// sessions.js —— 读取 / 解析 / 导出 / 备份 / 导入 Codex 会话记录。
// 直接读 ~/.codex/sessions / archived_sessions 下的 rollout-*.jsonl，不依赖数据库，跨平台。
const fs = require("fs");
const path = require("path");
const { spawnSync } = require("child_process");
const initSqlJs = require("sql.js");
const { cleanThreadTitle, cleanUserVisibleText, stripInternalThoughtBlocks, looksLikeSkillMentionTitle } = require("./title_clean");
const codexDataDir = require("./codex_data_dir");

let permanentDeleteBusy = false;

function paths() {
  const codexHome = codexDataDir.get();
  return {
    codexHome,
    sessionsDir: path.join(codexHome, "sessions"),
    archivedSessionsDir: path.join(codexHome, "archived_sessions"),
    sessionIndex: path.join(codexHome, "session_index.jsonl"),
    titleCleanMarker: path.join(codexHome, ".td-title-clean-v1.json"),
  };
}

function isInside(base, file) {
  const rel = path.relative(path.resolve(base), path.resolve(file));
  return rel && !rel.startsWith(".." + path.sep) && rel !== ".." && !path.isAbsolute(rel);
}

function sessionRoots() {
  const { sessionsDir, archivedSessionsDir } = paths();
  return [sessionsDir, archivedSessionsDir];
}

function sessionFileAllowed(file) {
  return sessionRoots().some((root) => isInside(root, file)) &&
    path.basename(file).startsWith("rollout-") && path.extname(file) === ".jsonl";
}

// 递归找出所有 rollout-*.jsonl
function findRolloutFiles(base) {
  const out = [];
  function walk(dir) {
    let ents;
    try {
      ents = fs.readdirSync(dir, { withFileTypes: true });
    } catch {
      return;
    }
    for (const ent of ents) {
      const full = path.join(dir, ent.name);
      if (ent.isDirectory()) walk(full);
      else if (ent.isFile() && ent.name.startsWith("rollout-") && ent.name.endsWith(".jsonl")) out.push(full);
    }
  }
  walk(base);
  return out;
}

// 读取 session_index.jsonl，得到 {会话id: Codex 生成的标题}
function loadIndexTitles() {
  const map = {};
  try {
    const txt = fs.readFileSync(paths().sessionIndex, "utf-8");
    for (const line of txt.split("\n")) {
      if (!line.trim()) continue;
      try {
        const d = JSON.parse(line);
        if (d.id && d.thread_name) map[d.id] = cleanThreadTitle(d.thread_name, "", 80);
      } catch {}
    }
  } catch {}
  return map;
}

// 只读文件开头一段，快速取元信息与首条用户消息（避免整读大文件）
function peekMeta(file) {
  let head = "";
  try {
    const fd = fs.openSync(file, "r");
    const buf = Buffer.alloc(262144); // 256KB：足够越过超长系统提示找到首条用户消息
    const n = fs.readSync(fd, buf, 0, buf.length, 0);
    fs.closeSync(fd);
    head = buf.slice(0, n).toString("utf-8");
  } catch {
    return null;
  }
  const meta = { id: "", cwd: "", ts: "", source: "", threadSource: "", provider: "", title: "" };
  const lines = head.split("\n");
  for (const line of lines) {
    if (!line.trim()) continue;
    let d;
    try {
      d = JSON.parse(line);
    } catch {
      continue; // 可能是被截断的最后一行
    }
    const p = d.payload || {};
    if (d.type === "session_meta") {
      meta.id = p.session_id || p.id || "";
      meta.cwd = p.cwd || "";
      meta.ts = p.timestamp || d.timestamp || "";
      meta.source = p.source || "";
      meta.threadSource = p.thread_source || "";
      meta.provider = p.model_provider || "";
    } else if (d.type === "event_msg" && p.type === "user_message" && !meta.title) {
      meta.title = cleanThreadTitle(p.message || "", "", 200);
    }
    if (meta.id && meta.title) break;
  }
  return meta;
}

function sqlite3Available() {
  const r = spawnSync("sqlite3", ["--version"], { encoding: "utf-8" });
  return !r.error && r.status === 0;
}

