// @dsh-local/carbon-mcp-probe — host 半区（POC 探针）
//
// 本包在 host 侧只做一件事：**取证**。
// 真正的 MCP 挂载不在这里写代码，而是由同目录的 cordis.patch.yml
// insert 一条内核 `@deepseek-ai/dsh-mcp-client` entry 完成 —— 这正是本轮要验证的契约。
//
// 探针把「boot 后 ctx.tools 注册表里到底有没有 MCP 工具」落成 JSON 证据文件，
// 使验收不依赖 agent / 模型 / 界面。

import { appendFileSync, writeFileSync } from "node:fs";

const DUMP = process.env.CARBON_PROBE_DUMP || "/tmp/carbon-probe-dump.json";
const LOG = process.env.CARBON_PROBE_LOG || "/tmp/carbon-probe-host.log";
const DELAY_MS = Number(process.env.CARBON_PROBE_DELAY_MS || 8000);

function log(line) {
  const row = `${new Date().toISOString()} ${line}\n`;
  try { appendFileSync(LOG, row); } catch { /* 日志不可写不致命 */ }
  process.stdout.write(`[carbon-mcp-probe] ${row}`);
}

/** 在有界预算内 BFS 一个对象图，收集所有含 needle 的键/字符串路径。 */
function bfsFind(root, needle, maxDepth = 5, maxNodes = 600) {
  const seen = new Set();
  const hits = [];
  const queue = [[root, "$", 0]];
  let visited = 0;
  while (queue.length && visited < maxNodes) {
    const [value, path, depth] = queue.shift();
    if (value === null || value === undefined) continue;
    const t = typeof value;
    if (t !== "object" && t !== "function") {
      if (t === "string" && value.includes(needle)) hits.push({ path, kind: "string", value: value.slice(0, 160) });
      continue;
    }
    if (seen.has(value)) continue;
    seen.add(value);
    visited += 1;

    let keys = [];
    try { keys = Object.getOwnPropertyNames(value); } catch { continue; }
    for (const k of keys) {
      if (k.includes(needle)) hits.push({ path: `${path}.${k}`, kind: "KEY" });
      if (depth + 1 > maxDepth) continue;
      let child;
      try { child = value[k]; } catch { continue; }   // getter 抛错就跳过，绝不冒泡
      const childPath = `${path}.${k}`;
      if (child instanceof Map) {
        let i = 0;
        for (const [mk, mv] of child) {
          const mp = `${childPath}{Map}["${String(mk)}"]`;
          if (String(mk).includes(needle)) hits.push({ path: mp, kind: "MAPKEY" });
          if (i++ > 250) break;
          queue.push([mv, mp, depth + 1]);
        }
      } else if (Array.isArray(child)) {
        child.slice(0, 60).forEach((v, i) => queue.push([v, `${childPath}[${i}]`, depth + 1]));
      } else if (typeof child === "string") {
        if (child.includes(needle)) hits.push({ path: childPath, kind: "string", value: child.slice(0, 160) });
      } else if (child !== null && typeof child === "object") {
        queue.push([child, childPath, depth + 1]);
      }
    }
  }
  return { hits, visited, truncated: queue.length > 0 };
}

function probeTools(ctx) {
  const rec = { ts: new Date().toISOString(), pid: process.pid };

  // 通道 A：直接属性（未声明 inject 时应报错 —— 这本身是契约事实）
  try {
    const direct = ctx.tools;
    rec.channelA = { ok: true, type: typeof direct };
  } catch (e) {
    rec.channelA = { ok: false, error: String(e) };
  }

  // 通道 B：ctx.get(name)
  let tools = null;
  try {
    tools = typeof ctx.get === "function" ? ctx.get("tools") : null;
    rec.channelB = { ok: !!tools, name: tools && tools.name };
  } catch (e) {
    rec.channelB = { ok: false, error: String(e) };
  }
  if (!tools) return rec;

  // 通道 C：已知候选方法（不预设签名，逐个试）
  rec.channelC = {};
  for (const m of ["list", "view", "schemas", "sdkSchemas", "get", "names"]) {
    try {
      if (typeof tools[m] !== "function") { rec.channelC[m] = { skipped: "not a function" }; continue; }
      const v = typeof tools[m] === "function" ? tools[m]() : undefined;
      if (v && typeof v.then === "function") { rec.channelC[m] = { async: true }; continue; }
      rec.channelC[m] = { type: typeof v, preview: JSON.stringify(v).slice(0, 400) };
    } catch (e) {
      rec.channelC[m] = { threw: String(e).slice(0, 200) };
    }
  }

  // 通道 D：有界 BFS —— 不依赖任何 API 形状，直接找 mcp__ 命名
  try {
    rec.channelD = bfsFind(tools, "mcp__");
    rec.hasMcpQualified = rec.channelD.hits.length > 0;
  } catch (e) {
    rec.channelD = { error: String(e) };
    rec.hasMcpQualified = false;
  }

  // 通道 E：同上，只要 carbonprobe 片段（防命名前缀差异）
  try {
    rec.channelE = bfsFind(tools, "carbonprobe", 5, 600);
  } catch (e) {
    rec.channelE = { error: String(e) };
  }

  return rec;
}

export function apply(ctx) {
  log(`apply pid=${process.pid} node=${process.version} dump=${DUMP}`);
  const timer = setTimeout(() => {
    let rec;
    try { rec = probeTools(ctx); }
    catch (e) { rec = { ts: new Date().toISOString(), fatal: String(e) }; }
    try { writeFileSync(DUMP, JSON.stringify(rec, null, 2)); log(`dump written -> ${DUMP}`); }
    catch (e) { log(`dump write failed: ${e}`); }
    log(`SUMMARY hasMcpQualified=${rec.hasMcpQualified} D.hits=${JSON.stringify(rec.channelD?.hits || []).slice(0, 800)}`);
  }, DELAY_MS);
  timer.unref?.();
}