gitFlow/internal/presenter/presenter.go

// Package presenter renders scan results as human- or machine-readable
// output: a colorized terminal table, indented JSON, or a compact
// one-liner format.
package presenter

import (
	"fmt"
	"io"
	"os"
	"path/filepath"
	"strings"

	"gitea.oblak.solutions/dimitar/gitFlow/pkg/status"
)

// ColorMode controls ANSI color rendering.
type ColorMode int

const (
	ColorAuto   ColorMode = iota // color only when writing to a terminal
	ColorAlways                  // always emit ANSI color
	ColorNever                   // never emit ANSI color
)

// ParseColorMode converts a CLI string to a ColorMode; anything unknown
// falls back to auto.
func ParseColorMode(s string) ColorMode {
	switch s {
	case "always":
		return ColorAlways
	case "never":
		return ColorNever
	default:
		return ColorAuto
	}
}

// Options control rendering behaviour.
type Options struct {
	Color ColorMode
}

// Formatter renders a ScanResult to a writer.
type Formatter interface {
	Format(w io.Writer, result status.ScanResult) error
}

// For returns the formatter matching a format name ("table", "json", or
// "compact").
func For(format string, opts Options) (Formatter, error) {
	switch format {
	case "table":
		return &TableFormatter{opts: opts}, nil
	case "json":
		return &JSONFormatter{}, nil
	case "compact":
		return &CompactFormatter{opts: opts}, nil
	default:
		return nil, fmt.Errorf("presenter: unsupported format %q (want table, json, or compact)", format)
	}
}

// Present renders result to w in the given format.
func Present(w io.Writer, format string, result status.ScanResult, opts Options) error {
	formatter, err := For(format, opts)
	if err != nil {
		return err
	}
	return formatter.Format(w, result)
}

// renderer resolves ANSI escape codes according to the color mode, the
// destination, and the NO_COLOR convention (https://no-color.org).
type renderer struct {
	green  string
	yellow string
	red    string
	cyan   string
	blue   string
	reset  string
}

func newRenderer(mode ColorMode, w io.Writer) renderer {
	useColor := false
	switch mode {
	case ColorAlways:
		useColor = true
	case ColorNever:
		useColor = false
	default: // ColorAuto
		useColor = isTTY(w) && os.Getenv("NO_COLOR") == ""
	}
	if !useColor {
		return renderer{}
	}
	return renderer{
		green:  "\x1b[32m",
		yellow: "\x1b[33m",
		red:    "\x1b[31m",
		cyan:   "\x1b[36m",
		blue:   "\x1b[34m",
		reset:  "\x1b[0m",
	}
}

// paint wraps text in the color for the given status.
func (r renderer) paint(s status.RepoStatus, text string) string {
	var code string
	switch s {
	case status.StatusClean:
		code = r.green
	case status.StatusModified:
		code = r.yellow
	case status.StatusDiverged, status.StatusError:
		code = r.red
	case status.StatusAhead:
		code = r.blue
	case status.StatusBehind:
		code = r.yellow
	case status.StatusDetached, status.StatusBare:
		code = r.cyan
	}
	if code == "" {
		return text
	}
	return code + text + r.reset
}

func isTTY(w io.Writer) bool {
	f, ok := w.(*os.File)
	if !ok {
		return false
	}
	info, err := f.Stat()
	if err != nil {
		return false
	}
	return info.Mode()&os.ModeCharDevice != 0
}

// shortPath renders a path with the home directory collapsed to "~".
func shortPath(p string) string {
	home, err := os.UserHomeDir()
	if err != nil || home == "" {
		return p
	}
	rel, err := filepath.Rel(home, p)
	if err != nil || rel == "." || strings.HasPrefix(rel, "..") {
		return p
	}
	return filepath.Join("~", rel)
}