function runSqlite3(dbPath, sql) {
  const r = spawnSync("sqlite3", ["-json", dbPath, sql], {
    encoding: "utf-8",
    maxBuffer: 20 * 1024 * 1024,
  });
  if (r.error || r.status !== 0) {
    throw new Error((r.stderr || (r.error && r.error.message) || "sqlite3 执行失败").trim());
  }
  return r.stdout || "";
}

function quoteIdent(value) {
  return "\"" + String(value || "").replace(/"/g, "\"\"") + "\"";
}

function sqliteTables(dbPath) {
  try {
    return JSON.parse(runSqlite3(dbPath, "SELECT name FROM sqlite_master WHERE type='table' AND name NOT LIKE 'sqlite_%';") || "[]");
  } catch {
    return [];
  }
}

function sqliteTableInfo(dbPath, table) {
  try {
    return JSON.parse(runSqlite3(dbPath, "PRAGMA table_info(" + quoteIdent(table) + ");") || "[]");
  } catch {
    return [];
  }
}

function sqliteForeignKeys(dbPath, table) {
  try {
    return JSON.parse(runSqlite3(dbPath, "PRAGMA foreign_key_list(" + quoteIdent(table) + ");") || "[]");
  } catch {
    return [];
  }
}

function sqlJsRows(db, statement) {
  const result = db.exec(statement);
  if (!result.length) return [];
  const columns = result[0].columns;
  return result[0].values.map((values) => Object.fromEntries(columns.map((name, index) => [name, values[index]])));
}

function sqliteBufferWithCommittedWal(dbPath) {
  let main = fs.readFileSync(dbPath);
  const walPath = dbPath + "-wal";
  if (!fs.existsSync(walPath)) return main;
  const wal = fs.readFileSync(walPath);
  if (wal.length < 32) return main;
  const magic = wal.readUInt32BE(0);
  if (magic !== 0x377f0682 && magic !== 0x377f0683) throw new Error("SQLite WAL 头无效，已停止删除");
  let pageSize = wal.readUInt32BE(8);
  if (pageSize === 1) pageSize = 65536;
  if (!pageSize || (pageSize & (pageSize - 1)) !== 0) throw new Error("SQLite WAL 页大小无效，已停止删除");
  const frameSize = 24 + pageSize;
  const salt1 = wal.readUInt32BE(16);
  const salt2 = wal.readUInt32BE(20);
  const littleEndianChecksum = magic === 0x377f0682;
  const checksum = (buffer, start, end, sums) => {
    let [s1, s2] = sums;
    for (let offset = start; offset < end; offset += 8) {
      const a = littleEndianChecksum ? buffer.readUInt32LE(offset) : buffer.readUInt32BE(offset);
      const b = littleEndianChecksum ? buffer.readUInt32LE(offset + 4) : buffer.readUInt32BE(offset + 4);
      s1 = (s1 + a + s2) >>> 0;
      s2 = (s2 + b + s1) >>> 0;
    }
    return [s1, s2];
  };
  let sums = checksum(wal, 0, 24, [0, 0]);
  if (sums[0] !== wal.readUInt32BE(24) || sums[1] !== wal.readUInt32BE(28)) {
    throw new Error("SQLite WAL 校验失败，已停止删除");
  }
  let lastCommitOffset = -1;
  let committedPages = 0;
  for (let offset = 32; offset + frameSize <= wal.length; offset += frameSize) {
    if (wal.readUInt32BE(offset + 8) !== salt1 || wal.readUInt32BE(offset + 12) !== salt2) break;
    sums = checksum(wal, offset, offset + 8, sums);
    sums = checksum(wal, offset + 24, offset + 24 + pageSize, sums);
    if (sums[0] !== wal.readUInt32BE(offset + 16) || sums[1] !== wal.readUInt32BE(offset + 20)) break;
    const dbSize = wal.readUInt32BE(offset + 4);
    if (dbSize > 0) {
      lastCommitOffset = offset;
      committedPages = dbSize;
    }
  }
  if (lastCommitOffset < 0) return main;
  const merged = Buffer.alloc(committedPages * pageSize);
  main.copy(merged, 0, 0, Math.min(main.length, merged.length));
  for (let offset = 32; offset <= lastCommitOffset; offset += frameSize) {
    const pageNo = wal.readUInt32BE(offset);
    if (!pageNo || pageNo > committedPages) continue;
    wal.copy(merged, (pageNo - 1) * pageSize, offset + 24, offset + 24 + pageSize);
  }
  return merged;
}

