1) * pageSize
	query := tx.Model(&AnalyticsEvent{}).Where("user_id = ?", userID)

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

	err = query.Offset(offset).Limit(pageSize).
		Order(clause.OrderByColumn{Column: clause.Column{Name: "created_at"}, Desc: true}).
		Find(&events).Error

	return events, total, err
}

// GetEventsByName 根据事件名称获取事件列表
func (dao *AnalyticsEventDao) GetEventsByName(tx *gorm.DB, eventName string, page, pageSize int) ([]*AnalyticsEvent, int64, error) {
	var events []*AnalyticsEvent
	var total int64

	offset := (page - 1) * pageSize
	query := tx.Model(&AnalyticsEvent{}).Where("event_name = ?", eventName)

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

	err = query.Offset(offset).Limit(pageSize).
		Order(clause.OrderByColumn{Column: clause.Column{Name: "created_at"}, Desc: true}).
		Find(&events).Error

	return events, total, err
}

// GetUserEventsByName 获取用户指定事件的列表
func (dao *AnalyticsEventDao) GetUserEventsByName(tx *gorm.DB, userID int64, eventName string, page, pageSize int) ([]*AnalyticsEvent, int64, error) {
	var events []*AnalyticsEvent
	var total int64

	offset := (page - 1) * pageSize
	query := tx.Model(&AnalyticsEvent{}).Where("user_id = ? AND event_name = ?", userID, eventName)

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

	err = query.Offset(offset).Limit(pageSize).
		Order(clause.OrderByColumn{Column: clause.Column{Name: "created_at"}, Desc: true}).
		Find(&events).Error

	return events, total, err
}

// GetEventsByTimeRange 根据时间范围获取事件列表
func (dao *AnalyticsEventDao) GetEventsByTimeRange(tx *gorm.DB, startTime, endTime time.Time, page, pageSize int) ([]*AnalyticsEvent, int64, error) {
	var events []*AnalyticsEvent
	var total int64

	offset := (page - 1) * pageSize
	query := tx.Model(&AnalyticsEvent{}).Where("created_at BETWEEN ? AND ?", startTime, endTime)

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

	err = query.Offset(offset).Limit(pageSize).
		Order(clause.OrderByColumn{Column: clause.Column{Name: "created_at"}, Desc: true}).
		Find(&events).Error

	return events, total, err
}

// CountEventsByName 统计指定事件的数量
func (dao *AnalyticsEventDao) CountEventsByName(tx *gorm.DB, eventName string) (int64, error) {
	var count int64
	err := tx.Model(&AnalyticsEvent{}).Where("event_name = ?", eventName).Count(&count).Error
	return count, err
}

// CountUserEvents 统计用户的事件数量
func (dao *AnalyticsEventDao) CountUserEvents(tx *gorm.DB, userID int64) (int64, error) {
	var count int64
	err := tx.Model(&AnalyticsEvent{}).Where("user_id = ?", userID).Count(&count).Error
	return count, err
}

// GetEventStats 获取事件统计信息（按事件名称分组）
func (dao *AnalyticsEventDao) GetEventStats(tx *gorm.DB, startTime, endTime time.Time) ([]map[string]interface{}, error) {
	var results []map[string]interface{}

	err := tx.Model(&AnalyticsEvent{}).
		Select("event_name, COUNT(*) as count, COUNT(DISTINCT user_id) as unique_users").
		Where("created_at BETWEEN ? AND ?", startTime, endTime).
		Group("event_name").
		Order("count DESC").
		Find(&results).Error

	return results, err
}

// DeleteOldEvents 删除旧事件（数据清理）
func (dao *AnalyticsEventDao) DeleteOldEvents(tx *gorm.DB, beforeTime time.Time) error {
	return tx.Where("created_at < ?", beforeTime).Delete(&AnalyticsEvent{}).Error
}