main.go

package main

import (
	"fmt"
	"io/ioutil"
	"log"
	"os"
	"path/filepath"
	"regexp"
	"strings"

	flag "github.com/spf13/pflag"

	ref "github.com/idlephysicist/go-latex/reference"
)

var (
	commit, version string

	files      []string
	ext        string
	versionFlg bool
)

func main() {
	// Read file arg
	flag.BoolVar(&versionFlg, "v", false, "Print version and exit")
	flag.StringVarP(&ext, "ext", "e", "go", "File type to process")
	flag.Parse()
	fileArg := flag.Arg(0)

	if versionFlg {
		fmt.Printf("go-latex version: %s\nbuild commit: %s\n", version, commit)
		os.Exit(0)
	}

	// Determine the arg we got i.e. a single .go file or a .
	if fileArg == `.` {
		err := findFiles(fileArg)
		if err != nil {
			log.Println(err)
		}

	} else {

		if fileExists(fileArg) && filepath.Ext(fileArg) == `.` + ext {
			files = append(files, fileArg)

		} else {
			log.Println("Error invalid file name")
			os.Exit(1)
		}
	}

	// Iterate through the files that we've found
	for _, file := range files {
		contents, err := ioutil.ReadFile(file)
		if err != nil {
			log.Println("An Error occured reading %s", err)
			continue
		}

		fmt.Println(`Processing file:`, file)
		updatedText := process(string(contents))

		err = ioutil.WriteFile(file, []byte(updatedText), 0644)
		if err != nil {
			log.Fatalln(err)
		}
	}
}

// process takes the text from the source file, regexes it for LaTeX commands
// 
func process(text string) string {
	regex := regexp.MustCompile(`\\[A-Za-z][a-z]*[a-z]`)
	var unicodedText []string

	for _, line := range strings.Split(text, `\n`) {
		allIndices := regex.FindAllStringIndex(line, -1)

		for _, loc := range allIndices {
			latexCmd := text[loc[0]:loc[1]]
			unicodeString := ref.Chart[latexCmd]

			line = strings.Replace(line, latexCmd, unicodeString, -1)
		}

		unicodedText = append(unicodedText, line)
	}

	return strings.Join(unicodedText, `\n`)
}


func findFiles(root string) error {
	return filepath.Walk(root,
		func(path string, info os.FileInfo, err error) error {
			if err != nil {
					return err
			}

			if filepath.Ext(path) == `.go` {
				fmt.Println(`Found`, path)
				files = append(files, path)
			}
			return nil
	})
}

func fileExists(name string) bool {
	info, err := os.Stat(name)
	if os.IsNotExist(err) {
			return false
	}
	return !info.IsDir()
}