package html
import (
"fmt"
"html"
"io"
"sort"
"strings"
"github.com/alecthomas/chroma"
)
// Option sets an option of the HTML formatter.
type Option func(h *HTMLFormatter)
// Standalone configures the HTML formatter for generating a standalone HTML document.
func Standalone() Option { return func(h *HTMLFormatter) { h.standalone = true } }
// ClassPrefix sets the CSS class prefix.
func ClassPrefix(prefix string) Option { return func(h *HTMLFormatter) { h.prefix = prefix } }
// WithClasses emits HTML using CSS classes, rather than inline styles.
func WithClasses() Option { return func(h *HTMLFormatter) { h.classes = true } }
// New HTML formatter.
func New(options ...Option) *HTMLFormatter {
h := &HTMLFormatter{}
for _, option := range options {
option(h)
}
return h
}
type HTMLFormatter struct {
standalone bool
prefix string
classes bool
}
func (h *HTMLFormatter) Format(w io.Writer, style *chroma.Style) (func(*chroma.Token), error) {
if h.classes {
return h.formatWithClasses(w, style)
}
return h.formatWithoutClasses(w, style)
}
func (h *HTMLFormatter) formatWithoutClasses(w io.Writer, style *chroma.Style) (func(*chroma.Token), error) {
classes := h.typeStyles(style)
bg := compressStyle(classes[chroma.Background])
if h.standalone {
fmt.Fprint(w, "<html>\n")
fmt.Fprintf(w, "<body style=\"%s\">\n", bg)
}
fmt.Fprintf(w, "<pre style=\"%s\">\n", bg)
for t, style := range classes {
classes[t] = compressStyle(style)
}
return func(token *chroma.Token) {
if token.Type == chroma.EOF {
fmt.Fprint(w, "</pre>\n")
if h.standalone {
fmt.Fprint(w, "</body>\n")
fmt.Fprint(w, "</html>\n")
}
} else {
html := html.EscapeString(token.String())
style := classes[token.Type]
if style == "" {
style = classes[token.Type.SubCategory()]
if style == "" {
style = classes[token.Type.Category()]
}
}
if style == "" {
fmt.Fprint(w, html)
} else {
fmt.Fprintf(w, "<span style=\"%s\">%s</span>", style, html)
}
}
}, nil
}
func compressStyle(s string) string {
s = strings.Replace(s, " ", "", -1)
parts := strings.Split(s, ";")
out := []string{}
for _, p := range parts {
if strings.Contains(p, "#") {
c := p[len(p)-6:]
if c[0] == c[1] && c[2] == c[3] && c[4] == c[5] {
p = p[:len(p)-6] + c[0:1] + c[2:3] + c[4:5]
}
}
out = append(out, p)
}
return strings.Join(out, ";")
}
func (h *HTMLFormatter) formatWithClasses(w io.Writer, style *chroma.Style) (func(*chroma.Token), error) {
classes := h.typeStyles(style)
if h.standalone {
fmt.Fprint(w, "<html>\n")
}
fmt.Fprint(w, "<style type=\"text/css\">\n")
h.WriteStyles(w, style)
if h.standalone {
fmt.Fprintf(w, "body { %s; }\n", classes[chroma.Background])
}
fmt.Fprint(w, "</style>\n")
if h.standalone {
fmt.Fprint(w, "<body>\n")
}
fmt.Fprint(w, "<pre class=\"chroma\">\n")
return func(token *chroma.Token) {
if h.standalone && token.Type == chroma.EOF {
fmt.Fprint(w, "</body>\n")
fmt.Fprint(w, "</html>\n")
} else {
tt := token.Type
class := classes[tt]
if class == "" {
tt = tt.SubCategory()
class = classes[tt]
if class == "" {
tt = tt.Category()
class = classes[tt]
}
}
if class == "" {
fmt.Fprint(w, token)
} else {
html := html.EscapeString(token.String())
fmt.Fprintf(w, "<span class=\"%ss%x\">%s</span>", h.prefix, int(tt), html)
}
}
}, nil
}
// WriteStyles writes style definitions.
func (h *HTMLFormatter) WriteStyles(w io.Writer, style *chroma.Style) {
classes := h.typeStyles(style)
fmt.Fprintf(w, "/* %s */ .chroma { %s }\n", chroma.Background, classes[chroma.Background])
tts := []int{}
for tt := range classes {
tts = append(tts, int(tt))
}
sort.Ints(tts)
for _, ti := range tts {
tt := chroma.TokenType(ti)
styles := classes[tt]
if tt < 0 {
continue
}
fmt.Fprintf(w, "/* %s */ .chroma .%ss%x { %s }\n", tt, h.prefix, int(tt), styles)
}
}
func (h *HTMLFormatter) typeStyles(style *chroma.Style) map[chroma.TokenType]string {
// Generate maps.
bg := style.Get(chroma.Background)
classes := map[chroma.TokenType]string{}
for t := range style.Entries {
e := style.Entries[t]
if t != chroma.Background {
e = e.Sub(bg)
}
styles := h.class(e)
classes[t] = strings.Join(styles, "; ")
}
return classes
}
func (h *HTMLFormatter) class(e *chroma.StyleEntry) []string {
styles := []string{}
if e.Colour.IsSet() {
styles = append(styles, "color: "+e.Colour.String())
}
if e.Background.IsSet() {
styles = append(styles, "background-color: "+e.Background.String())
}
if e.Bold {
styles = append(styles, "font-weight: bold")
}
if e.Italic {
styles = append(styles, "font-style: italic")
}
return styles
}