Add lowest solid block

src/main/java/ch/njol/skript/expressions/ExprLowestHighestSolidBlock.java

@@ -0,0 +1,123 @@
+/**
+ *   This file is part of Skript.
+ *
+ *  Skript is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  Skript is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with Skript.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright Peter Güttinger, SkriptLang team and contributors
+ */
+package ch.njol.skript.expressions;
+
+import ch.njol.skript.Skript;
+import ch.njol.skript.doc.Description;
+import ch.njol.skript.doc.Examples;
+import ch.njol.skript.doc.Name;
+import ch.njol.skript.doc.Since;
+import ch.njol.skript.expressions.base.SimplePropertyExpression;
+import ch.njol.skript.lang.Expression;
+import ch.njol.skript.lang.ExpressionType;
+import ch.njol.skript.lang.SkriptParser.ParseResult;
+import ch.njol.util.Kleenean;
+import org.bukkit.Location;
+import org.bukkit.World;
+import org.bukkit.block.Block;
+import org.bukkit.block.BlockFace;
+import org.bukkit.generator.WorldInfo;
+import org.eclipse.jdt.annotation.Nullable;
+
+@Name("Lowest/Highest Solid Block")
+@Description({
+	"An expression to obtain the lowest or highest solid (impassable) block at a location.",
+	"Note that the y-coordinate of the location is not taken into account for this expression."
+})
+@Examples({
+	"teleport the player to the block above the highest block at the player",
+	"set the highest solid block at the player's location to the lowest solid block at the player's location"
+})
+@Since("2.2-dev34, INSERT VERSION (lowest solid block, 'non-air' option removed, additional syntax option)")
+public class ExprLowestHighestSolidBlock extends SimplePropertyExpression<Location, Block> {
+
+	private static final boolean HAS_MIN_HEIGHT =
+			Skript.classExists("org.bukkit.generator.WorldInfo") &&
+			Skript.methodExists(WorldInfo.class, "getMinHeight");
+
+	private static final boolean HAS_BLOCK_IS_SOLID = Skript.methodExists(Block.class, "isSolid");
+
+	// Before 1.15, getHighestSolidBlock actually returned the block directly ABOVE the highest solid block
+	private static final boolean RETURNS_FIRST_AIR = !Skript.isRunningMinecraft(1, 15);
+
+	static {
+		Skript.registerExpression(ExprLowestHighestSolidBlock.class, Block.class, ExpressionType.PROPERTY,
+				"[the] (highest|:lowest) [solid] block (at|of) %locations%",
+				"%locations%'[s] (highest|:lowest) [solid] block"
+		);
+	}
+
+	private boolean lowest;
+
+	@Override
+	public boolean init(Expression<?>[] exprs, int matchedPattern, Kleenean isDelayed, ParseResult parseResult) {
+		lowest = parseResult.hasTag("lowest");
+		return super.init(exprs, matchedPattern, isDelayed, parseResult);
+	}
+
+	@Override
+	@Nullable
+	public Block convert(Location location) {
+		World world = location.getWorld();
+		if (world == null) {
+			return null;
+		}
+
+		if (!lowest) {
+			return getHighestBlockAt(world, location);
+		}
+
+		location = location.clone();
+		location.setY(HAS_MIN_HEIGHT ? world.getMinHeight() : 0);
+		Block block = location.getBlock();
+		int maxHeight = world.getMaxHeight();
+		while (block.getY() < maxHeight && !isSolid(block)) { // work our way up
+			block = block.getRelative(BlockFace.UP);
+		}
+		// if this block isn't solid, there are no solid blocks at this location
+		// getHighestBlockAt is apparently NotNull, so let's just mimic that behavior by returning it
+		return isSolid(block) ? block : getHighestBlockAt(world, block.getLocation());
+	}
+
+	private static Block getHighestBlockAt(World world, Location location) {
+		Block block = world.getHighestBlockAt(location);
+		if (RETURNS_FIRST_AIR) {
+			block = block.getRelative(BlockFace.DOWN);
+			if (!isSolid(block)) { // if the one right below isn't solid let's just preserve the behavior
+				block.getRelative(BlockFace.UP);
+			}
+		}
+		return block;
+	}
+
+	private static boolean isSolid(Block block) {
+		return HAS_BLOCK_IS_SOLID ? block.isSolid() : block.getType().isSolid();
+	}
+
+	@Override
+	public Class<? extends Block> getReturnType() {
+		return Block.class;
+	}
+
+	@Override
+	protected String getPropertyName() {
+		return (lowest ? "lowest" : "highest") + " solid block";
+	}
+
+}

src/test/skript/tests/syntaxes/expressions/ExprLowestHighestSolidBlock.sk

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+test "lowest/highest solid block (old height)" when running below minecraft "1.18":
+
+	# highest solid block
+	set block at location(0.5, 255.5, 0.5, "world") to air
+	set block at location(0.5, 254.5, 0.5, "world") to air
+	set block at location(0.5, 253.5, 0.5, "world") to dirt
+	set {_highest} to highest solid block at location(0.5, 64, 0.5, "world")
+	assert type of {_highest} is dirt with "highest block is not dirt (got '%type of {_highest}%')"
+	assert location of {_highest} is location(0.5, 253.5, 0.5, "world") with "highest block is not at 0.5,253.5,0.5 (got '%location of {_highest}%')"
+
+	# lowest solid block
+	set block at location(0.5, 0.5, 0.5, "world") to air
+	set block at location(0.5, 1.5, 0.5, "world") to air
+	set block at location(0.5, 2.5, 0.5, "world") to dirt
+	set {_lowest} to lowest solid block at location(0.5, 64, 0.5, "world")
+	assert type of {_lowest} is dirt with "lowest block is not dirt (got '%type of {_lowest}%')"
+	assert location of {_lowest} is location(0.5, 2.5, 0.5, "world") with "lowest block is not at 0.5,2.5,0.5 (got '%location of {_lowest}%')"
+
+test "lowest/highest solid block (new height)" when running minecraft "1.18":
+
+	# highest solid block
+	set block at location(0.5, 319.5, 0.5, "world") to air
+	set block at location(0.5, 318.5, 0.5, "world") to air
+	set block at location(0.5, 317.5, 0.5, "world") to dirt
+	set {_highest} to highest solid block at location(0.5, 64, 0.5, "world")
+	assert type of {_highest} is dirt with "highest block is not dirt (got '%type of {_highest}%')"
+	assert location of {_highest} is location(0.5, 317.5, 0.5, "world") with "highest block is not at 0.5,317.5,0.5 (got '%location of {_highest}%')"
+
+	# lowest solid block
+	set block at location(0.5, -63.5, 0.5, "world") to air
+	set block at location(0.5, -62.5, 0.5, "world") to air
+	set block at location(0.5, -61.5, 0.5, "world") to dirt
+	set {_lowest} to lowest solid block at location(0.5, 64, 0.5, "world")
+	assert type of {_lowest} is dirt with "lowest block is not dirt (got '%type of {_lowest}%')"
+	assert location of {_lowest} is location(0.5, -61.5, 0.5, "world") with "lowest block is not at 0.5,-61.5,0.5 (got '%location of {_lowest}%')"
+