1 files changed, 186 insertions, 0 deletions
diff --git a/ui/messages/parser/htmlparser.go b/ui/messages/parser/htmlparser.go
new file mode 100644
index 0000000..9ca707f
--- /dev/null
+++ b/ui/messages/parser/htmlparser.go
@@ -0,0 +1,186 @@
+// gomuks - A terminal Matrix client written in Go.
+// Copyright (C) 2018 Tulir Asokan
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package parser
+
+import (
+	"fmt"
+	"io"
+	"math"
+	"regexp"
+	"strings"
+
+	"maunium.net/go/gomatrix"
+	"maunium.net/go/gomuks/debug"
+	"maunium.net/go/gomuks/lib/htmlparser"
+	"maunium.net/go/gomuks/matrix/rooms"
+	"maunium.net/go/gomuks/ui/messages/tstring"
+	"maunium.net/go/gomuks/ui/widget"
+	"maunium.net/go/tcell"
+)
+
+var matrixToURL = regexp.MustCompile("^(?:https?://)?(?:www\\.)?matrix\\.to/#/([#@!].*)")
+
+type MatrixHTMLProcessor struct {
+	text tstring.TString
+
+	indent    string
+	listType  string
+	lineIsNew bool
+	openTags  *TagArray
+
+	room *rooms.Room
+}
+
+func (parser *MatrixHTMLProcessor) newline() {
+	if !parser.lineIsNew {
+		parser.text = parser.text.Append("\n" + parser.indent)
+		parser.lineIsNew = true
+	}
+}
+
+func (parser *MatrixHTMLProcessor) Preprocess() {}
+
+func (parser *MatrixHTMLProcessor) HandleText(text string) {
+	style := tcell.StyleDefault
+	for _, tag := range *parser.openTags {
+		switch tag.Tag {
+		case "b", "strong":
+			style = style.Bold(true)
+		case "i", "em":
+			style = style.Italic(true)
+		case "s", "del":
+			style = style.Strikethrough(true)
+		case "u", "ins":
+			style = style.Underline(true)
+		case "a":
+			tag.Text += text
+			return
+		}
+	}
+
+	if !parser.openTags.Has("pre", "code") {
+		text = strings.Replace(text, "\n", "", -1)
+	}
+	parser.text = parser.text.AppendStyle(text, style)
+	parser.lineIsNew = false
+}
+
+func (parser *MatrixHTMLProcessor) HandleStartTag(tagName string, attrs map[string]string) {
+	tag := &TagWithMeta{Tag: tagName}
+	switch tag.Tag {
+	case "h1", "h2", "h3", "h4", "h5", "h6":
+		length := int(tag.Tag[1] - '0')
+		parser.text = parser.text.Append(strings.Repeat("#", length) + " ")
+		parser.lineIsNew = false
+	case "a":
+		tag.Meta, _ = attrs["href"]
+	case "ol", "ul":
+		parser.listType = tag.Tag
+	case "li":
+		indentSize := 2
+		if parser.listType == "ol" {
+			list := parser.openTags.Get(parser.listType)
+			list.Counter++
+			parser.text = parser.text.Append(fmt.Sprintf("%d. ", list.Counter))
+			indentSize = int(math.Log10(float64(list.Counter))+1) + len(". ")
+		} else {
+			parser.text = parser.text.Append("* ")
+		}
+		parser.indent += strings.Repeat(" ", indentSize)
+		parser.lineIsNew = false
+	case "blockquote":
+		parser.indent += "> "
+		parser.text = parser.text.Append("> ")
+		parser.lineIsNew = false
+	}
+	parser.openTags.PushMeta(tag)
+}
+
+func (parser *MatrixHTMLProcessor) HandleSelfClosingTag(tagName string, attrs map[string]string) {
+	if tagName == "br" {
+		parser.newline()
+	}
+}
+
+func (parser *MatrixHTMLProcessor) HandleEndTag(tagName string) {
+	tag := parser.openTags.Pop(tagName)
+
+	switch tag.Tag {
+	case "li", "blockquote":
+		indentSize := 2
+		if tag.Tag == "li" && parser.listType == "ol" {
+			list := parser.openTags.Get(parser.listType)
+			indentSize = int(math.Log10(float64(list.Counter))+1) + len(". ")
+		}
+		if len(parser.indent) >= indentSize {
+			parser.indent = parser.indent[0 : len(parser.indent)-indentSize]
+		}
+		// TODO this newline is sometimes not good
+		parser.newline()
+	case "a":
+		match := matrixToURL.FindStringSubmatch(tag.Meta)
+		if len(match) == 2 {
+			pillTarget := match[1]
+			if pillTarget[0] == '@' {
+				if member := parser.room.GetMember(pillTarget); member != nil {
+					parser.text = parser.text.AppendColor(member.DisplayName, widget.GetHashColor(member.DisplayName))
+				} else {
+					parser.text = parser.text.Append(pillTarget)
+				}
+			} else {
+				parser.text = parser.text.Append(pillTarget)
+			}
+		} else {
+			// TODO make text clickable rather than printing URL
+			parser.text = parser.text.Append(fmt.Sprintf("%s (%s)", tag.Text, tag.Meta))
+		}
+		parser.lineIsNew = false
+	case "p", "pre", "ol", "ul", "h1", "h2", "h3", "h4", "h5", "h6", "div":
+		// parser.newline()
+	}
+}
+
+func (parser *MatrixHTMLProcessor) ReceiveError(err error) {
+	if err != io.EOF {
+		debug.Print("Unexpected error parsing HTML:", err)
+	}
+}
+
+func (parser *MatrixHTMLProcessor) Postprocess() {
+	if len(parser.text) > 0 && parser.text[len(parser.text)-1].Char == '\n' {
+		parser.text = parser.text[:len(parser.text)-1]
+	}
+}
+
+// ParseHTMLMessage parses a HTML-formatted Matrix event into a UIMessage.
+func ParseHTMLMessage(room *rooms.Room, evt *gomatrix.Event) tstring.TString {
+	htmlData, _ := evt.Content["formatted_body"].(string)
+
+	processor := &MatrixHTMLProcessor{
+		room:      room,
+		text:      tstring.NewBlankTString(),
+		indent:    "",
+		listType:  "",
+		lineIsNew: true,
+		openTags:  &TagArray{},
+	}
+
+	parser := htmlparser.NewHTMLParserFromString(htmlData, processor)
+	parser.Process()
+
+	return processor.text
+}