import '../models/programmer_task_work_log.model.dart';

/// Formats a worked duration compactly, e.g. `2h 15m` or `45m`.
String formatDurationHm(Duration d) {
  final h = d.inHours;
  final m = d.inMinutes.remainder(60);
  if (h > 0) return '${h}h ${m}m';
  return '${m}m';
}

/// One contributor's share of a task's time.
class LedgerEntry {
  final String userId;
  final Duration duration;
  final bool isAssignee;

  const LedgerEntry({
    required this.userId,
    required this.duration,
    required this.isAssignee,
  });
}

/// Per-contributor time breakdown for a task: the assignee's effective running
/// duration plus each helper's summed logged minutes.
class TaskTimeLedger {
  final LedgerEntry? assignee;
  final List<LedgerEntry> helpers;

  const TaskTimeLedger({required this.assignee, required this.helpers});

  Duration get total =>
      (assignee?.duration ?? Duration.zero) +
      helpers.fold(Duration.zero, (a, e) => a + e.duration);

  List<LedgerEntry> get all => [?assignee, ...helpers];
}

/// Builds the per-contributor ledger for a task.
///
/// [assigneeDuration] is the assignee's effective running duration (already
/// computed from the activity log, including any adjustments). Helper entries
/// sum the `minutes` of work logs authored by someone other than the assignee;
/// assignee work logs (minutes == null progress notes) are excluded because the
/// assignee's time comes from the running clock.
TaskTimeLedger computeTaskLedger({
  required String? assigneeId,
  required Duration assigneeDuration,
  required List<ProgrammerTaskWorkLog> workLogs,
}) {
  final byHelper = <String, int>{};
  for (final log in workLogs) {
    final minutes = log.minutes;
    if (minutes == null || minutes <= 0) continue;
    if (log.authorId == assigneeId) continue;
    byHelper[log.authorId] = (byHelper[log.authorId] ?? 0) + minutes;
  }

  final helpers = byHelper.entries
      .map((e) => LedgerEntry(
            userId: e.key,
            duration: Duration(minutes: e.value),
            isAssignee: false,
          ))
      .toList()
    ..sort((a, b) => b.duration.compareTo(a.duration));

  return TaskTimeLedger(
    assignee: assigneeId == null
        ? null
        : LedgerEntry(
            userId: assigneeId,
            duration: assigneeDuration,
            isAssignee: true,
          ),
    helpers: helpers,
  );
}