package live

import (
	"context"
	"errors"

	"gorm.io/gorm"
	bizlive "kra/internal/biz/live"
)

type followPO struct {
	ID           uint  `gorm:"primaryKey"`
	UserID       uint  `gorm:"not null;uniqueIndex:idx_live_room_follow_user_room"`
	RoomID       uint  `gorm:"not null;uniqueIndex:idx_live_room_follow_user_room"`
	AnchorUserID uint  `gorm:"not null;index"`
	CreatedAt    int64 `gorm:"autoCreateTime:milli"`
}

func (followPO) TableName() string { return "live_room_follows" }

type followRepo struct{ data Provider }

func NewFollowRepo(data Provider) bizlive.FollowRepo { return &followRepo{data: data} }

func (r *followRepo) Get(ctx context.Context, userID, roomID uint) (*bizlive.Follow, error) {
	var row followPO
	err := r.db(ctx).Where("user_id = ? AND room_id = ?", userID, roomID).First(&row).Error
	if errors.Is(err, gorm.ErrRecordNotFound) {
		return nil, bizlive.ErrFollowNotFound
	}
	if err != nil {
		return nil, err
	}
	return followToBiz(&row), nil
}

func (r *followRepo) Create(ctx context.Context, item *bizlive.Follow) (*bizlive.Follow, error) {
	var room roomPO
	if err := r.db(ctx).First(&room, item.RoomID).Error; err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, bizlive.ErrRoomNotFound
		}
		return nil, err
	}
	item.AnchorUserID = room.AnchorUserID
	po := &followPO{UserID: item.UserID, RoomID: item.RoomID, AnchorUserID: item.AnchorUserID}
	if err := r.db(ctx).Create(po).Error; err != nil {
		if errors.Is(err, gorm.ErrDuplicatedKey) {
			return r.Get(ctx, item.UserID, item.RoomID)
		}
		return nil, err
	}
	return followToBiz(po), nil
}

func (r *followRepo) Delete(ctx context.Context, userID, roomID uint) error {
	result := r.db(ctx).Where("user_id = ? AND room_id = ?", userID, roomID).Delete(&followPO{})
	if result.Error != nil {
		return result.Error
	}
	if result.RowsAffected == 0 {
		return bizlive.ErrFollowNotFound
	}
	return nil
}

func (r *followRepo) db(ctx context.Context) *gorm.DB {
	if r == nil || r.data == nil || r.data.DB() == nil {
		return nil
	}
	return r.data.DB().WithContext(ctx)
}

func followToBiz(row *followPO) *bizlive.Follow {
	return &bizlive.Follow{ID: row.ID, UserID: row.UserID, RoomID: row.RoomID, AnchorUserID: row.AnchorUserID}
}