Blur/src/main/java/com/tterrag/blur/util/ShaderResourcePack.java

package com.tterrag.blur.util;

import java.io.ByteArrayInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;
import java.util.Set;
import java.util.function.Predicate;

import com.google.common.collect.ImmutableSet;
import com.tterrag.blur.Blur;

import net.minecraft.resource.ResourceManager;
import net.minecraft.resource.ResourcePack;
import net.minecraft.resource.ResourceReloadListener;
import net.minecraft.resource.ResourceType;
import net.minecraft.resource.metadata.PackResourceMetadata;
import net.minecraft.resource.metadata.ResourceMetadataReader;
import net.minecraft.text.StringTextComponent;
import net.minecraft.util.Identifier;

public class ShaderResourcePack implements ResourcePack, ResourceReloadListener {
	
	protected boolean validPath(Identifier location) {
		return location.getNamespace().equals("minecraft") && location.getPath().startsWith("shaders/");
	}
	
	private final Map<Identifier, String> loadedData = new HashMap<>();

	@Override
	public InputStream open(ResourceType type, Identifier location) throws IOException {
        if (type == ResourceType.ASSETS && validPath(location)) {
            String s = loadedData.computeIfAbsent(location, loc -> {
                InputStream in = Blur.class.getResourceAsStream("/" + location.getPath());
                StringBuilder data = new StringBuilder();
                Scanner scan = new Scanner(in);
                try {
                    while (scan.hasNextLine()) {
                        data.append(scan.nextLine().replaceAll("@radius@", Integer.toString(Blur.instance.radius))).append('\n');
                    }
                } finally {
                    scan.close();
                }
                return data.toString();
            });

            return new ByteArrayInputStream(s.getBytes());
        }
        throw new FileNotFoundException(location.toString());
	}

	@Override
	public boolean contains(ResourceType type, Identifier location) {
		return type == ResourceType.ASSETS && validPath(location) && Blur.class.getResource("/" + location.getPath()) != null;
	}

	@Override
	public Set<String> getNamespaces(ResourceType type) {
		return ImmutableSet.of("minecraft");
	}

	@SuppressWarnings({ "unchecked", "null" })
    @Override
	public <T> T parseMetadata(ResourceMetadataReader<T> var1) throws IOException {
	    if ("pack".equals(var1.getKey())) {
	        return (T) new PackResourceMetadata(new StringTextComponent("Blur's default shaders"), 4);
	    }
	    return null;
    }

	@Override
	public String getName() {
		return "Blur Shaders";
	}
	
	@Override
	public void onResourceReload(ResourceManager resourceManager) {
	    loadedData.clear();
	}

	@Override
	public void close() throws IOException {}

	@Override
	public InputStream openRoot(String var1) throws IOException {
		return Blur.class.getResourceAsStream("/assets/blur/" + var1);
	}

	@Override
	public Collection<Identifier> findResources(ResourceType var1, String var2, int var3, Predicate<String> var4) {
		return Collections.emptyList();
	}
}