Initial commit: LoParkour v1.1.0

src/main/java/dev/loki/loparkour/world/Divider.java

@@ -0,0 +1,125 @@
+package dev.loki.loparkour.world;
+
+import dev.loki.loparkour.LoParkour;
+import dev.loki.loparkour.config.Option;
+import dev.loki.loparkour.session.Session;
+import dev.efnilite.vilib.util.Locations;
+import org.bukkit.Location;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.stream.IntStream;
+
+/**
+ * <p>Divides the parkour world in sections, each with an active session.</p>
+ * <p>Iteration 2.</p>
+ *
+ * @author loki
+ * @since 5.0.0
+ */
+public class Divider {
+
+    /**
+     * Map with all session ids map to the session instances.
+     */
+    public static final Map<Session, Integer> sections = new HashMap<>();
+
+    /**
+     * Associates a session to a specific section.
+     *
+     * @param session The session.
+     */
+    public static synchronized Location add(Session session) {
+        // attempts to get the closest available section to the center
+        var missing = IntStream.range(0, sections.size() + 1)
+                .filter(i -> !sections.containsValue(i))
+                .findFirst()
+                .orElseThrow();
+
+        sections.put(session, missing);
+
+        var location = toLocation(session);
+
+        LoParkour.log("Added session at %s".formatted(Locations.toString(location, true)));
+
+        return location;
+    }
+
+    /**
+     * Disassociates a session from a specific section.
+     *
+     * @param session The session.
+     */
+    public static void remove(Session session) {
+        LoParkour.log("Removed session at %s".formatted(Locations.toString(toLocation(session), true)));
+
+        sections.remove(session);
+    }
+
+    /**
+     * @param session The session.
+     * @return The location at the center of section n.
+     */
+    private static Location toLocation(Session session) {
+        int[] xz = spiralAt(sections.get(session));
+
+        return new Location(World.getWorld(),
+                xz[0] * Option.BORDER_SIZE,
+                (Option.MAX_Y + Option.MIN_Y) / 2.0,
+                xz[1] * Option.BORDER_SIZE);
+    }
+
+    /**
+     * @param session The session.
+     * @return Array where the first item is the smallest location and second item is the largest.
+     */
+    public static Location[] toSelection(Session session) {
+        Location center = toLocation(session);
+
+        // get the min and max locations
+        Location max = center.clone().add(Option.BORDER_SIZE / 2, 0, Option.BORDER_SIZE / 2);
+        Location min = center.clone().subtract(Option.BORDER_SIZE / 2, 0, Option.BORDER_SIZE / 2);
+
+        max.setY(Option.MAX_Y);
+        min.setY(Option.MIN_Y);
+
+        return new Location[]{min, max};
+    }
+
+    /**
+     * Gets a spiral
+     *
+     * @param n The number of  value
+     * @return the coords of this value
+     */
+    // https://math.stackexchange.com/a/163101
+    private static int[] spiralAt(int n) {
+        if (n < 0) {
+            throw new IllegalArgumentException("Invalid n bound: %d".formatted(n));
+        }
+
+        n++; // one-index
+        int k = (int) Math.ceil((Math.sqrt(n) - 1) / 2);
+        int t = 2 * k + 1;
+        int m = t * t;
+        t--;
+
+        if (n > m - t) {
+            return new int[]{k - (m - n), -k};
+        } else {
+            m -= t;
+        }
+
+        if (n > m - t) {
+            return new int[]{-k, -k + (m - n)};
+        } else {
+            m -= t;
+        }
+
+        if (n > m - t) {
+            return new int[]{-k + (m - n), k};
+        } else {
+            return new int[]{k, k - (m - n - t)};
+        }
+    }
+}