#!/usr/bin/env node
/**
 * 离线地图资源下载与本地化样式生成脚本
 * ---------------------------------------------------------------------------
 * 把项目当前使用的外网地图资源（OpenFreeMap）一次性抓取到本地 public/map 下，
 * 并生成一份所有地址都指向本地的 style.json，使内网 / 离线环境也能正常显示地图，
 * 且样式与线上（dev / prod）完全一致。
 *
 * 抓取内容：
 *   1. 矢量瓦片  tiles/{z}/{x}/{y}.pbf         （源自 tiles.openfreemap.org/planet）
 *   2. 字体字形  fonts/{fontstack}/{range}.pbf （glyphs，地图注记文字 / 点位数字依赖）
 *      !!! 默认抓全部 256 个区间，不要裁剪 !!!
 *      vjmap 解析字形时执行 `for (const g of parsed.glyphs)`，只要某个区间缺失、
 *      请求拿到空数据，glyphs 就是 undefined，直接抛 "glyphs is not iterable"。
 *   3. 图标雪碧  sprites/ofm.json|png|@2x.png   （地图 POI 图标）
 *   4. 生成样式  shanxi.offline.json            （源样式 shanxi.map.json 的本地化版本）
 *
 * 用法：
 *   node scripts/fetch-offline-map.mjs                         # 默认：陕西范围 z0-z9（体积最小）
 *   node scripts/fetch-offline-map.mjs --maxzoom=11           # 更细（+约 53MB），--maxzoom=12 再 +约 70MB
 *   node scripts/fetch-offline-map.mjs --skip-existing         # 断点续传，已存在的文件跳过
 *   node scripts/fetch-offline-map.mjs --bbox=105,31,112,40    # 自定义范围 lonMin,latMin,lonMax,latMax
 *   node scripts/fetch-offline-map.mjs --base=/map/            # 部署在子路径下时改写资源前缀
 *   node scripts/fetch-offline-map.mjs --fonts="Noto Sans Regular"  # 只保留一个字体栈（省约 78MB）
 *   node scripts/fetch-offline-map.mjs --no-strip              # 不精简瓦片（保留多语言 name 字段）
 *   node scripts/fetch-offline-map.mjs --glyphs=all            # 全量字形（最保险，体积大）
 *
 * 网络要求：只在能上网的机器上执行一次；执行完把 public/map 整个目录拷到内网即可。
 */

import { mkdir, readFile, readdir, rm, writeFile, stat } from 'node:fs/promises';
import path from 'node:path';

// --------------------------------------------------------------------------
// 参数
// --------------------------------------------------------------------------
const ROOT = process.cwd();

const args = {};
for (const rawArg of process.argv.slice(2)) {
  const m = /^--([^=]+)(?:=(.*))?$/.exec(rawArg);
  if (m) args[m[1]] = m[2] === undefined ? true : m[2];
}

// 陕西省大致范围，默认外扩 0.7 度，避免地图边缘缺瓦片
const PADDING = Number(args.padding ?? 0.7);
const [bLon, bLat, tLon, tLat] = String(args.bbox ?? '105.4,31.6,111.3,39.7')
  .split(',')
  .map(Number);

// lonMin, latMin, lonMax, latMax
const BBOX = [bLon - PADDING, bLat - PADDING, tLon + PADDING, tLat + PADDING];

const MINZOOM = Number(args.minzoom ?? 0);
const MAXZOOM = Number(args.maxzoom ?? 9);
const OUT_DIR = path.resolve(ROOT, args.out ?? 'public/map');
const BASE = String(args.base ?? '/map/');
// 源样式：保留 OpenFreeMap 外网地址的原始样式（生成器输入）
const STYLE_SRC = path.resolve(ROOT, args.style ?? 'scripts/map/shanxi.map.source.json');
// 产物：直接覆盖前端引用的样式文件，这样前端代码一行都不用改
const STYLE_OUT = path.resolve(ROOT, args['style-out'] ?? 'public/js/shanxi.map.json');
const CONCURRENCY = Number(args.concurrency ?? 12);
const SKIP_EXISTING = Boolean(args['skip-existing'] || args.resume);
// used=按瓦片文字推导(默认，体积最小) | all-cjk=全量 CJK | all=全部 256 个区间(最保险)
const GLYPH_MODE = String(args.glyphs ?? 'used');
// 精简瓦片：删除样式用不到的 name:* 字段、未被引用的键值、样式不引用的图层（约省 28%）
const STRIP_TILES = !args['no-strip'];
const KEEP_NAME_KEYS = new Set(
  String(args['keep-names'] ?? 'name,name:latin,name:nonlatin')
    .split(',')
    .map((s) => s.trim())
    .filter(Boolean),
);
// vjmap(mapbox-gl 1.x) 的 normalizeSpriteURL 会无条件 parseUrl()，
// 只接受 "协议://..." 形式的绝对地址，相对路径会抛 "Unable to parse URL object"。
// 因此默认不写 sprite 字段（地图照常渲染，只是 POI 图标不显示）；
// 需要图标时用 --sprite-base=http://your-host/map/sprites/ofm 传入绝对地址。
const SPRITE_BASE = args['sprite-base'] ? String(args['sprite-base']) : '';

