tile-game-reducer-sliding-puzzle.js

const initialState = {
    moves: 0,
    gameComplete: false,
    imageNumber: 1,
    tiles: [],
    size: undefined,
    gameId: undefined,
    gameName: undefined
};


// The reducer for the game
// The state is an object with game state and an array of tiles
// A tile is a number 1-N and the blank tile is represented by 0
function tileGame(state = initialState, action) {
    switch (action.type) {
        case INIT_GAME: {
            return Object.assign({}, initialState, {
                gameId: action.gameId,
                size: gameConfigs[action.gameId].size,
                gameName: gameConfigs[action.gameId].name,
                imageNumber: action.imageNumber,
                tiles: generateTileSet(gameConfigs[action.gameId].size, action.doShuffling)
            });
        }

        case MOVE_TILE: {
            if (action.id === 0) {
                // selected blank tile
                return state;
            }
            if (state.gameComplete) {
                return state;
            }
            if (action.id < 0 || action.id > (state.size * state.size - 1)) {
                return state;
            }

            if (!hasEmptyTileOnSides(state.size, action.id, state.tiles)) {
                return state;
            }

            //
            // Move the tile
            //
            const newTiles = state.tiles.map(t => t);
            const setWithSwappedTiles = swapTilesInSet(newTiles, 0, action.id);

            //
            // Check result
            //
            const gameComplete = allTilesAreAligned(setWithSwappedTiles);
            return Object.assign({}, state, {
                gameComplete,
                moves: state.moves + 1,
                tiles: setWithSwappedTiles
            });
        }

        default:
            return state;
    }
}

export default tileGame;