package storage

import (
	"crypto/sha256"
	"encoding/hex"
	"fmt"
	"io"
	"os"
	"path/filepath"
	"strings"
)

type Storage struct {
	filesDir string
}

func New(filesDir string) *Storage {
	return &Storage{filesDir: filesDir}
}

func (s *Storage) CopyFile(srcPath string, destFilename string) error {
	src, err := os.Open(srcPath)
	if err != nil {
		return fmt.Errorf("failed to open source file: %w", err)
	}
	defer src.Close()

	destPath := filepath.Join(s.filesDir, destFilename)
	dest, err := os.Create(destPath)
	if err != nil {
		return fmt.Errorf("failed to create destination file: %w", err)
	}
	defer dest.Close()

	if _, err := io.Copy(dest, src); err != nil {
		return fmt.Errorf("failed to copy file: %w", err)
	}

	return nil
}

func (s *Storage) RemoveFile(filename string) error {
	path := filepath.Join(s.filesDir, filename)
	return os.Remove(path)
}

func (s *Storage) CreateSymlink(originalPath, storedFilename string) error {
	storedPath := filepath.Join(s.filesDir, storedFilename)
	return os.Symlink(storedPath, originalPath)
}

func (s *Storage) RemoveSymlink(originalPath string) error {
	info, err := os.Lstat(originalPath)
	if err != nil {
		if os.IsNotExist(err) {
			return nil
		}
		return err
	}

	if info.Mode()&os.ModeSymlink != 0 {
		return os.Remove(originalPath)
	}

	return nil
}

func (s *Storage) FilePath(filename string) string {
	return filepath.Join(s.filesDir, filename)
}

func (s *Storage) FileExists(filename string) bool {
	path := filepath.Join(s.filesDir, filename)
	_, err := os.Stat(path)
	return err == nil
}

func GenerateFilename(originalPath string) string {
	base := filepath.Base(originalPath)
	ext := filepath.Ext(base)
	name := strings.TrimSuffix(base, ext)

	hash := sha256.Sum256([]byte(originalPath))
	shortHash := hex.EncodeToString(hash[:])[:8]

	return fmt.Sprintf("%s_%s%s", name, shortHash, ext)
}

func GetAbsolutePath(path string) (string, error) {
	if filepath.IsAbs(path) {
		return path, nil
	}

	cwd, err := os.Getwd()
	if err != nil {
		return "", err
	}

	return filepath.Join(cwd, path), nil
}