Feat: Added tabular markdown writer

docs.go

@@ -7,13 +7,94 @@
 	"bytes"
 	"fmt"
 	"io"
+	"os"
+	"regexp"
 	"sort"
+	"strconv"
 	"strings"
 	"text/template"
+	"unicode/utf8"
 
 	"github.com/cpuguy83/go-md2man/v2/md2man"
 )
 
+// ToTabularMarkdown creates a tabular markdown documentation for the `*App`.
+// The function errors if either parsing or writing of the string fails.
+func (a *App) ToTabularMarkdown(appPath string) (string, error) {
+	if appPath == "" {
+		appPath = "app"
+	}
+
+	const name = "cli"
+
+	t, err := template.New(name).Funcs(template.FuncMap{
+		"join": strings.Join,
+	}).Parse(MarkdownTabularDocTemplate)
+	if err != nil {
+		return "", err
+	}
+
+	var (
+		w  bytes.Buffer
+		tt tabularTemplate
+	)
+
+	if err = t.ExecuteTemplate(&w, name, cliTabularAppTemplate{
+		AppPath:     appPath,
+		Name:        a.Name,
+		Description: tt.PrepareMultilineString(a.Description),
+		Usage:       tt.PrepareMultilineString(a.Usage),
+		UsageText:   strings.FieldsFunc(a.UsageText, func(r rune) bool { return r == '\n' }),
+		ArgsUsage:   tt.PrepareMultilineString(a.ArgsUsage),
+		GlobalFlags: tt.PrepareFlags(a.VisibleFlags()),
+		Commands:    tt.PrepareCommands(a.VisibleCommands(), appPath, "", 0),
+	}); err != nil {
+		return "", err
+	}
+
+	return tt.Prettify(w.String()), nil
+}
+
+// ToTabularToFileBetweenTags creates a tabular markdown documentation for the `*App` and updates the file between
+// the tags in the file. The function errors if either parsing or writing of the string fails.
+func (a *App) ToTabularToFileBetweenTags(appPath, filePath string, startEndTags ...string) error {
+	var start, end = "<!--GENERATED:CLI_DOCS-->", "<!--/GENERATED:CLI_DOCS-->" // default tags
+
+	if len(startEndTags) == 2 {
+		start, end = startEndTags[0], startEndTags[1]
+	}
+
+	// read original file content
+	content, err := os.ReadFile(filePath)
+	if err != nil {
+		return err
+	}
+
+	// generate markdown
+	md, err := a.ToTabularMarkdown(appPath)
+	if err != nil {
+		return err
+	}
+
+	// prepare regexp to replace content between start and end tags
+	re, err := regexp.Compile("(?s)" + regexp.QuoteMeta(start) + "(.*?)" + regexp.QuoteMeta(end))
+	if err != nil {
+		return err
+	}
+
+	const comment = "<!-- Documentation inside this block generated by github.com/urfave/cli; DO NOT EDIT -->"
+
+	// replace content between start and end tags
+	updated := re.ReplaceAll(content, []byte(strings.Join([]string{start, comment, md, end}, "\n")))
+
+	// write updated content to file
+	if err = os.WriteFile(filePath, updated, 0664); err != nil {
+		return err
+	}
+
+	return nil
+}
+
 // ToMarkdown creates a markdown string for the `*App`
 // The function errors if either parsing or writing of the string fails.
 func (a *App) ToMarkdown() (string, error) {
@@ -196,3 +277,235 @@
 
