Add syntax highlighting. Fixes #28

4 files changed, 148 insertions, 15 deletions

diff --git a/go.mod b/go.mod
index aa49e6a..e201049 100644
--- a/go.mod
+++ b/go.mod
@@ -3,6 +3,7 @@ module maunium.net/go/gomuks
 go 1.12
 
 require (
+	github.com/alecthomas/chroma v0.6.3
 	github.com/disintegration/imaging v1.6.0
 	github.com/kyokomi/emoji v2.1.0+incompatible
 	github.com/lithammer/fuzzysearch v1.0.2
diff --git a/go.sum b/go.sum
index b5b2657..fc46446 100644
--- a/go.sum
+++ b/go.sum
@@ -1,5 +1,16 @@
+github.com/alecthomas/assert v0.0.0-20170929043011-405dbfeb8e38/go.mod h1:r7bzyVFMNntcxPZXK3/+KdruV1H5KSlyVY0gc+NgInI=
+github.com/alecthomas/chroma v0.6.3 h1:8H1D0yddf0mvgvO4JDBKnzLd9ERmzzAijBxnZXGV/FA=
+github.com/alecthomas/chroma v0.6.3/go.mod h1:quT2EpvJNqkuPi6DmBHB+E33FXBgBBPzyH5++Dn1LPc=
+github.com/alecthomas/colour v0.0.0-20160524082231-60882d9e2721/go.mod h1:QO9JBoKquHd+jz9nshCh40fOfO+JzsoXy8qTHF68zU0=
+github.com/alecthomas/kong v0.1.15/go.mod h1:0m2VYms8rH0qbCqVB2gvGHk74bqLIq0HXjCs5bNbNQU=
+github.com/alecthomas/repr v0.0.0-20180818092828-117648cd9897/go.mod h1:xTS7Pm1pD1mvyM075QCDSRqH6qRLXylzS24ZTpRiSzQ=
+github.com/danwakefield/fnmatch v0.0.0-20160403171240-cbb64ac3d964 h1:y5HC9v93H5EPKqaS1UYVg1uYah5Xf51mBfIoWehClUQ=
+github.com/danwakefield/fnmatch v0.0.0-20160403171240-cbb64ac3d964/go.mod h1:Xd9hchkHSWYkEqJwUGisez3G1QY8Ryz0sdWrLPMGjLk=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/disintegration/imaging v1.6.0 h1:nVPXRUUQ36Z7MNf0O77UzgnOb1mkMMor7lmJMJXc/mA=
 github.com/disintegration/imaging v1.6.0/go.mod h1:xuIt+sRxDFrHS0drzXUlCJthkJ8k7lkkUojDSR247MQ=
+github.com/dlclark/regexp2 v1.1.6 h1:CqB4MjHw0MFCDj+PHHjiESmHX+N7t0tJzKvC6M97BRg=
+github.com/dlclark/regexp2 v1.1.6/go.mod h1:2pZnwuY/m+8K6iRw6wQdMtk+rH5tNGR1i55kozfMjCc=
 github.com/gdamore/encoding v1.0.0 h1:+7OoQ1Bc6eTm5niUzBa0Ctsh6JbMW6Ra+YNuAtDBdko=
 github.com/gdamore/encoding v1.0.0/go.mod h1:alR0ol34c49FCSBLjhosxzcPHQbf2trDkoo5dl+VrEg=
 github.com/kyokomi/emoji v2.1.0+incompatible h1:+DYU2RgpI6OHG4oQkM5KlqD3Wd3UPEsX8jamTo1Mp6o=
@@ -8,16 +19,21 @@ github.com/lithammer/fuzzysearch v1.0.2 h1:AjCE2iwc5y+8K+h2nXVc0Pmrpjvu+JVqMgiZ0
 github.com/lithammer/fuzzysearch v1.0.2/go.mod h1:bvAJyokfCQ7Vknrd4Kgc+izmMrPj5CiBAu2t6rK1Kak=
 github.com/lucasb-eyer/go-colorful v1.0.1 h1:nKJRBvZWPzvkwB4sY8A3U4zgqLf2Y9c02yzPsbXu/5c=
 github.com/lucasb-eyer/go-colorful v1.0.1/go.mod h1:tLy1nWSoU0DGtxQyNRrUmb6PUiB7usbds6gd97XTXwA=
