"use client";

import { useState, useCallback, useEffect } from "react";
import { createClient } from "@/lib/supabase/client";
import type { Conversation, Message, Contact, ConversationStatus } from "@/types";
import { useRealtime } from "@/hooks/use-realtime";
import { ConversationList } from "@/components/inbox/conversation-list";
import { MessageThread } from "@/components/inbox/message-thread";
import { ContactSidebar } from "@/components/inbox/contact-sidebar";
import { toast } from "sonner";
import { WifiOff } from "lucide-react";

export default function InboxPage() {
  const [conversations, setConversations] = useState<Conversation[]>([]);
  const [activeConversation, setActiveConversation] =
    useState<Conversation | null>(null);
  const [activeContact, setActiveContact] = useState<Contact | null>(null);
  const [messages, setMessages] = useState<Message[]>([]);
  const [whatsappConnected, setWhatsappConnected] = useState<boolean | null>(
    null
  );

  // Check WhatsApp connection status on mount
  useEffect(() => {
    const checkConnection = async () => {
      const supabase = createClient();
      const {
        data: { session },
      } = await supabase.auth.getSession();
      const user = session?.user;

      if (!user) return;

      // Table is `whatsapp_config` (singular) — the previous "whatsapp_configs"
      // query always returned no rows, so the banner always showed "not connected".
      const { data } = await supabase
        .from("whatsapp_config")
        .select("status")
        .eq("user_id", user.id)
        .maybeSingle();

      setWhatsappConnected(data?.status === "connected");
    };

    checkConnection();
  }, []);

  // Handle realtime message events
  const handleMessageEvent = useCallback(
    (event: { eventType: string; new: Message; old: Partial<Message> }) => {
      const newMsg = event.new;

      if (event.eventType === "INSERT") {
        // Add to messages if it belongs to active conversation
        if (
          activeConversation &&
          newMsg.conversation_id === activeConversation.id
        ) {
          setMessages((prev) => {
            // Avoid duplicates
            if (prev.some((m) => m.id === newMsg.id)) return prev;
            // Replace optimistic message if it exists
            const withoutOptimistic = prev.filter(
              (m) => !m.id.startsWith("temp-")
            );
            return [...withoutOptimistic, newMsg];
          });
        }

        // Update conversation list preview
        setConversations((prev) =>
          prev.map((c) =>
            c.id === newMsg.conversation_id
              ? {
                  ...c,
                  last_message_text: newMsg.content_text ?? "",
                  last_message_at: newMsg.created_at,
                  unread_count:
                    activeConversation?.id === newMsg.conversation_id
                      ? 0
                      : c.unread_count + 1,
                }
              : c
          )
        );
      }

      if (event.eventType === "UPDATE") {
        // Update message status
        setMessages((prev) =>
          prev.map((m) => (m.id === newMsg.id ? { ...m, ...newMsg } : m))
        );
      }
    },
    [activeConversation]
  );

  // Handle realtime conversation events
  const handleConversationEvent = useCallback(
    (event: {
      eventType: string;
      new: Conversation;
      old: Partial<Conversation>;
    }) => {
      const conv = event.new;

      if (event.eventType === "INSERT") {
        setConversations((prev) => [conv, ...prev]);
      }

      if (event.eventType === "UPDATE") {
        setConversations((prev) =>
          prev.map((c) => (c.id === conv.id ? { ...c, ...conv } : c))
        );

        // Update active conversation if it changed
        if (activeConversation && conv.id === activeConversation.id) {
          setActiveConversation((prev) =>
            prev ? { ...prev, ...conv } : prev
          );
        }
      }
    },
    [activeConversation]
  );

  // Subscribe to realtime
  useRealtime({
    channelName: "inbox-realtime",
    onMessageEvent: handleMessageEvent,
    onConversationEvent: handleConversationEvent,
    enabled: true,
  });

  const handleConversationsLoaded = useCallback(
    (loaded: Conversation[]) => {
      setConversations(loaded);
    },
    []
  );

  const handleSelectConversation = useCallback((conv: Conversation) => {
    setActiveConversation(conv);
    setActiveContact(conv.contact ?? null);
    setMessages([]);
  }, []);

  const handleMessagesLoaded = useCallback((loaded: Message[]) => {
    setMessages(loaded);
  }, []);

  const handleNewMessage = useCallback((msg: Message) => {
    setMessages((prev) => {
      if (prev.some((m) => m.id === msg.id)) return prev;
      return [...prev, msg];
    });
  }, []);

  const handleUpdateMessage = useCallback(
    (id: string, updates: Partial<Message>) => {
      setMessages((prev) =>
        prev.map((m) => (m.id === id ? { ...m, ...updates } : m))
      );
    },
    []
  );

  const handleStatusChange = useCallback(
    (conversationId: string, status: ConversationStatus) => {
      setConversations((prev) =>
        prev.map((c) => (c.id === conversationId ? { ...c, status } : c))
      );
      if (activeConversation?.id === conversationId) {
        setActiveConversation((prev) => (prev ? { ...prev, status } : prev));
      }
    },
    [activeConversation]
  );

  return (
    <div className="-m-6 flex h-[calc(100vh-3.5rem)] flex-col overflow-hidden">
      {/* WhatsApp connection banner — in the flex column, not absolute,
          so it pushes the panels down instead of overlapping them. */}
      {whatsappConnected === false && (
        <div className="flex shrink-0 items-center justify-center gap-2 border-b border-amber-500/20 bg-amber-500/10 px-4 py-2">
          <WifiOff className="h-4 w-4 text-amber-400" />
          <p className="text-xs text-amber-400">
            WhatsApp is not connected. Go to Settings to connect your account.
          </p>
        </div>
      )}

      <div className="flex flex-1 overflow-hidden">
        {/* Left panel: Conversation list */}
        <ConversationList
          activeConversationId={activeConversation?.id ?? null}
          onSelect={handleSelectConversation}
          conversations={conversations}
          onConversationsLoaded={handleConversationsLoaded}
        />

        {/* Center panel: Message thread */}
        <MessageThread
          conversation={activeConversation}
          contact={activeContact}
          messages={messages}
          onMessagesLoaded={handleMessagesLoaded}
          onNewMessage={handleNewMessage}
          onUpdateMessage={handleUpdateMessage}
          onStatusChange={handleStatusChange}
        />

        {/* Right panel: Contact sidebar (hidden on small screens) */}
        <div className="hidden lg:block">
          <ContactSidebar contact={activeContact} />
        </div>
      </div>
    </div>
  );
}