Add update logic for single mods

curseforge/curseforge.go

@@ -281,8 +281,8 @@ func (u cfUpdater) DoUpdate(mods []*core.Mod, cachedState []interface{}) error {
 			Hash:       strconv.Itoa(modState.fileInfo.Fingerprint),
 		}
 
-		v.Update["curseforge"]["ProjectID"] = modState.ID
-		v.Update["curseforge"]["FileID"] = modState.fileInfo.ID
+		v.Update["curseforge"]["project-id"] = modState.ID
+		v.Update["curseforge"]["file-id"] = modState.fileInfo.ID
 	}
 
 	return nil

main.go

@@ -25,8 +25,7 @@ func init() {
 		Aliases: []string{"upgrade"},
 		Usage:   "Update a mod (or all mods) in the modpack",
 		Action: func(c *cli.Context) error {
-			// TODO: implement
-			return nil
+			return cmdUpdate(core.FlagsFromContext(c), c.Args().Get(0))
 		},
 	}, cli.Command{
 		Name:  "refresh",
@@ -121,3 +120,98 @@ func cmdRefresh(flags core.Flags) error {
 	fmt.Println("Index refreshed!")
 	return nil
 }
+
+func cmdUpdate(flags core.Flags, mod string) error {
+	fmt.Println("Loading modpack...")
+	pack, err := core.LoadPack(flags)
+	if err != nil {
+		return cli.NewExitError(err, 1)
+	}
+	index, err := pack.LoadIndex()
+	if err != nil {
+		return cli.NewExitError(err, 1)
+	}
+	mcVersion, err := pack.GetMCVersion()
+	if err != nil {
+		return cli.NewExitError(err, 1)
+	}
+
+	multiple := false
+	var singleUpdatedName string
+	if len(mod) == 0 || mod == "*" {
+		multiple = true
+		// TODO: implement
+		return cli.NewExitError("Not implemented yet!", 1)
+	} else {
+		modPath, ok := index.FindMod(mod)
+		if !ok {
+			return cli.NewExitError("You don't have this mod installed.", 1)
+		}
+		modData, err := core.LoadMod(modPath)
+		if err != nil {
+			return cli.NewExitError(err, 1)
+		}
+		singleUpdatedName = modData.Name
+		updaterFound := false
+		for k := range modData.Update {
+			updater, ok := core.Updaters[k]
+			if !ok {
+				continue
+			}
+			updaterFound = true
+
+			check, err := updater.CheckUpdate([]core.Mod{modData}, mcVersion)
+			if err != nil {
+				return cli.NewExitError(err, 1)
+			}
+			if len(check) != 1 {
+				return cli.NewExitError("Invalid update check response", 1)
+			}
+
+			if check[0].UpdateAvailable {
+				fmt.Printf("Update available: %s\n", check[0].UpdateString)
+
+				err = updater.DoUpdate([]*core.Mod{&modData}, []interface{}{check[0].CachedState})
+				if err != nil {
+					return cli.NewExitError(err, 1)
+				}
+
+				format, hash, err := modData.Write()
+				if err != nil {
+					return cli.NewExitError(err, 1)
+				}
+				err = index.RefreshFileWithHash(modPath, format, hash, true)
+				if err != nil {
+					return cli.NewExitError(err, 1)
+				}
+			} else {
+				fmt.Printf("\"%s\" is already up to date!\n", modData.Name)
+				return nil
+			}
+
+			break
+		}
+		if !updaterFound {
+			return cli.NewExitError("A supported update system for this mod cannot be found.", 1)
+		}
+	}
+
+	err = index.Write()
+	if err != nil {
+		return cli.NewExitError(err, 1)
+	}
+	err = pack.UpdateIndexHash()
+	if err != nil {
+		return cli.NewExitError(err, 1)
+	}
+	err = pack.Write()
+	if err != nil {
+		return cli.NewExitError(err, 1)
+	}
+	if multiple {
+		fmt.Println("Mods updated!")
+	} else {
+		fmt.Printf("\"%s\" updated!\n", singleUpdatedName)
+	}
+	return nil
+}