minify.go

package main

import (
	"bytes"
	"crypto/md5"
	"encoding/hex"
	"fmt"
	"log"
	"os"
	"path"
	"path/filepath"
	"sort"
	"strings"

	"github.com/tdewolff/minify/v2"
	"github.com/tdewolff/minify/v2/css"
	"github.com/tdewolff/minify/v2/js"
)

func cssMinifier(inputDir, outputFile string, hash bool) {
	err := removeOutputFile(outputFile)
	if err != nil {
		log.Panicln("removeOutputFileError", err)
	}

	files, err := getInputFiles(inputDir)
	if err != nil {
		log.Panicln("getInputFilesError", err)
	}

	notMinifiedString, err := combineFiles(files, inputDir)
	if err != nil {
		log.Panicln("combineFilesError", err)
	}

	minifiedString, err := makeMini(notMinifiedString, "text/css")
	if err != nil {
		log.Panicln("doTheMinifyingError", err)
	}

	if hash && filepath.Ext(outputFile) == ".css" {
		m5 := md5.New()
		_, err := m5.Write([]byte(minifiedString))
		if err != nil {
			log.Panicln("combineFilesError", err)
		}
		m5res := hex.EncodeToString(m5.Sum(nil))
		outputFile = strings.ReplaceAll(outputFile, ".css", "."+m5res[len(m5res)-10:]+".css")
	}

	err = writeOutputFile(minifiedString, outputFile)
	if err != nil {
		log.Panicln("writeOutputFileError", err)
	}
}

func jsMinifier(inputDir, outputFile string, hash bool) {
	err := removeOutputFile(outputFile)
	if err != nil {
		log.Panicln("removeOutputFileError", err)
	}

	files, err := getInputFiles(inputDir)
	if err != nil {
		log.Panicln("getInputFilesError", err)
	}

	var b bytes.Buffer

	for _, name := range files {

		if path.Ext(name) != ".js" {
			continue
		}

		filePath := inputDir + name
		fileTxt, err := os.ReadFile(filePath)
		if err != nil {
			checkError(err)
		}

		fmt.Println("file path", filePath)

		_, err = b.Write(append(fileTxt, []byte("\n")...))
		if err != nil {
			checkError(err)
		}
	}

	if hash && filepath.Ext(outputFile) == ".js" {
		m5 := md5.New()
		_, err := m5.Write(b.Bytes())
		if err != nil {
			checkError(err)
		}
		m5res := hex.EncodeToString(m5.Sum(nil))
		outputFile = strings.ReplaceAll(outputFile, ".js", "."+m5res[len(m5res)-10:]+".js")
	}

	err = writeOutputFile(b.String(), outputFile)
	if err != nil {
		checkError(err)
	}
}

func removeOutputFile(outputFile string) error {
	if _, err := os.Stat(outputFile); err == nil {

		if err := os.Remove(outputFile); err != nil {
			return err
		}

		return nil
	}

	return nil
}

func getInputFiles(inputDir string) ([]string, error) {
	filenames := make([]string, 0, 1)

	files, err := os.ReadDir(inputDir)
	if err != nil {
		log.Panicln("readInputDirError", err)
		return filenames, err
	}

	for _, f := range files {
		if f.IsDir() {
			continue
		}

		filenames = append(filenames, f.Name())
	}

	sort.Strings(filenames)

	return filenames, nil
}

func combineFiles(filenames []string, inputDir string) (string, error) {
	var b bytes.Buffer

	for _, name := range filenames {

		if path.Ext(name) != ".css" {
			continue
		}

		filePath := inputDir + name
		fileTxt, err := os.ReadFile(filePath)
		if err != nil {
			return "", err
		}

		fmt.Println("file path", filePath)

		_, err = b.Write(fileTxt)
		if err != nil {
			return "", nil
		}
	}

	combinedFiles := b.String()

	return combinedFiles, nil
}

func makeMini(notMinifiedString, fileType string) (string, error) {
	m := minify.New()
	m.AddFunc("text/css", css.Minify)
	m.AddFunc("text/javascript", js.Minify)

	minifiedString, err := m.String(fileType, notMinifiedString)
	if err != nil {
		return "", err
	}

	return minifiedString, nil
}

func writeOutputFile(outputText, outputFile string) error {
	err := os.WriteFile(outputFile, []byte(outputText), 0644)
	if err != nil {
		return err
	}

	return nil
}