import 'package:app/global/config.dart';
import 'package:app/request/api/room_api.dart';
import 'package:app/request/dto/room/board_token_dto.dart';
import 'package:flutter/material.dart';
import 'package:flutter_easyloading/flutter_easyloading.dart';
import 'package:webview_flutter/webview_flutter.dart';

import 'board_dialog.dart';

class BoardManager {
  BoardManager._();

  static final BoardManager _instance = BoardManager._();

  factory BoardManager() => _instance;

  WebViewController? _webViewController;
  BoardTokenDto? _boardToken;

  ///获取token
  Future<void> _fetchToken(int roomId) async {
    final now = DateTime.now();

    if (_boardToken == null) {
      EasyLoading.show(status: "开启白板中");
      _boardToken = await getBoardTokenApi(roomId);
    } else {
      //离过期差多少小时
      int remainSeconds = _boardToken!.expiresAt.difference(now).inSeconds;
      // 剩余不足 2 小时 = 7200 秒
      if (remainSeconds <= 7200) {
        EasyLoading.show(status: "开启白板中");
        _boardToken = await getBoardTokenApi(roomId);
      }
    }
    EasyLoading.dismiss();
  }

  ///生成完整 URL
  /// -[uid] 用户
  /// -[roomId] 房间id
  /// -[isTeacher] 是否是老师
  Future<String> buildUrl({
    required String uid,
    required int roomId,
    required bool isTeacher,
  }) async {
    await _fetchToken(roomId);

    Map<String, dynamic> params = {
      "appid": _boardToken!.whiteboardAppid,
      "uid": uid,
      "uuid": _boardToken!.whiteboardUuid,
      "room_token": _boardToken!.whiteboardToken,
      "write": isTeacher ? 1 : 0,
    };
    String paramStr = params.entries.map((e) => "${e.key}=${e.value}").join("&");

    return "${Config.webUrl}/board?$paramStr";
  }

  /// 获取全局唯一 WebViewController
  Future<WebViewController> getController(String url) async {
    if (_webViewController != null) return _webViewController!;

    _webViewController = WebViewController()
      ..setJavaScriptMode(JavaScriptMode.unrestricted)
      ..setNavigationDelegate(
        // ⭐ 加上加载监听（BoardDialog 再 listen 一次也没关系）
        NavigationDelegate(
          onPageStarted: (_) {},
          onPageFinished: (_) {},
        ),
      )
      ..loadRequest(Uri.parse(url));

    return _webViewController!;
  }

  ///打开白板
  /// -[uid] 用户名+id
  /// -[roomId] 房间id
  /// -[isTeacher] 是否是老师
  Future<void> showBoardDialog(
    BuildContext context, {
    required String uid,
    required int roomId,
    required bool isTeacher,
  }) async {
    String url = await buildUrl(
      uid: uid,
      roomId: roomId,
      isTeacher: isTeacher,
    );
    final controller = await getController(url);
    showDialog(
      context: context,
      builder: (_) => BoardDialog(controller: controller),
    );
  }
}