import Foundation

final class TableManagement {

    /// A list of table ids for public games
    private var publicTables = Set<TableId>()

    /// A mapping from table id to table name (for all tables)
    private var tableNames = [TableId: TableName]()

    /// A mapping from table id to participating players
    private var tablePlayers = [TableId: [PlayerName]]()

    /// A reverse list of players and their table id
    private var playerTables = [PlayerName: TableId]()

    init() {
        
    }

    func tableExists(withId id: TableId) -> Bool {
        tableNames[id] != nil
    }

    func tableIsFull(withId id: TableId) -> Bool {
        (tablePlayers[id]?.count ?? playerPerTable) < playerPerTable
    }

    /**
     Create a new table with optional players.
     - Parameter name: The name of the table
     - Parameter players: The player creating the table
     - Parameter visible: Indicates that this is a game joinable by everyone
     - Returns: The table id
     */
    func createTable(named name: TableName, player: PlayerName, visible: Bool) -> TableId {
        let tableId = TableId.newToken()

        tableNames[tableId] = name
        tablePlayers[tableId] = [player]
        playerTables[player] = tableId

        if visible {
            publicTables.insert(tableId)
        }
        return tableId
    }

    func getPublicTableInfos() -> [TableInfo] {
        publicTables.map { tableId in
            TableInfo(id: tableId, name: tableNames[tableId]!, players: tablePlayers[tableId]!)
        }.sorted()
    }

    /**
     Join a table.
     - Returns: The player names present at the table
     */
    func join(tableId: TableId, player: PlayerName) -> [PlayerName] {
        guard var players = tablePlayers[tableId] else {
            return []
        }
        players.append(player)
        if let oldTable = playerTables[tableId] {
            remove(player: player, fromTable: oldTable)
        }
        tablePlayers[tableId] = players
        playerTables[tableId] = tableId
        return players
    }

    func remove(player: PlayerName, fromTable tableId: TableId) {
        tablePlayers[tableId] = tablePlayers[tableId]?.filter { $0 != player }
    }
}