import {createGameCommandRegistry, Part, Entity, entity, RegionEntity} from '@/index';

const BOARD_SIZE = 6;
const MAX_PIECES_PER_PLAYER = 8;
const WIN_LENGTH = 3;

const DIRECTIONS = [
    [-1, -1], [-1, 0], [-1, 1],
    [0, -1],           [0, 1],
    [1, -1],  [1, 0],  [1, 1],
];

export type PlayerType = 'white' | 'black';
export type PieceType = 'kitten' | 'cat';
export type WinnerType = PlayerType | 'draw' | null;

type BoopPart = Part & { player: PlayerType; pieceType: PieceType };

export function createInitialState() {
    return {
        board: new RegionEntity('board', {
            id: 'board',
            axes: [
                { name: 'x', min: 0, max: BOARD_SIZE - 1 },
                { name: 'y', min: 0, max: BOARD_SIZE - 1 },
            ],
            children: [],
        }),
        parts: [] as Entity<BoopPart>[],
        currentPlayer: 'white' as PlayerType,
        winner: null as WinnerType,
        whiteKittensInSupply: MAX_PIECES_PER_PLAYER,
        blackKittensInSupply: MAX_PIECES_PER_PLAYER,
        whiteCatsInSupply: 0,
        blackCatsInSupply: 0,
    };
}
export type BoopState = ReturnType<typeof createInitialState>;
const registration = createGameCommandRegistry<BoopState>();
export const registry = registration.registry;

registration.add('setup', async function() {
    const {context} = this;
    while (true) {
        const currentPlayer = context.value.currentPlayer;
        const turnOutput = await this.run<{winner: WinnerType}>(`turn ${currentPlayer}`);
        if (!turnOutput.success) throw new Error(turnOutput.error);

        context.produce(state => {
            state.winner = turnOutput.result.winner;
            if (!state.winner) {
                state.currentPlayer = state.currentPlayer === 'white' ? 'black' : 'white';
            }
        });
        if (context.value.winner) break;
    }

    return context.value;
});

registration.add('turn <player>', async function(cmd) {
    const [turnPlayer] = cmd.params as [PlayerType];
    const maxRetries = 50;
    let retries = 0;

    while (retries < maxRetries) {
        retries++;
        const playCmd = await this.prompt('play <player> <row:number> <col:number>');
        const [player, row, col] = playCmd.params as [PlayerType, number, number];

        if (player !== turnPlayer) continue;
        if (!isValidMove(row, col)) continue;
        if (isCellOccupied(this.context, row, col)) continue;

        const state = this.context.value;
        const kittensInSupply = player === 'white' ? state.whiteKittensInSupply : state.blackKittensInSupply;
        if (kittensInSupply <= 0) continue;

        placeKitten(this.context, row, col, turnPlayer);
        applyBoops(this.context, row, col, 'kitten');

        const graduatedRows = checkGraduation(this.context, turnPlayer);
        if (graduatedRows.length > 0) {
            processGraduation(this.context, turnPlayer, graduatedRows);
        }

        const winner = checkWinner(this.context);
        if (winner) return { winner };

        return { winner: null };
    }

    throw new Error('Too many invalid attempts');
});

function isValidMove(row: number, col: number): boolean {
    return !isNaN(row) && !isNaN(col) && row >= 0 && row < BOARD_SIZE && col >= 0 && col < BOARD_SIZE;
}

export function getBoardRegion(host: Entity<BoopState>) {
    return host.value.board;
}

export function isCellOccupied(host: Entity<BoopState>, row: number, col: number): boolean {
    const board = getBoardRegion(host);
    return board.partsMap.value[`${row},${col}`] !== undefined;
}

export function getPartAt(host: Entity<BoopState>, row: number, col: number): Entity<BoopPart> | null {
    const board = getBoardRegion(host);
    return (board.partsMap.value[`${row},${col}`] as Entity<BoopPart> | undefined) || null;
}

