Respackopts/src/main/java/io/gitlab/jfronny/respackopts/filters/FileFilterEventImpl.java

package io.gitlab.jfronny.respackopts.filters;

import io.gitlab.jfronny.libjf.ResourcePath;
import io.gitlab.jfronny.libjf.data.manipulation.api.UserResourceEvents;
import io.gitlab.jfronny.respackopts.Respackopts;
import io.gitlab.jfronny.respackopts.util.MetaCache;
import io.gitlab.jfronny.respackopts.model.enums.PackCapability;
import io.gitlab.jfronny.respackopts.filters.util.FileExclusionProvider;
import io.gitlab.jfronny.respackopts.filters.util.FileExpansionProvider;
import io.gitlab.jfronny.respackopts.filters.util.FileFallbackProvider;
import net.minecraft.resource.AbstractFileResourcePack;
import net.minecraft.resource.ResourcePack;
import net.minecraft.util.Identifier;

import java.io.IOException;
import java.io.InputStream;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;

public class FileFilterEventImpl {
    private static final Map<Long, Boolean> containsFileWasFallback = new HashMap<>();
    private static boolean containsFileWasFallback() {
        boolean v = FileFilterEventImpl.containsFileWasFallback.getOrDefault(Thread.currentThread().getId(), false);
        containsFileWasFallback(false);
        return v;
    }

    private static void containsFileWasFallback(boolean value) {
        FileFilterEventImpl.containsFileWasFallback.put(Thread.currentThread().getId(), value);
    }

    public static void init() {
        UserResourceEvents.OPEN.register((type, id, previous, pack) -> {
            if (skip(pack)) return previous.get();
            String name = new ResourcePath(type, id).getName();
            if (pack.contains(type, id)) {
                return containsFileWasFallback()
                        ? FileFallbackProvider.getReplacement(pack, name)
                        : FileExpansionProvider.replace(previous.get(), pack, name);
            }
            else return null;
        });
        UserResourceEvents.FIND_RESOURCE.register((type, namespace, prefix, allowedPathPredicate, previous, pack) -> {
            // Warning: the Identifiers here DON'T CONTAIN THE TYPE!
            // Therefore, it needs to be added when calling a method that generates a ResourcePath!
            Collection<Identifier> prevVals = previous.get();
            if (skip(pack)) return prevVals;
            prevVals.removeIf(s -> {
                String fileName = type.getDirectory() + "/" + s.getNamespace() + "/" + s.getPath();
                return FileExclusionProvider.fileHidden(pack, fileName) && !FileFallbackProvider.fileHasFallback(pack, fileName);
            });
            // Completion of the path is handled separately here
            FileFallbackProvider.addFallbackResources(pack, prevVals, namespace, type);
            return prevVals;
        });
        UserResourceEvents.CONTAINS.register((type, id, previous, pack) -> {
            if (skip(pack)) return previous.get();
            containsFileWasFallback(false);
            return containsHook(previous.get(), pack, new ResourcePath(type, id).getName());
        });
        UserResourceEvents.OPEN_ROOT.register((fileName, previous, pack) -> {
            if (skip(pack)) return previous.get();
            InputStream is = previous.get();
            if (containsHook(is != null, pack, fileName)) {
                return containsFileWasFallback()
                        ? FileFallbackProvider.getReplacement(pack, fileName)
                        : FileExpansionProvider.replace(previous.get(), pack, fileName);
            }
            else return null;
        });
    }

    private static boolean containsHook(boolean previous, ResourcePack pack, String name) {
        if (previous) {
            if (FileExclusionProvider.fileHidden(pack, name)) {
                if (FileFallbackProvider.fileHasFallback(pack, name)) {
                    containsFileWasFallback(true);
                } else {
                    return false;
                }
            }
            return true;
        }
        else {
            boolean hasRpo;
            try {
                hasRpo = UserResourceEvents.disable(() -> {
                    if (name.contains("/")) {
                        ResourcePath rp = new ResourcePath(name + Respackopts.FILE_EXTENSION);
                        return pack.contains(rp.getType(), rp.getId());
                    }
                    return pack.openRoot(name + Respackopts.FILE_EXTENSION) != null;
                });
            } catch (IOException e) {
                hasRpo = false;
            }
            if (hasRpo && FileFallbackProvider.fileHasFallback(pack, name)) {
                containsFileWasFallback(true);
                return true;
            }
            return false;
        }
    }

    private static boolean skip(ResourcePack pack) {
        return !(pack instanceof AbstractFileResourcePack) || !MetaCache.hasCapability(pack, PackCapability.FileFilter);
    }
}