function replaceStateDb(dbPath, data) {
  const tmp = dbPath + ".td-delete-" + process.pid + ".tmp";
  const old = dbPath + ".td-delete-" + process.pid + ".old";
  const oldWal = old + "-wal";
  const oldShm = old + "-shm";
  fs.rmSync(old, { force: true });
  fs.rmSync(oldWal, { force: true });
  fs.rmSync(oldShm, { force: true });
  const fd = fs.openSync(tmp, "w");
  try {
    fs.writeFileSync(fd, data);
    fs.fsyncSync(fd);
  } finally {
    fs.closeSync(fd);
  }
  let movedMain = false;
  let movedWal = false;
  let movedShm = false;
  let installed = false;
  try {
    fs.renameSync(dbPath, old);
    movedMain = true;
    if (fs.existsSync(dbPath + "-wal")) { fs.renameSync(dbPath + "-wal", oldWal); movedWal = true; }
    if (fs.existsSync(dbPath + "-shm")) { fs.renameSync(dbPath + "-shm", oldShm); movedShm = true; }
    fs.renameSync(tmp, dbPath);
    installed = true;
  } catch (e) {
    if (installed) { try { fs.rmSync(dbPath, { force: true }); } catch {} }
    if (movedMain && fs.existsSync(old) && !fs.existsSync(dbPath)) fs.renameSync(old, dbPath);
    if (movedWal && fs.existsSync(oldWal) && !fs.existsSync(dbPath + "-wal")) fs.renameSync(oldWal, dbPath + "-wal");
    if (movedShm && fs.existsSync(oldShm) && !fs.existsSync(dbPath + "-shm")) fs.renameSync(oldShm, dbPath + "-shm");
    throw e;
  } finally {
    fs.rmSync(tmp, { force: true });
  }
  try { fs.rmSync(old, { force: true }); } catch {}
  try { fs.rmSync(oldWal, { force: true }); } catch {}
  try { fs.rmSync(oldShm, { force: true }); } catch {}
}

async function deleteSessionFromStateDb(SQL, dbPath, id) {
  let db;
  try {
    db = new SQL.Database(sqliteBufferWithCommittedWal(dbPath));
    const tables = sqlJsRows(db, "SELECT name FROM sqlite_master WHERE type='table' AND name NOT LIKE 'sqlite_%'").map((row) => row.name).filter(Boolean);
    if (!tables.includes("threads")) return false;
    db.run("PRAGMA foreign_keys=ON");
    db.run("PRAGMA secure_delete=ON");
    db.run("BEGIN");
    let changed = false;
    for (const table of tables) {
      if (table === "threads") continue;
      const columns = sqlJsRows(db, "PRAGMA table_info(" + quoteIdent(table) + ")").map((row) => String(row.name || ""));
      const fks = sqlJsRows(db, "PRAGMA foreign_key_list(" + quoteIdent(table) + ")");
      const direct = columns.filter((name) => /(^|_)thread_id$/i.test(name));
      const referencesThread = fks.filter((fk) => String(fk.table || "").toLowerCase() === "threads").map((fk) => fk.from).filter(Boolean);
      for (const column of Array.from(new Set(direct.concat(referencesThread)))) {
        db.run("DELETE FROM " + quoteIdent(table) + " WHERE " + quoteIdent(column) + "=?", [id]);
        changed = db.getRowsModified() > 0 || changed;
      }
    }
    db.run("DELETE FROM " + quoteIdent("threads") + " WHERE " + quoteIdent("id") + "=?", [id]);
    changed = db.getRowsModified() > 0 || changed;
    db.run("COMMIT");
    if (changed) {
      db.run("VACUUM");
      const fkErrors = sqlJsRows(db, "PRAGMA foreign_key_check");
      const integrity = sqlJsRows(db, "PRAGMA integrity_check");
      if (fkErrors.length || !integrity.length || integrity.some((row) => String(Object.values(row)[0] || "").toLowerCase() !== "ok")) {
        throw new Error("SQLite 删除后完整性校验失败，已停止替换");
      }
      for (const table of tables) {
        const columns = sqlJsRows(db, "PRAGMA table_info(" + quoteIdent(table) + ")").map((row) => String(row.name || ""));
        for (const column of columns.filter((name) => /(^|_)thread_id$/i.test(name))) {
          const hit = sqlJsRows(db, "SELECT 1 AS hit FROM " + quoteIdent(table) + " WHERE " + quoteIdent(column) + "=" + sql(id) + " LIMIT 1");
          if (hit.length) throw new Error("SQLite 仍有会话关联记录，已停止替换");
        }
      }
      replaceStateDb(dbPath, Buffer.from(db.export()));
    }
    return changed;
  } catch (e) {
    if (db) try { db.run("ROLLBACK"); } catch {}
    throw e;
  } finally {
    if (db) try { db.close(); } catch {}
  }
}

