// selftest.js - MakeWriter 往返自检：拿抓包里的真实空间帧，逐字段解码 → 再编码 → 与原字节比对
//
// 这是写包能力的唯一验收手段：真服务器要能发 s2c，前提是「解出来再写回去」必须逐字节一致。
// 覆盖不到的地方（容器 lt/pt/zt、模块内建 codec 如 Ea）会被单独计数并列出，作为 M2 的待补清单。
//
// 用法: node server/selftest.js [--dir ../packets/plain] [--limit 0] [--show 5]
'use strict';
const fs = require('fs');
const path = require('path');
const { LoadTables, MakeReader } = require('../lib_space_codec');
const Link = require('./link');
const { MakeWriter, ResolveFields } = require('./codec');
const { MakeContainerCodec } = require('./container');

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('dir', path.join(PROJECT, 'packets', 'plain')));
const Limit = Number(Arg('limit', '0')) || 0;
const Show = Number(Arg('show', '5')) || 5;

const Tables = LoadTables(path.join(PROJECT, 'names'));
const Reader = MakeReader(Tables, { EnumBytes: 4 });
const Writer = MakeWriter(Tables, { EnumBytes: 4 });
const Container = MakeContainerCodec(Tables, Reader, Writer);

// 容器帧（methodId 不在普通 codec / 上行表里）：用容器三布局判定，要求恰好吃到帧尾
const BoxStat = { Tried: 0, Detected: 0, Exact: 0, Bad: 0, ByLayout: new Map(), FailSamples: [] };
function TryContainer(Body, At, File) {
  if (At + 16 > Body.length) return;
  const MethodId = Body.readBigInt64BE(At + 8).toString();
  if (Tables.CodecByMethod.has(MethodId) || Tables.UplinkByMethod.has(MethodId)) return;
  BoxStat.Tried++;
  const Off = At + 16;
  const Hits = ['zt', 'pt', 'lt'].filter((L) => {
    const R = Container.Read(L, Body, Off);
    return !R.Bad && R.Next === Body.length;
  });
  if (!Hits.length) {
    BoxStat.Bad++;
    if (BoxStat.FailSamples.length < 5) BoxStat.FailSamples.push(File + ' methodId=' + MethodId);
    return;
  }
  BoxStat.Detected++;
  const Layout = Hits[0];
  BoxStat.ByLayout.set(Layout, (BoxStat.ByLayout.get(Layout) || 0) + 1);
  const R = Container.Read(Layout, Body, Off);
  try {
    if (Container.Write(Layout, R.Value).equals(Body.slice(Off))) BoxStat.Exact++;
    else Note('容器写回不一致', File + ' ' + Layout);
  } catch (Err) {
    Note('容器写侧抛错', File + ' ' + Layout + ' ' + Err.message);
  }
}

// 首字节是第一个 id 的最高位，且 8 字节后的 methodId 在「下行 codec 表」或「上行命令表」里 → 认作空间记录流
// （实测两张表的 methodId 基本不重合：上行 360 条只在 uplink_table，下行 codec 只在 codec_fields）
function IsSpaceLike(Body, At) {
  if (At >= Body.length) return false;
  const B0 = Body[At];
  if (B0 !== 0x00 && B0 !== 0xff) return false;
  if (At + 16 > Body.length) return false;
  const M = Body.readBigInt64BE(At + 8).toString();
  return Tables.CodecByMethod.has(M) || Tables.UplinkByMethod.has(M);
}

const Stats = { Dirs: 0, Files: 0, Frames: 0, SpaceFrames: 0, Records: 0, Exact: 0, Bad: 0, Unsupported: 0, Mismatch: 0 };
const UnsupportedKinds = new Map();
const BadSamples = [];
const MismatchSamples = [];

function Note(Kind, Msg) {
  UnsupportedKinds.set(Kind, (UnsupportedKinds.get(Kind) || 0) + 1);
  if (BadSamples.length < 20) BadSamples.push(Kind + '  ' + Msg);
}

