<?php
/*************************************************************
# 076 License

Copyright (c) テクニカル諏訪子

Permission is hereby granted to any person obtaining a copy of the software
Little Beast (the "Software") to use, modify, merge, copy, publish, distribute,
sublicense, and/or sell copies of the Software, subject to the following conditions:

    1. **Origin Attribution**:
       - You must not misrepresent the origin of the Software; you must not claim
         you created the original Software.
       - If the Software is used in a product, you must either:
         a. Provide clear attribution in the product's documentation, user interface,
            or other visible areas, **OR**
         b. Pay the original developers a fee they specify in writing.
    2. **Usage Restriction**:
       - The Software, or any derivative works, dependencies, or libraries
         incorporating it, must not be used for censorship or to suppress freedom of
         speech, expression, or creativity. Prohibited uses include, but are not
         limited to:
         - Censorship of so-called "hate speech", visuals, non-mainstream opinions,
           ideas, or objective reality.
         - Tools or systems designed to restrict access to information or
           artistic works.
    3. **Notice Preservation**:
       - This license and the above copyright notice must remain intact in all copies
         of the source code.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
namespace Std\Lib\Fedi;

use Std\Lib\Crypto\Rsa;

/**
 * ローカルのユーザーのアクター（鍵、プロフィール、WebFinger、コレクション）
 */
final class Actor {
  /**
   * ユーザーの秘密鍵（無ければ作る）
   *
   * @return Rsa|null  作れない・読めない場合はnull
   */
  public static function privateKey(string $username): ?Rsa {
    $file = Fedi::userPath($username, 'private.pem');
    if (!is_file($file)) {
      $lock = fopen($file.'.lock', 'c');
      if ($lock) flock($lock, LOCK_EX);
      try {
        if (!is_file($file)) {
          $key = Rsa::generate(2048);
          file_put_contents($file, $key->toPem());
          @chmod($file, 0600);
          file_put_contents(Fedi::userPath($username, 'public.pem'), $key->publicPem());
        }
      } finally {
        if ($lock) {
          flock($lock, LOCK_UN);
          fclose($lock);
        }
      }
    }
    try {
      $key = Rsa::fromPem((string)file_get_contents($file));
    } catch (\InvalidArgumentException $e) {
      logger(\LogType::ActivityPub, "「{$username}」の鍵を読めませんでした：".$e->getMessage());
      return null;
    }
    return $key->isPrivate() ? $key : null;
  }

  public static function publicKeyPem(string $username): ?string {
    $file = Fedi::userPath($username, 'public.pem');
    if (!is_file($file) && self::privateKey($username) === null) return null;
    return is_file($file) ? (string)file_get_contents($file) : null;
  }

  public static function keyId(string $username): string {
    return Fedi::actorUrl($username).'#main-key';
  }

  /** ユーザーの設定（locked：フォローを承認制にする） */
  public static function settings(string $username): array {
    return Fedi::read(Fedi::userPath($username, 'settings.json'), []) + ['locked' => false];
  }

  public static function saveSettings(string $username, array $settings): void {
    Fedi::update(Fedi::userPath($username, 'settings.json'), fn($s) => array_merge($s, $settings));
  }

  /**
   * アクターのJSON-LD
   *
   * @param \stdClass $user  ローカルのユーザー（Fedi::localActor()）
   * @return array
   */
  public static function document(\stdClass $user): array {
    $url = Fedi::actorUrl($user->username);
    $avatar = avatar_url($user);
    $doc = [
      '@context' => Fedi::CONTEXT,
      'id' => $url,
      'type' => 'Person',
      'preferredUsername' => $user->username,
      'name' => ($user->displayname ?? '') !== '' ? $user->displayname : $user->username,
      'summary' => ($user->bio ?? '') !== '' ? Html::render($user->bio) : '',
      'url' => Fedi::base().'/microblog/user/'.$user->username,
      'inbox' => "{$url}/inbox",
      'outbox' => "{$url}/outbox",
      'followers' => "{$url}/followers",
      'following' => "{$url}/following",
      'endpoints' => ['sharedInbox' => Fedi::sharedInbox()],
      'manuallyApprovesFollowers' => (bool)self::settings($user->username)['locked'],
      'discoverable' => true,
      'published' => Fedi::now((int)($user->regDate ?? time())),
      'icon' => [
        'type' => 'Image',
        'mediaType' => self::mediaTypeOf($avatar),
        'url' => preg_match('#^https?://#i', $avatar) ? $avatar : Fedi::base().$avatar,
      ],
    ];
    $pem = self::publicKeyPem($user->username);
    if ($pem !== null) $doc['publicKey'] = ['id' => self::keyId($user->username), 'owner' => $url, 'publicKeyPem' => $pem];
    return $doc;
  }

