Add migrate command (#207)

* Add base and loader command

* Support updating to latest

* Support explicit fabric versions

* Support explicit Forge version

* Support quilt

* Add support for updating Minecraft

* Add support for Forge recommended

* Fix Forge version sorting

* Various fixes

* Add documentation to the use

* More suggestions

migrate/loader.go

@@ -0,0 +1,154 @@
+package migrate
+
+import (
+	"fmt"
+	"github.com/packwiz/packwiz/cmdshared"
+	"github.com/packwiz/packwiz/core"
+	"github.com/spf13/cobra"
+	"golang.org/x/exp/slices"
+	"os"
+)
+
+var loaderCommand = &cobra.Command{
+	Use:   "loader [version|latest|recommended]",
+	Short: "Migrate your modloader version to a newer version.",
+	Args:  cobra.ExactArgs(1),
+	Run: func(cmd *cobra.Command, args []string) {
+		modpack, err := core.LoadPack()
+		if err != nil {
+			// Check if it's a no such file or directory error
+			if os.IsNotExist(err) {
+				fmt.Println("No pack.toml file found, run 'packwiz init' to create one!")
+				os.Exit(1)
+			}
+			fmt.Printf("Error loading pack: %s\n", err)
+			os.Exit(1)
+		}
+		// Get our current loader, would use the modpack.GetLoaders function
+		// but, it supplements Quilt with Fabric, which isn't needed for this
+		var currentLoaders []string
+		// Add all the keys from modpack.Versions
+		for key := range modpack.Versions {
+			// If it ain't in core.ModLoaders, we don't want it
+			if _, ok := core.ModLoaders[key]; !ok {
+				continue
+			}
+			currentLoaders = append(currentLoaders, key)
+		}
+		// Do some sanity checks on the current loader slice
+		if len(currentLoaders) == 0 {
+			fmt.Println("No loader is currently set in your pack.toml!")
+			os.Exit(1)
+		} else if len(currentLoaders) > 1 {
+			fmt.Println("You have multiple loaders set in your pack.toml, this is not supported!")
+			os.Exit(1)
+		}
+		// Get the Minecraft version for the pack
+		mcVersion, err := modpack.GetMCVersion()
+		if err != nil {
+			fmt.Printf("Error getting Minecraft version: %s\n", err)
+			os.Exit(1)
+		}
+		if args[0] == "latest" {
+			fmt.Println("Updating to latest loader version")
+			// We'll be updating to the latest loader version
+			for _, loader := range currentLoaders {
+				_, latest, gottenLoader := getVersionsForLoader(loader, mcVersion)
+				if !updatePackToVersion(latest, modpack, gottenLoader) {
+					continue
+				}
+				// Write the pack to disk
+				err = modpack.Write()
+				if err != nil {
+					fmt.Printf("Error writing pack.toml: %s\n", err)
+					continue
+				}
+			}
+		} else if args[0] == "recommended" {
+			// TODO: Figure out a way to get the recommended version, this is Forge only
+			// Ensure we're on Forge
+			if !slices.Contains(currentLoaders, "forge") {
+				fmt.Println("The recommended loader version is only available on Forge!")
+				os.Exit(1)
+			}
+			// We'll be updating to the recommended loader version
+			recommendedVer := core.GetForgeRecommended(mcVersion)
+			if recommendedVer == "" {
+				fmt.Println("Error getting recommended Forge version!")
+				os.Exit(1)
+			}
+			if ok := updatePackToVersion(recommendedVer, modpack, core.ModLoaders["forge"]); !ok {
+				os.Exit(1)
+			}
+			// Write the pack to disk
+			err = modpack.Write()
+			if err != nil {
+				fmt.Printf("Error writing pack.toml: %s", err)
+				os.Exit(1)
+			}
+		} else {
+			fmt.Println("Updating to explicit loader version")
+			// This one is easy :D
+			versions, _, loader := getVersionsForLoader(currentLoaders[0], mcVersion)
+			// Check if the loader happens to be Forge, since there's two version formats
+			if loader.Name == "forge" {
+				wantedVersion := cmdshared.GetRawForgeVersion(args[0])
+				validateVersion(versions, wantedVersion, loader)
+				_ = updatePackToVersion(wantedVersion, modpack, loader)
+			} else if loader.Name == "liteloader" {
+				// These are weird and just have a MC version
+				fmt.Println("LiteLoader only has 1 version per Minecraft version so we're unable to update!")
+				os.Exit(0)
+			} else {
+				// We're on Fabric or quilt
+				validateVersion(versions, args[0], loader)
+				if ok := updatePackToVersion(args[0], modpack, loader); !ok {
+					os.Exit(1)
+				}
+			}
+			// Write the pack to disk
+			err = modpack.Write()
+			if err != nil {
+				fmt.Printf("Error writing pack.toml: %s\n", err)
+				os.Exit(1)
+			}
+		}
+	},
+}
+
+func init() {
+	migrateCmd.AddCommand(loaderCommand)
+}
+
+func getVersionsForLoader(loader, mcVersion string) ([]string, string, core.ModLoaderComponent) {
+	gottenLoader, ok := core.ModLoaders[loader]
+	if !ok {
+		fmt.Printf("Unknown loader %s\n", loader)
+		os.Exit(1)
+	}
+	versions, latestVersion, err := gottenLoader.VersionListGetter(mcVersion)
+	if err != nil {
+		fmt.Printf("Error getting version list for %s: %s\n", gottenLoader.FriendlyName, err)
+		os.Exit(1)
+	}
+	return versions, latestVersion, gottenLoader
+}
+
+func validateVersion(versions []string, version string, gottenLoader core.ModLoaderComponent) {
+	if !slices.Contains(versions, version) {
+		fmt.Printf("Version %s is not a valid version for %s\n", version, gottenLoader.FriendlyName)
+		os.Exit(1)
+	}
+}
+
+func updatePackToVersion(version string, modpack core.Pack, loader core.ModLoaderComponent) bool {
+	// Check if the version is already set
+	if version == modpack.Versions[loader.Name] {
+		fmt.Printf("%s is already on version %s!\n", loader.FriendlyName, version)
+		return false
+	}
+	// Set the latest version
+	modpack.Versions[loader.Name] = version
+	fmt.Printf("Updated %s to version %s\n", loader.FriendlyName, version)
+	return true
+}

