'use strict';

const test = require('node:test');
const assert = require('node:assert');

const { ExpansionPlanner } = require('../src/core/expansionPlanner');
const { TerritoryModel } = require('../src/core/territoryModel');
const { defaultConfig } = require('../src/config/expansionConfig');
const chunkPos = require('../src/core/chunkPos');

/**
 * 构造领土模型。
 * @param {Record<string, Array<[number, number]>>} states 邦国名 → 区块坐标列表
 * @param {string} [selfName] 己方邦国名
 */
function makeModel(states, selfName) {
  const map = new Map();
  for (const [name, coords] of Object.entries(states)) {
    const chunks = new Set(coords.map(([x, z]) => chunkPos.key(x, z)));
    map.set(name, {
      name,
      capital: { x: coords[0][0], z: coords[0][1] },
      chunks,
      color: 0x75bd20
    });
  }
  const model = new TerritoryModel(map);
  if (selfName) model.setSelfStateName(selfName);
  return model;
}

const planner = new ExpansionPlanner();

test('策略 1：只返回与己方领土相邻的未占领区块', () => {
  const model = makeModel({ A: [[0, 0]] }, 'A');
  const config = Object.assign(defaultConfig(), { strategy: 1 });
  const result = planner.generate(model, config, { x: 0, z: 0 });
  // 接壤只算四个正方向，因此单个己方区块只有 4 个合法邻居（对角线不算）
  assert.strictEqual(result.length, 4, '单个己方区块应产生 4 个正方向邻居候选');
  for (const chunk of result) {
    assert.strictEqual(
      Math.abs(chunk.x) + Math.abs(chunk.z),
      1,
      `候选 ${chunk.x},${chunk.z} 不是 (0,0) 的正方向邻居`
    );
  }
});

test('策略 1：绝不选中「只与其他邦国相邻」的区块（历史 bug 回归）', () => {
  // 己方只有 (0,0)；其他邦国占据 (1,0) 与 (1,1)
  const model = makeModel({ A: [[0, 0]], B: [[1, 0], [1, 1]] }, 'A');
  const config = Object.assign(defaultConfig(), { strategy: 1 });
  const result = planner.generate(model, config, { x: 0, z: 0 });
  const keys = result.map((c) => chunkPos.key(c.x, c.z));
  assert.ok(!keys.includes(chunkPos.key(1, 0)), '不能选中已被 B 占领的区块');
  assert.ok(!keys.includes(chunkPos.key(1, 1)), '不能选中已被 B 占领的区块');
  // (2,0) 只与 B 的 (1,0) 相邻，与 A 不相邻，必须被排除
  assert.ok(!keys.includes(chunkPos.key(2, 0)), '不能选中只与他国相邻的区块');
  for (const chunk of result) {
    const adjacentToOwn = chunkPos.cardinalNeighbors(chunk.x, chunk.z)
      .some((n) => n.x === 0 && n.z === 0);
    assert.ok(adjacentToOwn, `候选 ${chunk.x},${chunk.z} 必须与己方领土接壤`);
  }
});

test('策略 1：矩形内部的空洞优先于外部边界', () => {
  // 己方占 3×3 外圈，中心 (1,1) 是空洞
  const ring = [];
  for (let x = 0; x <= 2; x++) {
    for (let z = 0; z <= 2; z++) {
      if (x === 1 && z === 1) continue;
      ring.push([x, z]);
    }
  }
  const model = makeModel({ A: ring }, 'A');
  const config = Object.assign(defaultConfig(), { strategy: 1 });
  const result = planner.generate(model, config, { x: 1, z: 1 });
  assert.deepStrictEqual(result[0], { x: 1, z: 1 }, '内部空洞应排在最前');
});

test('策略 1：maxRings 影响搜索圈数（扩张轮数为 0 时只看第一圈）', () => {
  const model = makeModel({ A: [[0, 0]] }, 'A');
  const config = Object.assign(defaultConfig(), { strategy: 1, maxRings: 1 });
  const result = planner.generate(model, config, { x: 0, z: 0 });
  // maxRings=1 → maxExpansions=2，第一圈就能找到候选，结果仍是 4 个正方向邻居
  assert.strictEqual(result.length, 4);
});

