Recover market demand every four hours

pom.xml

@@ -61,6 +61,12 @@
                 </exclusion>
             </exclusions>
         </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <version>5.14.0</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <repositories>
@@ -93,6 +99,11 @@
                 <artifactId>maven-compiler-plugin</artifactId>
                 <version>3.14.1</version>
             </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <version>3.5.4</version>
+            </plugin>
         </plugins>
     </build>
 </project>

src/main/java/net/tfminecraft/marketblock/Cache.java

@@ -7,11 +7,13 @@
 
 import org.bukkit.block.Block;
 
+import net.tfminecraft.marketblock.util.DemandSchedule;
 import net.tfminecraft.tlibs.TLibs;
 
 public class Cache {
     public static List<Integer> slots = new ArrayList<>();
     public static String marketBlock;
+    public static double demandRecoveryHours = DemandSchedule.DEFAULT_HOURS;
     public static final Map<String, Double> freshnessPrice = new LinkedHashMap<>();
 
     public static boolean blockIsMarketBlock(Block b) {

src/main/java/net/tfminecraft/marketblock/MarketBlock.java

@@ -86,5 +86,6 @@ public void reload(Player p) {
 
 	public void reload() {
 		loadConfigs();
+		tradeManager.rescheduleDemandCycle();
 	}
 }

src/main/java/net/tfminecraft/marketblock/loader/ConfigLoader.java

@@ -7,8 +7,9 @@
 import org.bukkit.configuration.file.FileConfiguration;
 import org.bukkit.configuration.file.YamlConfiguration;
 
-import net.tfminecraft.tlibs.interfaces.LoaderInterface;
 import net.tfminecraft.marketblock.Cache;
+import net.tfminecraft.marketblock.util.DemandSchedule;
+import net.tfminecraft.tlibs.interfaces.LoaderInterface;
 
 public class ConfigLoader implements LoaderInterface{
 
@@ -22,6 +23,8 @@ public void load(File configFile) {
         }
 
 		Cache.marketBlock = config.getString("market-block");
+		Cache.demandRecoveryHours = DemandSchedule.normalizeHours(
+				config.getDouble("demand-recovery-hours", DemandSchedule.DEFAULT_HOURS));
 
 		Cache.slots = config.getIntegerList("slots");
 

src/main/java/net/tfminecraft/marketblock/manager/TradeManager.java

@@ -14,6 +14,7 @@
 import org.bukkit.inventory.ItemStack;
 import org.bukkit.persistence.PersistentDataType;
 import org.bukkit.scheduler.BukkitRunnable;
+import org.bukkit.scheduler.BukkitTask;
 
 import net.tfminecraft.marketblock.Cache;
 import net.tfminecraft.marketblock.MarketBlock;
@@ -25,12 +26,14 @@
 import net.tfminecraft.marketblock.loader.TradeLoader;
 import net.tfminecraft.marketblock.trade.Category;
 import net.tfminecraft.marketblock.trade.Trade;
+import net.tfminecraft.marketblock.util.DemandSchedule;
 import net.tfminecraft.marketblock.util.InventoryUtils;
 import net.tfminecraft.marketblock.util.PriceCalculator;
 import net.tfminecraft.marketblock.util.SaleTake;
 
 public class TradeManager implements Listener {
     InventoryManager inv = new InventoryManager();
+    private BukkitTask demandTask;
 
     public void update() {
         for(Player p : Bukkit.getOnlinePlayers()) {
@@ -61,19 +64,32 @@ private String getItemId(MBGUI type, ItemStack i) {
     }
 
     public void start() {
-        demandCycle();
+        scheduleDemand(0L);
     }
 
-    public void demandCycle() {
-        new BukkitRunnable() {
+    public void rescheduleDemandCycle() {
+        scheduleDemand(DemandSchedule.periodTicks(Cache.demandRecoveryHours));
+    }
+
+    private void scheduleDemand(long delayTicks) {
+        if (demandTask != null) {
+            demandTask.cancel();
+            demandTask = null;
+        }
+        long period = DemandSchedule.periodTicks(Cache.demandRecoveryHours);
+        demandTask = new BukkitRunnable() {
             @Override
             public void run() {
-                for(Trade t : TradeLoader.getTrades().values()) {
-                    t.demand();
-                }
-                update();
+                recoverDemand();
             }
-        }.runTaskTimer(MarketBlock.plugin, 0, 60*60*20L);
+        }.runTaskTimer(MarketBlock.plugin, delayTicks, period);
+    }
+
+    public void recoverDemand() {
+        for (Trade t : TradeLoader.getTrades().values()) {
+            t.demand();
+        }
+        update();
     }
 
     @EventHandler

src/main/java/net/tfminecraft/marketblock/util/DemandSchedule.java

@@ -0,0 +1,24 @@
+package net.tfminecraft.marketblock.util;
+
+public final class DemandSchedule {
+    public static final double DEFAULT_HOURS = 4.0;
+    public static final long TICKS_PER_HOUR = 60L * 60L * 20L;
+
+    private DemandSchedule() {
+    }
+
+    public static double normalizeHours(double configuredHours) {
+        if (!Double.isFinite(configuredHours) || configuredHours <= 0.0) {
+            return DEFAULT_HOURS;
+        }
+        return configuredHours;
+    }
+
+    public static long periodTicks(double configuredHours) {
+        double ticks = normalizeHours(configuredHours) * TICKS_PER_HOUR;
+        if (!Double.isFinite(ticks) || ticks >= Long.MAX_VALUE) {
+            return Long.MAX_VALUE;
+        }
+        return Math.max(1L, Math.round(ticks));
+    }
+}