function removeSessionIndexEntry(id) {
  const { sessionIndex } = paths();
  if (!fs.existsSync(sessionIndex)) return false;
  const lines = fs.readFileSync(sessionIndex, "utf-8").split("\n");
  const kept = lines.filter((line) => {
    if (!line.trim()) return true;
    try { return JSON.parse(line).id !== id; } catch { return true; }
  });
  if (kept.length === lines.length) return false;
  const tmp = sessionIndex + ".td-delete-" + process.pid + ".tmp";
  const old = sessionIndex + ".td-delete-" + process.pid + ".old";
  fs.rmSync(old, { force: true });
  const fd = fs.openSync(tmp, "w");
  try {
    fs.writeFileSync(fd, kept.join("\n"), "utf-8");
    fs.fsyncSync(fd);
  } finally {
    fs.closeSync(fd);
  }
  try {
    fs.renameSync(sessionIndex, old);
    try { fs.renameSync(tmp, sessionIndex); } catch (e) { fs.renameSync(old, sessionIndex); throw e; }
    try { fs.rmSync(old, { force: true }); } catch {}
  } finally { fs.rmSync(tmp, { force: true }); }
  return true;
}

// 永久删除一个会话：正文、归档正文、Codex 标题/状态索引一起清理。
// 只接受本机 sessions/archived_sessions 下的 rollout 文件，禁止借此 IPC 删除任意路径。
async function deleteConversation(filePath) {
  if (permanentDeleteBusy) throw new Error("已有永久删除任务正在执行，请稍后重试");
  permanentDeleteBusy = true;
  try {
  const requested = path.resolve(String(filePath || ""));
  if (!sessionFileAllowed(requested) || !fs.existsSync(requested)) throw new Error("无效的会话文件");
  const meta = peekMeta(requested);
  if (!meta || !meta.id) throw new Error("无法识别会话 ID，已停止删除");
  const files = [];
  for (const root of sessionRoots()) {
    for (const file of findRolloutFiles(root)) {
      const m = peekMeta(file);
      if (m && m.id === meta.id) files.push(file);
    }
  }
  const { codexHome } = paths();
  const stateDbs = fs.readdirSync(codexHome).filter((name) => /^state_.*\.sqlite$/.test(name));
  const SQL = await initSqlJs({
    locateFile: (file) => path.join(global.__BUNDLE_ROOT__ || path.join(__dirname, "..", ".."), "node_modules", "sql.js", "dist", file),
  });
  let stateRowsRemoved = 0;
  for (const name of stateDbs) {
    if (await deleteSessionFromStateDb(SQL, path.join(codexHome, name), meta.id)) stateRowsRemoved++;
  }
  const indexRemoved = removeSessionIndexEntry(meta.id);
  for (const file of files) fs.rmSync(file, { force: true });
  return { id: meta.id, cwd: meta.cwd || "", filesRemoved: files.length, indexRemoved, stateDbs: stateDbs.length, stateRowsRemoved };
  } finally {
    permanentDeleteBusy = false;
  }
}

