tatuchat/lib/utils/miniapp_bridge.dart

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

import 'dart:convert';

import 'package:http/http.dart' as http;
import 'package:material_ui/material_ui.dart';
import 'package:matrix/matrix.dart';
import 'package:tatchat/utils/miniapp_store.dart';

/// Wire protocol between an HTML mini app and the TatuChat client.
///
/// The mini app sends a request object via `window.parent.postMessage`:
/// ```
/// {
///   "api": "fromMiniApp",
///   "widgetId": "<appId>",
///   "requestId": "...",
///   "action": "<action>",
///   "data": <any>
/// }
/// ```
/// The host answers with `{api, widgetId, requestId, response: {data, error}}`.
class MiniappBridge {
  /// No-op instantiation guard; this class only holds static helpers.
  MiniappBridge._();

  static const String api = 'fromMiniApp';
  static const String actionLoad = 'io.tatuchat.storage.load';
  static const String actionSave = 'io.tatuchat.storage.save';
  static const String actionIdentity = 'io.tatuchat.identity.get';
  static const String actionTheme = 'io.tatuchat.theme.get';
  static const String actionAccountDataList = 'io.tatuchat.accountdata.list';
  static const String actionAccountDataGet = 'io.tatuchat.accountdata.get';
  static const String actionAccountDataSet = 'io.tatuchat.accountdata.set';

  /// Handles one request coming from a mini app and returns the payload that
  /// gets sent back inside `response.data`, or `response.error` on failures.
  static Future<Map<String, Object?>> handleRequest(
    Client client,
    String appId,
    Map<String, dynamic> request, {
    Map<String, Object?>? palette,
  }) async {
    final action = request['action'];
    final data = request['data'];
    switch (action) {
      case actionLoad:
        return {'data': client.getMiniAppData(appId)};
      case actionSave:
        return _handleSave(client, appId, data);
      case actionIdentity:
        return _handleIdentity(client);
      case actionTheme:
        return {
          'data': {
            'palette': palette ?? const {},
            'brightness': palette?['brightness'] ?? 'light',
          },
        };
      case actionAccountDataList:
        return _handleAccountDataList(client);
      case actionAccountDataGet:
        return _handleAccountDataGet(client, data);
      case actionAccountDataSet:
        return _handleAccountDataSet(client, data);
      default:
        return const {'error': 'UNKNOWN_ACTION'};
    }
  }

  /// Builds the theme palette map sent to mini apps. Colors are serialized as
  /// `#RRGGBBAA` hex strings (CSS 8-digit order) so they can be used directly
  /// in CSS/JS.
  static Map<String, Object?> buildPalette(
    ColorScheme scheme,
    Brightness brightness,
  ) {
    String hex(Color c) {
      final value = c.toARGB32();
      final rgb = value & 0xFFFFFF;
      final alpha = (value >> 24) & 0xFF;
      return '#${rgb
              .toRadixString(16)
              .padLeft(6, '0')}${alpha.toRadixString(16).padLeft(2, '0')}'
          .toUpperCase();
    }