const UA =
  'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0 Safari/537.36';

const VECTOR_SOURCE_ID = 'openmaptiles';
// 样式里声明了但没有图层使用的源，本地化时直接移除
const UNUSED_SOURCES = ['ne2_shaded'];

// --------------------------------------------------------------------------
// 工具函数
// --------------------------------------------------------------------------
const log = (...a) => console.log(...a);
const fmtMB = (bytes) => (bytes / 1048576).toFixed(1) + 'MB';

function lonLatToTile(lon, lat, z) {
  const n = 2 ** z;
  const latClamped = Math.min(Math.max(lat, -85.05112878), 85.05112878);
  const x = Math.floor(((lon + 180) / 360) * n);
  const rad = (latClamped * Math.PI) / 180;
  const y = Math.floor(((1 - Math.log(Math.tan(rad) + 1 / Math.cos(rad)) / Math.PI) / 2) * n);
  return [Math.min(Math.max(x, 0), n - 1), Math.min(Math.max(y, 0), n - 1)];
}

/**
 * 分层范围：低层级看到的范围远大于省界（全屏地图在 z6 时横向能看到 40 多度经度），
 * 若只下载省内瓦片，屏幕上会出现大片空白。因此按层级给不同范围：
 *   z0-z6  中国范围（张数很少，成本低）
 *   z7-z8  陕西周边
 *   z9+    陕西省内
 * 可用 --tiers="0-6:73,3,136,54;7-8:98,24,122,45;9-11:104.7,30.9,112,40.4" 覆盖。
 */
function buildTiers() {
  const custom = args.tiers ? String(args.tiers) : null;
  const parse = (s) => s.split(',').map(Number);
  if (custom) {
    return custom
      .split(';')
      .filter(Boolean)
      .map((seg) => {
        const [zooms, bbox] = seg.split(':');
        const [z0, z1] = zooms.split('-').map(Number);
        return { min: z0, max: z1, bbox: parse(bbox) };
      });
  }
  return [
    // z0-z6：中国范围（首页默认 z6）
    { min: 0, max: Math.min(6, MAXZOOM), bbox: parse(String(args['china-bbox'] ?? '73,3,136,54')) },
    // z7-z8：陕西周边
    { min: 7, max: Math.min(8, MAXZOOM), bbox: parse(String(args['region-bbox'] ?? '98,24,122,45')) },
    // z9+：陕西省内
    { min: 9, max: MAXZOOM, bbox: BBOX },
  ].filter((t) => t.min <= t.max);
}

const TIERS = buildTiers();

function bboxForZoom(z) {
  const tier = TIERS.find((t) => z >= t.min && z <= t.max);
  return tier ? tier.bbox : BBOX;
}

function tileRangeForZoom(z) {
  const [lonMin, latMin, lonMax, latMax] = bboxForZoom(z);
  const [x0, y0] = lonLatToTile(lonMin, latMax, z);
  const [x1, y1] = lonLatToTile(lonMax, latMin, z);
  return { x0, x1, y0, y1, count: (x1 - x0 + 1) * (y1 - y0 + 1), bbox: bboxForZoom(z) };
}

async function ensureDir(p) {
  await mkdir(p, { recursive: true });
}

async function fileSize(p) {
  try {
    return (await stat(p)).size;
  } catch {
    return -1;
  }
}

const sleep = (ms) => new Promise((r) => setTimeout(r, ms));

async function fetchBuffer(url, retries = 4) {
  let lastErr;
  for (let i = 0; i <= retries; i++) {
    try {
      const res = await fetch(url, { headers: { 'User-Agent': UA } });
      if (res.status === 404) return { notFound: true, buffer: Buffer.alloc(0) };
      if (!res.ok) throw new Error('HTTP ' + res.status);
      const ab = await res.arrayBuffer();
      return { notFound: false, buffer: Buffer.from(ab) };
    } catch (e) {
      lastErr = e;
      if (i < retries) await sleep(300 * (i + 1) * (i + 1));
    }
  }
  throw new Error('下载失败 ' + url + ' : ' + (lastErr && lastErr.message));
}