  /**
   * WebFingerの応答
   *
   * @param string $resource  acct:ユーザー@ホスト又はアクターのURL
   * @return array|null  見つからなければnull
   */
  public static function webfinger(string $resource): ?array {
    $username = null;
    if (preg_match('/^(?:acct:)?@?([A-Za-z0-9]+)@(.+)$/', $resource, $m) && strtolower($m[2]) === strtolower(Fedi::host())) {
      $username = $m[1];
    } else {
      $username = Fedi::localUsername($resource);
    }
    if ($username === null || Fedi::localActor($username) === null) return null;

    return [
      'subject' => "acct:{$username}@".Fedi::host(),
      'aliases' => [Fedi::actorUrl($username), Fedi::base().'/microblog/user/'.$username],
      'links' => [
        ['rel' => 'self', 'type' => 'application/activity+json', 'href' => Fedi::actorUrl($username)],
        ['rel' => 'http://webfinger.net/rel/profile-page', 'type' => 'text/html', 'href' => Fedi::base().'/microblog/user/'.$username],
      ],
    ];
  }

  //////// フォロワーとフォロー

  /** フォロワー（アクターのURL => [inbox, sharedInbox, since]） */
  public static function followers(string $username): array {
    return Fedi::read(Fedi::userPath($username, 'followers.json'));
  }

  /** フォロー（アクターのURL => [state（pending/accepted）, id, since]） */
  public static function following(string $username): array {
    return Fedi::read(Fedi::userPath($username, 'following.json'));
  }

  /** 承認待ちのフォローリクエスト（アクターのURL => [activity, at]） */
  public static function requests(string $username): array {
    return Fedi::read(Fedi::userPath($username, 'requests.json'));
  }

  public static function isFollowing(string $username, string $actor): bool {
    return (self::following($username)[$actor]['state'] ?? '') === 'accepted';
  }

  public static function isFollowedBy(string $username, string $actor): bool {
    return isset(self::followers($username)[$actor]);
  }

  /**
   * フォロワー・フォローのOrderedCollection（一覧は公開しない。数だけ）
   */
  public static function collection(string $username, string $which): array {
    $list = $which === 'followers' ? self::followers($username)
          : array_filter(self::following($username), fn($f) => ($f['state'] ?? '') === 'accepted');
    return [
      '@context' => 'https://www.w3.org/ns/activitystreams',
      'id' => Fedi::actorUrl($username)."/{$which}",
      'type' => 'OrderedCollection',
      'totalItems' => count($list),
    ];
  }

  //////// ブロック

  /** ブロック（actors：アクターのURL、domains：ドメイン） */
  public static function blocks(string $username): array {
    return Fedi::read(Fedi::userPath($username, 'blocks.json')) + ['actors' => [], 'domains' => []];
  }

  /**
   * このユーザー（又はサイト全体）がブロックしているか
   */
  public static function isBlocked(string $username, string $actor): bool {
    if (self::isDomainBlocked($actor)) return true;
    $b = self::blocks($username);
    return in_array($actor, $b['actors'], true) || in_array(Fedi::domainOf($actor), $b['domains'], true);
  }

  /** サイト全体でブロックしているドメイン（管理者） */
  public static function blockedDomains(): array {
    return Fedi::read(Fedi::path('blocked_domains.json'));
  }

  public static function isDomainBlocked(string $url): bool {
    $d = Fedi::domainOf($url);
    if ($d === '') return false;
    foreach (self::blockedDomains() as $b) {
      if ($d === $b || str_ends_with($d, '.'.$b)) return true;
    }
    return false;
  }

  //////// 通知

  /**
   * 通知を追加する（新しい順、200件まで）
   *
   * @param string $username  ユーザー
   * @param string $type  follow, follow_request, mention, reply, like, boost
   * @param string $actor  誰から
   * @param string|null $object  対象の投稿
   */
  public static function notify(string $username, string $type, string $actor, ?string $object = null): void {
    Fedi::update(Fedi::userPath($username, 'notifications.json'), function(array $list) use ($type, $actor, $object): array {
      // 同じ通知を重複させない
      foreach ($list as $n) {
        if ($n['type'] === $type && $n['actor'] === $actor && ($n['object'] ?? null) === $object && $n['at'] > time() - 3600) return $list;
      }
      array_unshift($list, ['type' => $type, 'actor' => $actor, 'object' => $object, 'at' => time(), 'read' => false]);
      return array_slice($list, 0, 200);
    });
  }

  public static function notifications(string $username): array {
    return Fedi::read(Fedi::userPath($username, 'notifications.json'));
  }

  public static function unreadCount(string $username): int {
    return count(array_filter(self::notifications($username), fn($n) => !$n['read']));
  }

  public static function markRead(string $username): void {
    Fedi::update(Fedi::userPath($username, 'notifications.json'), fn($l) => array_map(fn($n) => ['read' => true] + $n, $l));
  }

  //////

  private static function mediaTypeOf(string $path): string {
    return match (strtolower(pathinfo($path, PATHINFO_EXTENSION))) {
      'png' => 'image/png',
      'gif' => 'image/gif',
      'webp' => 'image/webp',
      default => 'image/jpeg',
    };
  }
}