/**
 * @file AgentHub's own git credentials — what a dashboard fetch/pull/push
 * authenticates with when the machine's git has nothing (issue #45). The
 * dashboard runs git with no terminal, so without this a remote needing a
 * login fails with "could not read Username … terminal prompts disabled".
 *
 * One JSON file under `<CLAUDE_HOME>/agenthub-git-credentials/` (dir 0700,
 * file 0600, written through a temp file), one record per protocol + host,
 * shared by everyone using this AgentHub. Like the AI Proxy store, **no route
 * ever returns a password** — `list` reports `hasToken`.
 *
 * `gitConfigFor` is how a credential reaches git: `-c` args that make OUR
 * helper (git-credential-helper.js) the ONLY one, plus the env it reads. Only
 * ours, because a stale token in the machine's helper would win over the one
 * just typed, and git's post-success `store` would copy a use-once token into
 * the OS user's own helper. The secret itself never reaches argv.
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */

const fs = require("node:fs");
const path = require("node:path");

const { getClaudeHome } = require("./claude-home");

const HOST_RE = /^[a-z0-9]([a-z0-9.-]*[a-z0-9])?(:\d{1,5})?$/;
const PROTOCOLS = new Set(["https", "http"]);
const HELPER = path.join(__dirname, "git-credential-helper.js");

function err(code, message) {
  return Object.assign(new Error(message), { code });
}

function credentialsFile() {
  return path.join(getClaudeHome(), "agenthub-git-credentials", "credentials.json");
}

/** `{protocol, host}` normalised, or EBADHOST — a host is also a lookup key. */
function key(protocol, host) {
  const p = String(protocol || "").toLowerCase();
  const h = String(host || "").toLowerCase();
  if (!PROTOCOLS.has(p) || !HOST_RE.test(h)) {
    throw err("EBADHOST", "protocol must be http(s) and host a plain host[:port]");
  }
  return { protocol: p, host: h };
}

function readAll() {
  try {
    const rows = JSON.parse(fs.readFileSync(credentialsFile(), "utf8"));
    return Array.isArray(rows) ? rows : [];
  } catch {
    return [];
  }
}

function writeAll(rows) {
  const file = credentialsFile();
  fs.mkdirSync(path.dirname(file), { recursive: true, mode: 0o700 });
  const tmp = `${file}.agenthub-tmp`;
  fs.writeFileSync(tmp, `${JSON.stringify(rows, null, 2)}\n`, { mode: 0o600 });
  fs.renameSync(tmp, file);
}

function list() {
  return readAll().map(({ protocol, host, username, savedAt }) => ({
    protocol,
    host,
    username,
    savedAt,
    hasToken: true,
  }));
}

function find(protocol, host) {
  const k = key(protocol, host);
  return readAll().find((r) => r.protocol === k.protocol && r.host === k.host) || null;
}

function save({ protocol, host, username, password }) {
  const k = key(protocol, host);
  if (typeof username !== "string" || !username.trim() || /[\r\n]/.test(username)) {
    throw err("EBADCRED", "username is required");
  }
  if (typeof password !== "string" || !password || /[\r\n]/.test(password)) {
    throw err("EBADCRED", "password or access token is required");
  }
  const rows = readAll().filter((r) => !(r.protocol === k.protocol && r.host === k.host));
  rows.push({ ...k, username: username.trim(), password, savedAt: new Date().toISOString() });
  writeAll(rows);
}

function remove(protocol, host) {
  const k = key(protocol, host);
  const rows = readAll();
  const kept = rows.filter((r) => !(r.protocol === k.protocol && r.host === k.host));
  if (kept.length === rows.length) return false;
  writeAll(kept);
  return true;
}

/**
 * git's wording for "I needed a login and did not get one (or it was wrong)",
 * and the URL it names. null for every other failure.
 */
function authFailure(stderr) {
  const text = String(stderr || "");
  if (
    !/could not read (Username|Password)|Authentication failed|terminal prompts disabled|Invalid username or password/i.test(
      text
    )
  ) {
    return null;
  }
  const m = text.match(/'(https?):\/\/(?:[^@'/]*@)?([^/'\s]+)/i);
  if (!m) return null;
  try {
    return key(m[1], m[2]);
  } catch {
    return null;
  }
}

/** The http(s) hosts a repo's remotes point at. */
async function remoteHosts(dir) {
  // Required lazily: worktree.js is heavy and only this path needs it.
  const { git } = require("./worktree");
  const out = await git(dir, ["remote", "-v"]).then(
    (r) => r.stdout,
    () => ""
  );
  const hosts = new Map();
  // A username in the URL (https://vi@host/…) pre-fills the login form; a
  // password in it (user:pass@) is never read back out.
  for (const m of out.matchAll(/\t(https?):\/\/(?:([^@\s/:]*)(?::[^@\s/]*)?@)?([^/\s]+)/gi)) {
    try {
      const k = key(m[1], m[3]);
      hosts.set(`${k.protocol}://${k.host}`, {
        ...k,
        username: m[2] ? decodeURIComponent(m[2]) : null,
      });
    } catch {
      /* not a host we can hold a credential for */
    }
  }
  return [...hosts.values()];
}

const shq = (s) => `'${String(s).replace(/'/g, `'\\''`)}'`;

/**
 * The `-c` args and env a network git command runs with. `once` is a
 * credential from the request, accepted only for one of the repo's own
 * remote hosts — a key typed for one server is never sent to another.
 */
async function gitConfigFor(dir, once) {
  const hosts = await remoteHosts(dir);
  const env = {};
  if (once) {
    const k = key(once.protocol, once.host);
    if (!hosts.some((h) => h.protocol === k.protocol && h.host === k.host)) {
      throw err("EBADHOST", `${k.host} is not a remote of this repository`);
    }
    env.AGENTHUB_GIT_ONCE = JSON.stringify({
      ...k,
      username: String(once.username || ""),
      password: String(once.password || ""),
    });
  } else if (!hosts.some((h) => find(h.protocol, h.host))) {
    return { args: [], env: {} };
  }
  // ponytail: while AgentHub answers for one host, a remote on ANOTHER host
  // gets no machine helper either (see the file header); chain the machine's
  // helpers for unknown hosts if mixed-host `fetch --all` ever matters.
  env.AGENTHUB_GIT_CRED_FILE = credentialsFile();
  return {
    args: [
      "-c",
      "credential.helper=",
      "-c",
      `credential.helper=!${shq(process.execPath)} ${shq(HELPER)}`,
    ],
    env,
  };
}

module.exports = {
  credentialsFile,
  list,
  find,
  save,
  remove,
  authFailure,
  remoteHosts,
  gitConfigFor,
};