ice-puzzle-mcp

import { describe, expect, it } from 'vitest';
import {
  buildUnsolvableDiagnostics,
  computeDirectionBalance,
  exploreReachability,
  suggestStopPoints,
  traceMovePositions,
} from './design-assist.js';
import { solve } from './solver.js';
import type { PuzzleData } from './types.js';

function makeBasicPuzzle(overrides?: Partial<PuzzleData>): PuzzleData {
  return {
    id: 'test',
    name: 'Assist Test',
    theme: 'ice',
    width: 8,
    height: 6,
    par: 0,
    start: { x: 1, y: 4 },
    goal: { x: 6, y: 1 },
    obstacles: [],
    ...overrides,
  };
}

describe('design-assist utilities', () => {
  it('computes direction balance', () => {
    const balance = computeDirectionBalance(['up', 'right', 'right', 'down']);
    expect(balance.up).toBe(1);
    expect(balance.right).toBe(2);
    expect(balance.left).toBe(0);
  });

  it('explores reachable landing positions from start', () => {
    const puzzle = makeBasicPuzzle({
      start: { x: 1, y: 1 },
      goal: { x: 6, y: 1 },
    });
    const report = exploreReachability(puzzle);
    expect(report.positions.length).toBeGreaterThan(0);
    expect(report.goalReachable).toBe(true);
  });

  it('traces move stop positions', () => {
    const puzzle = makeBasicPuzzle({
      start: { x: 1, y: 1 },
      goal: { x: 6, y: 1 },
    });
    const trace = traceMovePositions(puzzle, ['right']);
    expect(trace.positions[0]).toEqual({ x: 1, y: 1 });
    expect(trace.positions[trace.positions.length - 1]).toEqual({ x: 6, y: 1 });
  });

  it('suggests stop points along a slide direction', () => {
    const puzzle = makeBasicPuzzle({
      start: { x: 1, y: 1 },
      goal: { x: 6, y: 4 },
    });
    const report = suggestStopPoints(puzzle, { x: 1, y: 1 }, 'right');
    expect(report.currentLanding.x).toBe(6);
    expect(report.suggestions.length).toBeGreaterThan(0);
  });

  it('produces unsolvable diagnostics reasons', () => {
    const puzzle = makeBasicPuzzle({
      start: { x: 2, y: 2 },
      goal: { x: 3, y: 1 },
      obstacles: [
        { x: 1, y: 2, type: 'rock' },
        { x: 3, y: 2, type: 'rock' },
        { x: 2, y: 1, type: 'rock' },
        { x: 2, y: 3, type: 'rock' },
      ],
    });
    const result = solve(puzzle);
    expect(result.solvable).toBe(false);
    const diagnostics = buildUnsolvableDiagnostics(puzzle, result);
    expect(diagnostics.reasons.length).toBeGreaterThan(0);
    expect(diagnostics.suggestions.length).toBeGreaterThan(0);
  });
});