// match_methods.js - 用客户端 dump 出的 methodId 表去扫抓包帧，验证"线上哪个字段是 methodId"
// 用法: node match_methods.js [--root ../packets/plain] [--table ../names/method_table.json] [--limit 40]
// 原理:
//   names/method_table.json 是 methodId(64 位) → modelId → 模型类/codec（客户端注册表 dump）。
//   空间层的 RPC 分发是 mr.l7n(ctx, methodId, data)，所以帧里应能找到 methodId 的 8 字节大端。
//   命中即说明该帧属于哪个模型（命令），从而把命令语义一个个钉死。
const fs = require('fs');
const path = require('path');
const zlib = require('zlib');

const Argv = process.argv.slice(2);
const Arg = (Name, Def) => {
  const I = Argv.indexOf('--' + Name);
  return I >= 0 && Argv[I + 1] ? Argv[I + 1] : Def;
};

const PROJECT = path.resolve(__dirname, '..');
const Root = path.resolve(Arg('root', path.join(PROJECT, 'packets', 'plain')));
const TablePath = path.resolve(Arg('table', path.join(PROJECT, 'names', 'method_table.json')));
const Limit = Number(Arg('limit', '40')) || 40;

const Table = JSON.parse(fs.readFileSync(TablePath, 'utf8'));
// methodId → 模型信息；同时准备 8 字节大端字节串
const ByHex = new Map();
for (const R of Table.Rows) {
  const Big = BigInt(R.MethodId);
  const Buf = Buffer.alloc(8);
  Buf.writeBigInt64BE(Big);
  ByHex.set(Buf.toString('hex'), R);
}

function Unwrap(Buf) {
  const B0 = Buf[0];
  const HeaderSize = B0 & 0x80 ? 4 : 2;
  let Body = Buf.slice(HeaderSize);
  if (B0 & 0x40) {
    try {
      Body = zlib.inflateSync(Body);
    } catch (Err) {
      return null;
    }
  }
  return Body;
}

if (!fs.existsSync(Root)) {
  console.log('目录不存在: ' + Root);
  process.exit(1);
}

const Hits = [];
let Scanned = 0;
for (const Space of fs.readdirSync(Root).sort()) {
  const Dir = path.join(Root, Space);
  if (!fs.statSync(Dir).isDirectory()) continue;
  for (const F of fs.readdirSync(Dir)) {
    if (!/\.bin$/.test(F)) continue;
    const Raw = fs.readFileSync(path.join(Dir, F));
    const Body = Unwrap(Raw);
    if (!Body || Body.length < 8) continue;
    Scanned++;
    for (let Off = 0; Off + 8 <= Body.length; Off++) {
      const Hex = Body.slice(Off, Off + 8).toString('hex');
      const R = ByHex.get(Hex);
      if (R) Hits.push({ File: Space + '/' + F, Off, Size: Raw.length, Model: R.Model, MethodId: R.MethodId, Codec: R.Codec, CodecFields: R.CodecFields });
    }
  }
}

console.log('扫描文件 ' + Scanned + ' 个，命中 methodId ' + Hits.length + ' 处');
const Count = {};
for (const H of Hits) Count[H.Model] = (Count[H.Model] || 0) + 1;
console.log('命中模型分布: ' + JSON.stringify(Count));
console.log('');
for (const H of Hits.slice(0, Limit)) {
  console.log(
    H.File.padEnd(30) + ' @' + String(H.Off).padStart(5) + '  ' + H.Size + 'B  model=' + H.Model +
      '  codec=' + H.Codec + '  codecFields=' + String(H.CodecFields).slice(0, 70),
  );
}