/**
 * @file The AI Tools catalog: which AI coding CLIs AgentHub can run in a lane
 * (`server/data/ai-tools/*.json` plus overrides in `DASHBOARD_AI_TOOLS_DIR`),
 * which of them are installed (a walk of the PATH directories — no process per
 * tool), and the user's enable/default choice (`<data dir>/ai-tools.json`).
 * A catalog file is data only: its args and env reach an argv in pty-run.js,
 * never a shell, and a custom file may not claim a hand-written `launcher`.
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */

const fs = require("node:fs");
const path = require("node:path");
const { getDataDir } = require("./claude-home");

const BUILTIN_DIR = path.join(__dirname, "..", "data", "ai-tools");
const ID_RE = /^[a-z0-9][a-z0-9-]{0,39}$/;
const CMD_RE = /^[A-Za-z0-9._+-]+$/;
const ENV_RE = /^[A-Za-z_][A-Za-z0-9_]*$/;
const LAUNCHERS = new Set(["claude", "codex"]);
const PROMPT_MODES = new Set(["argv", "flag", "after-start"]);
const ROUTER_CAPABLE = new Set(["claude", "codex"]);

let dirsOverride = null;
let catalog = null; // Map id -> tool, in catalog order
const detected = new Map();

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

const isStrArray = (v, re) =>
  Array.isArray(v) && v.every((s) => typeof s === "string" && s && (!re || re.test(s)));

/** A normalised tool, or null when the file breaks any rule. */
function validate(doc, source) {
  if (!doc || typeof doc !== "object") return null;
  if (typeof doc.id !== "string" || !ID_RE.test(doc.id)) return null;
  if (typeof doc.label !== "string" || !doc.label.trim()) return null;
  if (!isStrArray(doc.detect, CMD_RE) || !doc.detect.length) return null;
  if (doc.requires !== undefined && !isStrArray(doc.requires, CMD_RE)) return null;
  for (const k of ["args", "resume", "bypass"]) {
    if (doc[k] !== undefined && !isStrArray(doc[k])) return null;
  }
  if (doc.bypassEnv !== undefined) {
    const e = doc.bypassEnv;
    if (!e || typeof e !== "object" || Array.isArray(e)) return null;
    if (!Object.entries(e).every(([k, v]) => ENV_RE.test(k) && typeof v === "string")) return null;
  }
  let launcher = null;
  if (doc.launcher !== undefined) {
    if (source !== "builtin" || !LAUNCHERS.has(doc.launcher) || doc.launcher !== doc.id)
      return null;
    launcher = doc.launcher;
  }
  let prompt = null;
  if (!launcher) {
    const p = doc.prompt;
    if (!p || !PROMPT_MODES.has(p.mode)) return null;
    if (p.mode === "flag" && (typeof p.flag !== "string" || !p.flag.startsWith("-"))) return null;
    if (p.mode === "argv" && p.separator !== undefined && p.separator !== "--") return null;
    prompt = { mode: p.mode };
    if (p.mode === "flag") prompt.flag = p.flag;
    if (p.mode === "argv" && p.separator) prompt.separator = p.separator;
    if (p.mode === "after-start") {
      const d = Number(p.delayMs);
      prompt.delayMs = Number.isFinite(d) && d >= 0 && d <= 60000 ? d : 3000;
    }
  }
  return {
    id: doc.id,
    label: doc.label.trim(),
    detect: doc.detect,
    requires: doc.requires || [],
    args: doc.args || [],
    homepageUrl:
      typeof doc.homepageUrl === "string" && /^https:\/\//.test(doc.homepageUrl)
        ? doc.homepageUrl
        : null,
    faviconDomain: typeof doc.faviconDomain === "string" ? doc.faviconDomain : null,
    prompt,
    resume: doc.resume || null,
    bypass: doc.bypass || null,
    bypassEnv: doc.bypassEnv || null,
    launcher,
    source,
  };
}

function load() {
  const dirs = dirsOverride || [BUILTIN_DIR, process.env.DASHBOARD_AI_TOOLS_DIR].filter(Boolean);
  const byId = new Map();
  dirs.forEach((dir, i) => {
    const source = i === 0 ? "builtin" : "custom";
    let files = [];
    try {
      files = fs
        .readdirSync(dir)
        .filter((f) => f.endsWith(".json"))
        .sort();
    } catch {
      return; // dir absent — fine
    }
    for (const f of files) {
      let tool = null;
      try {
        tool = validate(JSON.parse(fs.readFileSync(path.join(dir, f), "utf8")), source);
      } catch {
        /* fall through to the log line */
      }
      if (!tool) {
        console.warn(`ai-tools: skipping invalid catalog file ${path.join(dir, f)}`);
        continue;
      }
      // Custom beats built-in; within one dir the first file wins.
      if (!byId.has(tool.id) || (source === "custom" && byId.get(tool.id).source === "builtin")) {
        byId.set(tool.id, tool);
      }
    }
  });
  const rank = (t) => (t.id === "claude" ? 0 : t.id === "codex" ? 1 : 2);
  const sorted = [...byId.values()].sort(
    (a, b) => rank(a) - rank(b) || a.label.localeCompare(b.label)
  );
  return new Map(sorted.map((t) => [t.id, t]));
}

