Python script to launch Minecraft on linux from terminal

minecraft.py

import os
import json
import subprocess

DIRNAME = os.path.join(os.path.dirname(__file__), ".minecraft")
LIBRARIES = os.path.join(DIRNAME, "libraries")
VERSIONS = os.path.join(DIRNAME, "versions")
VERSION = "1.12.2"


def get_os_name() -> str:
    match os.name:
        case "nt":
            return "windows"
        case "posix":
            return "linux"
        case _:
            return "osx"


def splitlib(libname: str) -> list[str]:
    tokens = libname.split(":")
    if len(tokens) == 0:
        return []

    if "." in tokens[0]:
        return tokens[0].split(".") + tokens[1:]

    return tokens


def get_lib_path(tokens: list[str], native_prefix: str = None) -> str:
    return "%s/%s%s.jar" % (
        "/".join(tokens),
        "-".join(tokens[-2:]),
        (f"-{native_prefix}" if native_prefix else ""),
    )


#
def get_libs(filepath: str, os_name: str) -> list[str]:
    libs = []

    with open(filepath) as file:
        schema = json.load(file)

    for lib in schema["libraries"]:
        libname = lib["name"]
        native_prefix = (
            lib["natives"][os_name]
            if "natives" in lib and os_name in lib["natives"]
            else ""
        )

        libpath = os.path.join(
            LIBRARIES, get_lib_path(splitlib(libname), native_prefix=native_prefix)
        )
        libs.append(libpath)

    return libs


def main():
    os_name = get_os_name()

    libs = []

    libs.extend(
        get_libs(os.path.join(VERSIONS, f"{VERSION}/{VERSION}.json"), os_name=os_name)
    )

    # Extra from 1.12.2-forge1.12.2-14.23.5.2838
    libs.extend(
        get_libs(
            os.path.join(
                VERSIONS,
                "1.12.2-forge1.12.2-14.23.5.2838/1.12.2-forge1.12.2-14.23.5.2838.json",
            ),
            os_name=os_name,
        )
    )

    libs.append(os.path.join(VERSIONS, VERSION, f"{VERSION}.jar"))

    args = [
        "java",
        "-Xmx512M",
        "-Xmx1G",
        f"-Djava.library.path={DIRNAME}/versions/{VERSION}/natives",
        "-cp",
        ":".join(libs),
        f"-Dminecraft.applet.TargetDirectory={DIRNAME}",
        "-XX:+UseConcMarkSweepGC",
        "-Dfml.ignoreInvalidMinecraftCertificates=true",
        "-Dfml.ignorePatchDiscrepancies=true",
        "net.minecraft.launchwrapper.Launch",
        "--username",
        "tinytengu",
        "--version",
        "1.12.2",
        "--gameDir",
        DIRNAME,
        "--assetsDir",
        f"{DIRNAME}/assets",
        "--assetIndex",
        "1.12",
        "--uuid",
        "17d6b4af8-481a-11ed-ad98-0538d0a6bd5c",
        "--userType",
        "legacy",
        "--accessToken",
        "accessToken",
        "--tweakClass",
        "net.minecraftforge.fml.common.launcher.FMLTweaker",
        "--versionType",
        "Forge",
        "--width",
        "800",
        "--height",
        "600",
    ]
    print(" ".join(args))
    subprocess.run(args)


if __name__ == "__main__":
    main()