/** 简单并发池 */
async function pool(items, limit, worker, onProgress) {
  let cursor = 0;
  let done = 0;
  const results = new Array(items.length);
  const runners = Array.from({ length: Math.min(limit, items.length) }, async () => {
    while (cursor < items.length) {
      const idx = cursor++;
      results[idx] = await worker(items[idx], idx);
      done += 1;
      if (onProgress && (done % 100 === 0 || done === items.length)) onProgress(done, items.length);
    }
  });
  await Promise.all(runners);
  return results;
}

// --------------------------------------------------------------------------
// 矢量瓦片精简（protobuf / MVT 原地重写，无第三方依赖）
//   - 删除样式用不到的 name:xx 字段（本样式只用 name:latin / name:nonlatin / ref）
//   - 删除因此不再被任何要素引用的 value，以及这些 key
//   - 删除样式没有引用的 source-layer（如 mountain_peak）
// 对同一文件重复执行是幂等的。
// --------------------------------------------------------------------------
function pbReadVarint(buf, i) {
  let v = 0;
  let sh = 0;
  let c;
  do {
    if (i >= buf.length) throw new Error('truncated varint');
    c = buf[i++];
    v += (c & 0x7f) * Math.pow(2, sh);
    sh += 7;
    if (sh > 63) throw new Error('varint too long');
  } while (c & 0x80);
  return [v, i];
}

function pbWriteVarint(out, v) {
  while (v > 0x7f) {
    out.push((v & 0x7f) | 0x80);
    v = Math.floor(v / 128);
  }
  out.push(v & 0x7f);
}

function pbPush(out, bytes) {
  for (let i = 0; i < bytes.length; i++) out.push(bytes[i]);
}

function pbWriteBytes(out, field, bytes) {
  pbWriteVarint(out, field * 8 + 2);
  pbWriteVarint(out, bytes.length);
  pbPush(out, bytes);
}

function* pbFields(buf) {
  let i = 0;
  while (i < buf.length) {
    let tag;
    [tag, i] = pbReadVarint(buf, i);
    const field = Math.floor(tag / 8);
    const wire = tag % 8;
    if (wire === 0) {
      let v;
      [v, i] = pbReadVarint(buf, i);
      yield { field, wire, value: v };
    } else if (wire === 2) {
      let len;
      [len, i] = pbReadVarint(buf, i);
      if (i + len > buf.length) throw new Error('length overflow');
      yield { field, wire, value: buf.subarray(i, i + len) };
      i += len;
    } else if (wire === 5) {
      yield { field, wire, value: buf.subarray(i, i + 4) };
      i += 4;
    } else if (wire === 1) {
      yield { field, wire, value: buf.subarray(i, i + 8) };
      i += 8;
    } else {
      throw new Error('unsupported wire type ' + wire);
    }
  }
}

function encodeFeature(feat, keyRemap, valRemap) {
  const out = [];
  if (feat.id != null) {
    pbWriteVarint(out, 1 * 8 + 0);
    pbWriteVarint(out, feat.id);
  }
  const tags = [];
  for (let i = 0; i + 1 < feat.tags.length; i += 2) {
    const k = keyRemap.get(feat.tags[i]);
    if (k === undefined) continue;
    tags.push(k, valRemap.get(feat.tags[i + 1]));
  }
  if (tags.length) {
    const tb = [];
    tags.forEach((v) => pbWriteVarint(tb, v));
    pbWriteBytes(out, 2, tb);
  }
  if (feat.type != null) {
    pbWriteVarint(out, 3 * 8 + 0);
    pbWriteVarint(out, feat.type);
  }
  if (feat.geom) pbWriteBytes(out, 4, feat.geom);
  return Buffer.from(out);
}