function findConversationById(id) {
  const target = String(id || "").trim();
  if (!target || target.length > 160) return null;
  for (const root of sessionRoots()) {
    for (const file of findRolloutFiles(root)) {
      const meta = peekMeta(file);
      if (meta && meta.id === target) return { ...meta, path: file };
    }
  }
  return null;
}

function sql(v) {
  return "'" + String(v == null ? "" : v).replace(/'/g, "''") + "'";
}

function findFallbackTitlesById() {
  const map = {};
  for (const root of sessionRoots()) {
    for (const file of findRolloutFiles(root)) {
      const m = peekMeta(file);
      if (m && m.id && m.title) map[m.id] = m.title;
    }
  }
  return map;
}

function repairStateDbTitles(fallbackTitles, log = () => {}) {
  if (!sqlite3Available()) return 0;
  let fixed = 0;
  let files = [];
  const { codexHome } = paths();
  try {
    files = fs.readdirSync(codexHome).filter((f) => /^state_.*\.sqlite$/.test(f));
  } catch {
    return 0;
  }
  for (const name of files) {
    const dbPath = path.join(codexHome, name);
    try {
      const out = runSqlite3(dbPath, "SELECT id,title,first_user_message FROM threads WHERE title LIKE '[$%' OR title LIKE '$%';");
      const rows = JSON.parse(out || "[]");
      const updates = [];
      for (const row of rows) {
        const next = cleanThreadTitle(row.title, row.first_user_message || fallbackTitles[row.id] || "", 80);
        if (next && next !== row.title) updates.push({ id: row.id, title: next });
      }
      if (!updates.length) continue;
      const statements = ["BEGIN;"].concat(
        updates.map((u) => `UPDATE threads SET title=${sql(u.title)} WHERE id=${sql(u.id)};`),
        ["COMMIT;"]
      ).join("\n");
      runSqlite3(dbPath, statements);
      fixed += updates.length;
    } catch (e) {
      log(`标题清洗跳过 ${name}：${e.message || e}`);
    }
  }
  return fixed;
}

function repairSkillMentionTitles(log = () => {}) {
  let raw = "";
  let indexMtimeMs = 0;
  const { sessionIndex, titleCleanMarker } = paths();
  try {
    indexMtimeMs = fs.statSync(sessionIndex).mtimeMs;
    const marker = JSON.parse(fs.readFileSync(titleCleanMarker, "utf-8"));
    if (marker && Number(marker.indexMtimeMs) >= indexMtimeMs) return { indexFixed: 0, dbFixed: 0, skipped: true };
  } catch {}
  try {
    raw = fs.readFileSync(sessionIndex, "utf-8");
  } catch {
    return { indexFixed: 0, dbFixed: 0 };
  }
  const fallbackTitles = findFallbackTitlesById();
  let indexFixed = 0;
  const lines = raw.split("\n").map((line) => {
    if (!line.trim()) return line;
    try {
      const d = JSON.parse(line);
      if (!d || !d.id || !d.thread_name || !looksLikeSkillMentionTitle(d.thread_name)) return line;
      const next = cleanThreadTitle(d.thread_name, fallbackTitles[d.id] || "", 80);
      if (!next || next === d.thread_name) return line;
      d.thread_name = next;
      indexFixed++;
      return JSON.stringify(d);
    } catch {
      return line;
    }
  });
  if (indexFixed) {
    const backup = sessionIndex + ".bak-title-clean-" + new Date().toISOString().replace(/[-:T.Z]/g, "").slice(0, 14);
    try {
      fs.copyFileSync(sessionIndex, backup);
    } catch {}
    fs.writeFileSync(sessionIndex, lines.join("\n"), "utf-8");
  }
  const dbFixed = repairStateDbTitles(fallbackTitles, log);
  try {
    fs.writeFileSync(titleCleanMarker, JSON.stringify({ indexMtimeMs, checkedAt: new Date().toISOString() }, null, 2), "utf-8");
  } catch {}
  return { indexFixed, dbFixed };
}

function normalizeListOptions(opts) {
  if (typeof opts === "boolean") return { includeSubagent: opts, includeArchived: false };
  return {
    includeSubagent: !!(opts && opts.includeSubagent),
    includeArchived: !!(opts && opts.includeArchived),
  };
}

