// SPDX-FileCopyrightText: 2026 TatuChat
//
// SPDX-License-Identifier: AGPL-3.0-or-later

import 'package:flutter_inappwebview/flutter_inappwebview.dart';
import 'package:material_ui/material_ui.dart';
import 'package:tatchat/l10n/l10n.dart';

/// Native implementation of [MiniAppShell] using an isolated [InAppWebView].
///
/// The mini app HTML is shipped with a small bridge shim injected before
/// `</body>` that forwards `window.parent.postMessage` calls to Dart through
/// `flutter_inappwebview`'s JavaScript handler, and delivers the response
/// back to the mini app via a `postMessage` with the same `requestId`.
class MiniAppShell extends StatefulWidget {
  final String html;
  final String appId;
  final String title;
  final Future<Map<String, Object?>> Function(Map<String, dynamic> request)
  onRequest;

  const MiniAppShell({
    super.key,
    required this.html,
    required this.appId,
    required this.title,
    required this.onRequest,
  });

  @override
  State<MiniAppShell> createState() => _MiniAppShellState();
}

class _MiniAppShellState extends State<MiniAppShell> {
  static const String _handlerName = 'com.tatuchat.miniapp.bridge';

  InAppWebViewController? _webViewController;

  String get _injectedHtml {
    const shim =
        '''
<script>
window.addEventListener('message', function (event) {
  var msg = event.data;
  if (!msg || msg.api !== 'fromMiniApp' || msg.response !== undefined) return;
  window.flutter_inappwebview.callHandler('$_handlerName', msg).then(function (response) {
    var reply = Object.assign({}, msg, { response: response });
    window.postMessage(reply, '*');
  });
});
</script>
''';
    final bodyEnd = widget.html.lastIndexOf('</body>');
    if (bodyEnd == -1) {
      return '${widget.html}\n$shim';
    }
    return widget.html.replaceRange(bodyEnd, bodyEnd, '\n$shim');
  }

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
        backgroundColor: theme.colorScheme.surface,
        surfaceTintColor: Colors.transparent,
        foregroundColor: theme.colorScheme.onSurface,
        actions: [
          IconButton(
            tooltip: L10n.of(context).refresh,
            icon: const Icon(Icons.refresh_rounded),
            onPressed: () => _webViewController?.reload(),
          ),
        ],
      ),
      backgroundColor: theme.colorScheme.surface,
      body: InAppWebView(
        initialSettings: InAppWebViewSettings(
          javaScriptEnabled: true,
          javaScriptCanOpenWindowsAutomatically: false,
          domStorageEnabled: true,
          transparentBackground: false,
          verticalScrollBarEnabled: true,
          horizontalScrollBarEnabled: false,
        ),
        initialData: InAppWebViewInitialData(
          data: _injectedHtml,
          mimeType: 'text/html',
          encoding: 'utf8',
          baseUrl: WebUri('https://tatuchat.local'),
        ),
        onWebViewCreated: (controller) {
          _webViewController = controller;
          controller.addJavaScriptHandler(
            handlerName: _handlerName,
            callback: (args) async {
              if (args.isEmpty) return null;
              final raw = args.first;
              if (raw is Map<String, dynamic>) {
                return widget.onRequest(Map<String, dynamic>.from(raw));
              }
              return null;
            },
          );
        },
      ),
    );
  }
}