installation and launching of vanilla minecraft working

fclauncher/InstanceManager.go

@@ -7,17 +7,23 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"os/exec"
 	"path/filepath"
 	"runtime"
 	"strconv"
 	"strings"
-	"time"
 )
 
 type Instance struct {
 	InstanceName string
 	ModpackId string
 	ModpackVersion string
+	MinecraftVersion string
+	ForgeVersion string
+	NeoForgeVersion string
+	FabricVersion string
+	QuiltVersion string
+	JavaVersion int
 }
 
 type InstanceManager struct {
@@ -36,7 +42,8 @@ type component struct {
 
 func (i *InstanceManager)SearchInstances() {
 	i.instances = []Instance{}
-	dir := i.app.PrismLauncher.GetInstanceDir()
+	dir, _ := os.UserConfigDir()
+	dir = filepath.Join(dir, "FCLauncher", "instances")
 	if _, err := os.Stat(dir); err != nil {
 		return
 	}
@@ -148,13 +155,59 @@ func (i *InstanceManager)InstallModpack(modpack Modpack, instanceName string){
 }
 
 func (i *InstanceManager)InstallVanilla(version string, instanceName string) {
+	dir, _ := os.UserConfigDir()
+	err := DownloadAssets(version, filepath.Join(dir, "FCLauncher", "assets"), *i.app)
+	if err != nil {
+		fmt.Printf("Unable to download assets: %s\n", err)
+	} else {
+		fmt.Printf("Assets Downloaded")
+	}
+	err = DownloadLibraries(version, filepath.Join(dir, "FCLauncher", "lib"), *i.app)
+	if err != nil {
+		fmt.Printf("Unable to download libs: %s\n", err)
+	} else {
+		fmt.Printf("Libs Downloaded")
+	}
+	InstallNatives(version, filepath.Join(dir, "FCLauncher", "instances", instanceName, "minecraft", "natives"))
+	err = DownloadExecutable(version, filepath.Join(dir, "FCLauncher", "bin"), *i.app)
+	if err != nil {
+		fmt.Printf("Unable to download binaries: %s\n", err)
+	} else {
+		fmt.Printf("Binaries Downloaded")
+	}
 	metadata, err := GetVersionMetadata(version)
 	if err != nil {
-		fmt.Printf("Unable to obtain metadata: %s\n", err)
-	} else {
-		fmt.Printf("Version Metadata: %+v", metadata)
+		fmt.Printf("unable to pull metadata: %s\n", err)	
 	}
-	time.Sleep(time.Second * 1)
+
+	err = os.MkdirAll(filepath.Join(dir, "FCLauncher", "instances", instanceName, "minecraft"), 0755)
+	if err != nil {
+		fmt.Printf("unable to create directory: %s\n", err)	
+	}
+
+
+	instance := Instance{InstanceName: instanceName, MinecraftVersion: version, JavaVersion: metadata.JavaVersion.MajorVersion}
+	data, err := json.Marshal(instance)
+	if err != nil {
+		fmt.Printf("unable to marshal json data: %s\n", err)	
+	}
+	f, err := os.OpenFile(filepath.Join(dir, "FCLauncher", "instances", instanceName, "instance.json"), os.O_CREATE|os.O_RDWR, 0755)
+	if err != nil {
+		fmt.Printf("unable to open file: %s\n", err)	
+	}
+
+	defer f.Close()
+	_, err = f.Write(data)
+	if err != nil {
+		fmt.Printf("unable to write data: %s\n", err)	
+	}
+	i.instances = append(i.instances, instance)
+	
+	if !i.app.Java.CheckJavaVer(instance.JavaVersion) {
+		i.app.Status(fmt.Sprintf("Installing Java Version %d", instance.JavaVersion))
+		i.app.Java.InstallJavaVer(instance.JavaVersion)
+	}
+
 	return
 }
 
@@ -163,6 +216,7 @@ func (i *InstanceManager)GetInstances() []Instance{
 }
 
 func (i *InstanceManager)CheckUpdate(instance Instance){
+	return
 	i.app.Status("Checking for Updates")
 	i.app.Modpacks.QuerryModpacks()
 	pack := i.app.Modpacks.GetModpack(instance.ModpackId)
@@ -185,3 +239,37 @@ func (i *InstanceManager)CheckUpdate(instance Instance){
 	i.SearchInstances()
 }
 
+func (i *InstanceManager)LaunchInstance(instance string) {
+	dir, err := os.UserConfigDir()
+	if err != nil {
+		fmt.Printf("unable to get config directory\n")
+	}
+	instanceObject := Instance{}
+	found := false
+	for _, inst := range i.instances {
+		if inst.InstanceName == instance {
+			instanceObject = inst
+			found = true
+			break
+		}
+	}
+	if !found {
+		fmt.Printf("unable to find instance %s\n", instance)
+	}
+	execName := "java"
+	suffix := "lin"
+	if runtime.GOOS == "windows" {
+		execName = "Java.exe"
+		suffix = "win"
+	}
+	dir = filepath.Join(dir, "FCLauncher")
+	args, err := GetOfflineLaunchArgs(instanceObject.MinecraftVersion, filepath.Join(dir, "lib"), filepath.Join(dir, "bin"), filepath.Join(dir, "assets"), filepath.Join(dir, "instances", instance, "minecraft"), "Player")
+	if err != nil {
+		fmt.Printf("unable to get launch args: %s\n", err)
+	}
+	fmt.Printf("Args: %+v", args)
+	child := exec.Command(filepath.Join(dir, "java", fmt.Sprintf("java-%d-%s", instanceObject.JavaVersion, suffix), "bin", execName), args...)
+	data, err := child.CombinedOutput()
+	fmt.Printf("Command Output: %s\n", data)
+}
+

fclauncher/app.go

@@ -7,6 +7,9 @@ import (
 	"github.com/wailsapp/wails/v2/pkg/runtime"
 )
 
+
+const client_id string = "9305aeb8-5ecb-4e7a-b28f-c33aefcfbd8d"
+
 // App struct
 type App struct {
 	Ctx   context.Context

fclauncher/frontend/src/Instances.svelte

@@ -1,7 +1,6 @@
 <script lang="ts">
   import {GetModpacks, GetModpack} from '../wailsjs/go/main/ModpackManager.js'
-	import {InstallVanilla, GetInstances, CheckUpdate} from '../wailsjs/go/main/InstanceManager.js'
-	import {LaunchInstance} from '../wailsjs/go/main/Prism.js'
+	import {InstallVanilla, LaunchInstance, GetInstances, CheckUpdate} from '../wailsjs/go/main/InstanceManager.js'
 	import {GetVersions} from '../wailsjs/go/main/App.js'
 	import {onMount} from 'svelte'
 	import {loading} from './global.ts'
@@ -10,7 +9,7 @@
   let modpacks: string[] = []
 	let pack: string
 	let instances: Instance[] = []
-	let instance: Instance
+	let instance: string
 	let addingInstance: boolean = false
 	let name: string = "New Modpack"
 
@@ -22,7 +21,7 @@
 		})
 		GetInstances().then((result) => {
 			instances = result
-			instance = instances[0]
+			instance = instances[0].InstanceName
 		})
 	}
 
@@ -32,11 +31,9 @@
 
 	function onclick(event) {
 		$loading = true
-		CheckUpdate(instance).then(() => {
-			LaunchInstance(instance).then(() => {
-			  $loading = false
-				window.runtime.Quit()
-			})
+		LaunchInstance(instance).then(() => {
+			$loading = false
+			window.runtime.Quit()
 		})
 	}
 
