/**
 * Projectless thread workspaces.
 *
 * Codex keeps two kinds of conversation: one attached to a project directory and
 * one that starts from nothing. The desktop main process owns the second kind —
 * it picks a folder under the user's workspace root, creates it, and hands the
 * paths back to the renderer through `projectlessThreads.createPaths`.
 *
 * The browser cannot touch the filesystem, so the Node host does it here and
 * exposes the same three paths over HTTP:
 *
 *   cwd             the directory this conversation runs in
 *   outputDirectory where generated files land (same folder)
 *   workspaceRoot   the shared root that contains every thread
 *
 * Layout mirrors the desktop app: <root>/<YYYY-MM-DD>/<slug>
 */

import fs from "node:fs";
import os from "node:os";
import path from "node:path";

export const WORKSPACE_ROOT =
  // Linux server default: ~/Codex. The desktop default ~/Documents/Codex
  // does not exist on a server, so it is not used here.
  process.env.CODEX_WEB_WORKSPACE_ROOT || path.join(os.homedir(), "Codex");

export function ensureWorkspaceRoot() {
  fs.mkdirSync(WORKSPACE_ROOT, { recursive: true });
  return WORKSPACE_ROOT;
}

/** Lowercase, collapse anything awkward, keep CJK, cap the length. */
function slugify(value) {
  const text = String(value ?? "").trim();
  if (!text) return "";
  return text
    .toLowerCase()
    .replace(/[^\p{Letter}\p{Number}]+/gu, "-")
    .replace(/^-+|-+$/g, "")
    .slice(0, 40);
}

export function createProjectlessPaths({ directoryName, prompt } = {}) {
  const root = ensureWorkspaceRoot();
  const day = new Date().toISOString().slice(0, 10);
  const base = slugify(directoryName) || slugify(prompt) || "thread";

  let dir = path.join(root, day, base);
  let suffix = 1;
  while (fs.existsSync(dir)) {
    suffix += 1;
    dir = path.join(root, day, `${base}-${suffix}`);
  }
  fs.mkdirSync(dir, { recursive: true });

  return { cwd: dir, outputDirectory: dir, workspaceRoot: root };
}

export function readWorkspaceRoot() {
  return { workspaceRoot: ensureWorkspaceRoot() };
}