/**
 * [Gitea #203] Build and send an inline reply typed into a notification's
 * text action. Lives outside sw.ts so it can be unit-tested; the SW passes in
 * the notification account's session and the global fetch.
 */
export type SwReplySession = { accessToken: string; baseUrl: string; userId?: string };

export type SwReplyResult = 'sent' | 'failed' | 'encrypted' | 'no-session';

/**
 * [Gitea #299] The session to reply with: the notification's own account. A
 * notification without a user id (shown before this change) may only use the
 * session if it is the only one, so a reply never posts as another account.
 */
export const pickReplySession = (
  sessions: SwReplySession[],
  userId: string | undefined,
): SwReplySession | undefined => {
  if (userId) return sessions.filter((x) => x.userId === userId).pop();
  return sessions.length === 1 ? sessions[0] : undefined;
};

/** What the "Reply not sent" notification says for each failure. */
export const replyFailureText = (result: SwReplyResult, text: string): string => {
  const quoted = `"${text.slice(0, 60)}"`;
  if (result === 'encrypted') {
    return `This room is now encrypted, so ${quoted} wasn't sent. Open the app to reply.`;
  }
  if (result === 'no-session') {
    return `You're no longer signed in to that account here, so ${quoted} wasn't sent.`;
  }
  return `Couldn't send ${quoted}. Open the app to retry.`;
};

export const encryptionStateUrl = (baseUrl: string, roomId: string): string =>
  new URL(
    `/_matrix/client/v3/rooms/${encodeURIComponent(roomId)}/state/m.room.encryption/`,
    baseUrl,
  ).href;

export const buildReplyContent = (text: string, threadId?: string): Record<string, unknown> => {
  const content: Record<string, unknown> = { msgtype: 'm.text', body: text, 'm.mentions': {} };
  if (threadId) {
    content['m.relates_to'] = {
      rel_type: 'm.thread',
      event_id: threadId,
      is_falling_back: true,
      'm.in_reply_to': { event_id: threadId },
    };
  }
  return content;
};

export const replySendUrl = (baseUrl: string, roomId: string, txnId: string): string =>
  new URL(
    `/_matrix/client/v3/rooms/${encodeURIComponent(roomId)}/send/m.room.message/${txnId}`,
    baseUrl,
  ).href;

export async function sendNotificationReply(
  session: SwReplySession | undefined,
  roomId: string,
  threadId: string | undefined,
  text: string,
  fetchFn: typeof fetch = fetch,
): Promise<SwReplyResult> {
  if (!session?.accessToken || !session.baseUrl) return 'no-session';
  const headers = { Authorization: `Bearer ${session.accessToken}` };
  try {
    // [Gitea #299] The SW can't encrypt, and the reply action was offered when
    // the notification was shown — possibly hours ago. Re-check now: only a
    // definite "no encryption state" (404) lets the plain reply go out.
    const enc = await fetchFn(encryptionStateUrl(session.baseUrl, roomId), { headers });
    if (enc.ok) return 'encrypted';
    if (enc.status !== 404) return 'failed';
    const txn = `swreply-${Date.now()}-${Math.random().toString(36).slice(2, 8)}`;
    const res = await fetchFn(replySendUrl(session.baseUrl, roomId, txn), {
      method: 'PUT',
      headers: { ...headers, 'Content-Type': 'application/json' },
      body: JSON.stringify(buildReplyContent(text, threadId)),
    });
    return res.ok ? 'sent' : 'failed';
  } catch {
    return 'failed';
  }
}