// 列出会话（默认只列当前 sessions，并排除子 agent 派生线程；全量模式会带 archived_sessions）
function listConversations(opts = {}) {
  const { includeSubagent, includeArchived } = normalizeListOptions(opts);
  const { sessionsDir, archivedSessionsDir } = paths();
  const roots = [{ dir: sessionsDir, archived: false }];
  if (includeArchived) roots.push({ dir: archivedSessionsDir, archived: true });
  const titles = loadIndexTitles();
  const items = [];
  for (const root of roots) {
    const files = findRolloutFiles(root.dir);
    for (const file of files) {
      const m = peekMeta(file);
      if (!m) continue;
      if (!includeSubagent && m.threadSource === "subagent") continue;
      let size = 0;
      try {
        size = fs.statSync(file).size;
      } catch {}
      items.push({
        id: m.id,
        title: cleanThreadTitle(titles[m.id] || "", m.title, 80) || "(无标题对话)",
        project: m.cwd ? path.basename(m.cwd) : "",
        cwd: m.cwd,
        ts: m.ts,
        source: m.source,
        threadSource: m.threadSource,
        provider: m.provider,
        path: file,
        size,
        archived: root.archived,
      });
    }
  }
  items.sort((a, b) => (b.ts || "").localeCompare(a.ts || ""));
  return items;
}

// 解析单个会话文件为可读消息列表
function readConversation(file) {
  const messages = [];
  let meta = {};
  let content;
  try {
    content = fs.readFileSync(file, "utf-8");
  } catch (e) {
    return { meta, messages, error: String(e) };
  }
  for (const line of content.split("\n")) {
    if (!line.trim()) continue;
    let d;
    try {
      d = JSON.parse(line);
    } catch {
      continue;
    }
    const p = d.payload || {};
    const ts = d.timestamp || "";
    if (d.type === "session_meta") {
      meta = { id: p.session_id || p.id || "", cwd: p.cwd || "", ts: p.timestamp || ts, provider: p.model_provider || "" };
    } else if (d.type === "event_msg" && p.type === "user_message") {
      messages.push({ role: "user", text: cleanUserVisibleText(String(p.message || "")), ts });
    } else if (d.type === "event_msg" && p.type === "agent_message") {
      messages.push({ role: "assistant", text: stripInternalThoughtBlocks(String(p.message || "")), ts });
    } else if (d.type === "response_item" && p.type === "function_call") {
      const name = p.name || "tool";
      messages.push({ role: "tool", text: `调用工具：${name}`, ts, collapsed: true });
    }
  }
  return { meta, messages };
}

// 导出为 Markdown 文本
function toMarkdown(item, conv) {
  const lines = [];
  lines.push(`# ${item.title || "Codex 会话记录"}`);
  lines.push("");
  if (item.project) lines.push(`- 项目：${item.project}`);
  if (item.cwd) lines.push(`- 目录：${item.cwd}`);
  if (item.ts) lines.push(`- 时间：${item.ts}`);
  if (item.provider) lines.push(`- Provider：${item.provider}`);
  lines.push("");
  lines.push("---");
  lines.push("");
  for (const m of conv.messages) {
    if (m.role === "user") lines.push(`## 👤 用户\n\n${m.text}\n`);
    else if (m.role === "assistant") lines.push(`## 🤖 Codex\n\n${m.text}\n`);
    else if (m.role === "tool") lines.push(`> 🔧 ${m.text}\n`);
  }
  return lines.join("\n");
}

