/* 规则引擎测试：node --test tests/ */
const { test } = require('node:test');
const assert = require('node:assert');
const E = require('../js/engine.js');

// 直接往棋盘上摆子，用于构造测试局面（绕过轮流落子）
function setStones(game, color, coords) {
  for (const [x, y] of coords) game.board[y][x] = color;
}

test('黑先并且落子后交替行棋', () => {
  const g = E.createGame();
  assert.strictEqual(g.currentPlayer, E.BLACK);
  const r = E.place(g, 7, 7);
  assert.strictEqual(r.ok, true);
  assert.strictEqual(g.currentPlayer, E.WHITE);
  E.place(g, 8, 8);
  assert.strictEqual(g.currentPlayer, E.BLACK);
});

test('横向五连判胜', () => {
  const g = E.createGame();
  setStones(g, E.BLACK, [[3, 7], [4, 7], [5, 7], [6, 7]]);
  g.currentPlayer = E.BLACK;
  const r = E.place(g, 7, 7);
  assert.strictEqual(r.win, true);
  assert.strictEqual(g.winner, E.BLACK);
  assert.strictEqual(g.gameOver, true);
  assert.deepStrictEqual(g.winningLine, [
    { x: 3, y: 7 }, { x: 4, y: 7 }, { x: 5, y: 7 }, { x: 6, y: 7 }, { x: 7, y: 7 },
  ]);
});

test('纵向五连判胜', () => {
  const g = E.createGame();
  setStones(g, E.WHITE, [[7, 3], [7, 4], [7, 5], [7, 6]]);
  g.currentPlayer = E.WHITE;
  const r = E.place(g, 7, 7);
  assert.strictEqual(r.win, true);
  assert.strictEqual(g.winner, E.WHITE);
});

test('斜向（左上到右下）五连判胜', () => {
  const g = E.createGame();
  setStones(g, E.BLACK, [[3, 3], [4, 4], [5, 5], [6, 6]]);
  g.currentPlayer = E.BLACK;
  const r = E.place(g, 7, 7);
  assert.strictEqual(r.win, true);
});

test('斜向（左下到右上）五连判胜', () => {
  const g = E.createGame();
  setStones(g, E.BLACK, [[3, 10], [4, 9], [5, 8], [6, 7]]);
  g.currentPlayer = E.BLACK;
  const r = E.place(g, 7, 6);
  assert.strictEqual(r.win, true);
  assert.strictEqual(g.winningLine.length, 5);
});

test('长连（六连）同样判胜', () => {
  const g = E.createGame();
  setStones(g, E.BLACK, [[3, 5], [4, 5], [5, 5], [6, 5], [8, 5]]);
  g.currentPlayer = E.BLACK;
  const r = E.place(g, 7, 5);
  assert.strictEqual(r.win, true);
  assert.strictEqual(g.winningLine.length, 6);
});

test('四连不判胜', () => {
  const g = E.createGame();
  setStones(g, E.BLACK, [[3, 7], [4, 7], [5, 7], [6, 7]]);
  g.currentPlayer = E.BLACK;
  const r = E.place(g, 9, 9); // 与四连无关的落子
  assert.strictEqual(r.win, undefined);
  assert.strictEqual(g.gameOver, false);
});

test('非法落子被拒绝：已占用', () => {
  const g = E.createGame();
  E.place(g, 7, 7);
  const r = E.place(g, 7, 7);
  assert.strictEqual(r.ok, false);
});

test('非法落子被拒绝：越界', () => {
  const g = E.createGame();
  assert.strictEqual(E.place(g, -1, 0).ok, false);
  assert.strictEqual(E.place(g, 0, -1).ok, false);
  assert.strictEqual(E.place(g, 15, 0).ok, false);
  assert.strictEqual(E.place(g, 0, 15).ok, false);
});

test('对局结束后拒绝继续落子', () => {
  const g = E.createGame();
  setStones(g, E.BLACK, [[3, 7], [4, 7], [5, 7], [6, 7]]);
  g.currentPlayer = E.BLACK;
  E.place(g, 7, 7);
  const r = E.place(g, 10, 10);
  assert.strictEqual(r.ok, false);
  assert.strictEqual(r.reason, '游戏已结束');
});

test('棋盘下满判平局', () => {
  const g = E.createGame();
  // 用 (x + 2y) mod 4 的双色填充，任意方向连续同色不超过 2，不会误判五连
  for (let y = 0; y < E.SIZE; y++) {
    for (let x = 0; x < E.SIZE; x++) {
      if (x === 14 && y === 14) continue;
      const v = ((x + 2 * y) % 4 + 4) % 4;
      g.board[y][x] = v === 0 || v === 1 ? E.BLACK : E.WHITE;
    }
  }
  g.currentPlayer = E.BLACK;
  const r = E.place(g, 14, 14);
  assert.strictEqual(r.draw, true);
  assert.strictEqual(g.gameOver, true);
  assert.strictEqual(g.winner, 0);
});

test('落子历史被完整记录', () => {
  const g = E.createGame();
  E.place(g, 7, 7);
  E.place(g, 8, 8);
  E.place(g, 7, 8);
  assert.strictEqual(g.moveHistory.length, 3);
  assert.deepStrictEqual(g.moveHistory[0], { x: 7, y: 7, player: E.BLACK });
  assert.deepStrictEqual(g.moveHistory[1], { x: 8, y: 8, player: E.WHITE });
  assert.deepStrictEqual(g.moveHistory[2], { x: 7, y: 8, player: E.BLACK });
});