cosinekitty/flywheel

A chess engine for the web browser

flywheel's Issues

When user presses Play button, computer should take over the current side.

Pressing the Play button should cause the computer to take over the player whose turn to move it is. Pressing Play should always make the current side be a computer player and the remaining side be a human player. When the computer is thinking, the Play button should change to a Pause button. If Pause is pressed, both players should revert to human players.

Using undo/redo buttons should set back to human-vs-human; otherwise computer will start thinking during undo/redo!

Support formatting a move as PGN

Given a board position and a legal move, generate the Portable Game Notation (PGN) string for it.

Search should allow callbacks to update UI with current best path

Client code (e.g. FlyWorker) should be able to pass callback function that receives updates with the current search status, including best path, node counters, etc. FlyWorker can in turn post messages back to the main thread for updating the UI.

Add function in Board class to generate Forsyth Edwards Notation (FEN) for the position.

Generate FEN for a given position.

Make it easier to cancel a move while piece is being dragged

After selecting the source square of a move, the demo must make it easier to cancel the move. One major problem is that currently, clicking back on the same source square does not cancel the move. Any illegal move, including source-source, should work to cancel the move! Also consider some other way to explicitly abort a move (press ESC? click on some cancel icon?)

Allow board to be initialized to an arbitrary position using FEN.

Initializing with FEN means the reported ply number is not the same as moveStack.length, so will need to fix all those existing assumptions first.
Ambiguity in NumTurnsPlayed() between how many moves can be popped (moveStack.length) and half-move clock for assessing draws.

When game ends, decorate the board with game status

When the game ends, the score (e.g. "1-0" or "1/2-1/2") should be superimposed on the board.

When moving pieces, the bitmap should move around with the mouse

After clicking on a piece or while dragging it, the piece bitmap should move around with the mouse. When dropped on a legal square, the piece should snap to that location. When moved to an illegal destination, the piece should sprite-slide back to its origin.

Make Board.CurrentPlayerCanMove() more efficient

Board.CurrentPlayerCanMove() currently generates a list of all legal moves just to find out whether there are any legal moves. Later, the AI will benefit greatly from a faster implementation that returns true after finding any legal move.

All exceptions should be derived from Error

No more throwing strings! Need to make all exceptions uniformly handled as nice error objects that hold stack traces, are classifiable by their types, etc.

Finish logic for timed search

Search should terminate within 10 milliseconds of time expiration, unless level 1 search has not yet completed, in which case it should be allowed to complete to find a decent move.

Should be able to select from time limit or search depth limit uniformly in either MateSearch or Search.

Choosing between time limit and max depth limit should be orthogonal to what kind of search is being performed (should be separate function calls).

Rotating the board while the computer is thinking causes exception

Repro steps:

1. Tell computer to think.
2. While it is thinking, rotate the board.
3. A couple of seconds after the computer moves, we get an exception:

• Uncaught TypeError: Cannot read property 'style' of undefined

It is in AnimateMove():

        var image = <HTMLElement> coords.source.squareDiv.children[0];
        image.style.position = 'absolute';

Allow cloning of moves and boards

To prevent unintended side-effects, it would be wise to avoid exposing any internal state in a mutable way to callers (at least ones that use TypeScript -- can't stop all the monkey-patchers out there). Moves pushed onto board.moveStack should be copies of the ones handed back to callers. Likewise, there needs to be a way to clone a chess board so that changes made to it have no effect on the original board object.

Prototype UI

Display board graphically.
Allow user to click, touch, or drag pieces to move them.
Prompt for promotion piece.
Reject illegal moves.
Provide command for letting the computer think.
Rotate board.

Demo needs to handle pawn promotion

When the user promotes a pawn in the demo, it should present a menu of 4 pieces (same color as the player): Queen, Rook, Bishop, Knight. User should click on one of these to choose the promotion piece, or a Cancel icon to abort the move. The mouse should start out positioned above the Queen option because it is the most likely choice.

Demo should allow moving pieces by dragging them

Currently the demo allows moving pieces only by single-clicking on the piece to be moved, then clicking on the target square. It should also allow moving pieces by dragging the piece (holding down the mouse and releasing it on the target square).

Unit tests: make big green or red pass/fail indicator at bottom

Make the unit tests unambiguously pass/fail with big green (pass) or red (fail) marker at bottom of screen. Maybe nice green check box or red X (for color-blind people).

Remove usage of jQuery in demo

Demo should use Vanilla JS only.

Demo computer player does not work on iPhone

Demo app loads on iPhone but when I press Play button, the computer never finishes its move. Should test using Safari on Mac also.

Eliminate forced-loss moves from top-level move list

If all top-level moves lead to a forced loss, pick whichever one postpones the loss the longest (has the best score) and terminate the search immediately.
Otherwise (if at least one move is not yet a forced loss), remove all forced-loss moves from the top-level move list to avoid re-thinking them at deeper levels.
Any time there is exactly one move remaining in the top-level list, immediately choose it. (This handles the case where there is exactly one legal move.)

PushNotation function should accept long algebraic or PGN

Will need to implement PGN generator first.

Animate computer's moves

When the computer makes a move, animate it. Afterward, leave the source and target squares subtly highlighted somehow (perhaps draw a border around them).

Detect all possible ways a chess game can end

Create a function board.GameResult() that returns data indicating whether the game is over. If so, it should also indicate whether White won, Black won, or the game is a draw. If the game is a draw, should indicate which kind of draw it is:

• stalemate
• threefold repetition
• 50-move rule
• insufficient material

Report history of game as an array of moves, algebraic text, or PGN text

Moves in the array should be cloned, to prevent unintended side-effects.