Worklog, anti geo spoofing and UI Polish

lib/utils/task_duration.dart

@@ -0,0 +1,65 @@
+import '../models/task_activity_log.dart';
+
+/// Finds the canonical execution start time for a task.
+///
+/// [logs] is expected in DESCENDING order (newest first), matching the
+/// `order('created_at', ascending: false)` used by Supabase queries.
+/// The reversed iteration therefore walks chronologically forward and stops
+/// at the earliest 'started' event.
+DateTime? resolveTaskExecutionStart(
+  List<TaskActivityLog> logs,
+  DateTime? fallbackStartedAt,
+) {
+  DateTime? started;
+  for (final entry in logs.reversed) {
+    if (entry.actionType == 'started') {
+      started = entry.createdAt;
+      break;
+    }
+  }
+  return started ?? fallbackStartedAt;
+}
+
+/// Computes the effective worked duration for a task, subtracting all
+/// paused intervals between [fallbackStartedAt] (or the first 'started'
+/// log event) and [endAt].
+///
+/// [logs] must be in DESCENDING order (newest first) — the same order
+/// returned by `task_activity_logs` queries with `ascending: false`.
+Duration computeEffectiveTaskDuration({
+  required DateTime? fallbackStartedAt,
+  required DateTime endAt,
+  required List<TaskActivityLog> logs,
+}) {
+  final start = resolveTaskExecutionStart(logs, fallbackStartedAt);
+  if (start == null || !endAt.isAfter(start)) return Duration.zero;
+
+  Duration pausedTotal = Duration.zero;
+  DateTime? pausedSince;
+
+  // logs.reversed → ascending (chronological) order within [start, endAt]
+  final events = logs.reversed.where((e) {
+    if (e.createdAt.isBefore(start)) return false;
+    if (e.createdAt.isAfter(endAt)) return false;
+    return e.actionType == 'paused' || e.actionType == 'resumed';
+  });
+
+  for (final event in events) {
+    if (event.actionType == 'paused') {
+      pausedSince ??= event.createdAt;
+    } else if (event.actionType == 'resumed' && pausedSince != null) {
+      if (event.createdAt.isAfter(pausedSince)) {
+        pausedTotal += event.createdAt.difference(pausedSince);
+      }
+      pausedSince = null;
+    }
+  }
+
+  // Task is still paused at endAt — count the open pause interval.
+  if (pausedSince != null && endAt.isAfter(pausedSince)) {
+    pausedTotal += endAt.difference(pausedSince);
+  }
+
+  final total = endAt.difference(start) - pausedTotal;
+  return total.isNegative ? Duration.zero : total;
+}