import 'package:flutter/material.dart';
import '../models/work_interval.dart';

int _toMinutes(TimeOfDay t) => t.hour * 60 + t.minute;

/// Effektive Arbeitsminuten eines Tages nach Pausenregel:
/// - <= 6h Arbeit: keine Pflichtpause
/// - > 6h Arbeit: 30 Min Pflichtpause, reduziert um die Summe der Lücken
///   zwischen Intervallen (maximal bis 0 reduzierbar).
int effectiveWorkedMinutes(
  List<WorkInterval> intervals, {
  int requiredBreakOver6h = 30,
}) {
  if (intervals.isEmpty) return 0;

  // sortieren
  final sorted = [...intervals]
    ..sort((a, b) => _toMinutes(a.start).compareTo(_toMinutes(b.start)));

  // Arbeitszeit summieren
  int worked = 0;
  for (final iv in sorted) {
    final w = _toMinutes(iv.end) - _toMinutes(iv.start);
    if (w > 0) worked += w;
  }

  if (worked <= 6 * 60) return worked;

  // Lücken summieren
  int gaps = 0;
  for (var i = 0; i < sorted.length - 1; i++) {
    final gap = _toMinutes(sorted[i + 1].start) - _toMinutes(sorted[i].end);
    if (gap > 0) gaps += gap;
  }

  final extraBreak = (requiredBreakOver6h - gaps).clamp(0, requiredBreakOver6h);
  final effective = worked - extraBreak;
  return effective < 0 ? 0 : effective;
}