package esmedia

import (
	"fmt"
	"time"

	"91porn-server/common/elastic"
	"91porn-server/common/log"
	"91porn-server/models/s/statrecordmod"
	"91porn-server/models/v/mediamod"
	"91porn-server/skd/skdg"

	"go.mongodb.org/mongo-driver/bson/primitive"
)

var es *elastic.Client

func RunSync(defaultDate time.Time) {
	es = skdg.VideoES
	log.Info("Elastic Search ACG media sync start...")
	defer log.Info("Elastic Search ACG media sync end.")
	// MongoDB 日期精度为毫秒；本轮开始后的修改必须留给下一轮再次同步。
	startedAt := time.Now().Truncate(time.Millisecond)
	lastSyncAt, err := statrecordmod.LastRecordTime(statrecordmod.ElasticSyncMediaJob, defaultDate)
	if err != nil {
		log.Error("Elastic sync ACG media get last record time failed", log.E(err))
		return
	}
	if !startedAt.After(lastSyncAt) {
		return
	}
	// 固定 ID 上界，避免持续新增数据使本轮无法结束。
	maxID, err := mediamod.GetLatestIDForESSync()
	if err != nil {
		log.Error("Elastic sync ACG media get latest ID failed", log.E(err))
		return
	}
	sync := mediaSync{
		read:  mediamod.GetListForESSync,
		write: SyncDataToES,
		checkpoint: func(at time.Time) error {
			return statrecordmod.UpsertOneTrans(nil, statrecordmod.ElasticSyncMediaJob, at)
		},
	}
	if err = sync.run(lastSyncAt, startedAt, maxID); err != nil {
		log.Error("Elastic sync ACG media failed; checkpoint not confirmed", log.E(err))
	}
}

type mediaSync struct {
	read       func(time.Time, primitive.ObjectID, primitive.ObjectID, int) ([]*mediamod.Media, error)
	write      func([]*mediamod.Media) error
	checkpoint func(time.Time) error
}

func (s mediaSync) run(since, startedAt time.Time, maxID primitive.ObjectID) error {
	const size = 1000
	var after primitive.ObjectID
	for !maxID.IsZero() {
		data, err := s.read(since, after, maxID, size)
		if err != nil {
			return fmt.Errorf("read media batch: %w", err)
		}
		if len(data) == 0 {
			break
		}
		if err = s.write(data); err != nil {
			return fmt.Errorf("write media batch: %w", err)
		}
		after = data[len(data)-1].ID
		if len(data) < size || after == maxID {
			break
		}
	}
	// 所有批次及每条 ES 写入均成功后才推进；失败时下一轮从原进度幂等重试。
	if err := s.checkpoint(startedAt); err != nil {
		return fmt.Errorf("save media checkpoint: %w", err)
	}
	return nil
}