migrate/migrate.go

@@ -0,0 +1,16 @@
+package migrate
+
+import (
+	"github.com/packwiz/packwiz/cmd"
+	"github.com/spf13/cobra"
+)
+
+// migrateCmd represents the base command when called without any subcommands
+var migrateCmd = &cobra.Command{
+	Use:   "migrate [minecraft|loader]",
+	Short: "Migrate your Minecraft and loader versions to newer versions.",
+}
+
+func init() {
+	cmd.Add(migrateCmd)
+}

migrate/minecraft.go

@@ -0,0 +1,70 @@
+package migrate
+
+import (
+	"fmt"
+	packCmd "github.com/packwiz/packwiz/cmd"
+	"github.com/packwiz/packwiz/cmdshared"
+	"github.com/packwiz/packwiz/core"
+	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
+	"os"
+)
+
+var minecraftCommand = &cobra.Command{
+	Use:     "minecraft [version]",
+	Short:   "Migrate your Minecraft version to a newer version.",
+	Aliases: []string{"mc"},
+	Args:    cobra.ExactArgs(1),
+	Run: func(cmd *cobra.Command, args []string) {
+		modpack, err := core.LoadPack()
+		if err != nil {
+			// Check if it's a no such file or directory error
+			if os.IsNotExist(err) {
+				fmt.Println("No pack.toml file found, run 'packwiz init' to create one!")
+				os.Exit(1)
+			}
+			fmt.Printf("Error loading pack: %s\n", err)
+			os.Exit(1)
+		}
+		currentVersion, err := modpack.GetMCVersion()
+		if err != nil {
+			fmt.Printf("Error getting Minecraft version from pack: %s\n", err)
+			os.Exit(1)
+		}
+		wantedMCVersion := args[0]
+		if wantedMCVersion == currentVersion {
+			fmt.Printf("Minecraft version is already %s!\n", wantedMCVersion)
+			os.Exit(0)
+		}
+		mcVersions, err := cmdshared.GetValidMCVersions()
+		if err != nil {
+			fmt.Printf("Error getting Minecraft versions: %s\n", err)
+			os.Exit(1)
+		}
+		mcVersions.CheckValid(wantedMCVersion)
+		// Set the version in the pack
+		modpack.Versions["minecraft"] = wantedMCVersion
+		// Write the pack to disk
+		err = modpack.Write()
+		if err != nil {
+			fmt.Printf("Error writing pack.toml: %s\n", err)
+			os.Exit(1)
+		}
+		fmt.Printf("Successfully updated Minecraft version to %s\n", wantedMCVersion)
+		// Prompt the user if they want to update the loader too while they're at it.
+		if cmdshared.PromptYesNo("Would you like to update your loader version to the latest version for this Minecraft version? [Y/n] ") {
+			// We'll run the loader command to update to latest
+			loaderCommand.Run(loaderCommand, []string{"latest"})
+		}
+		// Prompt the user to update their mods too.
+		if cmdshared.PromptYesNo("Would you like to update your mods to the latest versions for this Minecraft version? [Y/n] ") {
+			// Run the update command
+			viper.Set("update.all", true)
+			packCmd.UpdateCmd.Run(packCmd.UpdateCmd, []string{})
+		}
+	},
+}
+
+func init() {
+	migrateCmd.AddCommand(minecraftCommand)
+}