+github.com/mattn/go-colorable v0.0.9/go.mod h1:9vuHe8Xs5qXnSaW/c/ABM9alt+Vo+STaOChaDxuIBZU=
+github.com/mattn/go-isatty v0.0.4/go.mod h1:M+lRXTBqGeGNdLjl/ufCoiOlB5xdOkqRJdNxMWT7Zi4=
 github.com/mattn/go-runewidth v0.0.4 h1:2BvfKmzob6Bmd4YsL0zygOqfdFnK7GR4QL06Do4/p7Y=
 github.com/mattn/go-runewidth v0.0.4/go.mod h1:LwmH8dsx7+W8Uxz3IHJYH5QSwggIsqBzpuz5H//U1FU=
 github.com/nu7hatch/gouuid v0.0.0-20131221200532-179d4d0c4d8d h1:VhgPp6v9qf9Agr/56bj7Y/xa04UccTW04VP0Qed4vnQ=
 github.com/nu7hatch/gouuid v0.0.0-20131221200532-179d4d0c4d8d/go.mod h1:YUTz3bUH2ZwIWBy3CJBeOBEugqcmXREj14T+iG/4k4U=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/rivo/uniseg v0.0.0-20190313204849-f699dde9c340 h1:nOZbL5f2xmBAHWYrrHbHV1xatzZirN++oOQ3g83Ypgs=
 github.com/rivo/uniseg v0.0.0-20190313204849-f699dde9c340/go.mod h1:SOLvOL4ybwgLJ6TYoX/rtaJ8EGOulH4XU7E9/TLrTCE=
 github.com/russross/blackfriday/v2 v2.0.1 h1:lPqVAte+HuHNfhJ/0LC98ESWRz8afy9tM/0RK8m9o+Q=
 github.com/russross/blackfriday/v2 v2.0.1/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
+github.com/sergi/go-diff v1.0.0/go.mod h1:0CfEIISq7TuYL3j771MWULgwwjU+GofnZX9QAmXWZgo=
 github.com/shurcooL/sanitized_anchor_name v1.0.0 h1:PdmoCO6wvbs+7yrJyMORt4/BmY5IYyJwS/kOiWx8mHo=
 github.com/shurcooL/sanitized_anchor_name v1.0.0/go.mod h1:1NzhyTcUVG4SuEtjjoZeVRXNmyL/1OwPU0+IJeTBvfc=
+github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/zyedidia/clipboard v0.0.0-20180718195219-bd31d747117d h1:Lhqt2eo+rgM8aswvM7nTtAMVm8ARPWzkE9n6eZDOccY=
 github.com/zyedidia/clipboard v0.0.0-20180718195219-bd31d747117d/go.mod h1:WDk3p8GiZV9+xFWlSo8qreeoLhW6Ik692rqXk+cNeRY=
 go.etcd.io/bbolt v1.3.2 h1:Z/90sZLPOeCy2PwprqkFa25PdkusRzaj9P8zm/KNyvk=
@@ -32,6 +48,7 @@ golang.org/x/net v0.0.0-20190110200230-915654e7eabc/go.mod h1:mL1N/T3taQHkDXs73r
 golang.org/x/net v0.0.0-20190326090315-15845e8f865b/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3 h1:0GoQqolDA55aaLxZyTzK/Y2ePZzZTUrRacwib7cNsYQ=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/sys v0.0.0-20181128092732-4ed8d59d0b35/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190322080309-f49334f85ddc/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190403152447-81d4e9dc473e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
diff --git a/ui/messages/htmlmessage.go b/ui/messages/htmlmessage.go
index 51678ba..0ffb6c9 100644
--- a/ui/messages/htmlmessage.go
+++ b/ui/messages/htmlmessage.go
@@ -72,23 +72,23 @@ func (hw *HTMLMessage) Height() int {
 }
 
