import { useState, useCallback } from "react";
import { useTranslation } from 'react-i18next';
import { API_URL } from "../config/authConstants";
import { apiFetch } from "../api/apiClient";
import { cachePostsFromChats, setPostForChat } from "../stores/chatPostStore";
import { useUnread } from "../context/UnreadContext";

export function useChats() {
  const { t } = useTranslation();
  const [chats, setChats] = useState([]);
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState("");
  const { updateFromChats, clearChatUnread } = useUnread();

  const fetchChats = useCallback(async () => {
    setLoading(true);
    setError("");
    try {
      const res = await apiFetch(`${API_URL}/api/v1/chats`);
      if (!res.ok) throw new Error(t('chats.fetchError'));

      const data = await res.json();
      const list = Array.isArray(data) ? data : (data.items ?? data.content ?? []);
      cachePostsFromChats(list);
      setChats(list);
      updateFromChats(list);
    } catch (e) {
      setError(e.message || t('chats.fetchError'));
    } finally {
      setLoading(false);
    }
  }, [updateFromChats, t]);

  const createOrGetChat = useCallback(async (otherUserId, postId, postInfo) => {
    const url = new URL(`${API_URL}/api/v1/chats/with/${otherUserId}`);
    if (postId) url.searchParams.set("postId", postId);

    const res = await apiFetch(url, { method: "POST" });
    if (!res.ok) throw new Error(t('chats.createError'));
    const chat = await res.json();
    if (postInfo && chat.id) {
      setPostForChat(chat.id, postInfo);
    }
    return chat;
  }, [t]);

  const fetchMessages = useCallback(async (chatId) => {
    const res = await apiFetch(`${API_URL}/api/v1/chats/${chatId}/messages`);
    const data = await res.json();
    return Array.isArray(data) ? data : (data.items ?? data.content ?? []);
  }, []);

  const markAsRead = useCallback(async (chatId) => {
    clearChatUnread(chatId);
    try {
      await apiFetch(`${API_URL}/api/v1/chats/${chatId}/read`, {
        method: "POST",
      });
    } catch (e) {
      console.error("Failed to mark as read:", e);
    }
  }, [clearChatUnread]);

  return { chats, loading, error, fetchChats, createOrGetChat, fetchMessages, markAsRead };
}