import { readFile, readdir, stat } from 'node:fs/promises';
import { existsSync } from 'node:fs';
import { createHash } from 'node:crypto';
import path from 'node:path';
import { logger } from '@/lib/logger';
import { ALL_PERMISSIONS, MAX_PLUGIN_SIZE } from '@/lib/plugin-types';
import { auditLog } from './audit';
import { configManager } from './config-manager';
import { isConfigReadOnly } from './paths';
import {
  getPluginRegistry,
  savePlugin,
  updatePluginMeta,
  type ServerPlugin,
} from './plugin-registry';
import type { FeatureGates } from './types';

/**
 * First-party ("bundled") plugin installation.
 *
 * The plugin registry (`<CONFIG_DIR>/plugins/`) is the host's admin channel:
 * bundles served out of it are Ed25519-signed on the way out by
 * `app/api/admin/plugins/[id]/bundle`, and `/api/plugins` is what makes a
 * plugin `managed` on the client - which is what `resolvePluginTier` requires
 * before it will grant the privileged (same-origin) tier.
 *
 * This module installs the plugins this fork ships with THROUGH that same
 * channel, so nothing about the signing / approval / consent chain is
 * bypassed or relaxed: the operator's own server performs the install that an
 * operator would otherwise perform by uploading the ZIP in /admin.
 *
 * Input is the staging directory produced by `scripts/build-plugins.mjs`:
 *
 *   vnc/plugins/build/<id>/manifest.json
 *   vnc/plugins/build/<id>/<entrypoint>
 *
 * Nothing here is trusted blindly - the manifest is validated the same way the
 * admin upload route validates one, and an unknown permission or a bad id is a
 * refusal, not a warning.
 */

/** Where the staged bundles live, relative to cwd (override for odd layouts). */
function getBundledPluginsDir(): string {
  return (
    process.env.BUNDLED_PLUGINS_DIR ||
    path.join(process.cwd(), 'vnc', 'plugins', 'build')
  );
}

interface FirstPartyPlugin {
  id: string;
  /**
   * Feature gate that decides whether this plugin is installed and served.
   * Turning the gate off in the admin policy disables the plugin (and stops
   * it being re-installed on the next boot) - that, not the Delete button, is
   * the way to remove a bundled plugin, since a delete would be undone by the
   * next restart.
   */
  gate: keyof FeatureGates;
  /**
   * Force-enable for every user. Required for a bundled plugin to be reachable
   * at all under the default policy: `pluginsEnabled` defaults to false, which
   * hides the user-facing Settings > Plugins tab, so there would be no way for
   * a user to switch it on by hand.
   */
  forceEnable: boolean;
}

const FIRST_PARTY_PLUGINS: FirstPartyPlugin[] = [
  // The audited S/MIME implementation (vnc/plugins/smime). It IS the S/MIME
  // feature - the former in-host native pipeline is gone - so the long-standing
  // `smimeEnabled` policy gate now controls this plugin.
  { id: 'smime', gate: 'smimeEnabled', forceEnable: true },
  // VNCdirectory deep-link. Users are managed in the directory, not the
  // webmail; this plugin adds a "User management" Settings entry that opens
  // the directory's user list. Force-enabled so it is always present.
  { id: 'manage-users', gate: 'manageUsersEnabled', forceEnable: true },
  // SRC video meetings (VNCtalk / Jitsi). "Start a meeting" asks the server
  // for a signed JWT and opens the room in meet.src-advisory.com.
  { id: 'jitsi-meet', gate: 'jitsiMeetEnabled', forceEnable: true },
];

const ID_RE = /^[a-z0-9][a-z0-9-]*[a-z0-9]$/;
const VALID_TYPES = new Set(['ui-extension', 'sidebar-app', 'hook']);

function asString(v: unknown, fallback = ''): string {
  return typeof v === 'string' ? v : fallback;
}

