/**
 * @file ai-proxies.js
 * @description Named AI Proxy profiles — an endpoint (9Router, OpenRouter, a
 * self-hosted gateway) plus the model names to use against it, saved once and
 * chosen by a new session (`proxy-apply.js`).
 *
 * A profile is exactly what the two CLIs need to talk to a proxy and nothing
 * more: `baseUrl`, `apiKey`, a default `model`, and one slot per tier mirroring
 * the env keys Claude Code reads. Per-tier slots because a proxy may expose a
 * different id per tier — and the `model` field fills every one of them,
 * because the common case is a single symbolic name for everything.
 *
 * `baseUrl` is the proxy's ROOT, without `/v1`: Claude Code appends
 * `/v1/messages` to it, and the Codex layer appends `/v1` itself. A `/v1`
 * typed (or stored by an older build) is dropped by `normalizeBaseUrl`.
 *
 * Profiles are stored one JSON file per profile under
 * `<CLAUDE_HOME>/agenthub-proxies/` (dir 0700, files 0600; the pre-rename
 * `agenthub-routers/` is moved there on first read, see `proxiesDir`), the same
 * shape and the same reasoning as `cc-profiles.js`: they hold a live API key,
 * so **no route ever returns key material** — `listProxies` reports `hasKey`
 * and nothing else about it.
 *
 * **Shared and personal.** The store's top level holds the SHARED profiles —
 * the host's in local mode, the admin's in server mode. Each user may also keep
 * PERSONAL ones under `users/<user id>/`, named `u<id>_<slug>`: `slugify`
 * never emits `_`, so a personal name can never equal a shared one, and the
 * name alone (stored in `dashboard_runs.proxy`) says whose it is. Who may see,
 * write or start a session on which is decided by the routes and by
 * `proxy-apply.resolveProxy`, from `ownerOfName`.
 *
 * `native` is a built-in profile rather than a branch in the caller: it has no
 * endpoint and no model of its own (the session's model picker decides), so
 * "use the vendor's own API" is a choice like any profile. It cannot be
 * edited, removed, or shadowed by a saved profile.
 *
 * `testProxy` is the one thing here that talks to the network: the smallest
 * real request each CLI would make, so "saved" and "actually works" stop
 * being the same claim. It is deliberately NOT a generic forwarder — see the
 * note on its stored-key fallback.
 *
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */

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

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

/**
 * A profile's `name` is its filename, so the charset is deliberately narrow.
 * What the user reads and edits is `label`, which accepts spaces and diacritics
 * precisely because it never touches a path. Same split as cc-profiles.js.
 */
const NAME_RE = /^[a-zA-Z0-9][a-zA-Z0-9._-]{0,39}$/;

const LABEL_MIN = 3;
const LABEL_MAX = 60;

/** The per-tier model overrides Claude Code reads, in the order the UI shows them. */
const MODEL_SLOTS = ["opus", "sonnet", "haiku", "smallFast", "subagent"];

const BUILTIN_NAME = "native";

/**
 * The vendor's own API. Never written anywhere (`resolveProxy` answers null for
 * it), so it carries no model ids — the session's model picker picks.
 */
const NATIVE = Object.freeze({
  name: BUILTIN_NAME,
  label: "Native",
  builtin: true,
  baseUrl: "",
  apiKey: "",
  model: "",
  models: Object.freeze({}),
});

function err(code, message) {
  const e = new Error(message);
  e.code = code;
  return e;
}

/**
 * The profile store. The first read after the rename moves the old
 * `agenthub-routers/` here and leaves a symlink at the old name, so an older
 * build on the same CLAUDE_HOME still finds its profiles.
 */
function proxiesDir() {
  const dir = path.join(getClaudeHome(), "agenthub-proxies");
  if (fs.existsSync(dir)) return dir;
  const legacy = path.join(getClaudeHome(), "agenthub-routers");
  try {
    if (fs.lstatSync(legacy).isSymbolicLink()) return dir;
    fs.renameSync(legacy, dir);
  } catch {
    return dir; // no legacy store (or it could not be moved — read it next time)
  }
  try {
    fs.symlinkSync("agenthub-proxies", legacy, "dir");
  } catch {
    /* best effort — the profiles themselves are already in place */
  }
  return dir;
}

/** A personal profile's name: `u<owner id>_<slug>`. */
const PERSONAL_RE = /^u([1-9][0-9]{0,8})_[a-z0-9][a-z0-9-]*$/;

/** The user id a personal profile belongs to, or null for a shared one. */
function ownerOfName(name) {
  const m = typeof name === "string" ? PERSONAL_RE.exec(name) : null;
  return m ? Number(m[1]) : null;
}

