package fileutils

import (
	"crypto/rand"
	"fmt"
	"io"
	"math/big"
	"os"
	"path"
	"path/filepath"

	"github.com/mholt/archiver/v3"
	"github.com/spf13/afero"
)

// MoveFile moves file from src to dst.
// By default the rename filesystem system call is used. If src and dst point to different volumes
// the file copy is used as a fallback
func MoveFile(fs afero.Fs, src, dst string) error {
	if fs.Rename(src, dst) == nil {
		return nil
	}

	if info, err := fs.Stat(src); err == nil && info.IsDir() {
		return CopyFolder(fs, src, dst)
	}

	// fallback
	if err := CopyFile(fs, src, dst); err != nil {
		_ = fs.Remove(dst)
		return err
	}
	if err := fs.RemoveAll(src); err != nil {
		return err
	}
	return nil
}

// CopyFile copies a file from source to dest and returns
// an error if any.
func CopyFile(fs afero.Fs, source, dest string) error {
	// Open the source file.
	src, err := fs.Open(source)
	if err != nil {
		return err
	}
	defer src.Close()

	// Makes the directory needed to create the dst
	// file.
	err = fs.MkdirAll(filepath.Dir(dest), 0666) //nolint:gomnd
	if err != nil {
		return err
	}

	// Create the destination file.
	dst, err := fs.OpenFile(dest, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0775) //nolint:gomnd
	if err != nil {
		return err
	}
	defer dst.Close()

	// Copy the contents of the file.
	_, err = io.Copy(dst, src)
	if err != nil {
		return err
	}

	// Copy the mode
	info, err := fs.Stat(source)
	if err != nil {
		return err
	}
	err = fs.Chmod(dest, info.Mode())
	if err != nil {
		return err
	}

	return nil
}

// CopyFolder copies a folder to destination and returns
// an error if any. If the destination already exists,
// it gets overridden.
func CopyFolder(fs afero.Fs, source, dest string) error {
	tmpDest := ""
	_, err := fs.Stat(dest)
	if err == nil {
		// destination already exists - rename it so that src
		// could be moved to its place
		maxRn := 9999
		rn, errrn := rand.Int(rand.Reader, big.NewInt(int64(maxRn)))
		if errrn != nil {
			return errrn
		}

		tmpDest = fmt.Sprintf("%s.%d", dest, rn.Int64())

		err = fs.Rename(dest, tmpDest)
		if err != nil {
			return err
		}
	} else if !os.IsNotExist(err) {
		// unknown error, return
		return err
	}

	if err = fs.Rename(source, dest); err != nil {
		// if moving fails and we renamed an existing destination
		// in the previous step, then restore its name
		if tmpDest != "" {
			err = fs.Rename(tmpDest, dest)
		}
		return err
	}

	// if moving was successful, delete the renamed dest
	_ = fs.Remove(tmpDest)

	return nil
}

// CommonPrefix returns common directory path of provided files
func CommonPrefix(sep byte, paths ...string) string {
	// Handle special cases.
	switch len(paths) {
	case 0:
		return ""
	case 1:
		return path.Clean(paths[0])
	}

	// Note, we treat string as []byte, not []rune as is often
	// done in Go. (And sep as byte, not rune). This is because
	// most/all supported OS' treat paths as string of non-zero
	// bytes. A filename may be displayed as a sequence of Unicode
	// runes (typically encoded as UTF-8) but paths are
	// not required to be valid UTF-8 or in any normalized form
	// (e.g. "é" (U+00C9) and "é" (U+0065,U+0301) are different
	// file names.
	c := []byte(path.Clean(paths[0]))

	// We add a trailing sep to handle the case where the
	// common prefix directory is included in the path list
	// (e.g. /home/user1, /home/user1/foo, /home/user1/bar).
	// path.Clean will have cleaned off trailing / separators with
	// the exception of the root directory, "/" (in which case we
	// make it "//", but this will get fixed up to "/" bellow).
	c = append(c, sep)

	// Ignore the first path since it's already in c
	for _, v := range paths[1:] {
		// Clean up each path before testing it
		v = path.Clean(v) + string(sep)

		// Find the first non-common byte and truncate c
		if len(v) < len(c) {
			c = c[:len(v)]
		}
		for i := 0; i < len(c); i++ {
			if v[i] != c[i] {
				c = c[:i]
				break
			}
		}
	}

	// Remove trailing non-separator characters and the final separator
	for i := len(c) - 1; i >= 0; i-- {
		if c[i] == sep {
			c = c[:i]
			break
		}
	}

	return string(c)
}

func Decompress(src, dst string, decompressor archiver.Decompressor) error {
	reader, err := os.Open(src)
	if err != nil {
		return err
	}

	dstfd, err := os.OpenFile(dst, os.O_TRUNC|os.O_CREATE|os.O_RDWR, 0644) //nolint:gomnd
	if err != nil {
		return err
	}

	if err := decompressor.Decompress(reader, dstfd); err != nil {
		return err
	}

	return nil
}