    return {
      'brightness': brightness == Brightness.dark ? 'dark' : 'light',
      'primary': hex(scheme.primary),
      'onPrimary': hex(scheme.onPrimary),
      'primaryContainer': hex(scheme.primaryContainer),
      'onPrimaryContainer': hex(scheme.onPrimaryContainer),
      'secondary': hex(scheme.secondary),
      'onSecondary': hex(scheme.onSecondary),
      'secondaryContainer': hex(scheme.secondaryContainer),
      'onSecondaryContainer': hex(scheme.onSecondaryContainer),
      'tertiary': hex(scheme.tertiary),
      'onTertiary': hex(scheme.onTertiary),
      'tertiaryContainer': hex(scheme.tertiaryContainer),
      'onTertiaryContainer': hex(scheme.onTertiaryContainer),
      'background': hex(scheme.surface),
      'onBackground': hex(scheme.onSurface),
      'surface': hex(scheme.surface),
      'onSurface': hex(scheme.onSurface),
      'surfaceVariant': hex(scheme.surfaceContainerHighest),
      'onSurfaceVariant': hex(scheme.onSurfaceVariant),
      'surfaceContainerLowest': hex(scheme.surfaceContainerLowest),
      'surfaceContainerLow': hex(scheme.surfaceContainerLow),
      'surfaceContainer': hex(scheme.surfaceContainer),
      'surfaceContainerHigh': hex(scheme.surfaceContainerHigh),
      'surfaceContainerHighest': hex(scheme.surfaceContainerHighest),
      'outline': hex(scheme.outline),
      'outlineVariant': hex(scheme.outlineVariant),
      'error': hex(scheme.error),
      'onError': hex(scheme.onError),
      'errorContainer': hex(scheme.errorContainer),
      'onErrorContainer': hex(scheme.onErrorContainer),
      'inverseSurface': hex(scheme.inverseSurface),
      'onInverseSurface': hex(scheme.onInverseSurface),
      'shadow': hex(scheme.shadow),
      'scrim': hex(scheme.scrim),
    };
  }

  static Future<Map<String, Object?>> _handleSave(
    Client client,
    String appId,
    dynamic data,
  ) async {
    if (data is Map) {
      await client.setMiniAppData(
        appId,
        Map<String, Object?>.from(data.map((k, v) => MapEntry('$k', v))),
      );
      return const {'data': null};
    }
    return const {'error': 'INVALID_DATA'};
  }

  static Future<Map<String, Object?>> _handleIdentity(Client client) async {
    final profile = await client.fetchOwnProfile();
    final avatarUrl = profile.avatarUrl;
    String? avatarDataUri;
    if (avatarUrl != null) {
      final downloadUri = await avatarUrl.getDownloadUri(
        client,
        skipScanner: true,
      );
      if (downloadUri != Uri()) {
        try {
          final request = http.Request('GET', downloadUri);
          if (client.accessToken != null) {
            request.headers['authorization'] = 'Bearer ${client.accessToken}';
          }
          final streamed = await client.httpClient.send(request);
          final response = await http.Response.fromStream(streamed);
          if (response.statusCode >= 200 && response.statusCode < 300) {
            final mimeType = response.headers['content-type']?.split(';').first ??
                'application/octet-stream';
            avatarDataUri =
                'data:$mimeType;base64,${base64Encode(response.bodyBytes)}';
          }
        } catch (e) {
          Logs().d('Unable to download avatar for mini app', e);
        }
      }
    }
    return {
      'data': {
        'userId': client.userID?.toString(),
        'displayName':
            profile.displayName ?? client.userID?.localpart.toString(),
        'avatarUrl': avatarUrl?.toString(),
        'avatarHttpUrl': avatarUrl == null
            ? null
            : (await avatarUrl.getDownloadUri(
                client,
                skipScanner: true,
              ))
                  .toString(),
        'avatarDataUri': avatarDataUri,
        'homeserver': client.homeserver?.toString(),
      },
    };
  }

  static Map<String, Object?> _handleAccountDataList(Client client) {
    return {
      'data': client.accountData.map(
        (key, event) => MapEntry(key, event.content),
      ),
    };
  }

  static Map<String, Object?> _handleAccountDataGet(
    Client client,
    dynamic data,
  ) {
    final key = data is Map ? data['key'] : null;
    if (key is! String) return const {'error': 'INVALID_KEY'};
    final event = client.accountData[key];
    return {
      'data': {'key': key, 'content': event?.content ?? const {}},
    };
  }

  static Future<Map<String, Object?>> _handleAccountDataSet(
    Client client,
    dynamic data,
  ) async {
    if (data is! Map) return const {'error': 'INVALID_DATA'};
    final key = data['key'];
    final content = data['content'];
    if (key is! String || content is! Map) {
      return const {'error': 'INVALID_DATA'};
    }
    await client.setAccountData(
      client.userID!,
      key,
      Map<String, Object?>.from(content.map((k, v) => MapEntry('$k', v))),
    );
    return const {'data': null};
  }
}