import type { Db } from "../libs/db.js";
import type { ChatMember, MemberProfile } from "../types.js";

interface ChatMemberRow {
  chat_id: number;
  user_id: number;
  username: string | null;
  first_name: string;
  last_name: string | null;
  message_count: number;
  last_seen: number;
}

const toMember = (row: ChatMemberRow): ChatMember => ({
  chatId: row.chat_id,
  userId: row.user_id,
  username: row.username,
  firstName: row.first_name,
  lastName: row.last_name,
  messageCount: row.message_count,
  lastSeen: row.last_seen,
});

export const createChatMemberRepository = (db: Db) => {
  const statements = {
    upsert: db.prepare(`
      INSERT INTO chat_members (chat_id, user_id, username, first_name, last_name, message_count, last_seen)
      VALUES (@chatId, @userId, @username, @firstName, @lastName, @messages, @seenAt)
      ON CONFLICT(chat_id, user_id) DO UPDATE SET
        username      = excluded.username,
        first_name    = excluded.first_name,
        last_name     = excluded.last_name,
        message_count = message_count + excluded.message_count,
        last_seen     = MAX(last_seen, excluded.last_seen)
    `),
    listByChat: db.prepare("SELECT * FROM chat_members WHERE chat_id = ? ORDER BY last_seen DESC"),
    findById: db.prepare("SELECT * FROM chat_members WHERE chat_id = ? AND user_id = ?"),
  };

  /**
   * Сохраняет актуальные имя и ник участника.
   * `messages` добавляется к счётчику сообщений, `seenAt` сдвигает время последней активности вперёд.
   */
  const upsert = (chatId: number, profile: MemberProfile, activity: { messages: number; seenAt: number }): void => {
    statements.upsert.run({ chatId, ...profile, ...activity });
  };

  const listByChat = (chatId: number): ChatMember[] =>
    (statements.listByChat.all(chatId) as ChatMemberRow[]).map(toMember);

  const findById = (chatId: number, userId: number): ChatMember | undefined => {
    const row = statements.findById.get(chatId, userId) as ChatMemberRow | undefined;

    return row && toMember(row);
  };

  return { upsert, listByChat, findById };
};

export type ChatMemberRepository = ReturnType<typeof createChatMemberRepository>;