/**
 * Validate a staged manifest and turn it into a registry entry. Returns a list
 * of errors instead of throwing so one bad bundle can't take down startup.
 */
function toServerPlugin(
  manifest: Record<string, unknown>,
  code: string,
  opts: { enabled: boolean; forceEnabled: boolean; installedAt: string },
): { plugin: ServerPlugin } | { errors: string[] } {
  const errors: string[] = [];
  const id = asString(manifest.id);
  if (!ID_RE.test(id)) errors.push(`invalid id ${JSON.stringify(manifest.id)}`);
  if (!asString(manifest.name)) errors.push('missing "name"');
  if (!asString(manifest.version)) errors.push('missing "version"');
  if (!asString(manifest.author)) errors.push('missing "author"');
  const entrypoint = asString(manifest.entrypoint);
  if (!entrypoint) errors.push('missing "entrypoint"');
  if (!VALID_TYPES.has(asString(manifest.type))) {
    errors.push(`invalid type ${JSON.stringify(manifest.type)}`);
  }

  const permissions = Array.isArray(manifest.permissions)
    ? manifest.permissions.filter((p): p is string => typeof p === 'string')
    : [];
  const known = new Set<string>(ALL_PERMISSIONS as readonly string[]);
  const unknownPerms = permissions.filter(p => !known.has(p));
  if (unknownPerms.length > 0) {
    errors.push(`unknown permissions: ${unknownPerms.join(', ')}`);
  }

  const size = Buffer.byteLength(code, 'utf-8');
  if (size > MAX_PLUGIN_SIZE) {
    errors.push(`bundle is ${size} bytes, over the ${MAX_PLUGIN_SIZE} byte limit`);
  }

  if (errors.length > 0) return { errors };

  return {
    plugin: {
      id,
      name: asString(manifest.name),
      version: asString(manifest.version),
      author: asString(manifest.author),
      description: asString(manifest.description),
      type: asString(manifest.type),
      // Only 'privileged' is meaningful; anything else falls through to the
      // default untrusted tier. Same narrowing the admin upload route applies.
      ...(manifest.tier === 'privileged' ? { tier: 'privileged' } : {}),
      permissions,
      entrypoint,
      enabled: opts.enabled,
      forceEnabled: opts.forceEnabled,
      ...(manifest.configSchema && typeof manifest.configSchema === 'object'
        ? { configSchema: manifest.configSchema as ServerPlugin['configSchema'] }
        : {}),
      ...(manifest.settingsSchema && typeof manifest.settingsSchema === 'object'
        ? { settingsSchema: manifest.settingsSchema as ServerPlugin['settingsSchema'] }
        : {}),
      ...(manifest.locales && typeof manifest.locales === 'object'
        ? { locales: manifest.locales as ServerPlugin['locales'] }
        : {}),
      installedAt: opts.installedAt,
      updatedAt: opts.installedAt,
    },
  };
}

async function readStaged(dir: string, id: string): Promise<
  { manifest: Record<string, unknown>; code: string } | null
> {
  const manifestPath = path.join(dir, id, 'manifest.json');
  if (!existsSync(manifestPath)) return null;

  let manifest: Record<string, unknown>;
  try {
    const parsed = JSON.parse(await readFile(manifestPath, 'utf-8'));
    if (typeof parsed !== 'object' || parsed === null) throw new Error('not an object');
    manifest = parsed as Record<string, unknown>;
  } catch (err) {
    logger.error(`[bundled-plugins] ${id}: unreadable manifest`, {
      error: err instanceof Error ? err.message : String(err),
    });
    return null;
  }

  const entrypoint = asString(manifest.entrypoint, 'index.js');
  if (entrypoint.includes('/') || entrypoint.includes('\\')) {
    logger.error(`[bundled-plugins] ${id}: entrypoint must be a bare filename`);
    return null;
  }
  const codePath = path.join(dir, id, entrypoint);
  try {
    return { manifest, code: await readFile(codePath, 'utf-8') };
  } catch (err) {
    logger.error(`[bundled-plugins] ${id}: cannot read bundle ${entrypoint}`, {
      error: err instanceof Error ? err.message : String(err),
    });
    return null;
  }
}

