package files

import (
	"errors"
	"fmt"
	"io/fs"
	"os"
	"path/filepath"
	"strings"
	"time"
)

func TreeSize(root string) (int64, error) {
	var total int64
	err := filepath.WalkDir(root, func(_ string, entry fs.DirEntry, walkErr error) error {
		if walkErr != nil {
			return walkErr
		}
		if !entry.Type().IsRegular() {
			return nil
		}
		info, err := entry.Info()
		if err != nil {
			return err
		}
		total += info.Size()
		return nil
	})
	return total, err
}

func UniquePath(candidate string) string {
	if !exists(candidate) {
		return candidate
	}

	directory, name := filepath.Split(candidate)
	extension := filepath.Ext(name)
	base := strings.TrimSuffix(name, extension)
	for index := 1; index < 1000; index++ {
		next := filepath.Join(directory, fmt.Sprintf("%s (%d)%s", base, index, extension))
		if !exists(next) {
			return next
		}
	}
	return filepath.Join(directory, fmt.Sprintf("%s-%d%s", base, time.Now().UnixNano(), extension))
}

func exists(path string) bool {
	_, err := os.Lstat(path)
	return !errors.Is(err, fs.ErrNotExist)
}