// Registers the connector with the Claude apps on this computer, so the user
// clicks "Connect" instead of copying a command into a terminal.
//
// Claude Code: through its own CLI (`claude mcp add-json … --scope user`), so
// Claude Code writes its own config and nothing here edits ~/.claude.json,
// which a running Claude Code rewrites at will. That file is only READ, to
// show whether the entry is there and current.
//
// Claude Desktop: its claude_desktop_config.json is the file users are told
// to edit by hand. Only the `theseus` entry is added, changed or removed; the
// rest is kept as it was, a copy of the previous file is kept beside it, and
// a file that does not parse is left alone.

const fs = require("node:fs");
const path = require("node:path");
const os = require("node:os");
const { execFile } = require("node:child_process");

const NAME = "theseus";

function env(opts) {
  const e = opts.env || process.env;
  const platform = opts.platform || process.platform;
  const home = opts.home || os.homedir();
  return { e, platform, home };
}

// ---- Claude Code ---------------------------------------------------------

// The CLI as a native binary only: an npm `claude.cmd` would need a shell,
// and a shell would have to re-quote the JSON argument.
function findClaudeCli(opts = {}) {
  const { e, platform, home } = env(opts);
  if (opts.cli) return fs.existsSync(opts.cli) ? opts.cli : null;
  const names = platform === "win32" ? ["claude.exe"] : ["claude"];
  const dirs = [
    path.join(home, ".local", "bin"),
    path.join(home, ".claude", "local"),
    ...(platform === "win32" ? [] : ["/usr/local/bin", "/opt/homebrew/bin"]),
    ...String(e.PATH || e.Path || "").split(path.delimiter).filter(Boolean),
  ];
  for (const d of dirs) {
    for (const n of names) {
      const p = path.join(d, n);
      try { if (fs.statSync(p).isFile()) return p; } catch {}
    }
  }
  return null;
}

function claudeCodeConfigPath(opts = {}) {
  const { e, home } = env(opts);
  return e.CLAUDE_CONFIG_DIR ? path.join(e.CLAUDE_CONFIG_DIR, ".claude.json") : path.join(home, ".claude.json");
}

function readJson(file) {
  try { return JSON.parse(fs.readFileSync(file, "utf8")); } catch { return null; }
}

function httpEntry(url, token) {
  return { type: "http", url, headers: { Authorization: `Bearer ${token}` } };
}

function sameHttp(entry, url, token) {
  return !!entry && entry.url === url && entry.headers && entry.headers.Authorization === `Bearer ${token}`;
}

function run(cli, args, opts) {
  return new Promise((resolve) => {
    execFile(cli, args, { timeout: 30000, windowsHide: true, env: opts.env || process.env }, (err, stdout, stderr) => {
      resolve({ ok: !err, code: err ? (err.code ?? 1) : 0, out: `${stdout || ""}${stderr || ""}`.trim() });
    });
  });
}

const claudeCode = {
  status({ url, token }, opts = {}) {
    const cli = findClaudeCli(opts);
    const cfg = readJson(claudeCodeConfigPath(opts));
    const entry = cfg && cfg.mcpServers ? cfg.mcpServers[NAME] : null;
    return {
      installed: !!cli,
      configured: !!entry,
      current: !!url && sameHttp(entry, url, token),
    };
  },
  async register({ url, token }, opts = {}) {
    const cli = findClaudeCli(opts);
    if (!cli) throw new Error("Claude Code was not found on this computer (looked for the claude command)");
    // add-json refuses an existing name, so an update is remove + add.
    await run(cli, ["mcp", "remove", NAME, "--scope", "user"], opts);
    const r = await run(cli, ["mcp", "add-json", NAME, JSON.stringify(httpEntry(url, token)), "--scope", "user"], opts);
    if (!r.ok) throw new Error(`Claude Code refused the entry: ${r.out || `exit ${r.code}`}`);
    return { ok: true };
  },
  async unregister(opts = {}) {
    const cli = findClaudeCli(opts);
    if (!cli) throw new Error("Claude Code was not found on this computer");
    const r = await run(cli, ["mcp", "remove", NAME, "--scope", "user"], opts);
    if (!r.ok && !/not found|no .*server/i.test(r.out)) throw new Error(`Claude Code: ${r.out || `exit ${r.code}`}`);
    return { ok: true };
  },
};

