gamebanana: add function for downloading mods

kinda janky with the implementation right now, later i would like to
improve the way files are copied and allow for mods with multiple
downloads attached to the mod. probably split off some of the
functionality later to add installing mods not on gamebanana easier.

gamebanana/download.go

@@ -0,0 +1,143 @@
+package gamebanana
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"io/fs"
+	"net/http"
+	"os"
+	"path"
+	"path/filepath"
+	"strings"
+
+	"github.com/charmbracelet/log"
+	"github.com/gen2brain/go-unarr"
+)
+
+var dlurl string
+
+func DownloadGameBananaMod(id, outdir string) (error) {
+	modData, err := GetGameBananaMod(id)
+	if err != nil {
+		return err
+	}
+
+	// create temporary file to download mod to
+	tmpFolderDownload, err := os.MkdirTemp("", "diva-mod-download-*")
+	log.Info("created temp folder for downloading", "name", tmpFolderDownload)
+	if err != nil {
+		return err
+	}
+
+	// really really jank, but api doesn't really have a better way of doing this
+	for _, x := range modData.FilesAFiles {
+		dlurl = x.SDownloadURL
+		break
+	}
+
+	fileDlPath := path.Join(tmpFolderDownload, "download")
+	fileDl, err := os.Create(fileDlPath)
+	if err != nil {
+		return err
+	}
+  defer fileDl.Close()
+
+	// download mod
+	resp, err := http.Get(dlurl)
+	log.Info("downloading mod", "url", dlurl, "modid", id, "path", fileDl)
+	// TODO: handle error code properly
+	if err != nil || resp.StatusCode != 200 {
+		return err
+	}
+  defer resp.Body.Close()
+
+	// save to temp file
+	_, err = io.Copy(fileDl, resp.Body)
+	if err != nil {
+		return err
+	}
+
+	// extract files to same directory
+	a, err := unarr.NewArchive(fileDlPath)
+	if err != nil {
+		return err
+	}
+
+	_, err = a.Extract(tmpFolderDownload)
+	if err != nil {
+		return err
+	}
+
+	// such jank but ive spent wayyy too long on this
+	var moddir string = ""
+	err = filepath.Walk(tmpFolderDownload, func(filePath string, _ fs.FileInfo, err error) error {
+		if path.Base(filePath) == "config.toml" {
+			moddir = path.Dir(filePath)
+			log.Info("found mod folder", "configloc", filePath)
+		}
+
+		return nil
+	})
+
+	if moddir == "" {
+		errors.New("config.toml not found in mod dir")
+	}
+
+	if err != nil {
+		return err
+	}
+
+	// create a folder put the mod in
+	outpath := path.Join(outdir, fmt.Sprintf("%s@%d", id, modData.Udate))
+	err = os.Mkdir(outpath, 0600)
+	if err != nil {
+		return err
+	}
+
+	err = filepath.Walk(moddir, func(filePath string, fileinfo fs.FileInfo, err error)  error {
+		relativepath := strings.Replace(filePath, moddir, "", 1)
+		newpath := path.Join(outdir, relativepath)
+
+		if relativepath == "" { return nil }
+
+		if fileinfo.IsDir() == true {
+			log.Warn("found directory, creating it!", "path", filePath, "relpath", relativepath, "newpath", newpath)
+			err = os.Mkdir(newpath, 0744)
+			if err != nil { return err }
+			return nil
+		}
+
+		var src *os.File
+		var dst *os.File
+
+		if src, err = os.Open(filePath); err != nil {
+			return err
+		}
+		defer src.Close()
+
+		if dst, err = os.Create(newpath); err != nil {
+			return err
+		}
+		defer dst.Close()
+
+		if _, err = io.Copy(dst, src); err != nil {
+			return err
+		}
+
+		log.Info("copied file!!!", "src", filePath, "dst", newpath, "relativepath", relativepath)
+		return os.Chmod(newpath, 0744)
+
+	})
+
+	if err != nil {
+		return err
+	}
+
+	// TODO: cleanup temp files
+	err = os.RemoveAll(fileDlPath)
+	if err != nil {
+		return err
+	}
+	return nil
+}