export function placeKitten(host: Entity<BoopState>, row: number, col: number, player: PlayerType) {
    const board = getBoardRegion(host);
    const moveNumber = host.value.parts.length + 1;
    const piece: BoopPart = {
        id: `piece-${player}-${moveNumber}`,
        region: board,
        position: [row, col],
        player,
        pieceType: 'kitten',
    };
    host.produce(state => {
        const e = entity(piece.id, piece);
        state.parts.push(e);
        if (player === 'white') state.whiteKittensInSupply--;
        else state.blackKittensInSupply--;
        board.produce(draft => {
            draft.children.push(e);
        });
    });
}

export function applyBoops(host: Entity<BoopState>, placedRow: number, placedCol: number, placedType: PieceType) {
    const board = getBoardRegion(host);
    const partsMap = board.partsMap.value;

    const piecesToBoop: { part: Entity<BoopPart>; dr: number; dc: number }[] = [];

    for (const key in partsMap) {
        const part = partsMap[key] as Entity<BoopPart>;
        const [r, c] = part.value.position;
        if (r === placedRow && c === placedCol) continue;

        const dr = Math.sign(r - placedRow);
        const dc = Math.sign(c - placedCol);

        if (Math.abs(r - placedRow) <= 1 && Math.abs(c - placedCol) <= 1) {
            const booperIsKitten = placedType === 'kitten';
            const targetIsCat = part.value.pieceType === 'cat';

            if (booperIsKitten && targetIsCat) continue;

            piecesToBoop.push({ part, dr, dc });
        }
    }

    for (const { part, dr, dc } of piecesToBoop) {
        const [r, c] = part.value.position;
        const newRow = r + dr;
        const newCol = c + dc;

        if (newRow < 0 || newRow >= BOARD_SIZE || newCol < 0 || newCol >= BOARD_SIZE) {
            removePieceFromBoard(host, part);
            const player = part.value.player;
            host.produce(state => {
                if (player === 'white') state.whiteKittensInSupply++;
                else state.blackKittensInSupply++;
            });
            continue;
        }

        if (isCellOccupied(host, newRow, newCol)) continue;

        part.produce(p => {
            p.position = [newRow, newCol];
        });
    }
}

export function removePieceFromBoard(host: Entity<BoopState>, part: Entity<BoopPart>) {
    const board = getBoardRegion(host);
    host.produce(state => {
        state.parts = state.parts.filter(p => p.id !== part.id);
        board.produce(draft => {
            draft.children = draft.children.filter(p => p.id !== part.id);
        });
    });
}

export function checkGraduation(host: Entity<BoopState>, player: PlayerType): number[][][] {
    const parts = host.value.parts.filter(p => p.value.player === player && p.value.pieceType === 'kitten');
    const positions = parts.map(p => p.value.position);

    const winningLines: number[][][] = [];

    for (let r = 0; r < BOARD_SIZE; r++) {
        for (let c = 0; c <= BOARD_SIZE - WIN_LENGTH; c++) {
            const line = [];
            for (let i = 0; i < WIN_LENGTH; i++) {
                line.push([r, c + i]);
            }
            if (line.every(([lr, lc]) => positions.some(([pr, pc]) => pr === lr && pc === lc))) {
                winningLines.push(line);
            }
        }
    }

    for (let c = 0; c < BOARD_SIZE; c++) {
        for (let r = 0; r <= BOARD_SIZE - WIN_LENGTH; r++) {
            const line = [];
            for (let i = 0; i < WIN_LENGTH; i++) {
                line.push([r + i, c]);
            }
            if (line.every(([lr, lc]) => positions.some(([pr, pc]) => pr === lr && pc === lc))) {
                winningLines.push(line);
            }
        }
    }

    for (let r = 0; r <= BOARD_SIZE - WIN_LENGTH; r++) {
        for (let c = 0; c <= BOARD_SIZE - WIN_LENGTH; c++) {
            const line = [];
            for (let i = 0; i < WIN_LENGTH; i++) {
                line.push([r + i, c + i]);
            }
            if (line.every(([lr, lc]) => positions.some(([pr, pc]) => pr === lr && pc === lc))) {
                winningLines.push(line);
            }
        }
    }