 	return usage
 }
+
+type (
+	cliTabularAppTemplate struct {
+		AppPath          string
+		Name             string
+		Usage, ArgsUsage string
+		UsageText        []string
+		Description      string
+		GlobalFlags      []cliTabularFlagTemplate
+		Commands         []cliTabularCommandTemplate
+	}
+
+	cliTabularCommandTemplate struct {
+		AppPath          string
+		Name             string
+		Aliases          []string
+		Usage, ArgsUsage string
+		UsageText        []string
+		Description      string
+		Category         string
+		Flags            []cliTabularFlagTemplate
+		SubCommands      []cliTabularCommandTemplate
+		Level            uint
+	}
+
+	cliTabularFlagTemplate struct {
+		Name       string
+		Aliases    []string
+		Usage      string
+		TakesValue bool
+		Default    string
+		EnvVars    []string
+	}
+)
+
+// tabularTemplate is a struct for the tabular template preparation.
+type tabularTemplate struct{}
+
+// PrepareCommands converts CLI commands into a structs for the rendering.
+func (tt tabularTemplate) PrepareCommands(commands []*Command, appPath, parentCommandName string, level uint) []cliTabularCommandTemplate {
+	var result = make([]cliTabularCommandTemplate, 0, len(commands))
+
+	for _, cmd := range commands {
+		var command = cliTabularCommandTemplate{
+			AppPath:     appPath,
+			Name:        strings.TrimSpace(strings.Join([]string{parentCommandName, cmd.Name}, " ")),
+			Aliases:     cmd.Aliases,
+			Usage:       tt.PrepareMultilineString(cmd.Usage),
+			UsageText:   strings.FieldsFunc(cmd.UsageText, func(r rune) bool { return r == '\n' }),
+			ArgsUsage:   tt.PrepareMultilineString(cmd.ArgsUsage),
+			Description: tt.PrepareMultilineString(cmd.Description),
+			Category:    cmd.Category,
+			Flags:       tt.PrepareFlags(cmd.VisibleFlags()),
+			SubCommands: tt.PrepareCommands( // note: recursive call
+				cmd.Commands,
+				appPath,
+				strings.Join([]string{parentCommandName, cmd.Name}, " "),
+				level+1,
+			),
+			Level: level,
+		}
+
+		result = append(result, command)
+	}
+
+	return result
+}
+
+// PrepareFlags converts CLI flags into a structs for the rendering.
+func (tt tabularTemplate) PrepareFlags(flags []Flag) []cliTabularFlagTemplate {
+	var result = make([]cliTabularFlagTemplate, 0, len(flags))
+
+	for _, appFlag := range flags {
+		flag, ok := appFlag.(DocGenerationFlag)
+		if !ok {
+			continue
+		}
+
+		var f = cliTabularFlagTemplate{
+			Usage:      tt.PrepareMultilineString(flag.GetUsage()),
+			EnvVars:    flag.GetEnvVars(),
+			TakesValue: flag.TakesValue(),
+			Default:    flag.GetValue(),
+		}
+
+		if boolFlag, isBool := appFlag.(*BoolFlag); isBool {
+			f.Default = strconv.FormatBool(boolFlag.Value)
+		}
+
+		for i, name := range flag.Names() {
+			name = strings.TrimSpace(name)
+
+			if i == 0 {
+				f.Name = "--" + name
+
+				continue
+			}
+
+			if len(name) > 1 {
+				name = "--" + name
+			} else {
+				name = "-" + name
+			}
+
+			f.Aliases = append(f.Aliases, name)
+		}
+
+		result = append(result, f)
+	}
+
+	return result
+}
+
+// PrepareMultilineString prepares a string (removes line breaks).
+func (tabularTemplate) PrepareMultilineString(s string) string {
+	return strings.TrimRight(
+		strings.TrimSpace(
+			strings.ReplaceAll(s, "\n", " "),
+		),
+		".\r\n\t",
+	)
+}
+
+func (tabularTemplate) Prettify(s string) string {
+	var max = func(x, y int) int {
+		if x > y {
+			return x
+		}
+		return y
+	}
+
+	var b strings.Builder
+
+	// search for tables
+	for _, rawTable := range regexp.MustCompile(`(?m)^(\|[^\n]+\|\r?\n)((?:\|:?-+:?)+\|)(\n(?:\|[^\n]+\|\r?\n?)*)?$`).FindAllString(s, -1) {
+		var lines = strings.FieldsFunc(rawTable, func(r rune) bool { return r == '\n' })
+
+		if len(lines) < 3 { // header, separator, body
+			continue
+		}
+
+		// parse table into the matrix
+		var matrix = make([][]string, 0, len(lines))
+		for _, line := range lines {
+			items := strings.FieldsFunc(strings.Trim(line, "| "), func(r rune) bool { return r == '|' })
+
+			for i := range items {
+				items[i] = strings.TrimSpace(items[i]) // trim spaces in cells
+			}
+
+			matrix = append(matrix, items)
+		}
+
+		// determine centered columns
+		var centered = make([]bool, 0, len(matrix[1]))
+		for _, cell := range matrix[1] {
+			centered = append(centered, strings.HasPrefix(cell, ":") && strings.HasSuffix(cell, ":"))
+		}
+
+		// calculate max lengths
+		var lengths = make([]int, len(matrix[0]))
+		for n, row := range matrix {
+			for i, cell := range row {
+				if n == 1 {
+					continue // skip separator
+				}
+
+				if l := utf8.RuneCountInString(cell); l > lengths[i] {
+					lengths[i] = l
+				}
+			}
+		}
+
+		// format cells
+		for i, row := range matrix {
+			for j, cell := range row {
+				if i == 1 { // is separator
+					if centered[j] {
+						b.Reset()
+						b.WriteRune(':')
+						b.WriteString(strings.Repeat("-", max(0, lengths[j])))
+						b.WriteRune(':')
+
+						row[j] = b.String()
+					} else {
+						row[j] = strings.Repeat("-", max(0, lengths[j]+2))
+					}
+
+					continue
+				}
+
+				var (
+					cellWidth         = utf8.RuneCountInString(cell)
+					padLeft, padRight = 1, max(1, lengths[j]-cellWidth+1) // align to the left
+				)
+
+				if centered[j] { // is centered
+					padLeft = max(1, (lengths[j]-cellWidth)/2)
+					padRight = max(1, lengths[j]-cellWidth-(padLeft-1))
+				}
+
+				b.Reset()
+				b.WriteString(strings.Repeat(" ", padLeft))
+
+				if padLeft+cellWidth+padRight <= lengths[j]+1 {
+					b.WriteRune(' ') // add an extra space if the cell is not full
+				}
+
+				b.WriteString(cell)
+				b.WriteString(strings.Repeat(" ", padRight))
+
+				row[j] = b.String()
+			}
+		}
+
+		b.Reset()
+
+		for _, row := range matrix { // build new table
+			b.WriteRune('|')
+			b.WriteString(strings.Join(row, "|"))
+			b.WriteRune('|')
+			b.WriteRune('\n')
+		}
+
+		s = strings.Replace(s, rawTable, b.String(), 1)
+	}
+
+	s = regexp.MustCompile(`\n{2,}`).ReplaceAllString(s, "\n\n") // normalize newlines
+	s = strings.Trim(s, " \n")                                   // trim spaces and newlines
+
+	return s + "\n" // add an extra newline
+}