import { readdir } from 'node:fs/promises';
import { join } from 'node:path';
import { capabilitySources } from '../../capability-sources';

// Bun's own YAML, the same one `task-files.ts` uses. Not the `yaml` package — it is not a dependency,
// and adding one to read four lines of frontmatter is not a trade worth making.
const YAML = (Bun as unknown as { YAML: { parse(input: string): unknown } }).YAML;

/**
 * Commanders a plugin ships, ready to be created but not running.
 *
 * ── Presence is the declaration ──
 *
 * A plugin with a `commanders/<name>/COMMANDER.md` offers one. Nothing is added to `manifest.ts`, for
 * the same reason `tasks/` and `skills/` are not declared there: the directory already says it, and a
 * second place to say it is a second place for the two to disagree.
 *
 * Read IN PLACE, and only from installed-and-enabled plugins — `capabilitySources` handles both. So a
 * disabled plugin stops offering its commander, and `plugins:update` changes the template without
 * anything having to be republished.
 *
 * ── A template is not a commander ──
 *
 * What is here is an OFFER. Nothing runs, nothing is scheduled, and no directory exists until the
 * owner creates one from it and fills in the inputs. That is the whole shape the owner asked for:
 * a plugin may propose recurring work; only a person may start it.
 *
 * ── Why the inputs reuse TASK.md's vocabulary ──
 *
 * `inputs:` here is the same structure a task declares, so the same form renderer draws it and the
 * same validation applies. A commander asking "which folder, which extensions, what output" is asking
 * exactly what a task asks, and inventing a second schema for it would mean two form renderers to
 * keep in step for no gain.
 */

export type CommanderInput = {
  type: string;
  description?: string;
  default?: string;
  options?: string[];
  /** Unset and required means the commander cannot arm. See `missingInputs`. */
  required?: boolean;
};

export type PluginCommanderTemplate = {
  /** Directory name, unique within its plugin — `heic-to-webp`. */
  dirName: string;
  /** The plugin that ships it. Never null: an owner's own commanders do not come from a template. */
  plugin: string;
  name: string;
  description: string;
  /** What it watches, in a sentence, for the card. */
  watches?: string;
  inputs: Record<string, CommanderInput>;
  /** The prose that becomes the commander's `CLAUDE.md`. */
  body: string;
  /** Absolute path to the template directory, so the watcher script can be read at creation. */
  dir: string;
};

function parse(raw: string): { fm: Record<string, unknown>; body: string } {
  const match = raw.match(/^---\n([\s\S]*?)\n---\n?([\s\S]*)$/);
  if (!match) return { fm: {}, body: raw };
  try {
    return { fm: (YAML.parse(match[1]!) as Record<string, unknown>) ?? {}, body: match[2]! };
  } catch {
    // A template with unparseable frontmatter is skipped by the caller rather than crashing the list —
    // one plugin's bad YAML must not take away every other plugin's commanders.
    return { fm: {}, body: match[2]! };
  }
}

export async function listPluginCommanders(): Promise<PluginCommanderTemplate[]> {
  const sources = await capabilitySources('commanders');
  const found: PluginCommanderTemplate[] = [];

  for (const source of sources) {
    // Only plugins offer these. The owner's own `capabilities/commanders/` is not a thing that exists:
    // a commander somebody makes themselves is made in the UI, not from a template on disk.
    if (!source.plugin) continue;

    let entries;
    try {
      entries = await readdir(source.dir, { withFileTypes: true });
    } catch {
      continue; // most plugins ship none — ordinary, not a fault
    }

    for (const entry of entries) {
      if (!entry.isDirectory()) continue;
      const dir = join(source.dir, entry.name);
      const file = Bun.file(join(dir, 'COMMANDER.md'));
      if (!(await file.exists())) continue;

      const { fm, body } = parse(await file.text());
      if (!fm.name) continue; // no name means the frontmatter did not parse — skip it quietly

      found.push({
        dirName: entry.name,
        plugin: source.plugin,
        name: String(fm.name),
        description: String(fm.description ?? ''),
        watches: fm.watches ? String(fm.watches) : undefined,
        inputs: (fm.inputs as Record<string, CommanderInput>) ?? {},
        body,
        dir,
      });
    }
  }

  return found.sort((a, b) => a.name.localeCompare(b.name));
}

export async function getPluginCommander(plugin: string, dirName: string): Promise<PluginCommanderTemplate | null> {
  // Both halves reach this from a request body and are joined onto a path below.
  const unsafe = (v: string) => !v || v.includes('/') || v.includes('\\') || v === '.' || v === '..';
  if (unsafe(plugin) || unsafe(dirName)) return null;

  const all = await listPluginCommanders();
  return all.find((t) => t.plugin === plugin && t.dirName === dirName) ?? null;
}

/**
 * Which required inputs have no answer.
 *
 * This is the "configure before running" rule, and it is enforced at ARM time rather than at creation.
 * Creating a half-configured commander is fine and useful — it exists, it is visible, and it can be
 * finished later. Arming one is what would run somebody's disk against a blank setting.
 */
export function missingInputs(
  inputs: Record<string, CommanderInput>,
  config: Record<string, string> | null | undefined,
): string[] {
  return Object.entries(inputs)
    .filter(([key, spec]) => spec.required && !(config?.[key] ?? spec.default ?? '').trim())
    .map(([key]) => key);
}

/**
 * Everything a created commander needs on disk beyond its `CLAUDE.md`.
 *
 * ── `config.env`, not a JSON file ──
 *
 * The watcher is a shell script and this is what it sources. A JSON config would mean the script
 * parsing JSON in bash, which is either `jq` (another dependency for four values) or something
 * hand-rolled that breaks on the first path with a space in it. The database row remains the source
 * of truth; this is a projection of it that bash can read.
 *
 * ── Every value is quoted, and that is not decoration ──
 *
 * `WATCH_DIR` is a path the owner typed, and this fleet has directories called `ABOUT US` and
 * `70´S`. Unquoted, the first space ends the assignment and the watcher silently watches the wrong
 * folder — or, with `rm` involved downstream, the wrong folder's contents.
 */
export function configEnv(
  inputs: Record<string, CommanderInput>,
  config: Record<string, string> | null | undefined,
): string {
  const lines = ['# Written by Officer when this commander was created. Edit through the UI, not here.'];

  for (const [key, spec] of Object.entries(inputs)) {
    const value = config?.[key] ?? spec.default ?? '';
    // Single quotes, with any embedded single quote closed and re-opened around an escaped one — the
    // standard shell trick, and the only form that is safe for arbitrary text.
    const quoted = `'${String(value).replace(/'/g, `'\\''`)}'`;
    lines.push(`${key.toUpperCase()}=${quoted}`);
  }

  return lines.join('\n') + '\n';
}