/** Where one owner's profiles live: the top level is the shared store. */
function storeDir(owner) {
  return owner == null ? proxiesDir() : path.join(proxiesDir(), "users", String(owner));
}

function proxyFile(name) {
  if (typeof name !== "string" || !NAME_RE.test(name)) {
    throw err("EBADNAME", "name must be 1-40 chars of letters, digits, dot, dash or underscore");
  }
  return path.join(storeDir(ownerOfName(name)), `${name}.json`);
}

function readJson(file) {
  let raw;
  try {
    raw = fs.readFileSync(file, "utf8");
  } catch {
    return null;
  }
  try {
    return JSON.parse(raw);
  } catch {
    throw err("EBADJSON", `${file} is not valid JSON - fix it by hand first`);
  }
}

/** Write JSON at 0600 through a temp file, so a crash never truncates the original. */
function writeJson(file, value) {
  fs.mkdirSync(path.dirname(file), { recursive: true, mode: 0o700 });
  const tmp = `${file}.agenthub-tmp`;
  fs.writeFileSync(tmp, `${JSON.stringify(value, null, 2)}\n`, { mode: 0o600 });
  fs.renameSync(tmp, file);
}

/** Reduce any text to the narrow NAME_RE charset, for use as a filename. */
function slugify(text) {
  const base = String(text || "")
    .normalize("NFD")
    .replace(/[\u0300-\u036f]/g, "") // drop the combining accents NFD split off
    .toLowerCase()
    .replace(/[^a-z0-9]+/g, "-")
    .replace(/^-+|-+$/g, "")
    .slice(0, 32);
  return NAME_RE.test(base) ? base : "proxy";
}

/**
 * `base`, or `base-2`, `base-3`… — the first that is neither taken nor built
 * in — prefixed `u<owner>_` for a personal profile (the slug shortened so the
 * whole name still fits NAME_RE's 40 characters).
 */
function freeName(base, owner = null) {
  const prefix = owner == null ? "" : `u${owner}_`;
  const stem = base.slice(0, 40 - prefix.length - 4).replace(/-+$/, "") || "proxy";
  let name = prefix + stem;
  for (let n = 2; name === BUILTIN_NAME || fs.existsSync(proxyFile(name)); n += 1) {
    name = `${prefix}${stem}-${n}`;
  }
  return name;
}

function normalizeLabel(label) {
  const clean = typeof label === "string" ? label.trim() : "";
  if (clean.length < LABEL_MIN || clean.length > LABEL_MAX || /[\u0000-\u001f\u007f]/.test(clean)) {
    throw err(
      "EBADLABEL",
      `label must be ${LABEL_MIN}-${LABEL_MAX} characters and no control characters`
    );
  }
  return clean;
}

/**
 * A proxy endpoint is an http(s) URL and nothing else. A `file:` or
 * `javascript:` base URL is never a proxy — it is a mistake, or an attempt to
 * point a CLI somewhere it should not go. A trailing `/v1` is dropped: the
 * root is stored, and each CLI's path is added where it is used.
 */
function normalizeBaseUrl(baseUrl) {
  const raw = typeof baseUrl === "string" ? baseUrl.trim() : "";
  if (!raw) throw err("EBADURL", "baseUrl is required");
  let parsed;
  try {
    parsed = new URL(raw);
  } catch {
    throw err("EBADURL", `not a valid URL: ${raw}`);
  }
  if (parsed.protocol !== "http:" && parsed.protocol !== "https:") {
    throw err("EBADURL", "baseUrl must be http:// or https://");
  }
  return raw.replace(/\/+$/, "").replace(/\/v1$/, "");
}

/** A model name is free text — a proxy names its own models — but not blank. */
function normalizeModel(model) {
  const clean = typeof model === "string" ? model.trim() : "";
  if (!clean || clean.length > 200 || /[\u0000-\u001f\u007f]/.test(clean)) {
    throw err("EBADMODEL", "model must be 1-200 characters and no control characters");
  }
  return clean;
}

/**
 * Fill every slot from `model`, keeping any the caller set explicitly. This
 * is what makes "one symbolic name for every tier" — the 9Router case — a
 * single field to type instead of six.
 */
function normalizeModels(model, models) {
  const given = models && typeof models === "object" ? models : {};
  const out = {};
  for (const slot of MODEL_SLOTS) {
    out[slot] = given[slot] === undefined ? model : normalizeModel(given[slot]);
  }
  return out;
}

/**
 * A known Claude model id that Claude Code should treat the proxy's own model
 * names as (its `modelPicker` `behavesAs`, issue #56). Optional; `""` clears it.
 * The user picks it, never AgentHub: it also sets the context window Claude
 * Code compacts at, and a proxy may route a name to a non-Claude model.
 */
function normalizeBehavesAs(value) {
  const clean = typeof value === "string" ? value.trim() : null;
  if (clean === "") return "";
  if (!clean || !/^claude-[a-z0-9][a-z0-9.-]{0,99}$/.test(clean)) {
    throw err("EBADMODEL", "behavesAs must be a Claude model id, e.g. claude-opus-5-5");
  }
  return clean;
}

function assertNotBuiltin(name) {
  if (name === BUILTIN_NAME) {
    throw err("EBUILTIN", `'${BUILTIN_NAME}' is the built-in profile and cannot be changed`);
  }
}