// ---- Claude Desktop ------------------------------------------------------

function desktopConfigPath(opts = {}) {
  const { e, platform, home } = env(opts);
  if (platform === "win32") return path.join(e.APPDATA || path.join(home, "AppData", "Roaming"), "Claude", "claude_desktop_config.json");
  if (platform === "darwin") return path.join(home, "Library", "Application Support", "Claude", "claude_desktop_config.json");
  return path.join(e.XDG_CONFIG_HOME || path.join(home, ".config"), "Claude", "claude_desktop_config.json");
}

// Claude Desktop starts stdio servers only: it runs Theseus itself in Node
// mode with the relay, which reads the address from Theseus's endpoint file.
function desktopEntry({ exe, shim, url, token }) {
  return { command: exe, args: [shim], env: { ELECTRON_RUN_AS_NODE: "1", THESEUS_MCP_URL: url, THESEUS_MCP_TOKEN: token } };
}

function sameDesktop(entry, want) {
  return !!entry && entry.command === want.command && JSON.stringify(entry.args) === JSON.stringify(want.args)
    && entry.env && entry.env.THESEUS_MCP_URL === want.env.THESEUS_MCP_URL && entry.env.THESEUS_MCP_TOKEN === want.env.THESEUS_MCP_TOKEN;
}

function editDesktopConfig(file, edit) {
  let cfg = {};
  if (fs.existsSync(file)) {
    const text = fs.readFileSync(file, "utf8");
    try { cfg = text.trim() ? JSON.parse(text) : {}; }
    catch { throw new Error(`${file} is not valid JSON; fix or remove it in Claude Desktop first`); }
    fs.copyFileSync(file, file + ".theseus-backup");
  }
  if (!cfg || typeof cfg !== "object" || Array.isArray(cfg)) throw new Error(`${file} does not hold a settings object`);
  edit(cfg);
  const tmp = file + ".tmp-" + process.pid;
  fs.writeFileSync(tmp, JSON.stringify(cfg, null, 2) + "\n");
  fs.renameSync(tmp, file);
}

const claudeDesktop = {
  status(params, opts = {}) {
    const file = desktopConfigPath(opts);
    const cfg = readJson(file);
    const entry = cfg && cfg.mcpServers ? cfg.mcpServers[NAME] : null;
    return {
      installed: fs.existsSync(path.dirname(file)),
      configured: !!entry,
      current: !!params.url && sameDesktop(entry, desktopEntry(params)),
    };
  },
  async register(params, opts = {}) {
    const file = desktopConfigPath(opts);
    if (!fs.existsSync(path.dirname(file))) throw new Error("Claude Desktop was not found on this computer (no Claude settings folder)");
    editDesktopConfig(file, (cfg) => {
      if (!cfg.mcpServers || typeof cfg.mcpServers !== "object") cfg.mcpServers = {};
      cfg.mcpServers[NAME] = desktopEntry(params);
    });
    return { ok: true, restart: true };
  },
  async unregister(opts = {}) {
    const file = desktopConfigPath(opts);
    if (!fs.existsSync(file)) return { ok: true };
    editDesktopConfig(file, (cfg) => { if (cfg.mcpServers) delete cfg.mcpServers[NAME]; });
    return { ok: true, restart: true };
  },
};

module.exports = { claudeCode, claudeDesktop, findClaudeCli, claudeCodeConfigPath, desktopConfigPath, httpEntry, desktopEntry };