"use client";

import { useRef, useEffect } from "react";
import { Piece, Position } from "../types/chess";
import ChessPiece from "./ChessPiece";

interface ChessBoardProps {
  pieces: Piece[];
  selectedPieceId?: string;
  validMoves: Position[];
  lastMove?: { from: Position; to: Position };
  onPieceClick: (piece: Piece) => void;
  onEmptyClick: (pos: Position) => void;
}

// 棋盘配置
const GRID_SIZE = 55; // 格子大小
const PADDING = 40; // 边距
const BOARD_WIDTH = GRID_SIZE * 8 + PADDING * 2;
const BOARD_HEIGHT = GRID_SIZE * 9 + PADDING * 2;

export default function ChessBoard({
  pieces,
  selectedPieceId,
  validMoves,
  lastMove,
  onPieceClick,
  onEmptyClick,
}: ChessBoardProps) {
  const canvasRef = useRef<HTMLCanvasElement>(null);

  // 绘制棋盘网格
  useEffect(() => {
    const canvas = canvasRef.current;
    if (!canvas) return;
    const ctx = canvas.getContext("2d");
    if (!ctx) return;

    // 清空画布
    ctx.clearRect(0, 0, canvas.width, canvas.height);

    // 绘制背景
    ctx.fillStyle = "#fff9e6";
    ctx.fillRect(0, 0, canvas.width, canvas.height);

    // 设置线条样式
    ctx.strokeStyle = "#666666";
    ctx.lineWidth = 1.2;

    // 绘制横线
    for (let r = 0; r < 10; r++) {
      ctx.beginPath();
      ctx.moveTo(PADDING, PADDING + r * GRID_SIZE);
      ctx.lineTo(PADDING + 8 * GRID_SIZE, PADDING + r * GRID_SIZE);
      ctx.stroke();
    }

    // 绘制竖线（上半部分）
    for (let c = 0; c < 9; c++) {
      ctx.beginPath();
      ctx.moveTo(PADDING + c * GRID_SIZE, PADDING);
      ctx.lineTo(PADDING + c * GRID_SIZE, PADDING + 4 * GRID_SIZE);
      ctx.stroke();
    }

    // 绘制竖线（下半部分）
    for (let c = 0; c < 9; c++) {
      ctx.beginPath();
      ctx.moveTo(PADDING + c * GRID_SIZE, PADDING + 5 * GRID_SIZE);
      ctx.lineTo(PADDING + c * GRID_SIZE, PADDING + 9 * GRID_SIZE);
      ctx.stroke();
    }

    // 绘制九宫格斜线（黑方）
    ctx.beginPath();
    ctx.moveTo(PADDING + 3 * GRID_SIZE, PADDING);
    ctx.lineTo(PADDING + 5 * GRID_SIZE, PADDING + 2 * GRID_SIZE);
    ctx.stroke();

    ctx.beginPath();
    ctx.moveTo(PADDING + 5 * GRID_SIZE, PADDING);
    ctx.lineTo(PADDING + 3 * GRID_SIZE, PADDING + 2 * GRID_SIZE);
    ctx.stroke();

    // 绘制九宫格斜线（红方）
    ctx.beginPath();
    ctx.moveTo(PADDING + 3 * GRID_SIZE, PADDING + 7 * GRID_SIZE);
    ctx.lineTo(PADDING + 5 * GRID_SIZE, PADDING + 9 * GRID_SIZE);
    ctx.stroke();

    ctx.beginPath();
    ctx.moveTo(PADDING + 5 * GRID_SIZE, PADDING + 7 * GRID_SIZE);
    ctx.lineTo(PADDING + 3 * GRID_SIZE, PADDING + 9 * GRID_SIZE);
    ctx.stroke();

    // 绘制炮位和兵位标记
    drawPositionMarkers(ctx);

    // 绘制楚河汉界
    ctx.font = "bold 28px serif";
    ctx.fillStyle = "#8b7355";
    ctx.textAlign = "center";
    ctx.textBaseline = "middle";
    ctx.fillText("楚 河", PADDING + 2 * GRID_SIZE, PADDING + 4.5 * GRID_SIZE);
    ctx.fillText("汉 界", PADDING + 6 * GRID_SIZE, PADDING + 4.5 * GRID_SIZE);

    // 绘制上一步移动标记
    if (lastMove) {
      drawMoveMarker(ctx, lastMove.from, "#4a90d9");
      drawMoveMarker(ctx, lastMove.to, "#4a90d9");
    }

    // 绘制可移动位置标记
    for (const move of validMoves) {
      drawValidMoveMarker(ctx, move);
    }
  }, [validMoves, lastMove]);

