import { cp, readdir, rm } from 'node:fs/promises';
import { existsSync } from 'node:fs';
import { join } from 'node:path';
import { AFFORDANCES_DIR } from './load';
import type { DiscoveredPlugin } from '../plugins/manifest';

// Copying a plugin's affordances into the store the agent reads.
//
// A plugin is a new SURFACE arriving at runtime, which is the case hand-written prose could never cover:
// install gitea and no agent learns that `tea` is authenticated, or that `git` is the better tool for
// what git already does. The plugin knows; nothing was carrying that across.
//
// Same shape as `publishAssets` — a directory in the plugin repository, copied to a platform-managed
// place on install, removed on uninstall. Deliberately so: two mechanisms for "the plugin ships some
// files" would drift, and this one is already understood.
//
// ── Why the destination is namespaced ──
//
// `<publisher>/<appName>/`, mirroring `mountPrefix`. Two plugins called `gitea` from different publishers
// must not overwrite each other's affordances, and an affordance in the tree should say whose it is
// without opening it. `core` occupies the appName slot for the platform's own.

/** Where a plugin's affordances land. `officerdev/gitea/`, beside `officer/core/`. */
export const affordanceDirFor = (plugin: DiscoveredPlugin): string =>
  join(AFFORDANCES_DIR, plugin.manifest.publisher, plugin.appName);

/** What the plugin ships, if anything. */
export const affordanceSourceFor = (plugin: DiscoveredPlugin): string => join(plugin.dir, 'affordances');

/**
 * Publish a plugin's affordances. Returns the number of files, or 0 when it ships none — which is the
 * ordinary case and not a failure.
 *
 * Idempotent by overwriting, so re-running an install republishes rather than erroring. It does NOT
 * remove files the plugin has since dropped; that is what uninstall is for, and deleting on every
 * install would make a half-finished copy destructive.
 */
export async function publishAffordances(plugin: DiscoveredPlugin): Promise<number> {
  const source = affordanceSourceFor(plugin);
  if (!existsSync(source)) return 0;

  const dest = affordanceDirFor(plugin);
  await cp(source, dest, { recursive: true, force: true });

  try {
    return ((await readdir(dest, { recursive: true })) as string[]).filter((f) => f.endsWith('.md')).length;
  } catch {
    return 0;
  }
}

/**
 * Drop a plugin's affordances.
 *
 * Removes the plugin's own directory, never the publisher's: `officerdev/` holds every first-party
 * plugin's, and taking it out because one was uninstalled would silently strip the rest.
 *
 * Safe to call when nothing was ever published.
 */
export async function unpublishAffordances(plugin: DiscoveredPlugin): Promise<void> {
  await rm(affordanceDirFor(plugin), { recursive: true, force: true });
}