/**
 * Read one stored profile (key included), or null when it does not exist. A
 * base URL an older build stored with `/v1` comes back as the root.
 */
function readProxy(name) {
  const stored = readJson(proxyFile(name));
  if (!stored || typeof stored !== "object") return null;
  if (typeof stored.baseUrl === "string") {
    stored.baseUrl = stored.baseUrl.replace(/\/+$/, "").replace(/\/v1$/, "");
  }
  return stored;
}

/** The browser-safe view: everything except the key, plus whether one is set. */
function publicView(profile) {
  const { apiKey, ...rest } = profile;
  return {
    ...rest,
    scope: ownerOfName(profile.name) == null ? "shared" : "personal",
    hasKey: Boolean(apiKey),
  };
}

/** The profile names saved in one owner's store, sorted. */
function namesIn(owner) {
  try {
    return fs
      .readdirSync(storeDir(owner))
      .filter((f) => f.endsWith(".json"))
      .map((f) => f.slice(0, -5))
      .filter((n) => NAME_RE.test(n) && n !== BUILTIN_NAME && ownerOfName(n) === owner)
      .sort();
  } catch {
    return []; // nothing saved yet
  }
}

/**
 * The profiles `viewer` may choose: the built-in native one first, then the
 * shared ones, then the viewer's own personal ones (none for `null` — local
 * mode, or a request with no user). Nobody lists another user's personal
 * profiles, an admin included.
 * @param {number|null} [viewer] user id
 * @returns `{ items }` — key material is never included.
 */
function listProxies(viewer = null) {
  const items = [publicView(NATIVE)];
  const owners = viewer == null ? [null] : [null, viewer];
  for (const owner of owners) {
    for (const name of namesIn(owner)) {
      let stored;
      try {
        stored = readProxy(name);
      } catch {
        continue; // a corrupt profile file is skipped, not fatal for the list
      }
      if (!stored) continue;
      items.push(publicView({ ...stored, name, builtin: false }));
    }
  }
  return { items };
}

/**
 * One profile INCLUDING its key — for the server's own writers only. No route
 * may return this shape; `listProxies` is what the browser sees.
 */
function getProxy(name) {
  if (name === BUILTIN_NAME) return { ...NATIVE, models: { ...NATIVE.models } };
  const stored = readProxy(name);
  if (!stored) throw err("ENOTFOUND", `no proxy profile named '${name}'`);
  return { ...stored, name, builtin: false };
}

/**
 * @param {{label:string, baseUrl:string, apiKey?:string, model:string,
 *   models?:Record<string,string>, behavesAs?:string}} input
 * @param {number|null} [owner] user id for a personal profile, null = shared
 * @returns the browser-safe view of what was saved
 */
function createProxy(input = {}, owner = null) {
  const label = normalizeLabel(input.label);
  const slug = slugify(label);
  assertNotBuiltin(slug);

  const model = normalizeModel(input.model);
  const profile = {
    label,
    baseUrl: normalizeBaseUrl(input.baseUrl),
    apiKey: typeof input.apiKey === "string" ? input.apiKey.trim() : "",
    model,
    models: normalizeModels(model, input.models),
    behavesAs: input.behavesAs === undefined ? "" : normalizeBehavesAs(input.behavesAs),
    savedAt: new Date().toISOString(),
  };

  const name = freeName(slug, owner);
  writeJson(proxyFile(name), profile);
  return publicView({ ...profile, name, builtin: false });
}

/**
 * Merge changes into a saved profile. The `name` never changes — a session's
 * run row stores it for a resume, and renaming would orphan that. An omitted
 * `apiKey` keeps the stored one: the edit form cannot show a key, so it cannot
 * send one back either.
 */
function updateProxy(name, changes = {}) {
  assertNotBuiltin(name);
  const stored = readProxy(name);
  if (!stored) throw err("ENOTFOUND", `no proxy profile named '${name}'`);

  const model = changes.model === undefined ? stored.model : normalizeModel(changes.model);
  const next = {
    ...stored,
    label: changes.label === undefined ? stored.label : normalizeLabel(changes.label),
    baseUrl: changes.baseUrl === undefined ? stored.baseUrl : normalizeBaseUrl(changes.baseUrl),
    apiKey:
      typeof changes.apiKey === "string" && changes.apiKey.trim()
        ? changes.apiKey.trim()
        : stored.apiKey,
    model,
    models:
      changes.model === undefined && changes.models === undefined
        ? stored.models
        : normalizeModels(model, changes.models ?? stored.models),
    behavesAs:
      changes.behavesAs === undefined
        ? (stored.behavesAs ?? "")
        : normalizeBehavesAs(changes.behavesAs),
    savedAt: new Date().toISOString(),
  };

  writeJson(proxyFile(name), next);
  return publicView({ ...next, name, builtin: false });
}

function removeProxy(name) {
  assertNotBuiltin(name);
  const file = proxyFile(name);
  if (!fs.existsSync(file)) throw err("ENOTFOUND", `no proxy profile named '${name}'`);
  fs.rmSync(file);
  return { removed: name };
}

