packages/frontend/lib/features/agent/tools/preview/scroll_widget_tool.dart

import 'dart:convert';

import 'package:schemantic/schemantic.dart';

import '../../../shared/logic/app_event_bus.dart';
import '../../models/agent_tool_event.dart';
import '../../models/agent_tool_id.dart';
import '../base/agent_tool.dart';
import '../tool_schemas.dart';

/// Scrolls a widget or its scrollable ancestor/descendant.
class ScrollWidgetTool extends AgentTool<ScrollWidgetInput, ScrollWidgetOutput> {
  const ScrollWidgetTool({
    required this.commandBus,
  });

  final AppCommandBus commandBus;

  @override
  AgentToolId get toolId => AgentToolId.scrollWidget;

  @override
  String get description =>
      'Scroll a scrollable widget or scroll a specific widget into view in the running app preview using its node ID. '
      'Supports scrolling by delta or ensuring visibility.';

  @override
  SchemanticType<ScrollWidgetInput> get inputSchema => ScrollWidgetInput.$schema;

  @override
  SchemanticType<ScrollWidgetOutput> get outputSchema => ScrollWidgetOutput.$schema;

  Future<String?> _invokeExtension(String method, Map<String, String> args) {
    return commandBus.dispatchAsync(InvokePreviewExtensionCommand(
      method: method,
      args: args,
    ));
  }

  @override
  Future<ScrollWidgetOutput> run(ScrollWidgetInput input) async {
    final state = await commandBus.dispatchAsync(RequestPreviewStateCommand());
    if (!state.hasActiveRuntime) {
      return ScrollWidgetOutput(
        success: false,
        error: 'No app preview is running. Use controlApp to start the preview first.',
      );
    }

    try {
      final params = <String, String>{
        'id': input.nodeId,
      };
      if (input.ensureVisible != null) {
        params['ensureVisible'] = '${input.ensureVisible}';
      }
      if (input.delta != null) {
        params['delta'] = '${input.delta}';
      }

      final responseStr = await _invokeExtension(
        'ext.vibepad.scroll',
        params,
      );

      if (responseStr == null || responseStr.isEmpty) {
        return ScrollWidgetOutput(
          success: false,
          error: 'Could not scroll. No response from the running app.',
        );
      }

      final Map<String, dynamic> decoded = jsonDecode(responseStr) as Map<String, dynamic>;
      final success = decoded['success'] as bool? ?? false;
      if (!success) {
        return ScrollWidgetOutput(
          success: false,
          error: decoded['error'] as String? ?? 'Failed to scroll.',
        );
      }

      return ScrollWidgetOutput(
        success: true,
      );
    } catch (e) {
      return ScrollWidgetOutput(
        success: false,
        error: 'Failed to scroll widget "${input.nodeId}": $e',
      );
    }
  }

  @override
  AgentToolEvent mapStartToToolEvent(ScrollWidgetInput input) {
    final action = input.ensureVisible == true
        ? 'into view'
        : (input.delta != null ? 'by delta ${input.delta}' : '');
    return createToolEvent(
      status: ToolStatus.running,
      summary: 'Scrolling widget "${input.nodeId}" $action'.trim(),
    );
  }

  @override
  AgentToolEvent mapToToolEvent(
    ScrollWidgetInput input,
    ScrollWidgetOutput output,
  ) {
    final action = input.ensureVisible == true
        ? 'into view'
        : (input.delta != null ? 'by delta ${input.delta}' : '');
    final summaryText = output.success
        ? 'Scrolled widget "${input.nodeId}" $action'
        : 'Failed to scroll widget "${input.nodeId}" $action';
    return createToolEvent(
      status: output.success ? ToolStatus.success : ToolStatus.error,
      summary: summaryText.trim(),
      errorMessage: output.error,
    );
  }
}