    for (let r = WIN_LENGTH - 1; r < BOARD_SIZE; r++) {
        for (let c = 0; c <= BOARD_SIZE - WIN_LENGTH; c++) {
            const line = [];
            for (let i = 0; i < WIN_LENGTH; i++) {
                line.push([r - i, c + i]);
            }
            if (line.every(([lr, lc]) => positions.some(([pr, pc]) => pr === lr && pc === lc))) {
                winningLines.push(line);
            }
        }
    }

    return winningLines;
}

export function processGraduation(host: Entity<BoopState>, player: PlayerType, lines: number[][][]) {
    const allPositions = new Set<string>();
    for (const line of lines) {
        for (const [r, c] of line) {
            allPositions.add(`${r},${c}`);
        }
    }

    const board = getBoardRegion(host);
    const partsMap = board.partsMap.value;
    const partsToRemove: Entity<BoopPart>[] = [];

    for (const key in partsMap) {
        const part = partsMap[key] as Entity<BoopPart>;
        if (part.value.player === player && part.value.pieceType === 'kitten' && allPositions.has(`${part.value.position[0]},${part.value.position[1]}`)) {
            partsToRemove.push(part);
        }
    }

    for (const part of partsToRemove) {
        removePieceFromBoard(host, part);
    }

    const count = partsToRemove.length;
    host.produce(state => {
        const catsInSupply = player === 'white' ? state.whiteCatsInSupply : state.blackCatsInSupply;
        if (player === 'white') state.whiteCatsInSupply = catsInSupply + count;
        else state.blackCatsInSupply = catsInSupply + count;
    });
}

export function checkWinner(host: Entity<BoopState>): WinnerType {
    for (const player of ['white', 'black'] as PlayerType[]) {
        const parts = host.value.parts.filter(p => p.value.player === player && p.value.pieceType === 'cat');
        const positions = parts.map(p => p.value.position);

        if (hasWinningLine(positions)) return player;
    }

    const totalParts = host.value.parts.length;
    const whiteParts = host.value.parts.filter(p => p.value.player === 'white').length;
    const blackParts = host.value.parts.filter(p => p.value.player === 'black').length;

    if (whiteParts >= MAX_PIECES_PER_PLAYER && blackParts >= MAX_PIECES_PER_PLAYER) {
        return 'draw';
    }

    return null;
}

export function hasWinningLine(positions: number[][]): boolean {
    for (let r = 0; r < BOARD_SIZE; r++) {
        for (let c = 0; c <= BOARD_SIZE - WIN_LENGTH; c++) {
            const line = [];
            for (let i = 0; i < WIN_LENGTH; i++) line.push([r, c + i]);
            if (line.every(([lr, lc]) => positions.some(([pr, pc]) => pr === lr && pc === lc))) return true;
        }
    }

    for (let c = 0; c < BOARD_SIZE; c++) {
        for (let r = 0; r <= BOARD_SIZE - WIN_LENGTH; r++) {
            const line = [];
            for (let i = 0; i < WIN_LENGTH; i++) line.push([r + i, c]);
            if (line.every(([lr, lc]) => positions.some(([pr, pc]) => pr === lr && pc === lc))) return true;
        }
    }

    for (let r = 0; r <= BOARD_SIZE - WIN_LENGTH; r++) {
        for (let c = 0; c <= BOARD_SIZE - WIN_LENGTH; c++) {
            const line = [];
            for (let i = 0; i < WIN_LENGTH; i++) line.push([r + i, c + i]);
            if (line.every(([lr, lc]) => positions.some(([pr, pc]) => pr === lr && pc === lc))) return true;
        }
    }

    for (let r = WIN_LENGTH - 1; r < BOARD_SIZE; r++) {
        for (let c = 0; c <= BOARD_SIZE - WIN_LENGTH; c++) {
            const line = [];
            for (let i = 0; i < WIN_LENGTH; i++) line.push([r - i, c + i]);
            if (line.every(([lr, lc]) => positions.some(([pr, pc]) => pr === lr && pc === lc))) return true;
        }
    }

    return false;
}