package fileUtilities

import (
	"archive/zip"
	"fmt"
	"forever-files/types"
	"io"
	"os"
	"path"
	"strings"
)

func CreateZip(fileName, outDir, baseDir string, partition []types.FileMetadata) error {
	// Create a buffer to write our archive to.
	outFile := path.Join(outDir, fileName+".zip")
	zipFile, err := os.OpenFile(outFile, os.O_CREATE|os.O_WRONLY, 0644)
	if err != nil {
		return fmt.Errorf("error opening/creating zip file: %w", err)
	}

	// Create a new zip archive.
	w := zip.NewWriter(zipFile)

	files := prepFiles(baseDir, partition)

	for _, file := range files {
		zf, err := w.Create(file.Name)
		if err != nil {
			return fmt.Errorf("error creating zip file: %w", err)
		}
		f, err := os.Open(file.Path)
		if err != nil {
			fmt.Println(fmt.Sprintf("error opening file: %v", err))
			fmt.Println(fmt.Sprintf("skipping file: %v", file.Path))
			continue
		}
		if _, err := io.Copy(zf, f); err != nil {
			return fmt.Errorf("error copying file to zip file: %w", err)
		}
		err = f.Close()
		if err != nil {
			return fmt.Errorf("error closing file: %w", err)
		}
	}

	// Make sure to check the error on Close.
	err = w.Close()
	if err != nil {
		return fmt.Errorf("error closing zip file: %w", err)
	}

	err = zipFile.Close()
	if err != nil {
		return fmt.Errorf("error closing zip file: %w", err)
	}

	return nil
}

func prepFiles(baseDir string, partition []types.FileMetadata) []struct {
	Name, Path string
} {
	var files []struct {
		Name, Path string
	}
	for _, file := range partition {
		filePath := path.Join(file.Path, file.Name)

		// from zip.Create documentation:
		// ...The name must be a relative path: it must not start with a
		// drive letter (e.g. C:) or leading slash, and only forward slashes
		// are allowed...
		fileName := strings.Replace(replaceBackslashes(strings.Replace(filePath, baseDir, "", 1)), "/", "", 1)
		files = append(files, struct {
			Name, Path string
		}{
			Name: fileName,
			Path: filePath,
		})
	}
	return files
}

func replaceBackslashes(input string) string {
	return strings.ReplaceAll(input, "\\", "/")
}