 func (hw *HTMLMessage) PlainText() string {
-	// FIXME
-	return "Plaintext unavailable"
+	return hw.Root.PlainText()
 }
 
 func (hw *HTMLMessage) NotificationContent() string {
-	// FIXME
-	return "Notification content unavailable"
+	return hw.Root.PlainText()
 }
 
 type HTMLEntity struct {
 	// Permanent variables
-	Tag      string
-	Text     string
-	Style    tcell.Style
-	Children []*HTMLEntity
-	Block    bool
-	Indent   int
+	Tag       string
+	Text      string
+	Style     tcell.Style
+	Children  []*HTMLEntity
+	Block     bool
+	Indent    int
+
+	DefaultHeight int
 
 	// Non-permanent variables (calculated buffer data)
 	buffer    []string
@@ -130,8 +130,9 @@ func (he *HTMLEntity) Draw(screen mauview.Screen) {
 func (he *HTMLEntity) String() string {
 	var buf strings.Builder
 	buf.WriteString("&HTMLEntity{\n")
-	_, _ = fmt.Fprintf(&buf, `    Tag="%s", Style=%d, Block=%t, Indent=%d, startX=%d, height=%d,\n`,
+	_, _ = fmt.Fprintf(&buf, `    Tag="%s", Style=%d, Block=%t, Indent=%d, startX=%d, height=%d,`,
 		he.Tag, he.Style, he.Block, he.Indent, he.startX, he.height)
+	buf.WriteRune('\n')
 	_, _ = fmt.Fprintf(&buf, `    Buffer=["%s"]`, strings.Join(he.buffer, "\", \""))
 	if len(he.Text) > 0 {
 		buf.WriteString(",\n")
@@ -150,6 +151,27 @@ func (he *HTMLEntity) String() string {
 	return buf.String()
 }
 
+func (he *HTMLEntity) PlainText() string {
+	if len(he.Children) == 0 {
+		return he.Text
+	}
+	var buf strings.Builder
+	buf.WriteString(he.Text)
+	newlined := false
+	for _, child := range he.Children {
+		if child.Block && !newlined {
+			buf.WriteRune('\n')
+		}
+		newlined = false
+		buf.WriteString(child.PlainText())
+		if child.Block {
+			buf.WriteRune('\n')
+			newlined = true
+		}
+	}
+	return buf.String()
+}
+
 func (he *HTMLEntity) calculateBuffer(width, startX int, bare bool) int {
 	he.startX = startX
 	if he.Block {
@@ -178,6 +200,7 @@ func (he *HTMLEntity) calculateBuffer(width, startX int, bare bool) int {
 		text := he.Text
 		textStartX := he.startX
 		for {
+			// TODO add option no wrap and character wrap options
 			extract := runewidth.Truncate(text, width-textStartX, "")
 			extract, wordWrapped := trim(extract, text, bare)
 			if !wordWrapped && textStartX > 0 {
@@ -210,7 +233,10 @@ func (he *HTMLEntity) calculateBuffer(width, startX int, bare bool) int {
 			textStartX = 0
 		}
 	}
-	return 0
+	if len(he.Text) == 0 && len(he.Children) == 0 {
+		he.height = he.DefaultHeight
+	}
+	return he.startX
 }
 
 func trim(extract, full string, bare bool) (string, bool) {
diff --git a/ui/messages/parser/htmlparser.go b/ui/messages/parser/htmlparser.go
index 9a9c2d1..688deb3 100644
--- a/ui/messages/parser/htmlparser.go
+++ b/ui/messages/parser/htmlparser.go
@@ -23,6 +23,9 @@ import (
 	"strconv"
 	"strings"
 
+	"github.com/alecthomas/chroma"
+	"github.com/alecthomas/chroma/lexers"
+	"github.com/alecthomas/chroma/styles"
 	"github.com/lucasb-eyer/go-colorful"
 	"golang.org/x/net/html"
 
@@ -216,18 +219,102 @@ func (parser *htmlParser) linkToEntity(node *html.Node, stripLinebreak bool) *me
 			}
 		}
 	}
-	// TODO add click action for links
+	// TODO add click action and underline on hover for links
 	return entity
 }
 