@@ -59,7 +56,7 @@
 <main>
   <select bind:value={instance} name="pack">Select a Modpack: 
 		{#each instances as instance}
-				<option value={instance}>{instance.InstanceName}</option>
+				<option value={instance.InstanceName}>{instance.InstanceName}</option>
 		{/each}
   </select>
 	<button on:click={onclick}>Launch</button>

fclauncher/frontend/wailsjs/go/main/InstanceManager.d.ts

@@ -10,4 +10,6 @@ export function InstallModpack(arg1:main.Modpack,arg2:string):Promise<void>;
 
 export function InstallVanilla(arg1:string,arg2:string):Promise<void>;
 
+export function LaunchInstance(arg1:string):Promise<void>;
+
 export function SearchInstances():Promise<void>;

fclauncher/frontend/wailsjs/go/main/InstanceManager.js

@@ -18,6 +18,10 @@ export function InstallVanilla(arg1, arg2) {
   return window['go']['main']['InstanceManager']['InstallVanilla'](arg1, arg2);
 }
 
+export function LaunchInstance(arg1) {
+  return window['go']['main']['InstanceManager']['LaunchInstance'](arg1);
+}
+
 export function SearchInstances() {
   return window['go']['main']['InstanceManager']['SearchInstances']();
 }

fclauncher/frontend/wailsjs/go/models.ts

@@ -4,6 +4,12 @@ export namespace main {
 	    InstanceName: string;
 	    ModpackId: string;
 	    ModpackVersion: string;
+	    MinecraftVersion: string;
+	    ForgeVersion: string;
+	    NeoForgeVersion: string;
+	    FabricVersion: string;
+	    QuiltVersion: string;
+	    JavaVersion: number;
 	
 	    static createFrom(source: any = {}) {
 	        return new Instance(source);
@@ -14,6 +20,12 @@ export namespace main {
 	        this.InstanceName = source["InstanceName"];
 	        this.ModpackId = source["ModpackId"];
 	        this.ModpackVersion = source["ModpackVersion"];
+	        this.MinecraftVersion = source["MinecraftVersion"];
+	        this.ForgeVersion = source["ForgeVersion"];
+	        this.NeoForgeVersion = source["NeoForgeVersion"];
+	        this.FabricVersion = source["FabricVersion"];
+	        this.QuiltVersion = source["QuiltVersion"];
+	        this.JavaVersion = source["JavaVersion"];
 	    }
 	}
 	export class Version {

fclauncher/minecraft.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"bytes"
 	"crypto/sha1"
 	"encoding/hex"
 	"encoding/json"
@@ -9,7 +10,12 @@ import (
 	"net/http"
 	"os"
 	"path/filepath"
+	"runtime"
+	"strings"
 	"time"
+
+	wruntime "github.com/wailsapp/wails/v2/pkg/runtime"
+	"github.com/zhyee/zipstream"
 )
 
 type McVersionManifestEntry struct {
@@ -59,6 +65,7 @@ type McLibraryArtifact struct {
 
 type McLibraryDownload struct {
 	Artifact McLibraryArtifact
+	Classifiers map[string]interface{}
 }
 
 type McRuleOs struct {
@@ -77,6 +84,7 @@ type McLibrary struct {
 	Downloads McLibraryDownload
 	Name string
 	Rules []McRule
+	Natives map[string]string
 }
 
 type McDownload struct {
@@ -100,6 +108,7 @@ type McMetadata struct {
 	ReleaseTime time.Time
 	Time time.Time
 	Type string
+	MinecraftArguments string
 }
 
 func GetVersionManifest() (McVersionManifest, error) {
@@ -176,7 +185,6 @@ func GetVersionMetadata(wantedVersion string) (McMetadata, error) {
 							if hex.EncodeToString(sha[:20]) == version.Sha1{
 								metadata := McMetadata{}
 								json.Unmarshal(data, &metadata)
-								fmt.Printf("Found cache!\n")
 								return metadata, nil
 							}
 						}
@@ -214,3 +222,379 @@ func GetVersionMetadata(wantedVersion string) (McMetadata, error) {
 	}
 	return McMetadata{}, fmt.Errorf("Unable to find version %s\n", wantedVersion)
 }
+
+func GetAssetIndex(mcVersion string) ([]string, error) {
+	found := false
+	var data []byte
+	metadata, err := GetVersionMetadata(mcVersion)
+	if err != nil {
+		return []string{}, fmt.Errorf("Unable to pull manifest: %e\n", err)
+	}
+	dir, _ := os.UserConfigDir()
+	path := filepath.Join(dir, "FCLauncher", "assets", "indexes")
+	if _, err := os.Stat(filepath.Join(path, metadata.Assets+".json")); err == nil {
+		//cache file exists
+		if f, err := os.OpenFile(filepath.Join(path, metadata.Assets+".json"), os.O_RDONLY, 0755); err == nil {
+			defer f.Close()
+			if data, err = io.ReadAll(f); err == nil {
+				sha := sha1.Sum(data)
+				if hex.EncodeToString(sha[:20]) == metadata.AssetIndex.Sha1 {
+					found = true
+				}
+			}
+		}
+	}
+	if !found {
+		//no cache file
+		data = []byte{}
+		resp, err := http.Get(metadata.AssetIndex.Url)
+		if err != nil {
+			return []string{}, fmt.Errorf("Unable to pull asset index: %e\n", err)
+		}
+		defer resp.Body.Close()
+		data, err = io.ReadAll(resp.Body)
+		if err != nil {
+			return []string{}, fmt.Errorf("Unable to pull asset index: %e\n", err)
+		}
+		sha := sha1.Sum(data)
+		if hex.EncodeToString(sha[:20]) != metadata.AssetIndex.Sha1 {
+			return []string{}, fmt.Errorf("Sha mismatch!\n")
+		}
+		os.MkdirAll(path, 0755)
+		f, _ := os.OpenFile(filepath.Join(path, metadata.Assets+".json"), os.O_CREATE|os.O_RDWR, 0755)
+		defer f.Close()
+		f.Write(data)
+	}
+
+	//at this point data is populated
+	var index map[string]interface{}
+	json.Unmarshal(data, &index)
+	index = index["objects"].(map[string]interface{})
+	hashes := []string{}
+	for _, val := range index {
+		index_map := val.(map[string]interface{})
+		hashes = append(hashes, index_map["hash"].(string))
+	}
+	return hashes, nil
+}
+
+func DownloadAssets(mcVersion string, assetPath string, a App) error {
+	a.Status("Downloading Minecraft Assets")
+	assets, err := GetAssetIndex(mcVersion)
+	if err != nil {
+		return fmt.Errorf("Unable to get asset index: %e\n", err)
+	}
+	metadata, err := GetVersionMetadata(mcVersion)
+	if err != nil {
+		return fmt.Errorf("Unable to get version metadata: %e\n", err)
+	}
+	total := metadata.AssetIndex.TotalSize
+	downloaded := 0
+	wruntime.EventsEmit(a.Ctx, "download", downloaded, total)
+	for _, hash := range assets {
+		if _, err := os.Stat(filepath.Join(assetPath, "objects", hash[:2], hash)); err == nil {
+			f, _ := os.OpenFile(filepath.Join(assetPath, "objects", hash[:2], hash), os.O_RDONLY, 0755)
+			defer f.Close()
+			data, _ := io.ReadAll(f)
+			sha := sha1.Sum(data)
+			if hex.EncodeToString(sha[:20]) == hash {
+				downloaded += len(data)
+				wruntime.EventsEmit(a.Ctx, "download", downloaded, total)
+				continue
+			}
+		}
+		resp, err := http.Get(fmt.Sprintf("https://resources.download.minecraft.net/%s/%s", hash[:2], hash))
+		if err != nil {
+			return fmt.Errorf("unable to download assets: %e\n", err)
+		}
+		defer resp.Body.Close()
+		buff := new(bytes.Buffer)
+		for {
+			count, err := io.CopyN(buff, resp.Body, BlockSize)
+			if err == io.EOF {
+				downloaded += int(count)
+				break
+			}
+			if err != nil {
+				return fmt.Errorf("Error Downloading assets: %e\n", err)
+			}
+			downloaded += int(count)
+			wruntime.EventsEmit(a.Ctx, "download", downloaded, total)
+		}
+		data := buff.Bytes()
+		sha := sha1.Sum(data)
+		if hex.EncodeToString(sha[:20]) != hash {
+			return fmt.Errorf("unable to download assets: Sha1 Mismatch\n")
+		}
+		err = os.MkdirAll(filepath.Join(assetPath, "objects", hash[:2]), 0755)
+		if err != nil {
+			return fmt.Errorf("unable to download assets: Unable to create directory\n")
+		}
+		f, err := os.OpenFile(filepath.Join(assetPath, "objects", hash[:2], hash), os.O_CREATE|os.O_RDWR, 0755)
+		if err != nil {
+			return fmt.Errorf("unable to download assets: Unable to open file\n")
+		}
+		defer f.Close()
+		f.Write(data)
+		wruntime.EventsEmit(a.Ctx, "download", downloaded, total)
+	}
+	wruntime.EventsEmit(a.Ctx, "download_complete")
+	return nil
+}
+
+func DownloadLibraries(mcVersion string, libPath string, a App) error {
+	metadata, err := GetVersionMetadata(mcVersion)
+	if err != nil {
+		return fmt.Errorf("unable to pull version metadata: %e\n", err)
+	}
+	for _, lib := range metadata.Libraries {
+		a.Status(fmt.Sprintf("Checking %s\n", lib.Name))
+		if _, err := os.Stat(filepath.Join(libPath, lib.Downloads.Artifact.Path)); err == nil {
+			f, _ := os.OpenFile(filepath.Join(libPath, lib.Downloads.Artifact.Path), os.O_CREATE|os.O_RDWR, 0755)
+			defer f.Close()
+			data, _ := io.ReadAll(f)
+			sha := sha1.Sum(data)
+			if hex.EncodeToString(sha[:20]) == lib.Downloads.Artifact.Sha1 {
+				continue
+			}
+		}
+
+		a.Status(fmt.Sprintf("Downloading %s\n", lib.Name))
+		resp, err := http.Get(lib.Downloads.Artifact.Url)
+		if err != nil {
+			return fmt.Errorf("unable to download libs: %e\n", err)
+		}
+		defer resp.Body.Close()
+		buff := new(bytes.Buffer)
+		downloaded := 0
+		for {
+			count, err := io.CopyN(buff, resp.Body, BlockSize)
+			if err == io.EOF {
+				downloaded += int(count)
+				break
+			}
+			if err != nil {
+				return fmt.Errorf("Error Downloading libs: %e\n", err)
+			}
+			downloaded += int(count)
+			wruntime.EventsEmit(a.Ctx, "download", downloaded, resp.ContentLength)
+		}
+		data := buff.Bytes()
+		sha := sha1.Sum(data)
+		if hex.EncodeToString(sha[:20]) != lib.Downloads.Artifact.Sha1 {
+			return fmt.Errorf("unable to download libs: Sha1 Mismatch\n")
+		}
+		path := ""
+		tokens := strings.Split(lib.Downloads.Artifact.Path, "/")
+		for ind, token := range tokens {
+			if ind != len(tokens)-1 {
+				path = filepath.Join(path, token)
+			}	
+		}
+		err = os.MkdirAll(filepath.Join(libPath, path), 0755)