/** How long a connection test waits before calling the endpoint dead. */
const TEST_TIMEOUT_MS = 15_000;

/** Enough of a failing proxy's own words to be actionable, not enough to flood. */
const TEST_BODY_MAX = 300;

/** POST `body` to `url`; the outcome is a result, never a throw. */
async function probe(url, apiKey, headers, body, model) {
  let res;
  try {
    res = await fetch(url, {
      method: "POST",
      headers: {
        "content-type": "application/json",
        authorization: `Bearer ${apiKey}`,
        ...headers,
      },
      body: JSON.stringify(body),
      signal: AbortSignal.timeout(TEST_TIMEOUT_MS),
      // A redirect is an answer, never followed: fetch drops `authorization`
      // on a cross-origin hop but would carry `x-api-key` to the new host.
      redirect: "manual",
    });
  } catch (e) {
    // Unreachable, DNS failure, TLS refusal, timeout — a real answer about the
    // endpoint, so it is a result and not a 500.
    //
    // `cause` first: node's fetch reports every transport failure as the same
    // useless "fetch failed", and hides the part the user can act on
    // (ECONNREFUSED, ENOTFOUND, a TLS error) one level down.
    return {
      ok: false,
      status: null,
      message: e.name === "TimeoutError" ? "timed out" : (e.cause && e.cause.message) || e.message,
    };
  }
  const text = await res.text().catch(() => "");
  return {
    ok: res.ok,
    status: res.status,
    message: res.ok ? model : text.slice(0, TEST_BODY_MAX) || res.statusText,
  };
}

/**
 * Probe a proxy endpoint with the smallest real request each CLI makes, in
 * parallel: Claude Code's Anthropic message (`/v1/messages`, one output token)
 * and Codex's OpenAI Responses call (`/v1/responses`, the 16-token minimum). A
 * profile is not tool-specific, so a proxy that serves only one wire shape
 * shows up as one green line and one red.
 *
 * **The stored key is only ever sent to the endpoint it was stored against.**
 * A blank `apiKey` falls back to the saved profile named by `name` — but only
 * when the submitted `baseUrl` still matches the saved one. Without that check
 * this route would be a way to make the server POST a saved API key to any URL
 * a browser names, which is exactly the leak `listProxies` exists to prevent.
 *
 * A proxy that answers is a success even when it answers with an error: each
 * outcome is reported (`ok`, `status`, `message`), never thrown. Only bad
 * INPUT throws.
 *
 * @param {{name?:string, baseUrl:string, apiKey?:string, model:string}} input
 * @returns {Promise<{claude: TestResult, codex: TestResult}>} where TestResult
 *   is `{ok:boolean, status:number|null, message:string}`
 */
async function testProxy(input = {}) {
  const baseUrl = normalizeBaseUrl(input.baseUrl);
  const model = normalizeModel(input.model);

  let apiKey = typeof input.apiKey === "string" ? input.apiKey.trim() : "";
  if (!apiKey && input.name) {
    const stored = readProxy(input.name);
    if (stored && normalizeBaseUrl(stored.baseUrl || "") === baseUrl) apiKey = stored.apiKey || "";
  }
  if (!apiKey) throw err("EBADKEY", "enter the API key to test this endpoint");

  const [claude, codex] = await Promise.all([
    probe(
      `${baseUrl}/v1/messages`,
      apiKey,
      // `x-api-key` beside the Bearer header, because proxies disagree on which
      // one they read, and it is the same key going to the same endpoint.
      { "x-api-key": apiKey, "anthropic-version": "2023-06-01" },
      { model, max_tokens: 1, messages: [{ role: "user", content: "ping" }] },
      model
    ),
    probe(
      `${baseUrl}/v1/responses`,
      apiKey,
      {},
      { model, input: "ping", max_output_tokens: 16 },
      model
    ),
  ]);
  return { claude, codex };
}

module.exports = {
  listProxies,
  getProxy,
  createProxy,
  updateProxy,
  removeProxy,
  testProxy,
  MODEL_SLOTS,
  BUILTIN_NAME,
  NATIVE,
  ownerOfName,
};