"use client";

import { useEffect, useState, useRef } from "react";
import { WEBSOCKET_URL } from "../../lib/apiClient";

export type Message = {
  id: string;
  role: "user" | "assistant";
  text: string;
  timestamp: Date;
};

export type UseTranscriptChat = {
  messages: Message[];
  sendMessage: (text: string) => void;
  isStreaming: boolean;
  currentStreamingText: string;
};

export const useTranscriptChat = (transcriptId: string): UseTranscriptChat => {
  const [messages, setMessages] = useState<Message[]>([]);
  const [isStreaming, setIsStreaming] = useState(false);
  const [currentStreamingText, setCurrentStreamingText] = useState("");
  const wsRef = useRef<WebSocket | null>(null);
  const streamingTextRef = useRef<string>("");
  const isMountedRef = useRef<boolean>(true);

  useEffect(() => {
    isMountedRef.current = true;
    const url = `${WEBSOCKET_URL}/v1/transcripts/${transcriptId}/chat`;
    const ws = new WebSocket(url);
    wsRef.current = ws;

    ws.onopen = () => {
      console.log("Chat WebSocket connected");
    };

    ws.onmessage = (event) => {
      if (!isMountedRef.current) return;

      const msg = JSON.parse(event.data);

      switch (msg.type) {
        case "token":
          setIsStreaming(true);
          streamingTextRef.current += msg.text;
          setCurrentStreamingText(streamingTextRef.current);
          break;

        case "done":
          setMessages((prev) => [
            ...prev,
            {
              id: Date.now().toString(),
              role: "assistant",
              text: streamingTextRef.current,
              timestamp: new Date(),
            },
          ]);
          streamingTextRef.current = "";
          setCurrentStreamingText("");
          setIsStreaming(false);
          break;

        case "error":
          console.error("Chat error:", msg.message);
          setIsStreaming(false);
          break;
      }
    };

    ws.onerror = (error) => {
      console.error("WebSocket error:", error);
    };

    ws.onclose = () => {
      console.log("Chat WebSocket closed");
    };

    return () => {
      isMountedRef.current = false;
      ws.close();
    };
  }, [transcriptId]);

  const sendMessage = (text: string) => {
    if (!wsRef.current) return;

    setMessages((prev) => [
      ...prev,
      {
        id: Date.now().toString(),
        role: "user",
        text,
        timestamp: new Date(),
      },
    ]);

    wsRef.current.send(JSON.stringify({ type: "message", text }));
  };

  return { messages, sendMessage, isStreaming, currentStreamingText };
};