packages/frontend/lib/features/shared/utils/widget_tree_helper.dart

import 'dart:convert';

/// Shared utilities for widget tree agent tools.
///
/// Extracts tree simplification and node counting logic so it can be reused
/// across the widget tree tools and any future widget inspection tools.
class WidgetTreeHelper {
  const WidgetTreeHelper();

  static const _objectGroupName = 'vibepad_agent_inspector';

  /// Standard object-group args sent with every inspector extension call.
  static Map<String, String> get objectGroupArgs => const {
    'objectGroup': _objectGroupName,
    'groupName': _objectGroupName,
  };

  /// Simplifies a raw inspector tree node into a compact, LLM-friendly format.
  ///
  /// Each returned node contains:
  /// - `widget`: The widget type name
  /// - `id`: The node's valueId (for use with `inspectWidget`)
  /// - `description`: Optional human-readable description
  /// - `location`: Workspace-relative `file:line:col` string
  /// - `children`: Recursively simplified child nodes
  ///
  /// When [maxDepth] is provided, children beyond that depth are omitted and
  /// a `truncated` flag is set on the deepest included nodes.
  Map<String, dynamic> simplifySummaryTree(
    Map<String, dynamic> node, {
    int? maxDepth,
    int currentDepth = 0,
  }) {
    final name = node['name'] as String?;
    final description = node['description'] as String? ?? 'Widget';
    final valueId = node['valueId'] as String?;
    final creationLocation = node['creationLocation'] as Map<String, dynamic>?;

    String? simplifiedLocation;
    if (creationLocation != null) {
      var file = creationLocation['file'] as String? ?? '';
      final workspacePadRegex = RegExp(r'^file:///workspace/pad_\d+/');
      if (workspacePadRegex.hasMatch(file)) {
        file = file.replaceFirst(workspacePadRegex, '');
      }
      simplifiedLocation = '$file:${creationLocation['line']}:${creationLocation['column']}';
    }

    // If we've hit the depth limit, mark as truncated and omit children.
    final atDepthLimit = maxDepth != null && currentDepth >= maxDepth;
    final rawChildren = node['children'] as List<dynamic>? ?? const <dynamic>[];
    final hasChildren = rawChildren.whereType<Map<String, dynamic>>().isNotEmpty;

    List<Map<String, dynamic>>? children;
    if (!atDepthLimit && hasChildren) {
      children = rawChildren
          .whereType<Map<String, dynamic>>()
          .map(
            (child) => simplifySummaryTree(
              child,
              maxDepth: maxDepth,
              currentDepth: currentDepth + 1,
            ),
          )
          .toList();
    }

    return {
      'widget': name ?? description,
      'id': ?valueId,
      if (name != null) 'description': description,
      'location': ?simplifiedLocation,
      if (children != null && children.isNotEmpty) 'children': children,
      if (atDepthLimit && hasChildren) 'truncated': true,
    };
  }

  /// Counts the total number of nodes in a simplified tree.
  int countNodes(Map<String, dynamic> node) {
    var count = 1;
    final children = node['children'] as List<dynamic>?;
    if (children != null) {
      for (final child in children) {
        if (child is Map<String, dynamic>) {
          count += countNodes(child);
        }
      }
    }
    return count;
  }

  /// Extracts flat property information from a details-subtree response.
  ///
  /// Returns a list of `{name, description, value}` maps for each diagnostic
  /// property on the node.
  List<Map<String, String>> extractProperties(
    Map<String, dynamic> detailNode,
  ) {
    final properties = <Map<String, String>>[];
    final rawProperties = detailNode['properties'] as List<dynamic>? ?? const <dynamic>[];
    for (final prop in rawProperties) {
      if (prop is Map<String, dynamic>) {
        final name = prop['name'] as String? ?? '';
        final description = prop['description'] as String? ?? '';
        final value = prop['propertyType'] as String? ?? '';
        if (name.isNotEmpty) {
          properties.add({
            'name': name,
            'description': description,
            if (value.isNotEmpty) 'type': value,
          });
        }
      }
    }
    return properties;
  }

  /// Simplifies the creation location from a detail node to a `file:line:col` string.
  String? simplifyLocation(Map<String, dynamic> node) {
    final creationLocation = node['creationLocation'] as Map<String, dynamic>?;
    if (creationLocation == null) {
      return null;
    }

    var file = creationLocation['file'] as String? ?? '';
    final workspacePadRegex = RegExp(r'^file:///workspace/pad_\d+/');
    if (workspacePadRegex.hasMatch(file)) {
      file = file.replaceFirst(workspacePadRegex, '');
    }
    return '$file:${creationLocation['line']}:${creationLocation['column']}';
  }

  /// JSON-encodes a value, used to pass structured data as string fields in tool output.
  String toJsonString(Object? value) => jsonEncode(value);

  String escapeXml(String input) {
    return input
        .replaceAll('&', '&amp;')
        .replaceAll('<', '&lt;')
        .replaceAll('>', '&gt;')
        .replaceAll('"', '&quot;')
        .replaceAll("'", '&apos;');
  }

  String nodeToXml(Map<String, dynamic> node, [String indent = '']) {
    final widget = node['widget'] as String? ?? 'Widget';
    final id = node['id'] as String?;
    final description = node['description'] as String?;
    final children = node['children'] as List<dynamic>?;

    final sb = StringBuffer();
    sb.write('$indent<$widget');
    if (id != null) {
      sb.write(' id="${escapeXml(id)}"');
    }
    if (description != null) {
      sb.write(' description="${escapeXml(description)}"');
    }

    if (children == null || children.isEmpty) {
      sb.write(' />\n');
    } else {
      sb.write('>\n');
      for (final child in children) {
        if (child is Map<String, dynamic>) {
          sb.write(nodeToXml(child, '$indent  '));
        }
      }
      sb.write('$indent</$widget>\n');
    }
    return sb.toString();
  }

  String formatProperties(List<Map<String, String>> properties, [String indent = '']) {
    final sb = StringBuffer();
    for (final prop in properties) {
      final name = prop['name'] ?? '';
      final description = prop['description'] ?? '';
      final type = prop['type'];
      sb.write(indent);
      if (type != null && type.isNotEmpty) {
        sb.writeln('$name [$type]: $description');
      } else {
        sb.writeln('$name: $description');
      }
    }
    return sb.toString();
  }
}