-func (parser *htmlParser) codeblockToEntity(node *html.Node) *messages.HTMLEntity {
+func (parser *htmlParser) imageToEntity(node *html.Node) *messages.HTMLEntity {
+	alt := parser.getAttribute(node, "alt")
+	if len(alt) == 0 {
+		alt = parser.getAttribute(node, "title")
+		if len(alt) == 0 {
+			alt = "[inline image]"
+		}
+	}
+	entity := &messages.HTMLEntity{
+		Tag:  "img",
+		Text: alt,
+	}
+	// TODO add click action and underline on hover for inline images
+	return entity
+}
+
+func colourToColor(colour chroma.Colour) tcell.Color {
+	if !colour.IsSet() {
+		return tcell.ColorDefault
+	}
+	return tcell.NewRGBColor(int32(colour.Red()), int32(colour.Green()), int32(colour.Blue()))
+}
+
+func styleEntryToStyle(se chroma.StyleEntry) tcell.Style {
+	return tcell.StyleDefault.
+		Bold(se.Bold == chroma.Yes).
+		Italic(se.Italic == chroma.Yes).
+		Underline(se.Underline == chroma.Yes).
+		Foreground(colourToColor(se.Colour)).
+		Background(colourToColor(se.Background))
+}
+
+func (parser *htmlParser) syntaxHighlight(text, language string) *messages.HTMLEntity {
+	lexer := lexers.Get(language)
+	if lexer == nil {
+		return nil
+	}
+	iter, err := lexer.Tokenise(nil, text)
+	if err != nil {
+		return nil
+	}
+	style := styles.SolarizedDark
+	tokens := iter.Tokens()
+	children := make([]*messages.HTMLEntity, len(tokens))
+	for i, token := range tokens {
+		if token.Value == "\n" {
+			children[i] = &messages.HTMLEntity{Block: true, Tag: "br"}
+		} else {
+			children[i] = &messages.HTMLEntity{
+				Tag:   token.Type.String(),
+				Text:  token.Value,
+				Style: styleEntryToStyle(style.Get(token.Type)),
+
+				DefaultHeight: 1,
+			}
+		}
+	}
 	return &messages.HTMLEntity{
 		Tag:      "pre",
-		Children: parser.nodeToEntities(node.FirstChild, false),
 		Block:    true,
+		Children: children,
 	}
 }
 
+func (parser *htmlParser) codeblockToEntity(node *html.Node) *messages.HTMLEntity {
+	entity := &messages.HTMLEntity{
+		Tag:   "pre",
+		Block: true,
+	}
+	// TODO allow disabling syntax highlighting
+	if node.FirstChild.Type == html.ElementNode && node.FirstChild.Data == "code" {
+		text := (&messages.HTMLEntity{
+			Children: parser.nodeToEntities(node.FirstChild.FirstChild, false),
+		}).PlainText()
+		attr := parser.getAttribute(node.FirstChild, "class")
+		var lang string
+		for _, class := range strings.Split(attr, " ") {
+			if strings.HasPrefix(class, "language-") {
+				lang = class[len("language-"):]
+				break
+			}
+		}
+		if len(lang) != 0 {
+			if parsed := parser.syntaxHighlight(text, lang); parsed != nil {
+				return parsed
+			}
+		}
+	}
+	entity.Children = parser.nodeToEntities(node.FirstChild, false)
+	return entity
+}
+
 func (parser *htmlParser) tagNodeToEntity(node *html.Node, stripLinebreak bool) *messages.HTMLEntity {
 	switch node.Data {
 	case "blockquote":
@@ -242,6 +329,8 @@ func (parser *htmlParser) tagNodeToEntity(node *html.Node, stripLinebreak bool)
 		return parser.basicFormatToEntity(node, stripLinebreak)
 	case "a":
 		return parser.linkToEntity(node, stripLinebreak)
+	case "img":
+		return parser.imageToEntity(node)
 	case "pre":
 		return parser.codeblockToEntity(node)
 	default: