main.go

//
// dumber, a command line tool for numbering or denumbering Mardown sections file and accordingly adding or removing Table(s) of Contents
//
//      Copyright (c) 2021-2024 Michel Boucey
//
// Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
//
//      1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
//
//      2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer
//         in the documentation and/or other materials provided with the distribution.
//
//      3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived
//         from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PRO-
// CUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
// WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
// ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//

package main

import (
	"bufio"
	"flag"
	"fmt"
	"io"
	"log"
	"os"
	"path/filepath"
	"regexp"
	"runtime"
	"strconv"
	"strings"
)

var (
	commitShortHash = ""
)

func main() {

	version := "3.0.0"

        var firstH1Done bool = false
	var headerCounters [7]int
	var headerLines []string
	var isToCInsertionLine bool = false
	var mdLines []string
	var mdTmpFile *os.File
	var newLine string
	var pathSep string
	var rewrittenLine string
	var section string
	var upperHeaderLevel int

	switch runtime.GOOS {
	case "windows":
		pathSep = "\\"
		newLine = "\r\n"
	default:
		pathSep = "/"
		newLine = "\n"
	}

	helpFlag := flag.Bool("h", false, "Show help")
	removeFlag := flag.Bool("r", false, "Remove table of contents and section numbers from the .md file")
	versionFlag := flag.Bool("v", false, "Show version")
	writeFlag := flag.Bool("w", false, "Write section numbers to the .md file (default to stdout)")
	noTitleSkipFlag := flag.Bool("a", false, "Numbering all sections from the main document title (H1)")

	flag.Parse()

	if *versionFlag == true {
		fmt.Println("dumber v" + version + " (" + commitShortHash + ")" + newLine + "Copyright © 2021-2024 Michel Boucey" + newLine + "Released under 3-Clause BSD License")
		os.Exit(-1)
	}

	if len(os.Args) == 1 || len(flag.Args()) == 0 && *helpFlag == false {
		fmt.Println("See -h for help")
		os.Exit(-1)
	}

	if *helpFlag {
		fmt.Println("Usage: dumber [OPTION] FILE" + newLine)
		flag.PrintDefaults()
		fmt.Println("")
		os.Exit(-1)
	}

	mdFilePath, err := filepath.Abs(flag.Arg(0))
	if err != nil {
		log.Fatal(err)
	}

	mdFileHandler, err := os.Open(mdFilePath)
	if err != nil {
		log.Fatal(err)
	}

	tocInsertionLine := regexp.MustCompile(`^<!--\s+\bToC\b\s+-->\s*$`)
	tocLine := regexp.MustCompile(`^\s*-\s\[[\d\.]*\]\(#\d*`)
	headerLine := regexp.MustCompile(`^(#{1,6})\s+([\d\.]*)\s*(.*)$`)

	scanner := bufio.NewScanner(mdFileHandler)
	for scanner.Scan() {

		line := scanner.Text()
		matches := headerLine.FindStringSubmatch(line)

		if len(matches) == 4 {

			header := matches[1]
			currentHeaderType := len(matches[1])
			title := matches[3]

			if firstH1Done || *noTitleSkipFlag {

				headerCounters[currentHeaderType]++

			}

                        if !firstH1Done && currentHeaderType == 1 {

                                firstH1Done = true

                        }

			if *removeFlag {

				rewrittenLine = header + " " + title

			} else {

				for headerType := 1; headerType <= 6; headerType++ {

					addSectionChunk(&section, headerCounters[headerType], currentHeaderType, headerType)

				}

				if section != "" {
					section += " "
				}

				rewrittenLine = header + " " + section + title

				headerLines = append(headerLines, rewrittenLine)

				for i := currentHeaderType + 1; i <= 6; i++ {
					headerCounters[i] = 0
				}

				section = ""

			}

			mdLines = append(mdLines, rewrittenLine)

		} else if !tocLine.Match([]byte(line)) {

			if tocInsertionLine.Match([]byte(line)) {

				isToCInsertionLine = true

			}

			mdLines = append(mdLines, line)

		}

	}
	if err := scanner.Err(); err != nil {
		log.Fatal(err)
	}

	mdFileHandler.Close()

	if !*removeFlag && isToCInsertionLine {

		firstHeaderLine := headerLine.FindStringSubmatch(headerLines[0])

		upperHeaderLevel = len(firstHeaderLine[1])

	}

	if *writeFlag {

		mdTmpFile, err = os.CreateTemp(filepath.Dir(mdFilePath)+pathSep, ".dumber-*.tmp")
		if err != nil {
			log.Fatal(err)
		}

		for _, line := range mdLines {

			_, _ = io.WriteString(mdTmpFile, line+newLine)

			if !*removeFlag && isToCInsertionLine && tocInsertionLine.Match([]byte(line)) {

				for _, hline := range headerLines {

					_, _ = io.WriteString(mdTmpFile, toToCEntry(upperHeaderLevel, headerLine, hline)+newLine)

				}

			}

		}

		mdTmpFile.Close()

		err = os.Rename(mdTmpFile.Name(), mdFilePath)
		if err != nil {
			log.Fatal(err)
		}

	} else {

		for _, line := range mdLines {

			fmt.Println(line)

			if !*removeFlag && isToCInsertionLine && tocInsertionLine.Match([]byte(line)) {

				for _, hline := range headerLines {

					fmt.Println(toToCEntry(upperHeaderLevel, headerLine, hline))

				}

			}

		}
	}
}

func toToCEntry(u int, r *regexp.Regexp, l string) string {
	m := r.FindStringSubmatch(l)
	c := len(m[1]) - u
	if c < 0 {
		fmt.Println("Header level too low line : " + l)
		os.Exit(-1)
	}
	return (strings.Repeat("    ", c) + "- [" + m[2] + "](#" + strings.ToLower(strings.ReplaceAll(m[2], ".", "")+"-"+strings.ReplaceAll(m[3], " ", "-")) + ") " + m[3])
}

func addSectionChunk(s *string, hc int, cht int, ht int) {
	if hc > 0 && cht >= ht {
		*s += strconv.Itoa(hc) + "."
	}
}