"use client";

import { useEffect, useState } from "react";
import { ChatModal } from "@/components/chat/ChatModal";
import {
  Sheet,
  SheetContent,
  SheetDescription,
  SheetHeader,
  SheetTitle,
} from "@/components/ui/sheet";
import { Skeleton } from "@/components/ui/skeleton";
import type { Chat } from "@/lib/hooks/use-chat";
import { useSession } from "@/lib/hooks/use-session";
import { ChatListItem } from "./ChatListItem";

interface MessagesPanelProps {
  open: boolean;
  onOpenChange: (open: boolean) => void;
  onUnreadCountChange: (count: number) => void;
}

export function MessagesPanel({
  open,
  onOpenChange,
  onUnreadCountChange,
}: MessagesPanelProps) {
  const { user } = useSession();
  const [chats, setChats] = useState<Chat[]>([]);
  const [isLoading, setIsLoading] = useState(false);
  const [selectedChatId, setSelectedChatId] = useState<string | null>(null);
  const [showChatModal, setShowChatModal] = useState(false);

  // Buscar chats do usuário
  const fetchChats = async () => {
    if (!user) return;

    setIsLoading(true);
    try {
      const res = await fetch("/api/chats", {
        credentials: "include",
      });
      if (res.ok) {
        const data = await res.json();
        if (data.success) {
          setChats(data.chats || []);

          // Calcular contagem de usuários únicos com não lidas
          const uniqueUsersWithUnread = new Set<number>();
          data.chats.forEach((chat: Chat) => {
            const unreadCount =
              chat.buyer_id === user.userId
                ? chat.buyer_unread_count
                : chat.seller_unread_count;
            const otherUserId =
              chat.buyer_id === user.userId ? chat.seller_id : chat.buyer_id;

            if (unreadCount > 0) {
              uniqueUsersWithUnread.add(otherUserId);
            }
          });

          onUnreadCountChange(uniqueUsersWithUnread.size);
        }
      }
    } catch (error) {
      console.error("[CHAT-DEBUG] Erro ao buscar chats:", error);
    } finally {
      setIsLoading(false);
    }
  };
  const markAllAsRead = async () => {
    try {
      await fetch("/api/chats/mark-all-read", {
        method: "POST",
        credentials: "include",
      });
      // Atualizar estado local
      setChats((prev) =>
        prev.map((chat) => ({
          ...chat,
          buyer_unread_count:
            chat.buyer_id === user?.userId ? 0 : chat.buyer_unread_count,
          seller_unread_count:
            chat.seller_id === user?.userId ? 0 : chat.seller_unread_count,
        })),
      );
      onUnreadCountChange(0);
    } catch (error) {
      console.error("[CHAT-DEBUG] Erro ao marcar como lido:", error);
    }
  };

  useEffect(() => {
    if (open && user) {
      fetchChats();
      // Marcar todos como lidos ao abrir
      markAllAsRead();
    }
  }, [
    open,
    user,
    fetchChats, // Marcar todos como lidos ao abrir
    markAllAsRead,
  ]);

  const handleChatClick = (chatId: string, _listingId: number) => {
    setSelectedChatId(chatId);
    setShowChatModal(true);
    onOpenChange(false);
  };

  if (!user) {
    return null;
  }

  return (
    <>
      <Sheet open={open} onOpenChange={onOpenChange}>
        <SheetContent side="right" className="w-full sm:max-w-lg p-0">
          <SheetHeader className="px-6 pt-6 pb-4 border-b">
            <SheetTitle>Mensagens</SheetTitle>
            <SheetDescription>
              Suas conversas com compradores e vendedores
            </SheetDescription>
          </SheetHeader>

          <div
            className="mt-4 px-4 overflow-y-auto"
            style={{ maxHeight: "calc(100vh - 120px)" }}
          >
            {isLoading ? (
              <div className="space-y-4">
                {Array.from({ length: 5 }).map((_, i) => (
                  <Skeleton key={i} className="h-20 w-full" />
                ))}
              </div>
            ) : chats.length === 0 ? (
              <div className="text-center py-12 text-muted-foreground">
                <p>Nenhuma conversa ainda</p>
                <p className="text-sm mt-2">
                  Comece uma conversa a partir de um anúncio
                </p>
              </div>
            ) : (
              <div className="space-y-2">
                {chats.map((chat) => (
                  <ChatListItem
                    key={chat.chat_id}
                    chat={chat}
                    currentUserId={user.userId}
                    onChatClick={() =>
                      handleChatClick(chat.chat_id, chat.listing_id)
                    }
                  />
                ))}
              </div>
            )}
          </div>
        </SheetContent>
      </Sheet>

      {selectedChatId && (
        <ChatModal
          open={showChatModal}
          onOpenChange={(open) => {
            setShowChatModal(open);
            if (!open) {
              setSelectedChatId(null);
              // Recarregar chats quando fechar o modal
              fetchChats();
            }
          }}
          listingId={null}
          chatId={selectedChatId || undefined}
        />
      )}
    </>
  );
}