// telemetry.dart — Pillar 6: Opt-in local telemetry & feedback loop

import 'dart:convert';
import 'dart:io';
import 'package:path/path.dart' as p;
import 'logger.dart';

class Telemetry {
  /// Record a generation event (local-only, opt-in)
  static Future<void> record({
    required String projectName,
    required String outputDir,
    required List<String> templateFiles,
  }) async {
    final telemetryPath = p.join(outputDir, 'telemetry.json');
    Map<String, dynamic> data;
    try {
      final file = File(telemetryPath);
      data = file.existsSync()
          ? jsonDecode(await file.readAsString()) as Map<String, dynamic>
          : _emptyData(projectName);
    } catch (_) {
      data = _emptyData(projectName);
    }

    final generations = data['generations'] as List;
    generations.add({
      'timestamp': DateTime.now().toIso8601String(),
      'templateCount': templateFiles.length,
      'templates': templateFiles,
    });

    // Keep only last 100 events
    if (generations.length > 100) {
      data['generations'] = generations.sublist(generations.length - 100);
    }
    data['lastGeneratedAt'] = DateTime.now().toIso8601String();
    data['totalGenerations'] = (data['totalGenerations'] as int? ?? 0) + 1;

    final file = File(telemetryPath);
    await file.parent.create(recursive: true);
    await file.writeAsString(const JsonEncoder.withIndent('  ').convert(data));
  }

  /// Print the telemetry report
  static Future<void> printReport({required String outputDir}) async {
    final file = File(p.join(outputDir, 'telemetry.json'));
    if (!file.existsSync()) {
      Logger.warn(
          'No telemetry data found. Ensure telemetry_opt_in: true in project-brief.yaml');
      return;
    }
    final data = jsonDecode(await file.readAsString()) as Map<String, dynamic>;
    Logger.info('\n📊  Telemetry Report — ${data['projectName']}');
    Logger.info('─' * 42);
    Logger.info('Total generations:  ${data['totalGenerations']}');
    Logger.info('Last generated:     ${data['lastGeneratedAt']}');

    final generations = data['generations'] as List;
    if (generations.isNotEmpty) {
      final last = generations.last as Map;
      final templates = (last['templates'] as List).cast<String>();
      Logger.info('\nLast generation used ${templates.length} templates:');
      final ruleCount = templates.where((t) => t.startsWith('rules/')).length;
      final agentCount = templates.where((t) => t.startsWith('agents/')).length;
      final skillCount = templates.where((t) => t.startsWith('skills/')).length;
      Logger.dim(
          '  Rules: $ruleCount  |  Agents: $agentCount  |  Skills: $skillCount');
    }

    Logger.info('\n💡  Quarterly template quality review checklist:');
    Logger.dim(
        '  □ Review AI code review comments — which rules are most violated?');
    Logger.dim(
        '  □ Ask teams: which agents are actually consulted vs. ignored?');
    Logger.dim(
        '  □ Check if generated rules reduced hallucinations vs. last quarter');
    Logger.dim(
        '  □ Identify brief combinations that produce the most AI errors');
    Logger.dim(
        '  □ Update templates based on feedback, bump version in CHANGELOG.md');
  }

  static Map<String, dynamic> _emptyData(String projectName) => {
        'projectName': projectName,
        'totalGenerations': 0,
        'lastGeneratedAt': '',
        'generations': [],
        'note':
            'Local-only telemetry. Never sent anywhere. opt-in via telemetry_opt_in: true.',
      };
}