using Vector2 = Vector.Vector2I;
using System;
using System.Collections;
using static IBoard.IBoardOn;

namespace ChineseChess;

public class ChessCore {
    public enum Mode {
        SingleMode,
        MultiMode,
        DebugMode,
    };

    public enum TurnsSideType {
        Red,
        Black,
    };

    public enum PlayerSideType {
        Self,
        Opponent,
        Any,
    };

    private TurnsSideType sideType = TurnsSideType.Red;
    private readonly TurnsSideType selfSide;
    public readonly CCBoard board;
    private readonly Player playerSelf;
    private readonly Player playerOpponent;
    // public EventHandler<IBoard.MoveEventArgs> OnMove;
    public ChessCore(Mode mode, TurnsSideType selfSide, ICCBoardOn? boardOn = null) {
        this.selfSide = selfSide;
        board = new(boardOn);

        playerSelf = new(board, Player.PlayerType.Human);
        playerOpponent = new(board, Player.PlayerType.Human);

        void func(object? _self, MoveEventArgs record) {
            // 防止 Undo 时 Selected Clear 出现 Null Pointer Exception
            playerSelf.SelectedClear();
            playerOpponent.SelectedClear();

            // TODO FIXME it can be simple
            if (record.From is null || record.To is null) {
                return;
            }

            IPiece? from = record.From is not null ? board.GetPiece(record.From) : null;
            IPiece? to = record.To is not null ? board.GetPiece(record.To) : null; 
            board.AddRecord(from, to, record.From ?? new(), record.To ?? new());
        }
        playerSelf.OnMove += func;
        playerOpponent.OnMove += func;
        switch (mode) {
            case Mode.SingleMode:
                break;
            case Mode.MultiMode:
                break;
            default:
            case Mode.DebugMode:
                throw new NotImplementedException();
        }
    }

    public void Init() {
        (ArrayList blackPart, ArrayList redPart) = board.InitGame();
        if (selfSide == TurnsSideType.Red) {
            playerSelf.SetAllowedPieces(redPart);
            playerOpponent.SetAllowedPieces(blackPart);
        } else {
            playerSelf.SetAllowedPieces(blackPart);
            playerOpponent.SetAllowedPieces(redPart);
        }
    }

    public void OnPosClicked(Vector2 pos, PlayerSideType clickedSide = PlayerSideType.Any) {
        if (GetTurnsType() == selfSide) {
            playerSelf.CanMove = true;
            playerOpponent.CanMove = false;
        } else {
            playerSelf.CanMove = false;
            playerOpponent.CanMove = true;
        }

        switch (clickedSide) {
            case PlayerSideType.Any:
                playerSelf.HandleBoardPosClick(pos);
                playerOpponent.HandleBoardPosClick(pos);
                break;
            case PlayerSideType.Self:
                playerSelf.HandleBoardPosClick(pos);
                break;
            case PlayerSideType.Opponent:
                playerOpponent.HandleBoardPosClick(pos);
                break;
        }
    }

    public TurnsSideType GetTurnsType() {
        sideType = board.Steps % 2 == 0 ? TurnsSideType.Red : TurnsSideType.Black;
        return sideType;
    }

    public void Undo() {
		playerSelf.SelectedClear();
        playerOpponent.SelectedClear();
		board.UndoRecord();
	}

	public void ReInit() {
        playerSelf.SelectedClear();
        playerOpponent.SelectedClear();
		board.Clear(true);
        Init();
	}
}