function stripLayer(buf, keepLayers, stats) {
  let name = null;
  let extent = 4096;
  let version = 2;
  const keys = [];
  const values = [];
  const features = [];
  for (const f of pbFields(buf)) {
    if (f.field === 1 && f.wire === 2) name = f.value;
    else if (f.field === 2 && f.wire === 2) features.push(f.value);
    else if (f.field === 3 && f.wire === 2) keys.push(f.value);
    else if (f.field === 4 && f.wire === 2) values.push(f.value);
    else if (f.field === 5 && f.wire === 0) extent = f.value;
    else if (f.field === 15 && f.wire === 0) version = f.value;
  }

  const layerName = name ? name.toString('utf8') : '';
  if (keepLayers && keepLayers.size && !keepLayers.has(layerName)) {
    stats.droppedLayers += 1;
    return null;
  }

  const keyRemap = new Map();
  const keptKeys = [];
  keys.forEach((kb, idx) => {
    const k = kb.toString('utf8');
    // OpenMapTiles 里多语言字段有两套命名：name:xx（冒号）和 name_xx（下划线，如 name_en/name_de/name_int）
    const isName = k.startsWith('name:') || /^name_[a-z]{2,3}$/.test(k);
    if (!isName || KEEP_NAME_KEYS.has(k)) {
      keyRemap.set(idx, keptKeys.length);
      keptKeys.push(idx);
    } else {
      stats.droppedKeys += 1;
    }
  });

  const parsed = [];
  const usedValues = new Set();
  for (const fb of features) {
    const feat = { id: null, type: null, geom: null, tags: [] };
    for (const f of pbFields(fb)) {
      if (f.field === 1 && f.wire === 0) feat.id = f.value;
      else if (f.field === 3 && f.wire === 0) feat.type = f.value;
      else if (f.field === 4 && f.wire === 2) feat.geom = f.value;
      else if (f.field === 2 && f.wire === 2) {
        let i = 0;
        while (i < f.value.length) {
          let v;
          [v, i] = pbReadVarint(f.value, i);
          feat.tags.push(v);
        }
      }
    }
    for (let i = 0; i + 1 < feat.tags.length; i += 2) {
      if (keyRemap.has(feat.tags[i])) usedValues.add(feat.tags[i + 1]);
    }
    parsed.push(feat);
  }

  const valRemap = new Map();
  const keptValues = [];
  values.forEach((vb, idx) => {
    if (usedValues.has(idx)) {
      valRemap.set(idx, keptValues.length);
      keptValues.push(vb);
    } else {
      stats.droppedValues += 1;
    }
  });

  const out = [];
  pbWriteVarint(out, 15 * 8 + 0);
  pbWriteVarint(out, version);
  if (name) pbWriteBytes(out, 1, name);
  for (const feat of parsed) pbWriteBytes(out, 2, encodeFeature(feat, keyRemap, valRemap));
  for (const i of keptKeys) pbWriteBytes(out, 3, keys[i]);
  for (const vb of keptValues) pbWriteBytes(out, 4, vb);
  pbWriteVarint(out, 5 * 8 + 0);
  pbWriteVarint(out, extent);
  return Buffer.from(out);
}

function stripTile(buf, keepLayers) {
  const stats = { droppedKeys: 0, droppedValues: 0, droppedLayers: 0 };
  const out = [];
  for (const f of pbFields(buf)) {
    if (f.field === 3 && f.wire === 2) {
      const layer = stripLayer(f.value, keepLayers, stats);
      if (layer) pbWriteBytes(out, 3, layer);
    }
  }
  return { buffer: Buffer.from(out), stats };
}

/**
 * 清理不再需要的字体文件：
 *   - 删掉不在 FONTSTACKS 里的字体栈目录（例如 --fonts 只留 Regular 时，删掉 Italic/Bold）
 *   - 删掉不在 NEEDED_RANGES 里的区间文件
 * 保证反复执行 pnpm map:fetch 时体积会收敛，而不是越积越多。
 */
async function pruneFonts() {
  const fontsDir = path.join(OUT_DIR, 'fonts');
  let dirs = [];
  try {
    dirs = await readdir(fontsDir, { withFileTypes: true });
  } catch {
    return;
  }
  const keepStacks = new Set(FONTSTACKS);
  const keepRanges = new Set([...NEEDED_RANGES].map((r) => r * 256 + '-' + (r * 256 + 255)));
  let removed = 0;
  let freed = 0;
  for (const d of dirs) {
    if (!d.isDirectory()) continue;
    const full = path.join(fontsDir, d.name);
    if (!keepStacks.has(d.name)) {
      for (const f of await readdir(full)) {
        const s = await fileSize(path.join(full, f));
        if (s > 0) freed += s;
      }
      await rm(full, { recursive: true, force: true });
      removed += 1;
      log('  移除未使用的字体栈: ' + d.name);
      continue;
    }
    for (const f of await readdir(full)) {
      if (!f.endsWith('.pbf')) continue;
      if (!keepRanges.has(f.slice(0, -4))) {
        const s = await fileSize(path.join(full, f));
        if (s > 0) freed += s;
        await rm(path.join(full, f), { force: true });
        removed += 1;
      }
    }
  }
  if (removed) log('  清理多余字体文件 ' + removed + ' 个，释放 ' + fmtMB(freed));
}

