Implement pack importing/exporting for downloaded Curseforge packs

Abstract out hash implementations
Implement file saving/downloading

curseforge/export.go

@@ -1,8 +1,15 @@
 package curseforge
 
 import (
+	"archive/zip"
+	"bufio"
 	"fmt"
+	"github.com/spf13/viper"
 	"os"
+	"path/filepath"
+	"strconv"
+
+	"github.com/comp500/packwiz/curseforge/packinterop"
 
 	"github.com/comp500/packwiz/core"
 	"github.com/spf13/cobra"
@@ -12,7 +19,7 @@ import (
 var exportCmd = &cobra.Command{
 	Use:   "export",
 	Short: "Export the current modpack into a .zip for curseforge",
-	// TODO: argument for file name
+	// TODO: arguments for file name, author? projectID?
 	Args: cobra.NoArgs,
 	Run: func(cmd *cobra.Command, args []string) {
 		fmt.Println("Loading modpack...")
@@ -27,6 +34,155 @@ var exportCmd = &cobra.Command{
 			os.Exit(1)
 		}
 
-		_ = index
+		// TODO: should index just expose indexPath itself, through a function?
+		indexPath := filepath.Join(filepath.Dir(viper.GetString("pack-file")), filepath.FromSlash(pack.Index.File))
+
+		// TODO: filter mods for optional/server/etc
+		mods := loadMods(index)
+
+		expFile, err := os.Create("export.zip")
+		if err != nil {
+			fmt.Println(err)
+			os.Exit(1)
+		}
+		defer expFile.Close()
+		exp := zip.NewWriter(expFile)
+		defer exp.Close()
+
+		cfFileRefs := make([]packinterop.AddonFileReference, 0, len(mods))
+		for _, mod := range mods {
+			projectRaw, ok := mod.GetParsedUpdateData("curseforge")
+			// If the mod has curseforge metadata, add it to cfFileRefs
+			// TODO: how to handle files with CF metadata, but with different download path?
+			if ok {
+				p := projectRaw.(cfUpdateData)
+				cfFileRefs = append(cfFileRefs, packinterop.AddonFileReference{ProjectID: p.ProjectID, FileID: p.FileID})
+			} else {
+				// If the mod doesn't have the metadata, save it into the zip
+				path, err := filepath.Rel(filepath.Dir(indexPath), mod.GetDestFilePath())
+				if err != nil {
+					fmt.Printf("Error resolving mod file: %s\n", err.Error())
+					// TODO: exit(1)?
+					continue
+				}
+				modFile, err := exp.Create(filepath.ToSlash(filepath.Join("overrides", path)))
+				if err != nil {
+					fmt.Printf("Error creating mod file: %s\n", err.Error())
+					// TODO: exit(1)?
+					continue
+				}
+				err = mod.DownloadFile(modFile)
+				if err != nil {
+					fmt.Printf("Error downloading mod file: %s\n", err.Error())
+					// TODO: exit(1)?
+					continue
+				}
+			}
+		}
+
+		manifestFile, err := exp.Create("manifest.json")
+		if err != nil {
+			fmt.Println("Error creating manifest: " + err.Error())
+			os.Exit(1)
+		}
+
+		err = packinterop.WriteManifestFromPack(pack, cfFileRefs, manifestFile)
+		if err != nil {
+			fmt.Println("Error creating manifest: " + err.Error())
+			os.Exit(1)
+		}
+
+		err = createModlist(exp, mods)
+		if err != nil {
+			fmt.Println("Error creating mod list: " + err.Error())
+			os.Exit(1)
+		}
+
+		i := 0
+		for _, v := range index.Files {
+			if !v.MetaFile {
+				// Save all non-metadata files into the zip
+				path, err := filepath.Rel(filepath.Dir(indexPath), index.GetFilePath(v))
+				if err != nil {
+					fmt.Printf("Error resolving file: %s\n", err.Error())
+					// TODO: exit(1)?
+					continue
+				}
+				file, err := exp.Create(filepath.ToSlash(filepath.Join("overrides", path)))
+				if err != nil {
+					fmt.Printf("Error creating file: %s\n", err.Error())
+					// TODO: exit(1)?
+					continue
+				}
+				err = index.SaveFile(v, file)
+				if err != nil {
+					fmt.Printf("Error copying file: %s\n", err.Error())
+					// TODO: exit(1)?
+					continue
+				}
+				i++
+			}
+		}
+
+		fmt.Println("Modpack exported to export.zip!")
 	},
 }
+
+func createModlist(zw *zip.Writer, mods []core.Mod) error {
+	modlistFile, err := zw.Create("modlist.html")
+	if err != nil {
+		return err
+	}
+
+	w := bufio.NewWriter(modlistFile)
+
+	_, err = w.WriteString("<ul>\r\n")
+	if err != nil {
+		return err
+	}
+	for _, mod := range mods {
+		projectRaw, ok := mod.GetParsedUpdateData("curseforge")
+		if !ok {
+			// TODO: read homepage URL or something similar?
+			_, err = w.WriteString("<li>" + mod.Name + "</li>\r\n")
+			if err != nil {
+				return err
+			}
+			continue
+		}
+		project := projectRaw.(cfUpdateData)
+		projIDString := strconv.Itoa(project.ProjectID)
+		_, err = w.WriteString("<li><a href=\"https://minecraft.curseforge.com/mc-mods/" + projIDString + "\">" + mod.Name + "</a></li>\r\n")
+		if err != nil {
+			return err
+		}
+	}
+	_, err = w.WriteString("</ul>\r\n")
+	if err != nil {
+		return err
+	}
+	return w.Flush()
+}
+
+func loadMods(index core.Index) []core.Mod {
+	modPaths := index.GetAllMods()
+	mods := make([]core.Mod, len(modPaths))
+	i := 0
+	fmt.Println("Reading mod files...")
+	for _, v := range modPaths {
+		modData, err := core.LoadMod(v)
+		if err != nil {
+			fmt.Printf("Error reading mod file: %s\n", err.Error())
+			// TODO: exit(1)?
+			continue
+		}
+
+		mods[i] = modData
+		i++
+	}
+	return mods[:i]
+}
+
+func init() {
+	curseforgeCmd.AddCommand(exportCmd)
+}