function ScanFile(File) {
  Stats.Files++;
  const Buf = fs.readFileSync(File);
  const Frames = Link.ParseFrames(Buf);
  if (!Frames) return;
  for (const Frame of Frames) {
    Stats.Frames++;
    let Body;
    try {
      Body = Link.DecodeFrame(Frame);
    } catch (Err) {
      continue;
    }
    const At = Link.NullmapSize(Body, 0);
    if (!IsSpaceLike(Body, At)) {
      TryContainer(Body, At, path.basename(File));
      continue;
    }
    Stats.SpaceFrames++;
    let Off = At + 8;
    while (Off + 8 <= Body.length) {
      const MethodId = Body.readBigInt64BE(Off).toString();
      const { Codec, Fields } = ResolveFields(Tables, MethodId, Tables.UplinkByMethod.get(MethodId));
      if (!Codec && !Fields.length) break;
      const Label = Codec ? Codec.ModelName || Codec.ModelClassReal || '?' : '上行命令';
      const MethodRaw = Body.slice(Off, Off + 8);
      const Start = Off;
      Off += 8;
      const Values = [];
      let Bad = false;
      for (const F of Fields) {
        const R = Reader.ReadValue(Body, Off, F.Type, F.TypeCodec, 0);
        Values.push([F, R.Value]);
        if (R.Bad || R.Next <= Off) {
          Bad = true;
          break;
        }
        Off = R.Next;
      }
      Stats.Records++;
      if (Bad) {
        Stats.Bad++;
        Note('解码中断', Label + ' methodId=' + MethodId);
        continue;
      }
      const Original = Body.slice(Start, Off);
      let Encoded = null;
      try {
        const Parts = [MethodRaw];
        for (const [F, V] of Values) Parts.push(Writer.WriteValue(F.Type, F.TypeCodec, V, 0));
        Encoded = Buffer.concat(Parts);
      } catch (Err) {
        Stats.Unsupported++;
        Note(String(Err.message).split(':')[0], Label + ' methodId=' + MethodId);
        continue;
      }
      if (Encoded.equals(Original)) Stats.Exact++;
      else {
        Stats.Mismatch++;
        if (MismatchSamples.length < Show) {
          MismatchSamples.push(
            Label + ' methodId=' + MethodId + '\n      原 ' + Original.toString('hex').slice(0, 160) +
              '\n      写 ' + Encoded.toString('hex').slice(0, 160),
          );
        }
      }
    }
  }
}

function ScanDir(Dir) {
  for (const E of fs.readdirSync(Dir, { withFileTypes: true })) {
    const P = path.join(Dir, E.name);
    if (E.isDirectory()) {
      Stats.Dirs++;
      ScanDir(P);
    } else if (/^[cs]2[cs]_\d+\.bin$/.test(E.name)) {
      if (Limit && Stats.Files >= Limit) return;
      ScanFile(P);
    }
  }
}

ScanDir(Root);

console.log('MakeWriter 往返自检（' + Root + '）');
console.log('  目录 ' + Stats.Dirs + '  文件 ' + Stats.Files + '  帧 ' + Stats.Frames + '  空间帧 ' + Stats.SpaceFrames);
console.log('  记录 ' + Stats.Records + '');
console.log('    ✓ 逐字节一致 ' + Stats.Exact);
console.log('    ✗ 不一致     ' + Stats.Mismatch);
console.log('    ⚠ 解码中断   ' + Stats.Bad);
console.log('    ⚠ 写侧不支持 ' + Stats.Unsupported + '（类型/编码还没做）');
if (UnsupportedKinds.size) {
  console.log('  写侧不支持的原因（Top 10）:');
  for (const [K, V] of [...UnsupportedKinds].sort((A, B) => B[1] - A[1]).slice(0, 10)) console.log('    ' + String(V).padStart(6) + '  ' + K);
}
if (BadSamples.length) {
  console.log('  样本（前 10）:');
  for (const S of BadSamples.slice(0, 10)) console.log('    ' + S);
}
if (MismatchSamples.length) {
  console.log('  不一致样例:');
  for (const S of MismatchSamples) console.log('    ' + S);
}
console.log('  容器帧（methodId 不在普通 codec / 上行表里）: 候选 ' + BoxStat.Tried + '  判定出布局 ' + BoxStat.Detected + '  逐字节一致 ' + BoxStat.Exact + '  判定失败 ' + BoxStat.Bad);
if (BoxStat.ByLayout.size) console.log('    布局分布: ' + JSON.stringify([...BoxStat.ByLayout]));
for (const S of BoxStat.FailSamples) console.log('    判定失败样例: ' + S);