Inceptum/src/main/java/io/gitlab/jfronny/inceptum/util/api/FabricMetaApi.java

package io.gitlab.jfronny.inceptum.util.api;

import com.google.gson.reflect.TypeToken;
import io.gitlab.jfronny.inceptum.model.fabric.FabricVersionLoaderInfo;
import io.gitlab.jfronny.inceptum.model.inceptum.InstanceMeta;
import io.gitlab.jfronny.inceptum.model.mojang.Rules;
import io.gitlab.jfronny.inceptum.model.mojang.VersionInfo;
import io.gitlab.jfronny.inceptum.model.mojang.VersionsListInfo;
import io.gitlab.jfronny.inceptum.util.Utils;

import java.io.IOException;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

public class FabricMetaApi {
    private static final Type fabricLoaderVersionListType = new TypeToken<List<FabricVersionLoaderInfo>>() {}.getType();
    private static final String META_URL = "https://meta.fabricmc.net/";

    public static List<FabricVersionLoaderInfo> getLoaderVersions(VersionsListInfo version) {
        try {
            return Utils.downloadObject(META_URL + "v2/versions/loader/" + version.id, fabricLoaderVersionListType);
        } catch (IOException e) {
            throw new RuntimeException("Could not get fabric loader versions", e);
        }
    }

    public static FabricVersionLoaderInfo getLoaderVersion(String gameVersion, String fabricVersion) throws IOException {
        return Utils.downloadObject(META_URL + "v2/versions/loader/" + gameVersion + "/" + fabricVersion, FabricVersionLoaderInfo.WithMeta.class);
    }

    //TODO don't mutate the object to allow cache, then re-enable cache in McApi
    public static void addFabric(VersionInfo version, String fabricVersion, FabricVersionInfoType type) throws IOException {
        FabricVersionLoaderInfo ver = getLoaderVersion(version.id, fabricVersion);
        if (!(ver instanceof FabricVersionLoaderInfo.WithMeta verWithMeta)) throw new IOException("Doesn't hold metadata");
        FabricVersionLoaderInfo.WithMeta.LauncherMeta meta = verWithMeta.launcherMeta;
        if (meta.version != 1) throw new IOException("Unsupported fabric launcherMeta version: " + meta.version);
        version.mainClass = type == FabricVersionInfoType.Server ? meta.mainClass.server : meta.mainClass.client;
        List<VersionInfo.Library> libs = new ArrayList<>(version.libraries);
        for (FabricVersionLoaderInfo.WithMeta.LauncherMeta.Libraries.Library library : meta.libraries.common)
            libs.add(convertLib(library));
        if (type == FabricVersionInfoType.Client || type == FabricVersionInfoType.Both) {
            for (FabricVersionLoaderInfo.WithMeta.LauncherMeta.Libraries.Library library : meta.libraries.client)
                libs.add(convertLib(library));
        }
        if (type == FabricVersionInfoType.Server || type == FabricVersionInfoType.Both) {
            for (FabricVersionLoaderInfo.WithMeta.LauncherMeta.Libraries.Library library : meta.libraries.server)
                libs.add(convertLib(library));
        }
        var floader = new FabricVersionLoaderInfo.WithMeta.LauncherMeta.Libraries.Library();
        floader.name = "net.fabricmc:fabric-loader:" + fabricVersion;
        floader.url = "https://maven.fabricmc.net/";
        libs.add(convertLib(floader));
        floader.name = ver.intermediary.maven;
        libs.add(convertLib(floader));
        version.libraries = List.copyOf(libs);
        version.id = InstanceMeta.floaderPrefix + fabricVersion + "-" + version.id;
    }

    private static VersionInfo.Library convertLib(FabricVersionLoaderInfo.WithMeta.LauncherMeta.Libraries.Library library) {
        VersionInfo.Library res = new VersionInfo.Library();
        res.name = library.name;
        res.rules = new Rules(true);
        res.natives = new HashMap<>();
        res.downloads = new VersionInfo.Library.Downloads();
        res.downloads.classifiers = null;
        res.downloads.artifact = new VersionInfo.Library.Downloads.Artifact();
        String[] lib = library.name.split(":");
        assert lib.length == 3;
        res.downloads.artifact.path = lib[0].replace('.', '/') + '/' + lib[1] + '/' + lib[2] + '/' + lib[1] + '-' + lib[2] + ".jar";
        res.downloads.artifact.size = -1;
        res.downloads.artifact.sha1 = null;
        res.downloads.artifact.url = library.url + res.downloads.artifact.path;
        return res;
    }

    public enum FabricVersionInfoType {
        Client, Server, Both
    }
}