package hashid

import (
	"context"
	"joybuywork/internal/app"
	"joybuywork/internal/consts/ckey"
	"fmt"
	"gorm.io/gen/field"
	"time"
)

type IDbId interface {
	TableName() string
	GetFieldByName(fieldName string) (field.OrderExpr, bool)
}

// IncrDbId 借助redis来做自增主键
func IncrDbId(ctx context.Context, table IDbId, pks ...string) (id int64, err error) {
	key := fmt.Sprintf("joybuywork:dbid:%s", table.TableName())
	defer func() {
		if err != nil {
			return
		}
		id, err = app.Redis.Incr(ctx, key)
	}()

	exist, _ := app.Redis.Exists(ctx, key)
	if exist {
		return
	}

	lc := app.NewFollower(ctx, ckey.ForLock(key)).Lock()
	defer lc.Release()
	if lc.Error() != nil {
		err = lc.Error()
		return
	}

	exist, _ = app.Redis.Exists(ctx, key)
	if exist {
		return
	}

	var MaxId struct {
		Id int64 `json:"id"`
	}

	var pkField = "id"
	for _, pk := range pks {
		_, ok := table.GetFieldByName(pk)
		if ok {
			pkField = pk
			break
		}
	}

	err = app.DB.Client.WithContext(ctx).Table(table.TableName()).Select(fmt.Sprintf("MAX(%s) as id", pkField)).Scan(&MaxId).Error
	if err != nil {
		return
	}

	err = app.Redis.Cache.IncrBy(ctx, key, MaxId.Id).Err()
	app.Redis.Cache.ExpireAt(ctx, key, time.Now().AddDate(0, 6, 0))
	return
}