// --------------------------------------------------------------------------
// 1. 解析源样式
// --------------------------------------------------------------------------
log('> 读取源样式:', path.relative(ROOT, STYLE_SRC));
const style = JSON.parse(await readFile(STYLE_SRC, 'utf8'));

const srcVec = style.sources && style.sources[VECTOR_SOURCE_ID];
if (!srcVec) throw new Error('源样式里找不到矢量源 ' + VECTOR_SOURCE_ID);

let tileTemplate;
if (srcVec.url) {
  log('  矢量源 TileJSON:', srcVec.url);
  const { buffer } = await fetchBuffer(srcVec.url);
  const tilejson = JSON.parse(buffer.toString('utf8'));
  tileTemplate = tilejson.tiles[0];
} else {
  tileTemplate = srcVec.tiles[0];
}
log('  瓦片模板:', tileTemplate);

// 收集样式中实际使用的字体栈
const fontstacks = new Set();
for (const layer of style.layers || []) {
  const tf = layer.layout && layer.layout['text-font'];
  if (Array.isArray(tf)) tf.forEach((f) => fontstacks.add(f));
}
// 代码里 vjmap.Symbol 手动指定过的字体栈
for (const extra of String(args['extra-fonts'] ?? 'Noto Sans Regular').split(',')) {
  if (extra.trim()) fontstacks.add(extra.trim());
}
let FONTSTACKS = [...fontstacks];
// 字体是体积大头：字形是 SDF 位图，单个区间约 150KB，一个字体栈 150 个区间就约 25MB，
// 样式里 Regular/Italic/Bold 三个栈全下会到 75MB —— 比瓦片还大。
// 所以默认只保留一个字体栈（Noto Sans Regular），并把样式里所有 text-font 改写过去。
//   --fonts="Noto Sans Regular,Noto Sans Italic"  保留多个字体栈
//   --fonts=                                     留空则沿用样式里的全部字体栈
const FONTS_ARG = args.fonts === undefined ? 'Noto Sans Regular' : String(args.fonts);
if (FONTS_ARG) {
  const list = FONTS_ARG.split(',')
    .map((s) => s.trim())
    .filter(Boolean);
  if (list.length) FONTSTACKS = list;
}
log('  字体栈:', FONTSTACKS.join(' | '));
// 样式引用到的 source-layer，精简瓦片时只保留这些图层
const KEEP_SOURCE_LAYERS = new Set((style.layers || []).map((l) => l['source-layer']).filter(Boolean));

// --------------------------------------------------------------------------
// 2. 下载矢量瓦片
// --------------------------------------------------------------------------
await ensureDir(path.join(OUT_DIR, 'tiles'));

const tileJobs = [];
for (let z = MINZOOM; z <= MAXZOOM; z++) {
  const r = tileRangeForZoom(z);
  for (let x = r.x0; x <= r.x1; x++) {
    for (let y = r.y0; y <= r.y1; y++) tileJobs.push({ z, x, y });
  }
}
log('> 矢量瓦片: z' + MINZOOM + '-z' + MAXZOOM + '，共 ' + tileJobs.length + ' 张');
for (const t of TIERS) {
  log(
    '  z' + t.min + '-z' + t.max +
      '  lon[' + t.bbox[0] + ',' + t.bbox[2] + '] lat[' + t.bbox[1] + ',' + t.bbox[3] + ']',
  );
}

let tilesBytes = 0;
let tilesSkipped = 0;
const t0 = Date.now();