/**
 * Install / update / disable the bundled first-party plugins. Idempotent: a
 * boot where nothing changed writes nothing.
 *
 * Never throws - a failure here must not stop the server from starting, it
 * just means the plugin isn't there (and says so in the log).
 */
export async function seedBundledPlugins(): Promise<void> {
  try {
    const dir = getBundledPluginsDir();
    const staged = existsSync(dir);

    await configManager.ensureLoaded();
    const features = configManager.getPolicy().features;
    const registry = await getPluginRegistry();

    for (const spec of FIRST_PARTY_PLUGINS) {
      const gateOn = features[spec.gate] !== false;
      const existing = registry.plugins.find(p => p.id === spec.id);

      if (!gateOn) {
        // Policy says off. Stop serving it (the client's own sync then treats
        // it as removed and cleans it up) but leave the bundle on disk so
        // flipping the gate back on is instant.
        if (existing && (existing.enabled || existing.forceEnabled)) {
          if (isConfigReadOnly()) {
            logger.warn(
              `[bundled-plugins] ${spec.id}: policy "${spec.gate}" is off but the ` +
                'config dir is read-only, so it stays enabled',
            );
            continue;
          }
          await updatePluginMeta(spec.id, { enabled: false, forceEnabled: false });
          logger.info(`[bundled-plugins] ${spec.id} disabled ("${spec.gate}" is off in policy)`);
          await auditLog('plugin.bundled.disable', { id: spec.id, gate: spec.gate }, 'system');
        }
        continue;
      }

      if (!staged) continue;

      const read = await readStaged(dir, spec.id);
      if (!read) {
        logger.warn(
          `[bundled-plugins] ${spec.id}: not staged in ${dir} - ` +
            'run "npm run build:plugins" (the container and standalone builds do this for you)',
        );
        continue;
      }

      const bundleHash = createHash('sha256').update(read.code).digest('hex');
      const version = asString(read.manifest.version);
      const unchanged =
        existing !== undefined &&
        existing.version === version &&
        existing.bundleHash === bundleHash &&
        existing.enabled === true &&
        existing.forceEnabled === spec.forceEnable;
      if (unchanged) {
        logger.debug(`[bundled-plugins] ${spec.id} v${version} already installed`);
        continue;
      }

      if (isConfigReadOnly()) {
        logger.warn(
          `[bundled-plugins] ${spec.id} v${version} cannot be installed: the admin ` +
            'config dir is read-only. Remount it read-write (or unset ' +
            'ADMIN_CONFIG_READONLY) once, so the plugin registry can be written.',
        );
        continue;
      }

      const built = toServerPlugin(read.manifest, read.code, {
        enabled: true,
        forceEnabled: spec.forceEnable,
        installedAt: existing?.installedAt ?? new Date().toISOString(),
      });
      if ('errors' in built) {
        logger.error(`[bundled-plugins] ${spec.id}: manifest rejected`, {
          errors: built.errors.join('; '),
        });
        continue;
      }

      await savePlugin(built.plugin, read.code);
      const action = existing ? 'update' : 'install';
      logger.info(
        `[bundled-plugins] ${existing ? 'updated' : 'installed'} ${spec.id} v${version} ` +
          `(tier=${built.plugin.tier ?? 'untrusted'}, forceEnabled=${spec.forceEnable})`,
      );
      await auditLog(
        `plugin.bundled.${action}`,
        { id: spec.id, version, bundleHash, tier: built.plugin.tier ?? 'untrusted' },
        'system',
      );
    }
  } catch (err) {
    logger.error('[bundled-plugins] seeding failed', {
      error: err instanceof Error ? err.message : String(err),
    });
  }
}

/** Exposed for diagnostics / tests. */
export async function listStagedBundledPlugins(): Promise<string[]> {
  const dir = getBundledPluginsDir();
  if (!existsSync(dir)) return [];
  const names = await readdir(dir);
  const out: string[] = [];
  for (const name of names) {
    if (name.startsWith('.')) continue;
    try {
      if ((await stat(path.join(dir, name))).isDirectory()) out.push(name);
    } catch { /* ignore */ }
  }
  return out;
}