added categories, import export, settings

2026-08-29 16:45:27 +02:00
parent 2a5a922aab
commit 732a0dc14a
30 changed files with 3700 additions and 167 deletions
@@ -0,0 +1,159 @@
+/// Simple line chart of unit prices over time.
+library;
+
+import 'package:flutter/material.dart';
+
+import '../models/purchase.dart';
+import '../utils/dates.dart';
+import '../utils/money.dart';
+
+class PriceChart extends StatelessWidget {
+  const PriceChart({super.key, required this.purchases});
+
+  final List<Purchase> purchases;
+
+  @override
+  Widget build(BuildContext context) {
+    if (purchases.isEmpty) {
+      return const SizedBox.shrink();
+    }
+
+    final points = purchases.reversed.toList();
+    final theme = Theme.of(context);
+
+    return Column(
+      crossAxisAlignment: CrossAxisAlignment.stretch,
+      children: [
+        SizedBox(
+          height: 160,
+          child: CustomPaint(
+            painter: _PriceChartPainter(
+              prices: [
+                for (final purchase in points) purchase.unitOrLinePrice,
+              ],
+              lineColor: theme.colorScheme.primary,
+              fillColor: theme.colorScheme.primary.withValues(alpha: 0.12),
+              gridColor: theme.colorScheme.outlineVariant,
+              labelColor: theme.colorScheme.onSurfaceVariant,
+            ),
+            child: const SizedBox.expand(),
+          ),
+        ),
+        const SizedBox(height: 4),
+        Row(
+          mainAxisAlignment: MainAxisAlignment.spaceBetween,
+          children: [
+            Text(
+              formatDate(points.first.boughtAt),
+              style: theme.textTheme.labelMedium,
+            ),
+            Text(
+              formatDate(points.last.boughtAt),
+              style: theme.textTheme.labelMedium,
+            ),
+          ],
+        ),
+        const SizedBox(height: 4),
+        Text(
+          'Latest ${formatEuro(points.last.unitOrLinePrice)}',
+          style: theme.textTheme.labelMedium,
+        ),
+      ],
+    );
+  }
+}
+
+class _PriceChartPainter extends CustomPainter {
+  _PriceChartPainter({
+    required this.prices,
+    required this.lineColor,
+    required this.fillColor,
+    required this.gridColor,
+    required this.labelColor,
+  });
+
+  final List<double> prices;
+  final Color lineColor;
+  final Color fillColor;
+  final Color gridColor;
+  final Color labelColor;
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    final minPrice = prices.reduce((a, b) => a < b ? a : b);
+    final maxPrice = prices.reduce((a, b) => a > b ? a : b);
+    final span = (maxPrice - minPrice).abs() < 0.01 ? 1.0 : maxPrice - minPrice;
+    const left = 36.0;
+    const right = 8.0;
+    const top = 12.0;
+    const bottom = 8.0;
+    final chart = Rect.fromLTRB(left, top, size.width - right, size.height - bottom);
+
+    final gridPaint = Paint()
+      ..color = gridColor
+      ..strokeWidth = 1;
+    for (var i = 0; i < 3; i++) {
+      final y = chart.top + chart.height * i / 2;
+      canvas.drawLine(Offset(chart.left, y), Offset(chart.right, y), gridPaint);
+    }
+
+    final path = Path();
+    final fill = Path();
+    Offset? last;
+    for (var i = 0; i < prices.length; i++) {
+      final x = prices.length == 1
+          ? chart.center.dx
+          : chart.left + chart.width * i / (prices.length - 1);
+      final y = chart.bottom - chart.height * ((prices[i] - minPrice) / span);
+      final point = Offset(x, y);
+      last = point;
+      if (i == 0) {
+        path.moveTo(x, y);
+        fill.moveTo(x, chart.bottom);
+        fill.lineTo(x, y);
+      } else {
+        path.lineTo(x, y);
+        fill.lineTo(x, y);
+      }
+    }
+    if (last != null) {
+      fill.lineTo(last.dx, chart.bottom);
+      fill.close();
+    }
+
+    canvas.drawPath(fill, Paint()..color = fillColor);
+    canvas.drawPath(
+      path,
+      Paint()
+        ..color = lineColor
+        ..style = PaintingStyle.stroke
+        ..strokeWidth = 2.5
+        ..strokeCap = StrokeCap.round
+        ..strokeJoin = StrokeJoin.round,
+    );
+
+    final dot = Paint()..color = lineColor;
+    for (var i = 0; i < prices.length; i++) {
+      final x = prices.length == 1
+          ? chart.center.dx
+          : chart.left + chart.width * i / (prices.length - 1);
+      final y = chart.bottom - chart.height * ((prices[i] - minPrice) / span);
+      canvas.drawCircle(Offset(x, y), 3.5, dot);
+    }
+
+    final labels = [maxPrice, (minPrice + maxPrice) / 2, minPrice];
+    final textStyle = TextStyle(color: labelColor, fontSize: 10);
+    for (var i = 0; i < labels.length; i++) {
+      final tp = TextPainter(
+        text: TextSpan(text: labels[i].toStringAsFixed(2), style: textStyle),
+        textDirection: TextDirection.ltr,
+      )..layout(maxWidth: left - 4);
+      final y = chart.top + chart.height * i / 2 - tp.height / 2;
+      tp.paint(canvas, Offset(0, y));
+    }
+  }
+
+  @override
+  bool shouldRepaint(covariant _PriceChartPainter oldDelegate) =>
+      oldDelegate.prices != prices || oldDelegate.lineColor != lineColor;
+}