add timeline edit/delete

lib/components/pages/loco_timeline.dart

@@ -1,6 +1,8 @@
 import 'dart:math' as math;
 
 import 'package:flutter/material.dart';
+import 'package:flutter/foundation.dart';
+import 'package:flutter/services.dart';
 import 'package:intl/intl.dart';
 import 'package:mileograph_flutter/objects/objects.dart';
 import 'package:mileograph_flutter/services/data_service.dart';
@@ -26,6 +28,7 @@ class LocoTimelinePage extends StatefulWidget {
 class _LocoTimelinePageState extends State<LocoTimelinePage> {
   final List<_EventDraft> _draftEvents = [];
   bool _isSaving = false;
+  bool _isDeleting = false;
 
   @override
   void initState() {
@@ -51,6 +54,143 @@ class _LocoTimelinePageState extends State<LocoTimelinePage> {
     });
   }
 
+  String? _eventDateForEntry(LocoAttrVersion entry) {
+    final masked = entry.maskedValidFrom?.trim();
+    if (masked != null && masked.isNotEmpty) return masked;
+    final from = entry.validFrom ?? entry.txnFrom;
+    if (from == null) return null;
+    return DateFormat('yyyy-MM-dd').format(from);
+  }
+
+  EventField? _fieldForAttr(String attrCode, List<EventField> fields) {
+    final normalized = attrCode.trim().toLowerCase();
+    for (final field in fields) {
+      if (field.name.trim().toLowerCase() == normalized) return field;
+    }
+    return null;
+  }
+
+  dynamic _valueForEntry(LocoAttrVersion entry) {
+    if (entry.valueInt != null) return entry.valueInt;
+    if (entry.valueBool != null) return entry.valueBool;
+    if (entry.valueEnum != null && entry.valueEnum!.isNotEmpty) {
+      return entry.valueEnum;
+    }
+    if (entry.valueStr != null && entry.valueStr!.isNotEmpty) {
+      return entry.valueStr;
+    }
+    if (entry.valueDate != null) {
+      return DateFormat('yyyy-MM-dd').format(entry.valueDate!);
+    }
+    if (entry.valueNorm != null && entry.valueNorm.toString().isNotEmpty) {
+      return entry.valueNorm;
+    }
+    final label = entry.valueLabel;
+    return label == '—' ? '' : label;
+  }
+
+  void _prefillDraftFromEntry(LocoAttrVersion entry, List<EventField> fields) {
+    final dateStr = _eventDateForEntry(entry);
+    if (dateStr == null || dateStr.isEmpty) {
+      ScaffoldMessenger.of(context).showSnackBar(
+        const SnackBar(content: Text('Cannot edit: timeline block date unknown.')),
+      );
+      return;
+    }
+    final field = _fieldForAttr(entry.attrCode, fields);
+    if (field == null) {
+      ScaffoldMessenger.of(context).showSnackBar(
+        SnackBar(
+          content: Text(
+            'Cannot edit: no event field found for ${_formatAttrLabel(entry.attrCode)}.',
+          ),
+        ),
+      );
+      return;
+    }
+
+    final draft = _EventDraft();
+    draft.dateController.text = dateStr;
+    draft.detailsController.text = '';
+    draft.details = '';
+    draft.fields.add(
+      _FieldEntry(field: field)
+        ..value = _valueForEntry(entry),
+    );
+
+    setState(() {
+      _draftEvents.add(draft);
+    });
+  }
+
+  Future<void> _deleteEntry(LocoAttrVersion entry) async {
+    if (_isDeleting) return;
+    final blockId = entry.versionId;
+    if (blockId == null) {
+      ScaffoldMessenger.of(context).showSnackBar(
+        const SnackBar(content: Text('Cannot delete: timeline block has no ID.')),
+      );
+      return;
+    }
+
+    final data = context.read<DataService>();
+    final messenger = ScaffoldMessenger.of(context);
+
+    final dateStr = _eventDateForEntry(entry);
+    final ok = await showDialog<bool>(
+      context: context,
+      builder: (context) {
+        return AlertDialog(
+          title: const Text('Delete timeline block?'),
+          content: Text(
+            dateStr == null || dateStr.isEmpty
+                ? 'This will delete the selected block for ${_formatAttrLabel(entry.attrCode)}.'
+                : 'This will delete the block for ${_formatAttrLabel(entry.attrCode)} starting at $dateStr.',
+          ),
+          actions: [
+            TextButton(
+              onPressed: () => Navigator.of(context).pop(false),
+              child: const Text('Cancel'),
+            ),
+            FilledButton(
+              onPressed: () => Navigator.of(context).pop(true),
+              child: const Text('Delete'),
+            ),
+          ],
+        );
+      },
+    );
+    if (ok != true) return;
+    if (!mounted) return;
+
+    setState(() {
+      _isDeleting = true;
+    });
+    try {
+      await data.deleteTimelineBlock(
+        blockId: blockId,
+      );
+      await _load();
+      if (mounted) {
+        messenger.showSnackBar(
+          const SnackBar(content: Text('Timeline block deleted')),
+        );
+      }
+    } catch (e) {
+      if (mounted) {
+        messenger.showSnackBar(
+          SnackBar(content: Text('Failed to delete timeline block: $e')),
+        );
+      }
+    } finally {
+      if (mounted) {
+        setState(() {
+          _isDeleting = false;
+        });
+      }
+    }
+  }
+
   void _removeDraftAt(int index) {
     if (index < 0 || index >= _draftEvents.length) return;
     final draft = _draftEvents.removeAt(index);
@@ -241,6 +381,11 @@ class _LocoTimelinePageState extends State<LocoTimelinePage> {
               children: [
                 _TimelineGrid(
                   entries: timeline,
+                  onEditEntry: (entry) => _prefillDraftFromEntry(
+                    entry,
+                    data.eventFields,
+                  ),
+                  onDeleteEntry: _deleteEntry,
                 ),
                 const SizedBox(height: 16),
                 _EventEditor(