Add concrete transformations per hour metrics chart.

src/main/java/community/leaf/survival/concretemixer/CauldronPowderDropListener.java

@@ -12,6 +12,7 @@
 import community.leaf.eventful.bukkit.ListenerOrder;
 import community.leaf.eventful.bukkit.annotations.CancelledEvents;
 import community.leaf.eventful.bukkit.annotations.EventListener;
+import community.leaf.survival.concretemixer.metrics.TransformationsPerHour;
 import community.leaf.tasks.TaskContext;
 import org.bukkit.Material;
 import org.bukkit.block.Block;
@@ -38,10 +39,12 @@ public class CauldronPowderDropListener implements Listener
     private final Map<UUID, TaskContext<BukkitTask>> transformationTasksByItemUuid = new HashMap<>();
 
     private final ConcreteMixerPlugin plugin;
+    private final TransformationsPerHour counter;
 
-    public CauldronPowderDropListener(ConcreteMixerPlugin plugin)
+    public CauldronPowderDropListener(ConcreteMixerPlugin plugin, TransformationsPerHour counter)
     {
         this.plugin = plugin;
+        this.counter = counter;
     }
 
     @EventListener
@@ -187,6 +190,7 @@ class IterationCounter
                 item.setPickupDelay(10);
 
                 plugin.effects().concreteTransform(cauldron);
+                counter.transformed(stack.getAmount());
 
                 if (!lowerWaterLevel) { return; }
                 if (!(cauldron.getBlockData() instanceof Levelled levelled)) { return; }

src/main/java/community/leaf/survival/concretemixer/ConcreteMixerPlugin.java

@@ -10,8 +10,10 @@
 import com.github.zafarkhaja.semver.Version;
 import community.leaf.eventful.bukkit.BukkitEventSource;
 import community.leaf.survival.concretemixer.hooks.HookHandler;
+import community.leaf.survival.concretemixer.metrics.TransformationsPerHour;
 import community.leaf.tasks.bukkit.BukkitTaskSource;
 import org.bstats.bukkit.Metrics;
+import org.bstats.charts.SingleLineChart;
 import org.bukkit.plugin.Plugin;
 import org.bukkit.plugin.java.JavaPlugin;
 import pl.tlinkowski.annotation.basic.NullOr;
@@ -36,12 +38,18 @@ public void onEnable()
         this.effects = new EffectHandler(config);
         this.hooks = new HookHandler(this);
         this.permissions = new PermissionHandler(this);
-
-        events().register(new CauldronPowderDropListener(this));
+
+        TransformationsPerHour counter = new TransformationsPerHour(config);
+        events().register(new CauldronPowderDropListener(this, counter));
 
         if (config.getOrDefault(Config.METRICS))
         {
-            new Metrics(this, 15590);
+            Metrics metrics = new Metrics(this, 15590);
+
+            metrics.addCustomChart(new SingleLineChart(
+                "transformations-per-hour",
+                counter::totalTransformationsInTheLastHour
+            ));
         }
     }
 

src/main/java/community/leaf/survival/concretemixer/metrics/TransformationsPerHour.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright © 2022, RezzedUp and Contributors <https://github.com/LeafCommunity/ConcreteMixer>
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+package community.leaf.survival.concretemixer.metrics;
+
+import community.leaf.survival.concretemixer.Config;
+
+import java.time.Instant;
+import java.time.temporal.ChronoUnit;
+import java.util.Iterator;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+public class TransformationsPerHour
+{
+    private final Map<Instant, Integer> countersByMinute = new LinkedHashMap<>();
+
+    private final Config config;
+
+    public TransformationsPerHour(Config config)
+    {
+        this.config = config;
+    }
+
+    public void transformed(int totalPowderToConcrete)
+    {
+        if (totalPowderToConcrete < 0) { throw new IllegalArgumentException(); }
+        if (!config.getOrDefault(Config.METRICS)) { return; }
+
+        Instant minute = Instant.now().truncatedTo(ChronoUnit.MINUTES);
+        int counter = countersByMinute.computeIfAbsent(minute, k -> 0);
+        countersByMinute.put(minute, counter + totalPowderToConcrete);
+    }
+
+    public int totalTransformationsInTheLastHour()
+    {
+        int total = 0;
+        Instant now = Instant.now();
+        Iterator<Map.Entry<Instant, Integer>> it = countersByMinute.entrySet().iterator();
+
+        while (it.hasNext())
+        {
+            Map.Entry<Instant, Integer> entry = it.next();
+
+            if (ChronoUnit.MINUTES.between(entry.getKey(), now) >= 60) { it.remove(); }
+            else { total += entry.getValue(); }
+        }
+
+        return total;
+    }
+}

src/main/java/community/leaf/survival/concretemixer/metrics/package-info.java

@@ -0,0 +1,11 @@
+/*
+ * Copyright © 2022, RezzedUp and Contributors <https://github.com/LeafCommunity/ConcreteMixer>
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+@NonNullPackage
+package community.leaf.survival.concretemixer.metrics;
+
+import pl.tlinkowski.annotation.basic.NonNullPackage;