feat: chat raiding

closes #1

lib/widgets/goal.dart

@@ -0,0 +1,105 @@
+import 'package:flutter/material.dart';
+import 'package:ndk/ndk.dart';
+import 'package:zap_stream_flutter/rx_filter.dart';
+import 'package:zap_stream_flutter/theme.dart';
+import 'package:zap_stream_flutter/utils.dart';
+
+class GoalWidget extends StatelessWidget {
+  final Nip01Event goal;
+
+  const GoalWidget({super.key, required this.goal});
+
+  static Widget id(String id) {
+    return RxFilter<Nip01Event>(
+      Key("stream:goal:$id"),
+      leaveOpen: false,
+      filters: [
+        Filter(kinds: [9041], ids: [id]),
+      ],
+      builder: (ctx, state) {
+        final goal = state?.firstOrNull;
+        return goal != null ? GoalWidget(goal: goal) : SizedBox.shrink();
+      },
+    );
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final max = int.parse(goal.getFirstTag("amount") ?? "1");
+    return Container(
+      padding: EdgeInsets.symmetric(horizontal: 4, vertical: 4),
+      child: RxFilter<Nip01Event>(
+        Key("goal:$id:zaps"),
+        filters: [
+          Filter(kinds: [9735], eTags: [goal.id]),
+        ],
+        builder: (ctx, state) {
+          final zaps = (state ?? []).map((e) => ZapReceipt.fromEvent(e));
+          final totalZaps =
+              zaps.fold(0, (acc, v) => acc + (v.amountSats ?? 0)) * 1000;
+          final progress = totalZaps / max;
+          final remaining = ((max - totalZaps).clamp(0, max) / 1000).toInt();
+
+          final q = MediaQuery.of(ctx);
+          return Column(
+            spacing: 4,
+            crossAxisAlignment: CrossAxisAlignment.start,
+            children: [
+              Row(
+                children: [
+                  Expanded(child: Text(goal.content)),
+                  if (remaining > 0)
+                    Text(
+                      "Remaining: ${formatSats(remaining)}",
+                      style: TextStyle(fontSize: 10, color: LAYER_5),
+                    ),
+                ],
+              ),
+              Stack(
+                children: [
+                  Container(
+                    height: 10,
+                    decoration: BoxDecoration(
+                      color: LAYER_2,
+                      borderRadius: DEFAULT_BR,
+                    ),
+                  ),
+                  Container(
+                    height: 10,
+                    width: (q.size.width * progress).clamp(1, q.size.width),
+                    decoration: BoxDecoration(
+                      color: ZAP_1,
+                      borderRadius: DEFAULT_BR,
+                    ),
+                  ),
+                  if (remaining > 0)
+                    Positioned(
+                      right: 2,
+                      child: Text(
+                        "Goal: ${formatSats((max / 1000).toInt())}",
+                        style: TextStyle(
+                          fontSize: 8,
+                          fontWeight: FontWeight.bold,
+                        ),
+                      ),
+                    ),
+                  if (remaining == 0)
+                    Center(
+                      child: Text(
+                        "COMPLETE",
+                        style: TextStyle(
+                          color: LAYER_0,
+                          fontSize: 8,
+                          fontWeight: FontWeight.bold,
+                        ),
+                      ),
+                    ),
+                ],
+              ),
+            ],
+          );
+        },
+      ),
+    );
+  }
+}