await pool(
  tileJobs,
  CONCURRENCY,
  async (job) => {
    const dir = path.join(OUT_DIR, 'tiles', String(job.z), String(job.x));
    const file = path.join(dir, job.y + '.pbf');
    const existing = SKIP_EXISTING ? await fileSize(file) : -1;
    if (existing >= 0) {
      tilesBytes += existing;
      tilesSkipped += 1;
      return;
    }
    const url = tileTemplate
      .replace('{z}', job.z)
      .replace('{x}', job.x)
      .replace('{y}', job.y);
    const { buffer } = await fetchBuffer(url);
    await ensureDir(dir);
    // 空瓦片也写空文件，避免浏览器 404 反复报错
    await writeFile(file, buffer);
    tilesBytes += buffer.length;
  },
  (d, total) => {
    const elapsed = (Date.now() - t0) / 1000;
    log(
      '  ' +
        d +
        '/' +
        total +
        '  ' +
        fmtMB(tilesBytes) +
        '  用时 ' +
        elapsed.toFixed(0) +
        's  (' +
        (d / Math.max(elapsed, 1)).toFixed(1) +
        ' 张/s)',
    );
  },
);
log('  OK 瓦片完成: ' + fmtMB(tilesBytes) + (tilesSkipped ? '（跳过已存在 ' + tilesSkipped + ' 张）' : ''));

// --------------------------------------------------------------------------
// 2.5 精简矢量瓦片（删除样式用不到的 name:xx / 值 / 图层）
// --------------------------------------------------------------------------
let strippedBytes = tilesBytes;
if (STRIP_TILES) {
  log('> 精简矢量瓦片：删除样式未使用的 name：xx 字段与图层 …');
  const t1 = Date.now();
  let before = 0;
  let after = 0;
  let droppedLayers = 0;
  let droppedKeys = 0;
  let touched = 0;
  await pool(
    tileJobs,
    32,
    async (job) => {
      const file = path.join(OUT_DIR, 'tiles', String(job.z), String(job.x), job.y + '.pbf');
      const size = await fileSize(file);
      if (size <= 0) return;
      const raw = await readFile(file);
      const { buffer, stats } = stripTile(raw, KEEP_SOURCE_LAYERS);
      droppedLayers += stats.droppedLayers;
      droppedKeys += stats.droppedKeys;
      if (buffer.length !== raw.length || stats.droppedLayers || stats.droppedKeys) {
        await writeFile(file, buffer);
        touched += 1;
      }
      before += raw.length;
      after += buffer.length;
    },
    (d, total) => {
      if (d % 1000 === 0 || d === total) log('  ' + d + '/' + total + '  用时 ' + ((Date.now() - t1) / 1000).toFixed(0) + 's');
    },
  );
  strippedBytes = after;
  log(
    '  OK 精简完成: ' + fmtMB(before) + ' -> ' + fmtMB(after) +
      '（省 ' + fmtMB(before - after) + '，改写 ' + touched + ' 张；删除 name 键 ' + droppedKeys + ' 个、图层 ' + droppedLayers + ' 个）',
  );
} else {
  log('  跳过瓦片精简（--no-strip）');
}

// --------------------------------------------------------------------------
// 3. 统计瓦片内文字字符 -> 推导需要的字形区间（避免下载 50MB+ 全量 CJK）
// --------------------------------------------------------------------------
const NEEDED_RANGES = new Set([0, 1]);

if (GLYPH_MODE === 'all') {
  // 全量：0-65535 的 256 个区间。虽然体积最大，但可以彻底避免
  // “某个字符所在区间没下载 → 空响应 → vjmap 报 i5.glyphs is not iterable”。
  for (let r = 0; r <= 255; r++) NEEDED_RANGES.add(r);
  log('  全量字形模式：每个字体栈 256 个区间');
} else if (GLYPH_MODE === 'all-cjk') {
  for (let r = 78; r <= 159; r++) NEEDED_RANGES.add(r);
  [2, 3, 4, 48, 49, 255].forEach((r) => NEEDED_RANGES.add(r));
} else {
  log('> 扫描瓦片文字，推导所需字形区间 …');
  // 按 MVT 规范只取真正的字符串：key（layer 的 field 3）和 value 里的 string_value（value 的 field 1）。
  // 不能用「把整个 value 消息当字符串解码」的做法——数字型 value 会被误解码成乱码字符，
  // 从而漏掉真正要用的区间（曾导致缺区间 → glyphs is not iterable）。
  const chars = new Set();
  const decoder = new TextDecoder('utf-8', { fatal: true });

