import 'dart:async';
import 'dart:convert';

import 'package:dsbridge_flutter/dsbridge_flutter.dart';
import 'package:flutter/material.dart';
import 'package:package_info_plus/package_info_plus.dart';

import 'js_api_result.dart';

class JsApi extends JavaScriptNamespaceInterface {
  JsApi({
    this.onClose,
    this.onLoginRequested,
    this.onMallStateChanged,
    Future<String> Function()? appVersionResolver,
  }) : _appVersionResolver = appVersionResolver ?? _readAppVersion;

  final VoidCallback? onClose;
  final VoidCallback? onLoginRequested;
  final ValueChanged<Map<dynamic, dynamic>?>? onMallStateChanged;
  final Future<String> Function() _appVersionResolver;

  @override
  void register() {
    registerFunction(close);
    registerFunction(getAppVersion);
    registerFunction(mallStateChanged);
    registerFunction(login);
  }

  @pragma('vm:entry-point')
  void close(dynamic arg, CompletionHandler handler) {
    onClose?.call();
    handler.complete(const JsApiResult.success().toMap());
  }

  @pragma('vm:entry-point')
  void getAppVersion(dynamic arg, CompletionHandler handler) {
    unawaited(_completeAppVersion(handler));
  }

  Future<void> _completeAppVersion(CompletionHandler handler) async {
    try {
      final version = await _appVersionResolver();
      handler.complete(
        JsApiResult(
          code: 0,
          message: 'success',
          data: <String, dynamic>{'version': version},
        ).toMap(),
      );
    } catch (_) {
      handler.complete(
        const JsApiResult(code: 1, message: 'app version unavailable').toMap(),
      );
    }
  }

  static Future<String> _readAppVersion() async =>
      (await PackageInfo.fromPlatform()).version;

  @pragma('vm:entry-point')
  void mallStateChanged(dynamic arg, CompletionHandler handler) {
    onMallStateChanged?.call(coerceMallStateMap(arg));
    handler.complete(const JsApiResult.success().toMap());
  }

  @pragma('vm:entry-point')
  void login(dynamic arg, CompletionHandler handler) {
    onLoginRequested?.call();
    handler.complete(const JsApiResult.success().toMap());
  }
}

Map<dynamic, dynamic>? coerceMallStateMap(dynamic arg) {
  if (arg is Map) return arg;
  if (arg is String && arg.isNotEmpty) {
    try {
      final decoded = jsonDecode(arg);
      if (decoded is Map) return decoded;
    } catch (_) {}
  }
  if (arg is List && arg.isNotEmpty && arg.first is Map) {
    return arg.first as Map<dynamic, dynamic>;
  }
  return null;
}