Move ANSIRenderer into a separate package

ansi/baseelement.go

@@ -0,0 +1,170 @@
+package ansi
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"strconv"
+	"text/template"
+
+	"github.com/logrusorgru/aurora"
+	"github.com/lucasb-eyer/go-colorful"
+)
+
+type BaseElement struct {
+	Token  string
+	Prefix string
+	Suffix string
+	Style  StylePrimitive
+}
+
+func color(c *string) (uint8, error) {
+	if c == nil || len(*c) == 0 {
+		return 0, errors.New("invalid color")
+	}
+	if (*c)[0] == '#' {
+		i, err := hexToANSIColor(*c)
+		return uint8(i), err
+	}
+	i, err := strconv.Atoi(*c)
+	return uint8(i), err
+}
+
+func colorSeq(fg *string, bg *string) (string, error) {
+	fc := ""
+	bc := ""
+	if fg != nil {
+		fc = *fg
+	}
+	if bg != nil {
+		bc = *bg
+	}
+
+	fs := ""
+	bs := ""
+	f, err := colorful.Hex(fc)
+	if err == nil {
+		fs = fmt.Sprintf("38;2;%d;%d;%d", uint8(f.R*255), uint8(f.G*255), uint8(f.B*255))
+	}
+	b, err := colorful.Hex(bc)
+	if err == nil {
+		bs = fmt.Sprintf("48;2;%d;%d;%d", uint8(b.R*255), uint8(b.G*255), uint8(b.B*255))
+	}
+
+	if len(fs) > 0 || len(bs) > 0 {
+		seq := "\x1b[" + fs
+		if len(fs) > 0 {
+			seq += ";"
+		}
+		return seq + bs + "m", nil
+	}
+
+	return "", errors.New("invalid color")
+}
+
+func formatToken(format string, token string) (string, error) {
+	var b bytes.Buffer
+
+	v := make(map[string]interface{})
+	v["text"] = token
+
+	tmpl, err := template.New(format).Funcs(TemplateFuncMap).Parse(format)
+	if err != nil {
+		return "", err
+	}
+
+	err = tmpl.Execute(&b, v)
+	return b.String(), err
+}
+
+func renderText(w io.Writer, rules StylePrimitive, s string) {
+	if len(s) == 0 {
+		return
+	}
+
+	truecolor := os.Getenv("COLORTERM") == "truecolor"
+	// FIXME: ugly true-color ANSI support hack
+	if truecolor {
+		seq, err := colorSeq(rules.Color, rules.BackgroundColor)
+		if err == nil {
+			s = seq + s
+		} else {
+			truecolor = false
+		}
+	}
+
+	out := aurora.Reset(s)
+
+	if !truecolor {
+		if rules.Color != nil {
+			i, err := color(rules.Color)
+			if err == nil {
+				out = out.Index(i)
+			}
+		}
+		if rules.BackgroundColor != nil {
+			i, err := color(rules.BackgroundColor)
+			if err == nil {
+				out = out.BgIndex(i)
+			}
+		}
+	}
+	if rules.Underline != nil && *rules.Underline {
+		out = out.Underline()
+	}
+	if rules.Bold != nil && *rules.Bold {
+		out = out.Bold()
+	}
+	if rules.Italic != nil && *rules.Italic {
+		out = out.Italic()
+	}
+	if rules.CrossedOut != nil && *rules.CrossedOut {
+		out = out.CrossedOut()
+	}
+	if rules.Overlined != nil && *rules.Overlined {
+		out = out.Overlined()
+	}
+	if rules.Inverse != nil && *rules.Inverse {
+		out = out.Reverse()
+	}
+	if rules.Blink != nil && *rules.Blink {
+		out = out.Blink()
+	}
+
+	_, _ = w.Write([]byte(out.String()))
+}
+
+func (e *BaseElement) Render(w io.Writer, ctx RenderContext) error {
+	bs := ctx.blockStack
+
+	renderText(w, bs.Current().Style.StylePrimitive, e.Prefix)
+	defer func() {
+		renderText(w, bs.Current().Style.StylePrimitive, e.Suffix)
+	}()
+
+	rules := bs.With(e.Style)
+	// render unstyled prefix/suffix
+	renderText(w, bs.Current().Style.StylePrimitive, rules.BlockPrefix)
+	defer func() {
+		renderText(w, bs.Current().Style.StylePrimitive, rules.BlockSuffix)
+	}()
+
+	// render styled prefix/suffix
+	renderText(w, rules, rules.Prefix)
+	defer func() {
+		renderText(w, rules, rules.Suffix)
+	}()
+
+	s := e.Token
+	if len(rules.Format) > 0 {
+		var err error
+		s, err = formatToken(rules.Format, s)
+		if err != nil {
+			return err
+		}
+	}
+	renderText(w, rules, s)
+	return nil
+}