  function addString(bytes) {
    let s = null;
    try {
      s = decoder.decode(bytes);
    } catch {
      return; // 不是合法 UTF-8，忽略
    }
    for (const ch of s) {
      const cp = ch.codePointAt(0);
      if (cp >= 0x20 && cp < 0x10000) chars.add(cp); // 字形只支持 BMP
    }
  }

  function collectTileStrings(buf) {
    for (const layerField of pbFields(buf)) {
      if (layerField.field !== 3 || layerField.wire !== 2) continue;
      for (const lf of pbFields(layerField.value)) {
        if (lf.field === 3 && lf.wire === 2) {
          addString(lf.value); // key
        } else if (lf.field === 4 && lf.wire === 2) {
          for (const vf of pbFields(lf.value)) {
            if (vf.field === 1 && vf.wire === 2) addString(vf.value); // Value.string_value
          }
        }
      }
    }
  }

  // 统计所有已下载瓦片里的文字：地图上渲染的每个字都来自这些瓦片，
  // 因此按瓦片字符集下载字形区间是完备的（精简瓦片后字符集会进一步变小）
  const scanMinzoom = Number(args['glyph-scan-minzoom'] ?? 0);
  let scanned = 0;
  for (const job of tileJobs) {
    if (job.z < scanMinzoom) continue;
    const fpath = path.join(OUT_DIR, 'tiles', String(job.z), String(job.x), job.y + '.pbf');
    const size = await fileSize(fpath);
    if (size <= 0) continue;
    collectTileStrings(await readFile(fpath));
    scanned++;
  }
  for (const cp of chars) NEEDED_RANGES.add(cp >> 8);
  // 兜底区间：ASCII、拉丁扩展、通用标点、CJK 标点、全角，以及数字（点位数量）
  [0, 1, 2, 3, 4, 32, 33, 48, 49, 255].forEach((r) => NEEDED_RANGES.add(r));
  log('  扫描 ' + scanned + ' 张瓦片，命中 ' + chars.size + ' 个字符，需要 ' + NEEDED_RANGES.size + ' 个字形区间');
}

// --------------------------------------------------------------------------
// 4. 下载 glyphs 字体
// --------------------------------------------------------------------------
log('> 下载 glyphs 字体 …');
const glyphTemplate = style.glyphs.replace('{fontstack}', '__FONT__').replace('{range}', '__RANGE__');
let glyphBytes = 0;
const glyphJobs = [];
for (const font of FONTSTACKS) {
  for (const r of [...NEEDED_RANGES].sort((a, b) => a - b)) {
    const lo = r * 256;
    glyphJobs.push({ font, range: lo + '-' + (lo + 255) });
  }
}

await pool(
  glyphJobs,
  CONCURRENCY,
  async ({ font, range }) => {
    const dir = path.join(OUT_DIR, 'fonts', font);
    const file = path.join(dir, range + '.pbf');
    if (SKIP_EXISTING && (await fileSize(file)) > 0) return;
    const url = glyphTemplate
      .replace('__FONT__', encodeURIComponent(font))
      .replace('__RANGE__', range);
    const { buffer, notFound } = await fetchBuffer(url);
    if (notFound || buffer.length === 0) return;
    await ensureDir(dir);
    await writeFile(file, buffer);
    glyphBytes += buffer.length;
  },
  (d, total) => {
    if (d % 30 === 0 || d === total) log('  ' + d + '/' + total + '  ' + fmtMB(glyphBytes));
  },
);
log(
  '  OK 字体完成: ' +
    fmtMB(glyphBytes) +
    '（' +
    FONTSTACKS.length +
    ' 个字体栈 x ' +
    NEEDED_RANGES.size +
    ' 个区间）',
);
await pruneFonts();

// --------------------------------------------------------------------------
// 5. 下载 sprite 图标
// --------------------------------------------------------------------------
log('> 下载 sprite 图标 …');
await ensureDir(path.join(OUT_DIR, 'sprites'));
const spriteBase = style.sprite;
let spriteBytes = 0;
for (const suffix of ['.json', '.png', '@2x.png']) {
  const { buffer } = await fetchBuffer(spriteBase + suffix);
  if (!buffer.length) continue;
  await writeFile(path.join(OUT_DIR, 'sprites', 'ofm' + suffix), buffer);
  spriteBytes += buffer.length;
}
log('  OK sprite 完成: ' + fmtMB(spriteBytes));

