From e42dd963c0322b7b2fe5e64af2f99dcdc9fe7e3c Mon Sep 17 00:00:00 2001
From: Eric Seidel <github@eseidel.com>
Date: Sat, 7 Oct 2023 10:45:36 -0700
Subject: [PATCH] feat: make ConnectedSystems cache much faster to build

---
 .../cli/bin/systems_reachable_from_factions.dart    |  4 +++-
 packages/cli/lib/nav/system_connectivity.dart       | 13 ++++++++++---
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/packages/cli/bin/systems_reachable_from_factions.dart b/packages/cli/bin/systems_reachable_from_factions.dart
index 0bc88bde..9a552607 100644
--- a/packages/cli/bin/systems_reachable_from_factions.dart
+++ b/packages/cli/bin/systems_reachable_from_factions.dart
@@ -1,7 +1,7 @@
 import 'package:cli/cache/caches.dart';
 import 'package:cli/cli.dart';
 import 'package:db/db.dart';
-import 'package:types/types.dart';
+import 'package:types/api.dart';
 
 Future<void> command(FileSystem fs, ArgResults argResults) async {
   final db = await defaultDatabase();
@@ -10,11 +10,13 @@ Future<void> command(FileSystem fs, ArgResults argResults) async {
   final factions = await loadFactions(db, factionsApi);
 
   final clusterCache = SystemConnectivity.fromSystemsCache(systemsCache);
+
   for (final faction in factions) {
     final hq = faction.headquartersSymbol;
     final reachable = clusterCache.connectedSystemCount(hq.systemSymbol);
     logger.info('${faction.symbol}: $reachable');
   }
+
   // Required or main will hang.
   await db.close();
 }
diff --git a/packages/cli/lib/nav/system_connectivity.dart b/packages/cli/lib/nav/system_connectivity.dart
index 49039dc5..64aee873 100644
--- a/packages/cli/lib/nav/system_connectivity.dart
+++ b/packages/cli/lib/nav/system_connectivity.dart
@@ -24,11 +24,12 @@ class _ClusterFinder {
     if (_clusterForSystem.containsKey(startSystemSymbol)) {
       return;
     }
-    final queue = [startSystemSymbol];
+    final queue = {startSystemSymbol};
     final cluster = _nextClusterId++;
 
     while (queue.isNotEmpty) {
-      final systemSymbol = queue.removeAt(0);
+      final systemSymbol = queue.first;
+      queue.remove(systemSymbol);
       final maybeCluster = _clusterForSystem[systemSymbol];
       if (maybeCluster != null) {
         if (maybeCluster != cluster) {
@@ -39,8 +40,14 @@ class _ClusterFinder {
         continue;
       }
       _clusterForSystem[systemSymbol] = cluster;
+      // The first time we run this, it builds the connectedSystems
+      // cache on demand, which takes about 2s on my machine.
       final connected = systemsCache.connectedSystems(systemSymbol);
-      queue.addAll(connected.map((s) => s.systemSymbol));
+      for (final symbol in connected.map((s) => s.systemSymbol)) {
+        if (!_clusterForSystem.containsKey(symbol)) {
+          queue.add(symbol);
+        }
+      }
     }
   }
 }