// 备份：把 sessions/、archived_sessions/ 与索引复制到目标目录下的 codex-sessions-backup/
function backupAll(destDir, log = () => {}) {
  const out = path.join(destDir, "codex-sessions-backup");
  fs.mkdirSync(out, { recursive: true });
  let n = 0;
  const { sessionsDir, archivedSessionsDir, sessionIndex } = paths();
  for (const [name, dir] of [["sessions", sessionsDir], ["archived_sessions", archivedSessionsDir]]) {
    const files = findRolloutFiles(dir);
    for (const f of files) {
      const rel = path.relative(dir, f);
      const dst = path.join(out, name, rel);
      fs.mkdirSync(path.dirname(dst), { recursive: true });
      fs.copyFileSync(f, dst);
      n++;
    }
  }
  if (fs.existsSync(sessionIndex)) fs.copyFileSync(sessionIndex, path.join(out, "session_index.jsonl"));
  log(`已备份 ${n} 个会话文件到 ${out}`);
  return { path: out, count: n };
}

function resolveImportRoot(srcDir) {
  const root = path.resolve(String(srcDir || ""));
  if (fs.existsSync(path.join(root, "sessions"))) return root;
  const nested = path.join(root, "codex-sessions-backup");
  if (fs.existsSync(path.join(nested, "sessions"))) return nested;
  return root;
}

function mergeSessionIndex(srcIndex, dstIndex) {
  if (!fs.existsSync(srcIndex)) return 0;
  const entries = new Map();
  const read = (file) => {
    try {
      for (const line of fs.readFileSync(file, "utf-8").split("\n")) {
        if (!line.trim()) continue;
        try {
          const value = JSON.parse(line);
          if (value && value.id) entries.set(String(value.id), value);
        } catch {}
      }
    } catch {}
  };
  // 目标机器已有的重命名优先，备份只补缺失条目。
  read(srcIndex);
  const imported = new Map(entries);
  entries.clear();
  read(dstIndex);
  const existing = new Map(entries);
  for (const [id, value] of imported) if (!existing.has(id)) existing.set(id, value);
  if (!existing.size) return 0;
  fs.mkdirSync(path.dirname(dstIndex), { recursive: true });
  const backup = dstIndex + ".bak-import-" + Date.now();
  try { if (fs.existsSync(dstIndex)) fs.copyFileSync(dstIndex, backup); } catch {}
  const tmp = dstIndex + ".tmp-import-" + process.pid;
  try {
    fs.writeFileSync(tmp, [...existing.values()].map((value) => JSON.stringify(value)).join("\n") + "\n", "utf-8");
    try { fs.renameSync(tmp, dstIndex); }
    catch {
      fs.rmSync(dstIndex, { force: true });
      fs.renameSync(tmp, dstIndex);
    }
  } finally {
    try { fs.rmSync(tmp, { force: true }); } catch {}
  }
  return imported.size;
}

// 导入：把外部备份目录里的 rollout-*.jsonl 合并进本机 sessions/ 与 archived_sessions/（已存在则跳过）
function importSessions(srcDir, log = () => {}) {
  // 支持传入 backup 根目录或其中的 sessions/ 子目录
  let added = 0;
  let skipped = 0;
  const sourceRoot = resolveImportRoot(srcDir);
  const { sessionsDir, archivedSessionsDir } = paths();
  const roots = fs.existsSync(path.join(sourceRoot, "sessions"))
    ? [
        { base: path.join(sourceRoot, "sessions"), dest: sessionsDir },
        { base: path.join(sourceRoot, "archived_sessions"), dest: archivedSessionsDir },
      ]
    : [{ base: sourceRoot, dest: sessionsDir }];
  for (const root of roots) {
    const files = findRolloutFiles(root.base);
    for (const f of files) {
      const rel = path.relative(root.base, f);
      const dst = path.join(root.dest, rel);
      if (fs.existsSync(dst)) {
        skipped++;
        continue;
      }
      fs.mkdirSync(path.dirname(dst), { recursive: true });
      fs.copyFileSync(f, dst);
      added++;
    }
  }
  const indexMerged = mergeSessionIndex(path.join(sourceRoot, "session_index.jsonl"), paths().sessionIndex);
  log(`导入完成：新增 ${added} 个，跳过 ${skipped} 个（已存在），合并索引 ${indexMerged} 条`);
  return { added, skipped, indexMerged };
}

module.exports = {
  getCodexHome: () => paths().codexHome,
  getSessionsDir: () => paths().sessionsDir,
  getArchivedSessionsDir: () => paths().archivedSessionsDir,
  listConversations,
  readConversation,
  toMarkdown,
  backupAll,
  importSessions,
  deleteConversation,
  findConversationById,
  repairSkillMentionTitles,
};