'use client';

import React, { useEffect, useRef } from 'react';

interface WhiteboardIframeProps {
  boardId: string;
  username?: string;
  token?: string;
  /** Только ментор может очищать холст. */
  isMentor?: boolean;
  onToggleView?: () => void;
  showingBoard?: boolean;
  className?: string;
  style?: React.CSSProperties;
}

/**
 * Интерактивная доска Excalidraw + Yjs.
 * Iframe создаётся императивно один раз — React не пересоздаёт его при переключении.
 */
export function WhiteboardIframe({
  boardId,
  username = 'Пользователь',
  token: tokenProp,
  isMentor = false,
  showingBoard = true,
  className = '',
  style = {},
}: WhiteboardIframeProps) {
  const containerRef = useRef<HTMLDivElement>(null);
  const iframeRef = useRef<HTMLIFrameElement | null>(null);
  const createdRef = useRef(false);

  useEffect(() => {
    if (typeof window === 'undefined' || !containerRef.current || !boardId) return;
    if (createdRef.current) return;

    const token = tokenProp ?? localStorage.getItem('access_token') ?? '';
    const apiBase = process.env.NEXT_PUBLIC_API_URL || 'http://127.0.0.1:8123/api';
    const apiUrl = apiBase.replace(/\/api\/?$/, '') || 'http://127.0.0.1:8123';
    // Вариант 1: отдельный URL доски (как LiveKit) — если app.uchill.online отдаёт один Next без nginx по путям
    const excalidrawBaseUrl = (process.env.NEXT_PUBLIC_EXCALIDRAW_URL || '').trim().replace(/\/?$/, '');
    const url: URL = excalidrawBaseUrl
      ? new URL(excalidrawBaseUrl.startsWith('http') ? excalidrawBaseUrl + '/' : `${window.location.origin}/${excalidrawBaseUrl}/`)
      : (() => {
          const path = process.env.NEXT_PUBLIC_EXCALIDRAW_PATH || '';
          if (path) {
            return new URL((path.startsWith('/') ? path : '/' + path) + '/', window.location.origin);
          }
          return new URL('/', `${window.location.protocol}//${window.location.hostname}:${process.env.NEXT_PUBLIC_EXCALIDRAW_PORT || '3001'}`);
        })();
    url.searchParams.set('boardId', boardId);
    url.searchParams.set('apiUrl', apiUrl);
    if (token) url.searchParams.set('token', token);
    if (isMentor) url.searchParams.set('isMentor', '1');

    const iframeSrc = excalidrawBaseUrl && excalidrawBaseUrl.startsWith('http')
      ? url.toString()
      : `${url.origin}${url.pathname.replace(/\/?$/, '/')}?${url.searchParams.toString()}`;

    const iframe = document.createElement('iframe');
    iframe.src = iframeSrc;
    iframe.style.cssText = 'width:100%;height:100%;border:none;display:block';
    iframe.title = 'Интерактивная доска (Excalidraw)';
    iframe.setAttribute('allow', 'camera; microphone; fullscreen');
    iframe.setAttribute('sandbox', 'allow-same-origin allow-scripts allow-forms allow-popups allow-modals');

    const decodeName = (raw: string): string => {
      if (!raw || typeof raw !== 'string') return raw;
      try {
        if (/%[0-9A-Fa-f]{2}/.test(raw)) return decodeURIComponent(raw);
        return raw;
      } catch {
        return raw;
      }
    };

    const sendUsername = () => {
      if (iframe.contentWindow) {
        try {
          iframe.contentWindow.postMessage(
            { type: 'excalidraw-username', username: decodeName(username) },
            url.origin
          );
        } catch (_) {}
      }
    };

    iframe.onload = () => {
      sendUsername();
      setTimeout(sendUsername, 500);
    };

    containerRef.current.appendChild(iframe);
    iframeRef.current = iframe;
    createdRef.current = true;

    setTimeout(sendUsername, 300);
    return () => {
      createdRef.current = false;
      iframeRef.current = null;
      iframe.remove();
    };
  }, [boardId, tokenProp, isMentor]);

  useEffect(() => {
    if (!iframeRef.current?.contentWindow || !createdRef.current) return;
    const excalidrawBaseUrl = (process.env.NEXT_PUBLIC_EXCALIDRAW_URL || '').trim().replace(/\/?$/, '');
    const targetOrigin = excalidrawBaseUrl.startsWith('http')
      ? new URL(excalidrawBaseUrl).origin
      : (() => {
          const path = process.env.NEXT_PUBLIC_EXCALIDRAW_PATH || '';
          if (path) return window.location.origin;
          return `${window.location.protocol}//${window.location.hostname}:${process.env.NEXT_PUBLIC_EXCALIDRAW_PORT || '3001'}`;
        })();
    const decodeName = (raw: string): string => {
      if (!raw || typeof raw !== 'string') return raw;
      try {
        if (/%[0-9A-Fa-f]{2}/.test(raw)) return decodeURIComponent(raw);
        return raw;
      } catch {
        return raw;
      }
    };
    try {
      iframeRef.current.contentWindow.postMessage(
        { type: 'excalidraw-username', username: decodeName(username) },
        targetOrigin
      );
    } catch (_) {}
  }, [username]);

  return (
    <div
      ref={containerRef}
      className={className}
      style={{ width: '100%', height: '100%', position: 'relative', ...style }}
    />
  );
}