package models

// A relation between two accounts
// There may be multiple relations from an account X to an account Y,
// each describing a different aspect
type UserToUserRelation struct {
	ID           uint64 `gorm:"primarykey"`
	User         User   // The user X described in [RelationType]
	UserId       string
	TargetUser   User // The user Y described in [RelationType]
	TargetUserId string
	Relation     string // `gorm:"type:relation_type"`
}

type IUserToUserRelation interface {
	// Get all inbox links for accounts following the user with the specified id
	//
	// SELECT u.inbox_link
	// FROM user_to_user_relations r
	// LEFT JOIN user_remote_links u
	// ON r.user_id = u.user_id
	// WHERE
	//   r.target_user_id = @id AND
	//   r.relation = 'follow'
	GetFollowerInboxesForId(id string) ([]string, error)

	// Get all Ids of the accounts following the user with the specified id
	//
	// SELECT u.ap_link
	// FROM user_to_user_relations r
	// LEFT JOIN user_remote_links u
	// ON r.user_id = u.user_id
	// WHERE
	//   r.target_user_id = @id AND
	//   r.relation = 'follow'
	// LIMIT 50
	// OFFSET @page * 50
	GetFollowerApLinksPagedForId(id string, page int) ([]string, error)

	// Get all Ids of the accounts followed by the user with the specified id
	//
	// SELECT u.ap_link
	// FROM user_to_user_relations r
	// LEFT JOIN user_remote_links u
	// ON r.user_id = u.user_id
	// WHERE
	//   r.user_id = @id AND
	//   r.relation = 'follow'
	// LIMIT 50
	// OFFSET @page * 50
	GetFollowingApLinksPagedForId(id string, page int) ([]string, error)

	// Count the accounts following the user with the specified id
	//
	// SELECT COUNT(*)
	// FROM user_to_user_relations r
	// WHERE
	//   r.target_user_id = @id AND
	//   r.relation = 'follow'
	CountFollowersForId(id string) (int, error)

	// Count the accounts following the user with the specified id
	//
	// SELECT COUNT(*)
	// FROM user_to_user_relations r
	// WHERE
	//   r.user_id = @id AND
	//   r.relation = 'follow'
	CountFollowingForId(id string) (int, error)

	// Get the ids of all local accounts following the user with the target id
	//
	// SELECT
	// r.user_id
	// FROM
	//   user_to_user_relations r
	//   LEFT JOIN users u ON r.user_id = u.id
	//   LEFT JOIN remote_servers s ON u.server_id = s.id
	// WHERE
	//   s.is_self = true
	//   AND r.target_user_id = @id;
	GetLocalFollowerIdsOfId(id string) ([]string, error)
}