src/main/resources/config.yml

@@ -1,5 +1,7 @@
 slots: [10, 11, 12, 13, 14, 15, 16, 19, 20, 21, 22, 23, 24, 25, 28, 29, 30, 31, 32, 33, 34, 37, 38, 39, 40, 41, 42, 43]
 market-block: iaf(tfmc:market_block)
+# Hours between demand recovery ticks. Each tick raises every item's demand.
+demand-recovery-hours: 4
 freshness-price:
   fresh: 1.0
   stale: 0.5

src/test/java/net/tfminecraft/marketblock/loader/ConfigLoaderTest.java

@@ -0,0 +1,55 @@
+package net.tfminecraft.marketblock.loader;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.io.File;
+import java.nio.file.Files;
+
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import net.tfminecraft.marketblock.Cache;
+import net.tfminecraft.marketblock.util.DemandSchedule;
+
+class ConfigLoaderTest {
+    private final ConfigLoader loader = new ConfigLoader();
+
+    @AfterEach
+    void restoreDefault() {
+        Cache.demandRecoveryHours = DemandSchedule.DEFAULT_HOURS;
+    }
+
+    @Test
+    void loadsDemandRecoveryHours(@TempDir File dir) throws Exception {
+        File config = write(dir, "demand-recovery-hours: 4\n");
+
+        loader.load(config);
+
+        assertEquals(4.0, Cache.demandRecoveryHours);
+    }
+
+    @Test
+    void missingKeyDefaultsToFourHours(@TempDir File dir) throws Exception {
+        File config = write(dir, "market-block: iaf(tfmc:market_block)\n");
+
+        loader.load(config);
+
+        assertEquals(DemandSchedule.DEFAULT_HOURS, Cache.demandRecoveryHours);
+    }
+
+    @Test
+    void nonPositiveHoursFallBackToFour(@TempDir File dir) throws Exception {
+        loader.load(write(dir, "demand-recovery-hours: 0\n"));
+        assertEquals(4.0, Cache.demandRecoveryHours);
+
+        loader.load(write(dir, "demand-recovery-hours: -1\n"));
+        assertEquals(4.0, Cache.demandRecoveryHours);
+    }
+
+    private static File write(File dir, String yaml) throws Exception {
+        File config = new File(dir, "config.yml");
+        Files.writeString(config.toPath(), yaml);
+        return config;
+    }
+}

src/test/java/net/tfminecraft/marketblock/trade/TradeDemandTest.java

@@ -0,0 +1,47 @@
+package net.tfminecraft.marketblock.trade;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+class TradeDemandTest {
+
+    @Test
+    void eachRecoveryTickRaisesDemandByOneUpToJustUnderSeven() {
+        Trade trade = trade(1_000);
+        trade.setDemand(10);
+
+        for (int i = 0; i < 20; i++) {
+            double before = trade.getDemand();
+            trade.demand();
+            double increase = trade.getDemand() - before;
+            assertTrue(increase + 1e-9 >= 1.0, "increase was " + increase);
+            assertTrue(increase < 7.0, "increase was " + increase);
+        }
+    }
+
+    @Test
+    void recoveryStopsAtTheDemandLimit() {
+        Trade trade = trade(20);
+        trade.setDemand(19.5);
+
+        trade.demand();
+
+        assertEquals(20.0, trade.getDemand());
+    }
+
+    @Test
+    void sellingCannotDropDemandBelowOne() {
+        Trade trade = trade(20);
+        trade.setDemand(1);
+
+        trade.sell();
+
+        assertEquals(1.0, trade.getDemand());
+    }
+
+    private static Trade trade(double limit) {
+        return new Trade("oak", new Category(), limit / 2, limit, 1, "v.oak_log", 2, 64, 0);
+    }
+}

src/test/java/net/tfminecraft/marketblock/util/DemandScheduleTest.java

@@ -0,0 +1,34 @@
+package net.tfminecraft.marketblock.util;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+class DemandScheduleTest {
+
+    @Test
+    void fourHoursIsTheDefaultPeriod() {
+        assertEquals(4.0 * DemandSchedule.TICKS_PER_HOUR, DemandSchedule.periodTicks(4));
+        assertEquals(288_000L, DemandSchedule.periodTicks(DemandSchedule.DEFAULT_HOURS));
+    }
+
+    @Test
+    void oneHourMatchesThePreviousHardcodedInterval() {
+        assertEquals(72_000L, DemandSchedule.periodTicks(1));
+    }
+
+    @Test
+    void fractionalHoursRoundToTheNearestTick() {
+        assertEquals(36_000L, DemandSchedule.periodTicks(0.5));
+        assertEquals(1L, DemandSchedule.periodTicks(1.0 / DemandSchedule.TICKS_PER_HOUR / 10));
+    }
+
+    @Test
+    void missingOrInvalidHoursFallBackToFour() {
+        assertEquals(DemandSchedule.DEFAULT_HOURS, DemandSchedule.normalizeHours(0));
+        assertEquals(DemandSchedule.DEFAULT_HOURS, DemandSchedule.normalizeHours(-2));
+        assertEquals(DemandSchedule.DEFAULT_HOURS, DemandSchedule.normalizeHours(Double.NaN));
+        assertEquals(DemandSchedule.DEFAULT_HOURS, DemandSchedule.normalizeHours(Double.POSITIVE_INFINITY));
+        assertEquals(288_000L, DemandSchedule.periodTicks(0));
+    }
+}