test('策略 2：矩形扩地严格按 S 形蛇形扫描', () => {
  const model = makeModel({ A: [[0, 0]] }, 'A');
  const config = Object.assign(defaultConfig(), {
    strategy: 2,
    regionMinX: 0,
    regionMaxX: 3,
    regionMinZ: 0,
    regionMaxZ: 3
  });
  const result = planner.generate(model, config, { x: 0, z: 0 });
  assert.strictEqual(result.length, 15, '4×4 区域去掉 1 个己方区块应为 15 个');
  // 王城在 (0,0)：起始边为 z=0（北），行内从 x 小到大
  assert.deepStrictEqual(result[0], { x: 1, z: 0 });
  assert.deepStrictEqual(result[1], { x: 2, z: 0 });
  assert.deepStrictEqual(result[2], { x: 3, z: 0 });
  // 第二行反向（蛇形）
  assert.deepStrictEqual(result[3], { x: 3, z: 1 });
  assert.deepStrictEqual(result[4], { x: 2, z: 1 });
  assert.deepStrictEqual(result[5], { x: 1, z: 1 });
  assert.deepStrictEqual(result[6], { x: 0, z: 1 });
  // 第三行再次反向
  assert.deepStrictEqual(result[7], { x: 0, z: 2 });
});

test('策略 2：每个入选区块都与己方领土（含本次已选）接壤', () => {
  const model = makeModel({ A: [[0, 0]] }, 'A');
  const config = Object.assign(defaultConfig(), {
    strategy: 2,
    regionMinX: -2,
    regionMaxX: 4,
    regionMinZ: -2,
    regionMaxZ: 4
  });
  const result = planner.generate(model, config, { x: 0, z: 0 });
  const claimed = new Set([chunkPos.key(0, 0)]);
  for (const chunk of result) {
    const adjacent = chunkPos.cardinalNeighbors(chunk.x, chunk.z)
      .some((n) => claimed.has(chunkPos.key(n.x, n.z)));
    assert.ok(adjacent, `区块 ${chunk.x},${chunk.z} 必须与己方领土接壤`);
    claimed.add(chunkPos.key(chunk.x, chunk.z));
  }
});

test('策略 2：跳过他国区块但不打乱 S 形顺序', () => {
  // 己方 (0,0)(1,0)，他国占 (1,1)，区域 0..3 × 0..1
  const model = makeModel({ A: [[0, 0], [1, 0]], B: [[1, 1]] }, 'A');
  const config = Object.assign(defaultConfig(), {
    strategy: 2,
    regionMinX: 0,
    regionMaxX: 3,
    regionMinZ: 0,
    regionMaxZ: 1
  });
  const result = planner.generate(model, config, { x: 0, z: 0 });
  const keys = result.map((c) => `${c.x},${c.z}`);
  assert.ok(!keys.includes('1,1'), '他国区块必须跳过');
  // S 形顺序保持不变：第一行向右扫，第二行向左扫，(1,1) 被跳过但顺序不被打乱；
  // 末尾的 (0,1) 因为与己方 (0,0) 正方向接壤而被选中
  assert.deepStrictEqual(keys, ['2,0', '3,0', '3,1', '2,1', '0,1']);
});

test('策略 2：他国区块会切断连通，其后不可达区块不入选', () => {
  // 己方只有 (0,0)，他国占 (2,0)：x=3 一列与他国相邻但离己方太远，必须排除
  const model = makeModel({ A: [[0, 0]], B: [[2, 0]] }, 'A');
  const config = Object.assign(defaultConfig(), {
    strategy: 2,
    regionMinX: 0,
    regionMaxX: 3,
    regionMinZ: 0,
    regionMaxZ: 0
  });
  const result = planner.generate(model, config, { x: 0, z: 0 });
  assert.deepStrictEqual(result.map((c) => `${c.x},${c.z}`), ['1,0']);
});

test('策略 3：按与玩家的距离由近到远排序', () => {
  const model = makeModel({ A: [[0, 0]] }, 'A');
  const config = Object.assign(defaultConfig(), { strategy: 3 });
  const playerChunk = { x: 5, z: 5 };
  const result = planner.generate(model, config, playerChunk);
  assert.strictEqual(result.length, 4);
  const distances = result.map((c) => chunkPos.manhattan(c, playerChunk));
  for (let i = 1; i < distances.length; i++) {
    assert.ok(distances[i] >= distances[i - 1], '距离必须非递减');
  }
  assert.strictEqual(distances[0], 9, '最近的邻居距离应为 9');
});

test('策略 4：绕国一圈按方位角均匀排序', () => {
  const model = makeModel({ A: [[0, 0], [1, 0], [0, 1], [1, 1]] }, 'A');
  const config = Object.assign(defaultConfig(), { strategy: 4, maxRings: 1 });
  const result = planner.generate(model, config, { x: 0, z: 0 });
  assert.strictEqual(result.length, 8, '2×2 领土外圈应有 8 个候选');
  // 质心 (0,0)：方位角从 -π/2 起
  assert.deepStrictEqual(result[0], { x: 0, z: -1 });
  assert.deepStrictEqual(result[1], { x: 1, z: -1 });
});