  // 绘制位置标记（炮位和兵位）
  const drawPositionMarkers = (ctx: CanvasRenderingContext2D) => {
    ctx.strokeStyle = "#666666";
    ctx.lineWidth = 1;

    const markerSize = 6;
    const positions = [
      // 黑方炮位
      { row: 2, col: 1, left: true, right: true, top: false, bottom: true },
      { row: 2, col: 7, left: true, right: true, top: false, bottom: true },
      // 黑方兵位
      { row: 3, col: 0, left: false, right: true, top: true, bottom: true },
      { row: 3, col: 2, left: true, right: true, top: true, bottom: true },
      { row: 3, col: 4, left: true, right: true, top: true, bottom: true },
      { row: 3, col: 6, left: true, right: true, top: true, bottom: true },
      { row: 3, col: 8, left: true, right: false, top: true, bottom: true },
      // 红方兵位
      { row: 6, col: 0, left: false, right: true, top: true, bottom: true },
      { row: 6, col: 2, left: true, right: true, top: true, bottom: true },
      { row: 6, col: 4, left: true, right: true, top: true, bottom: true },
      { row: 6, col: 6, left: true, right: true, top: true, bottom: true },
      { row: 6, col: 8, left: true, right: false, top: true, bottom: true },
      // 红方炮位
      { row: 7, col: 1, left: true, right: true, top: true, bottom: false },
      { row: 7, col: 7, left: true, right: true, top: true, bottom: false },
    ];

    for (const pos of positions) {
      const x = PADDING + pos.col * GRID_SIZE;
      const y = PADDING + pos.row * GRID_SIZE;

      ctx.beginPath();
      if (pos.left) {
        ctx.moveTo(x - markerSize, y - markerSize / 2);
        ctx.lineTo(x - markerSize / 2, y - markerSize / 2);
        ctx.lineTo(x - markerSize / 2, y - markerSize);

        ctx.moveTo(x - markerSize, y + markerSize / 2);
        ctx.lineTo(x - markerSize / 2, y + markerSize / 2);
        ctx.lineTo(x - markerSize / 2, y + markerSize);
      }
      if (pos.right) {
        ctx.moveTo(x + markerSize, y - markerSize / 2);
        ctx.lineTo(x + markerSize / 2, y - markerSize / 2);
        ctx.lineTo(x + markerSize / 2, y - markerSize);

        ctx.moveTo(x + markerSize, y + markerSize / 2);
        ctx.lineTo(x + markerSize / 2, y + markerSize / 2);
        ctx.lineTo(x + markerSize / 2, y + markerSize);
      }
      ctx.stroke();
    }
  };

  // 绘制移动标记
  const drawMoveMarker = (
    ctx: CanvasRenderingContext2D,
    pos: Position,
    color: string
  ) => {
    const x = PADDING + pos.col * GRID_SIZE;
    const y = PADDING + pos.row * GRID_SIZE;
    const size = 8;

    ctx.strokeStyle = color;
    ctx.lineWidth = 2;
    ctx.beginPath();
    ctx.arc(x, y, size, 0, Math.PI * 2);
    ctx.stroke();
  };

  // 绘制可移动位置标记
  const drawValidMoveMarker = (ctx: CanvasRenderingContext2D, pos: Position) => {
    const x = PADDING + pos.col * GRID_SIZE;
    const y = PADDING + pos.row * GRID_SIZE;

    ctx.fillStyle = "rgba(0, 150, 0, 0.4)";
    ctx.beginPath();
    ctx.arc(x, y, 6, 0, Math.PI * 2);
    ctx.fill();
  };

  // 处理点击事件
  const handleClick = (e: React.MouseEvent<HTMLDivElement>) => {
    const rect = e.currentTarget.getBoundingClientRect();
    const x = e.clientX - rect.left;
    const y = e.clientY - rect.top;

    const col = Math.round((x - PADDING) / GRID_SIZE);
    const row = Math.round((y - PADDING) / GRID_SIZE);

    if (col < 0 || col > 8 || row < 0 || row > 9) return;

    const clickedPiece = pieces.find(
      (p) => p.alive && p.position.row === row && p.position.col === col
    );

    if (clickedPiece) {
      onPieceClick(clickedPiece);
    } else {
      onEmptyClick({ row, col });
    }
  };

  return (
    <div
      style={{
        position: "relative",
        width: `${BOARD_WIDTH}px`,
        height: `${BOARD_HEIGHT}px`,
        backgroundColor: "#fff9e6",
        borderRadius: "8px",
        boxShadow: "0 4px 12px rgba(0,0,0,0.15), inset 0 1px 0 rgba(255,255,255,0.5)",
        border: "2px solid #d4c4a8",
        overflow: "hidden",
      }}
    >
      {/* 棋盘画布 */}
      <canvas
        ref={canvasRef}
        width={BOARD_WIDTH}
        height={BOARD_HEIGHT}
        style={{
          position: "absolute",
          top: 0,
          left: 0,
          pointerEvents: "none",
        }}
      />

      {/* 棋子层 */}
      <div
        onClick={handleClick}
        style={{
          position: "absolute",
          top: 0,
          left: 0,
          width: `${BOARD_WIDTH}px`,
          height: `${BOARD_HEIGHT}px`,
          cursor: "pointer",
        }}
      >
        {pieces
          .filter((p) => p.alive)
          .map((piece) => (
            <div
              key={piece.id}
              style={{
                position: "absolute",
                left: `${PADDING + piece.position.col * GRID_SIZE - 22}px`,
                top: `${PADDING + piece.position.row * GRID_SIZE - 22}px`,
              }}
            >
              <ChessPiece
                piece={piece}
                isSelected={piece.id === selectedPieceId}
                onClick={() => onPieceClick(piece)}
                size={44}
              />
            </div>
          ))}
      </div>
    </div>
  );
}

export { GRID_SIZE, PADDING, BOARD_WIDTH, BOARD_HEIGHT };