import 'package:shared_preferences/shared_preferences.dart';

import '../models/dokument_typ.dart';

/// Lokale Kennzahlen (keine Cloud) – Fokus: PDFs & Dokumenttypen.
class WorkflowMetricsService {
  WorkflowMetricsService._();

  static const _kPdfTotal = 'hp_metrics_pdf_total';
  static const _kPdfWeek = 'hp_metrics_pdf_week';
  static const _kPdfWeekId = 'hp_metrics_pdf_week_id';
  static const _kLastPdfAt = 'hp_metrics_last_pdf_at';
  static const _kPrefixDoc = 'hp_metrics_doc_';

  static DateTime _montagNullUhr(DateTime d) {
    final t = DateTime(d.year, d.month, d.day);
    return t.subtract(Duration(days: t.weekday - DateTime.monday));
  }

  static int _kalenderWocheSchluessel(DateTime d) {
    final m = _montagNullUhr(d);
    return m.year * 10000 + m.month * 100 + m.day;
  }

  static Future<void> recordPdfExported() async {
    final p = await SharedPreferences.getInstance();
    final now = DateTime.now();
    final wid = _kalenderWocheSchluessel(now);
    final stored = p.getInt(_kPdfWeekId);
    var week = p.getInt(_kPdfWeek) ?? 0;
    if (stored != wid) {
      week = 0;
      await p.setInt(_kPdfWeekId, wid);
    }
    week += 1;
    final total = (p.getInt(_kPdfTotal) ?? 0) + 1;
    await p.setInt(_kPdfWeek, week);
    await p.setInt(_kPdfTotal, total);
    await p.setString(_kLastPdfAt, now.toIso8601String());
  }

  static Future<void> recordDokumentGespeichert(DokumentTyp typ) async {
    final p = await SharedPreferences.getInstance();
    final k = '$_kPrefixDoc${typ.storageValue}';
    await p.setInt(k, (p.getInt(k) ?? 0) + 1);
  }

  static Future<WorkflowMetricsSnapshot> load() async {
    final p = await SharedPreferences.getInstance();
    final wid = _kalenderWocheSchluessel(DateTime.now());
    final stored = p.getInt(_kPdfWeekId);
    final week = (stored == wid) ? (p.getInt(_kPdfWeek) ?? 0) : 0;
    final total = p.getInt(_kPdfTotal) ?? 0;
    final last = DateTime.tryParse(p.getString(_kLastPdfAt) ?? '');
    final byDoc = <String, int>{};
    for (final t in DokumentTyp.values) {
      final k = '$_kPrefixDoc${t.storageValue}';
      final n = p.getInt(k);
      if (n != null && n > 0) byDoc[t.storageValue] = n;
    }
    return WorkflowMetricsSnapshot(
      pdfThisCalendarWeek: week,
      pdfAllTime: total,
      lastPdfAt: last,
      savesByDokumentTyp: byDoc,
    );
  }
}

class WorkflowMetricsSnapshot {
  WorkflowMetricsSnapshot({
    required this.pdfThisCalendarWeek,
    required this.pdfAllTime,
    required this.lastPdfAt,
    required this.savesByDokumentTyp,
  });

  final int pdfThisCalendarWeek;
  final int pdfAllTime;
  final DateTime? lastPdfAt;
  final Map<String, int> savesByDokumentTyp;
}