// --------------------------------------------------------------------------
// 6. 生成本地化样式
// --------------------------------------------------------------------------
log('> 生成本地化样式 …');
const outStyle = JSON.parse(JSON.stringify(style));

const usedSources = new Set((style.layers || []).map((l) => l.source).filter(Boolean));
const sources = {};
for (const [id, src] of Object.entries(style.sources)) {
  if (!usedSources.has(id) && UNUSED_SOURCES.includes(id)) {
    log('  移除未被引用的瓦片源: ' + id);
    continue;
  }
  if (id === VECTOR_SOURCE_ID) {
    sources[id] = {
      type: 'vector',
      scheme: 'xyz',
      tiles: [BASE + 'tiles/{z}/{x}/{y}.pbf'],
      minzoom: MINZOOM,
      maxzoom: MAXZOOM,
    };
    if (src.attribution) sources[id].attribution = src.attribution;
    continue;
  }
  sources[id] = src;
}
outStyle.sources = sources;
outStyle.glyphs = BASE + 'fonts/{fontstack}/{range}.pbf';
if (FONTS_ARG && FONTSTACKS.length) {
  const only = FONTSTACKS[0];
  for (const l of outStyle.layers || []) {
    if (l.layout && Array.isArray(l.layout['text-font'])) l.layout['text-font'] = [only];
  }
  log('  已将样式内全部 text-font 统一为: ' + only);
}
if (SPRITE_BASE) {
  outStyle.sprite = SPRITE_BASE;
  log('  sprite 使用绝对地址: ' + SPRITE_BASE);
} else {
  delete outStyle.sprite;
  log('  不写入 sprite 字段（vjmap 只接受绝对地址；地图正常，仅 POI 图标不显示）');
  log('  需要图标请加 --sprite-base=http://<内网域名或IP>/map/sprites/ofm');
}
outStyle.name = (style.name || 'Custom') + ' (offline)';
// 只记录 OpenFreeMap 的数据版本号，不残留任何外网 URL
const sourceVersion = (/:\/\/[^/]+\/planet\/([^/]+)\//.exec(tileTemplate) || [])[1] || '';
outStyle.metadata = Object.assign({}, outStyle.metadata || {}, {
  'x-offline': {
    generatedAt: new Date().toISOString(),
    sourceVersion,
    tiers: TIERS.map((t) => ({ zoom: 'z' + t.min + '-z' + t.max, bbox: t.bbox })),
    minzoom: MINZOOM,
    maxzoom: MAXZOOM,
  },
});

await ensureDir(path.dirname(STYLE_OUT));
// 样式内容没变化时不重写文件，避免每次 map:fetch 都产生一个只有时间戳差异的 diff
const sameStyle = await isSameStyle(outStyle);
if (sameStyle) {
  log('  样式内容未变化，跳过写入: ' + path.relative(ROOT, STYLE_OUT));
} else {
  await writeFile(STYLE_OUT, JSON.stringify(outStyle, null, 2));
}

/** 忽略 x-offline.generatedAt，判断新旧样式是否等价 */
async function isSameStyle(next) {
  let prevText;
  try {
    prevText = await readFile(STYLE_OUT, 'utf8');
  } catch {
    return false;
  }
  try {
    const prev = JSON.parse(prevText);
    const norm = (s) => {
      const c = JSON.parse(JSON.stringify(s));
      if (c.metadata && c.metadata['x-offline']) c.metadata['x-offline'].generatedAt = '';
      return JSON.stringify(c);
    };
    return norm(prev) === norm(next);
  } catch {
    return false;
  }
}

// --------------------------------------------------------------------------
// 汇总
// --------------------------------------------------------------------------
log('');
log('======== 完成 ========');
log('样式文件  :', path.relative(ROOT, STYLE_OUT));
log('矢量瓦片  :', fmtMB(strippedBytes), '(' + tileJobs.length + ' 张' + (STRIP_TILES ? '，已精简' : '') + ')');
log('字体字形  :', fmtMB(glyphBytes));
log('图标雪碧  :', fmtMB(spriteBytes));
log('合计      :', fmtMB(strippedBytes + glyphBytes + spriteBytes));
log('资源前缀  :', BASE);
log('提示      : 用 --skip-existing 断点续传；--maxzoom=12 可再细一级。');