package disk

import (
	"fmt"
	"io"
	"io/fs"
	"net/http"
	"os"
	"path/filepath"
	"runtime"
	"strings"

	"go.jolheiser.com/eget/forge"

	"github.com/mholt/archiver/v3"
)

func Install(name string, asset forge.Asset) error {
	tmp, err := os.MkdirTemp(os.TempDir(), "eget-*")
	if err != nil {
		return err
	}
	defer os.RemoveAll(tmp)

	resp, err := http.Get(asset.DownloadURL)
	if err != nil {
		return err
	}
	defer resp.Body.Close()

	tmpDest := filepath.Join(tmp, asset.Name)
	fi, err := os.Create(tmpDest)
	if err != nil {
		return err
	}

	if _, err := io.Copy(fi, resp.Body); err != nil {
		return err
	}
	if err := fi.Close(); err != nil {
		return err
	}

	if err := unpack(tmpDest, name); err != nil {
		return fmt.Errorf("could not unpack download: %w", err)
	}

	return nil
}

func unpack(src, name string) error {
	dest := Path(name)
	if err := os.MkdirAll(dest, os.ModePerm); err != nil {
		return fmt.Errorf("could not make all dest dirs: %w", err)
	}
	var binExt string
	if runtime.GOOS == "windows" {
		binExt = ".exe"
	}
	uaIface, err := archiver.ByExtension(src)
	if err != nil {
		ext := filepath.Ext(src)
		if ext == binExt || len(ext) > 3 {
			dest = filepath.Join(dest, name+binExt)
			if err := os.Rename(src, dest); err != nil {
				return err
			}
			return os.Chmod(dest, 0o755)
		}
		return err
	}
	u, ok := uaIface.(archiver.Unarchiver)
	if !ok {
		dest = filepath.Join(dest, name+binExt)
		d, ok := uaIface.(archiver.Decompressor)
		if !ok {
			return fmt.Errorf("format specified by source filename is not an archive or compression format: %s (%T)", src, uaIface)
		}
		c := archiver.FileCompressor{Decompressor: d}
		if err := c.DecompressFile(src, dest); err != nil {
			return err
		}
		return os.Chmod(dest, 0o755)
	}

	tmpDest := filepath.Join(filepath.Dir(src), name)
	if err := u.Unarchive(src, tmpDest); err != nil {
		return fmt.Errorf("could not unarchive source: %w", err)
	}

	tmpSrc := tmpDest
	infos, err := os.ReadDir(tmpSrc)
	if err != nil {
		return fmt.Errorf("could not read unarchived dir: %w", err)
	}
	if len(infos) == 1 && infos[0].IsDir() {
		tmpSrc = filepath.Join(tmpDest, infos[0].Name())
	}

	return moveDir(tmpSrc, dest)
}

func moveDir(src, dest string) error {
	return filepath.WalkDir(src, func(walkPath string, walkEntry fs.DirEntry, walkErr error) error {
		if walkErr != nil {
			return walkErr
		}
		if walkEntry.IsDir() {
			return nil
		}

		rel := strings.TrimPrefix(walkPath, src)
		destPath := filepath.Join(dest, rel)
		if err := os.MkdirAll(filepath.Dir(destPath), os.ModePerm); err != nil {
			return err
		}
		return os.Rename(walkPath, destPath)
	})
}

func Path(name string) string {
	home, err := os.UserHomeDir()
	if err != nil {
		home = "."
	}
	return filepath.Join(home, ".eget", name)
}