+		if err != nil {
+			return fmt.Errorf("unable to download libs: Unable to create directory\n")
+		}
+		f, err := os.OpenFile(filepath.Join(libPath, lib.Downloads.Artifact.Path), os.O_CREATE|os.O_RDWR, 0755)
+		if err != nil {
+			return fmt.Errorf("unable to download libs: Unable to open file\n")
+		}
+		defer f.Close()
+		f.Write(data)
+		wruntime.EventsEmit(a.Ctx, "download_complete")
+	}
+	return nil
+}
+
+func InstallNatives(mcVersion string, nativesDir string){
+	metadata, _ := GetVersionMetadata(mcVersion)
+	for _, lib := range metadata.Libraries {
+		if lib.Natives != nil {
+			glob := lib.Natives[runtime.GOOS]
+			fmt.Printf("glob is: %s\n", glob)
+			if lib.Downloads.Classifiers[glob] != nil {
+				artifact := lib.Downloads.Classifiers[glob].(map[string]interface{})
+				resp, _ := http.Get(artifact["url"].(string))
+				defer resp.Body.Close()
+				zr := zipstream.NewReader(resp.Body)
+				for {
+					e, err := zr.GetNextEntry()
+					if err == io.EOF {
+						break
+					}
+					if e.IsDir() {
+						os.MkdirAll(filepath.Join(nativesDir, e.Name), 0755)
+					} else {
+						zc, _ := e.Open()
+						f, _ := os.OpenFile(filepath.Join(nativesDir, e.Name), os.O_CREATE|os.O_RDWR, 0755)
+						defer zc.Close()
+						defer f.Close()
+						io.Copy(f, zc)
+					}
+				}
+			}
+		}
+	}
+}
+
+func DownloadExecutable(mcVersion string, binDir string, a App) error {
+	metadata, err := GetVersionMetadata(mcVersion)
+	if err != nil {
+		return fmt.Errorf("unable to pull version metadata: %e\n", err)
+	}
+	a.Status(fmt.Sprintf("Checking Minecraft %s Executable\n", mcVersion))
+	if _, err := os.Stat(filepath.Join(binDir, mcVersion, "client.jar")); err == nil {
+		f, _ := os.OpenFile(filepath.Join(binDir, mcVersion, "client.jar"), os.O_CREATE|os.O_RDWR, 0755)
+		defer f.Close()
+		data, _ := io.ReadAll(f)
+		sha := sha1.Sum(data)
+		if hex.EncodeToString(sha[:20]) == metadata.Downloads["client"].Sha1 {
+			return nil
+		}
+	}
+
+	a.Status(fmt.Sprintf("Downloading Minecraft %s Executable\n", mcVersion))
+	resp, err := http.Get(metadata.Downloads["client"].Url)
+	if err != nil {
+		return fmt.Errorf("unable to download executable: %e\n", err)
+	}
+	defer resp.Body.Close()
+	buff := new(bytes.Buffer)
+	downloaded := 0
+	for {
+		count, err := io.CopyN(buff, resp.Body, BlockSize)
+		if err == io.EOF {
+			downloaded += int(count)
+			break
+		}
+		if err != nil {
+			return fmt.Errorf("Error Downloading executable: %e\n", err)
+		}
+		downloaded += int(count)
+		wruntime.EventsEmit(a.Ctx, "download", downloaded, resp.ContentLength)
+	}
+	data := buff.Bytes()
+	sha := sha1.Sum(data)
+	if hex.EncodeToString(sha[:20]) != metadata.Downloads["client"].Sha1 {
+		return fmt.Errorf("unable to download executable: Sha1 Mismatch\n")
+	}
+	err = os.MkdirAll(filepath.Join(binDir, mcVersion), 0755)
+	if err != nil {
+		return fmt.Errorf("unable to download executable: Unable to create directory\n")
+	}
+	f, err := os.OpenFile(filepath.Join(binDir, mcVersion, "client.jar"), os.O_CREATE|os.O_RDWR, 0755)
+	if err != nil {
+		return fmt.Errorf("unable to download executable: Unable to open file\n")
+	}
+	defer f.Close()
+	f.Write(data)
+	wruntime.EventsEmit(a.Ctx, "download_complete")
+	return nil
+
+}
+
+func GetBaseLaunchArgs(mcVersion string, libDir string, binDir string, assetDir string, gameDir string) ([]string, error) {
+	args := []string{}
+	metadata, err := GetVersionMetadata(mcVersion)
+	if err != nil {
+		return args, fmt.Errorf("GetLaunchArgs: %e\n", err)
+	}
+
+	searchArgs := []string{}
+
+	if metadata.MinecraftArguments != "" {
+		searchArgs = strings.Split(metadata.MinecraftArguments, " ")
+	} else {
+		searchArgs = metadata.Arguments.Game
+	}
+
+	args = append(args, "-Djava.library.path="+filepath.Join(gameDir, "natives"))
+	args = append(args, "-Djna.tmpdir="+filepath.Join(gameDir, "natives"))
+	args = append(args, "-Dorg.lwjgl.system.SharedLibraryExtractpath="+filepath.Join(gameDir, "natives"))
+	args = append(args, "-Dio.netty.native.workdir="+filepath.Join(gameDir, "natives"))
+	args = append(args, "-Xms512m")
+	args = append(args, "-Xmx1024m")
+	args = append(args, "-cp")
+	arg := ""
+	for _, lib := range metadata.Libraries {
+		arg += filepath.Join(libDir, lib.Downloads.Artifact.Path) + ":"
+	}
+	arg += filepath.Join(binDir, mcVersion, "client.jar")
+	args = append(args, arg)
+
+
+
+	args = append(args, metadata.MainClass)
+
+	for _, val := range searchArgs {
+		switch val {
+		case "${version_name}":
+			args = append(args, mcVersion)
+		case "${game_directory}":
+			args = append(args, gameDir)
+		case "${assets_root}":
+			args = append(args, assetDir)
+		case "${clientid}":
+			args = append(args, client_id)
+		case "${version_type}":
+			args = append(args, metadata.Type)
+		case "${user_type}":
+			args = append(args, "mojang")
+		case "${assets_index_name}":
+			args = append(args, metadata.Assets)
+		case "${user_properties}":
+			args = append(args, "null")
+		default:
+			args = append(args, val)
+		}
+	}
+
+	return args, nil
+}
+
+
+func GetOfflineLaunchArgs(mcVersion string, libDir string, binDir string, assetDir string, gameDir string, playerName string) ([]string, error) {
+	args, err := GetBaseLaunchArgs(mcVersion, libDir, binDir, assetDir, gameDir)
+	if err != nil {
+		return []string{}, fmt.Errorf("GatOfflineLaunchArgs: %e\n", err)
+	}
+
+	for ind, val := range args {
+		switch val{
+		case "${auth_player_name}":
+			args[ind] = playerName
+		case "${auth_uuid}":
+			args[ind] = "null"
+		case "${auth_access_token}":
+			args[ind] = "null"
+		case "${auth_xuid}":
+			args[ind] = "null"
+		default:
+		}
+	}
+
+	return args, nil
+}
+
+func GetOnlineLaunchArgs(mcVersion string, libDir string, binDir string, assetDir string, gameDir string, playerName string) ([]string, error) {
+	args, err := GetBaseLaunchArgs(mcVersion, libDir, binDir, assetDir, gameDir)
+	if err != nil {
+		return []string{}, fmt.Errorf("GatOfflineLaunchArgs: %e\n", err)
+	}
+
+	for ind, val := range args {
+		switch val{
+		case "${auth_player_name}":
+			args[ind] = val
+		case "${auth_uuid}":
+			args[ind] = val
+		case "${auth_access_token}":
+			args[ind] = val
+		case "${auth_xuid}":
+			args[ind] = val
+		default:
+		}
+	}
+
+	return args, nil
+}