function cat() {
  if (!catalog) catalog = load();
  return catalog;
}

const list = () => [...cat().values()];
const get = (id) => cat().get(id) || null;
const has = (id) => typeof id === "string" && cat().has(id);

function which(name) {
  for (const dir of (process.env.PATH || "").split(path.delimiter)) {
    if (!dir) continue;
    const p = path.join(dir, name);
    try {
      if (fs.statSync(p).isFile()) {
        fs.accessSync(p, fs.constants.X_OK);
        return p;
      }
    } catch {
      /* not here */
    }
  }
  return null;
}

/** `{installed, path, command}` for one tool, cached until refresh() unless `fresh`. */
function detect(id, { fresh = false } = {}) {
  if (!fresh && detected.has(id)) return detected.get(id);
  const tool = get(id);
  let out = { installed: false, path: null, command: tool ? tool.detect[0] : null };
  if (tool) {
    for (const name of tool.detect) {
      const p = which(name);
      if (p) {
        out = { installed: tool.requires.every((r) => which(r)), path: p, command: name };
        break;
      }
    }
  }
  detected.set(id, out);
  return out;
}

function refresh() {
  catalog = null;
  detected.clear();
}

const statePath = () => path.join(getDataDir(), "ai-tools.json");

function readState() {
  try {
    const s = JSON.parse(fs.readFileSync(statePath(), "utf8"));
    return {
      disabled: Array.isArray(s.disabled) ? s.disabled.filter((x) => typeof x === "string") : [],
      default: typeof s.default === "string" ? s.default : null,
    };
  } catch {
    return { disabled: [], default: null };
  }
}

function writeState(state) {
  fs.mkdirSync(path.dirname(statePath()), { recursive: true });
  const tmp = `${statePath()}.${process.pid}.tmp`;
  fs.writeFileSync(tmp, JSON.stringify(state, null, 2) + "\n");
  fs.renameSync(tmp, statePath());
}

const isEnabled = (id) => !readState().disabled.includes(id);

function requireTool(id) {
  if (!has(id)) throw makeErr("ENOTOOL", `unknown AI tool: ${id}`);
}

function setEnabled(id, enabled) {
  requireTool(id);
  const s = readState();
  s.disabled = s.disabled.filter((x) => x !== id);
  if (!enabled) {
    s.disabled.push(id);
    if (s.default === id) s.default = null;
  }
  writeState(s);
}

function setDefault(id) {
  requireTool(id);
  if (!detect(id).installed || !isEnabled(id)) {
    throw makeErr("EBADDEFAULT", `${id} must be installed and enabled to be the default`);
  }
  writeState({ ...readState(), default: id });
}

function effectiveDefault() {
  const s = readState();
  const ok = (id) => has(id) && detect(id).installed && !s.disabled.includes(id);
  if (s.default && ok(s.default)) return s.default;
  if (ok("claude")) return "claude";
  return list().find((t) => ok(t.id))?.id || null;
}

/** The GET /api/ai-tools body — flags only, never the arg arrays. */
function view() {
  const disabled = new Set(readState().disabled);
  return {
    tools: list().map((t) => {
      const d = detect(t.id);
      return {
        id: t.id,
        label: t.label,
        command: d.command,
        homepageUrl: t.homepageUrl,
        installed: d.installed,
        path: d.path,
        enabled: !disabled.has(t.id),
        source: t.source,
        launcher: t.launcher,
        prompt: t.prompt ? { mode: t.prompt.mode } : null,
        resume: !!t.resume,
        bypass: !!(t.bypass || t.bypassEnv),
        routerCapable: ROUTER_CAPABLE.has(t.id),
      };
    }),
    default: effectiveDefault(),
  };
}

/** Test seam: `[builtinDir, customDir]`, or null for the real ones. */
function __setCatalogDirs(dirs) {
  dirsOverride = dirs;
  refresh();
}

module.exports = {
  list,
  get,
  has,
  detect,
  refresh,
  readState,
  isEnabled,
  setEnabled,
  setDefault,
  effectiveDefault,
  view,
  ROUTER_CAPABLE,
  __setCatalogDirs,
};