test('策略 4：多圈扩张时逐圈向外推进', () => {
  const model = makeModel({ A: [[0, 0]] }, 'A');
  const config = Object.assign(defaultConfig(), { strategy: 4, maxRings: 2 });
  const result = planner.generate(model, config, { x: 0, z: 0 });
  assert.ok(result.length > 4, '两圈应超过第一圈的 4 个候选');
  const firstRing = result.slice(0, 4).every((c) => Math.abs(c.x) + Math.abs(c.z) === 1);
  assert.ok(firstRing, '前 4 个应是第一圈的四个邻居');
});

test('prefixFlyingChunks：飞地优先且去重、受目标数量限制', () => {
  const ring = [];
  for (let x = 0; x <= 2; x++) {
    for (let z = 0; z <= 2; z++) {
      if (x === 1 && z === 1) continue;
      ring.push([x, z]);
    }
  }
  const model = makeModel({ A: ring }, 'A');
  const config = Object.assign(defaultConfig(), { strategy: 3, targetCount: 3 });
  const planned = [{ x: 3, z: 0 }, { x: 3, z: 1 }, { x: 3, z: 2 }];
  const result = planner.prefixFlyingChunks(model, config, { x: 0, z: 0 }, planned);
  assert.deepStrictEqual(result[0], { x: 1, z: 1 }, '飞地必须排在最前');
  assert.strictEqual(result.length, 3, '不得超过 targetCount');
  const keys = result.map((c) => `${c.x},${c.z}`);
  assert.strictEqual(new Set(keys).size, keys.length, '结果不得重复');
});

test('prefixFlyingChunks：区域外的飞地不被优先填入', () => {
  const ring = [];
  for (let x = 0; x <= 2; x++) {
    for (let z = 0; z <= 2; z++) {
      if (x === 1 && z === 1) continue;
      ring.push([x, z]);
    }
  }
  const model = makeModel({ A: ring }, 'A');
  const config = Object.assign(defaultConfig(), {
    strategy: 2,
    regionMinX: 10,
    regionMaxX: 12,
    regionMinZ: 10,
    regionMaxZ: 12
  });
  const planned = [{ x: 10, z: 10 }];
  const result = planner.prefixFlyingChunks(model, config, { x: 0, z: 0 }, planned);
  assert.deepStrictEqual(result, [{ x: 10, z: 10 }], '区域外的飞地应被过滤掉');
});

test('isInRegion：非策略 2 恒为 true，策略 2 支持矩形与中心+半径', () => {
  const base = defaultConfig();
  assert.strictEqual(planner.isInRegion({ x: 999, z: -999 }, Object.assign(base, { strategy: 1 })), true);

  const rect = Object.assign(defaultConfig(), {
    strategy: 2, regionMinX: 0, regionMaxX: 2, regionMinZ: 0, regionMaxZ: 2
  });
  assert.strictEqual(planner.isInRegion({ x: 2, z: 2 }, rect), true);
  assert.strictEqual(planner.isInRegion({ x: 3, z: 2 }, rect), false);

  const circle = Object.assign(defaultConfig(), {
    strategy: 2, regionMinX: 0, regionMaxX: -1, regionCenterX: 0, regionCenterZ: 0, regionRadius: 2
  });
  assert.strictEqual(planner.isInRegion({ x: 2, z: -2 }, circle), true);
  assert.strictEqual(planner.isInRegion({ x: 3, z: 0 }, circle), false);
});

test('己方领土为空时不做任何规划', () => {
  const model = makeModel({ B: [[5, 5]] }, 'A');
  const config = defaultConfig();
  for (const strategy of [1, 2, 3, 4]) {
    config.strategy = strategy;
    const result = planner.generate(model, config, { x: 0, z: 0 });
    assert.deepStrictEqual(result, [], `策略 ${strategy} 在己方无领土时应返回空`);
  }
});

test('规划结果始终在世界边界内', () => {
  const model = makeModel({ A: [[1279, 1279]] }, 'A');
  const config = Object.assign(defaultConfig(), { strategy: 1 });
  const result = planner.generate(model, config, { x: 1279, z: 1279 });
  for (const chunk of result) {
    assert.ok(chunkPos.withinWorldBorder(chunk.x, chunk.z), `${chunk.x},${chunk.z} 越界`);
  }
});