package mediamod

import (
	"time"

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

type moduleLatestContentAt struct {
	ModuleID             primitive.ObjectID `bson:"_id"`
	LatestCreatedAt      time.Time          `bson:"latestCreatedAt"`
	LatestContentUpdated time.Time          `bson:"latestContentUpdated"`
}

// LatestContentAtByModules 返回动漫、漫画等媒体亚模块最近一次新增或子集更新时间。
func LatestContentAtByModules(moduleIDs []primitive.ObjectID) (map[string]time.Time, error) {
	result := make(map[string]time.Time, len(moduleIDs))
	if len(moduleIDs) == 0 {
		return result, nil
	}
	pipeline := []bson.M{
		{"$match": bson.M{
			"status":   1,
			"isDelete": false,
			"mId":      bson.M{"$in": moduleIDs},
		}},
		{"$group": bson.M{
			"_id":                  "$mId",
			"latestCreatedAt":      bson.M{"$max": "$createdAt"},
			"latestContentUpdated": bson.M{"$max": "$contentUpdateTime"},
		}},
	}
	var rows []moduleLatestContentAt
	if err := coll(nil).Aggregate(&rows, pipeline); err != nil {
		return nil, err
	}
	for _, row := range rows {
		latest := row.LatestCreatedAt
		if row.LatestContentUpdated.After(latest) {
			latest = row.LatestContentUpdated
		}
		if !row.ModuleID.IsZero() && !latest.IsZero() {
			result[row.ModuleID.Hex()] = latest
		}
	}
	return result, nil
}