package pkg

import (
	"crypto/rand"
	"fmt"
	"os"
	"path/filepath"
	"time"
)

type Dir struct {
	Path           string
	PathCurrentDir string
	PathBackupDir  string
}

// NewDir creates a new Dir instance.
func NewDir(dir, nameCurrentDir string) *Dir {
	return &Dir{
		Path:           dir,
		PathCurrentDir: filepath.Join(dir, nameCurrentDir),
		PathBackupDir:  filepath.Join(dir, nameCurrentDir+".bak"),
	}
}

// CreateRandomTmpDir creates a temporary directory in the specified directory with a random name.
// The directory is created with permissions 0750.
// If the directory already exists, an error is returned.
// @return string - path to the temporary directory
// @return error - an error if the directory could not be created
func (d *Dir) CreateRandomTmpDir() (string, error) {
	tmpDir := filepath.Join(d.Path, time.Now().Format(time.RFC3339)+"_"+rand.Text()+".tmp")
	if _, err := os.Stat(tmpDir); err == nil {
		return "", fmt.Errorf("directory already exists: %s", tmpDir)
	}
	if err := os.MkdirAll(tmpDir, 0750); err != nil {
		return "", err
	}
	return tmpDir, nil
}

// ReplaceDirToCurrent replaces the current directory with a new directory.
// If the new directory already exists, it is renamed to a backup directory.
// If the backup directory already exists, it is removed.
// @return error - an error if the directory could not be replaced
func (d *Dir) ReplaceDirToCurrent(newDir string) error {
	if err := os.RemoveAll(d.PathBackupDir); err != nil {
		return err
	}

	if _, err := os.Stat(d.PathCurrentDir); err == nil {
		if err := os.Rename(d.PathCurrentDir, d.PathBackupDir); err != nil {
			return err
		}
	}

	if err := os.Rename(newDir, d.PathCurrentDir); err != nil {
		if _, statErr := os.Stat(d.PathBackupDir); statErr == nil {
			_ = os.Rename(d.PathBackupDir, d.PathCurrentDir)
		}
		return err
	}

	if err := os.RemoveAll(d.PathBackupDir); err != nil {
		return err
	}

	return nil
}

// MovingFiles moves all files from dirFrom to dirTo.
// If dirTo does not exist, it is created.
// @param dirFrom - path to the directory containing the files to move
// @param dirTo - path to the directory where the files will be moved
// @return error - an error if the files could not be moved
func MovingFiles(dirFrom, dirTo string) error {
	if _, err := os.Stat(dirTo); err != nil {
		if err := os.MkdirAll(dirTo, 0750); err != nil {
			return err
		}
	}

	entries, err := os.ReadDir(dirFrom)
	if err != nil {
		return err
	}

	for _, entry := range entries {
		if entry.IsDir() {
			if err := MovingFiles(filepath.Join(dirFrom, entry.Name()), dirTo); err != nil {
				return err
			}
			continue
		}
		src := filepath.Join(dirFrom, entry.Name())
		dst := filepath.Join(dirTo, entry.Name())
		if err := os.Rename(src, dst); err != nil {
			return err
		}
	}

	return nil
}

// FindMMDBFile finds the .mmdb file in the specified directory.
// @param dir - path to the directory to search
// @return string - path to the .mmdb file
// @return error - an error if the .mmdb file could not be found
func FindMMDBFile(dir string) (string, error) {
	entries, err := os.ReadDir(dir)
	if err != nil {
		return "", err
	}
	for _, entry := range entries {
		if entry.IsDir() {
			continue
		}
		if filepath.Ext(entry.Name()) == ".mmdb" {
			return filepath.Join(dir, entry.Name()), nil
		}
	}

	return "", fmt.Errorf("no .mmdb file found in %s", dir)
}