Refactor message parsing things

1 files changed, 380 insertions, 0 deletions

diff --git a/ui/messages/html/parser.go b/ui/messages/html/parser.go
new file mode 100644
index 0000000..dbd487e
--- /dev/null
+++ b/ui/messages/html/parser.go
@@ -0,0 +1,380 @@
+// gomuks - A terminal Matrix client written in Go.
+// Copyright (C) 2019 Tulir Asokan
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero 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 Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package html
+
+import (
+	"regexp"
+	"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"
+
+	"maunium.net/go/mautrix"
+	"maunium.net/go/tcell"
+
+	"maunium.net/go/gomuks/matrix/rooms"
+	"maunium.net/go/gomuks/ui/widget"
+)
+
+var matrixToURL = regexp.MustCompile("^(?:https?://)?(?:www\\.)?matrix\\.to/#/([#@!].*)")
+
+type htmlParser struct {
+	room *rooms.Room
+
+	keepLinebreak bool
+}
+
+func AdjustStyleBold(style tcell.Style) tcell.Style {
+	return style.Bold(true)
+}
+
+func AdjustStyleItalic(style tcell.Style) tcell.Style {
+	return style.Italic(true)
+}
+
+func AdjustStyleUnderline(style tcell.Style) tcell.Style {
+	return style.Underline(true)
+}
+
+func AdjustStyleStrikethrough(style tcell.Style) tcell.Style {
+	return style.Strikethrough(true)
+}
+
+func AdjustStyleTextColor(color tcell.Color) func(tcell.Style) tcell.Style {
+	return func(style tcell.Style) tcell.Style {
+		return style.Foreground(color)
+	}
+}
+
+func AdjustStyleBackgroundColor(color tcell.Color) func(tcell.Style) tcell.Style {
+	return func(style tcell.Style) tcell.Style {
+		return style.Background(color)
+	}
+}
+
+func (parser *htmlParser) getAttribute(node *html.Node, attribute string) string {
+	for _, attr := range node.Attr {
+		if attr.Key == attribute {
+			return attr.Val
+		}
+	}
+	return ""
+}
+
+func (parser *htmlParser) listToEntity(node *html.Node) Entity {
+	children := parser.nodeToEntities(node.FirstChild)
+	ordered := node.Data == "ol"
+	start := 1
+	if ordered {
+		if startRaw := parser.getAttribute(node, "start"); len(startRaw) > 0 {
+			var err error
+			start, err = strconv.Atoi(startRaw)
+			if err != nil {
+				start = 1
+			}
+		}
+	}
+	listItems := children[:0]
+	for _, child := range children {
+		if child.GetTag() == "li" {
+			listItems = append(listItems, child)
+		}
+	}
+	return NewListEntity(ordered, start, listItems)
+}
+
+func (parser *htmlParser) basicFormatToEntity(node *html.Node) Entity {
+	entity := &BaseEntity{
+		Tag:      node.Data,
+		Children: parser.nodeToEntities(node.FirstChild),
+	}
+	switch node.Data {
+	case "b", "strong":
+		entity.AdjustStyle(AdjustStyleBold)
+	case "i", "em":
+		entity.AdjustStyle(AdjustStyleItalic)
+	case "s", "del":
+		entity.AdjustStyle(AdjustStyleStrikethrough)
+	case "u", "ins":
+		entity.AdjustStyle(AdjustStyleUnderline)
+	case "font":
+		fgColor, ok := parser.parseColor(node, "data-mx-color", "color")
+		if ok {
+			entity.AdjustStyle(AdjustStyleTextColor(fgColor))
+		}
+		bgColor, ok := parser.parseColor(node, "data-mx-bg-color", "background-color")
+		if ok {
+			entity.AdjustStyle(AdjustStyleBackgroundColor(bgColor))
+		}
+	}
+	return entity
+}
+
+func (parser *htmlParser) parseColor(node *html.Node, mainName, altName string) (color tcell.Color, ok bool) {
+	hex := parser.getAttribute(node, mainName)
+	if len(hex) == 0 {
+		hex = parser.getAttribute(node, altName)
+		if len(hex) == 0 {
+			return
+		}
+	}
+
+	cful, err := colorful.Hex(hex)
+	if err != nil {
+		color2, found := colorMap[strings.ToLower(hex)]
+		if !found {
+			return
+		}
+		cful, _ = colorful.MakeColor(color2)
+	}
+
+	r, g, b := cful.RGB255()
+	return tcell.NewRGBColor(int32(r), int32(g), int32(b)), true
+}
+
+func (parser *htmlParser) headerToEntity(node *html.Node) Entity {
+	length := int(node.Data[1] - '0')
+	prefix := strings.Repeat("#", length) + " "
+	return (&BaseEntity{
+		Tag:      node.Data,
+		Text:     prefix,
+		Children: parser.nodeToEntities(node.FirstChild),
+	}).AdjustStyle(AdjustStyleBold)
+}
+
+func (parser *htmlParser) blockquoteToEntity(node *html.Node) Entity {
+	return NewBlockquoteEntity(parser.nodeToEntities(node.FirstChild))
+}
+
+func (parser *htmlParser) linkToEntity(node *html.Node) Entity {
+	entity := &BaseEntity{
+		Tag:      "a",
+		Children: parser.nodeToEntities(node.FirstChild),
+	}
+	href := parser.getAttribute(node, "href")
+	if len(href) == 0 {
+		return entity
+	}
+	match := matrixToURL.FindStringSubmatch(href)
+	if len(match) == 2 {
+		entity.Children = nil
+		pillTarget := match[1]
+		entity.Text = pillTarget
+		if pillTarget[0] == '@' {
+			if member := parser.room.GetMember(pillTarget); member != nil {
+				entity.Text = member.Displayname
+				entity.Style = entity.Style.Foreground(widget.GetHashColor(pillTarget))
+			}
+		}
+	}
+	// TODO add click action and underline on hover for links
+	return entity
+}
+
+func (parser *htmlParser) imageToEntity(node *html.Node) Entity {
+	alt := parser.getAttribute(node, "alt")
+	if len(alt) == 0 {
+		alt = parser.getAttribute(node, "title")
+		if len(alt) == 0 {
+			alt = "[inline image]"
+		}
+	}
+	entity := &BaseEntity{
+		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) Entity {
+	lexer := lexers.Get(strings.ToLower(language))
+	if lexer == nil {
+		return nil
+	}
+	iter, err := lexer.Tokenise(nil, text)
+	if err != nil {
+		return nil
+	}
+	// TODO allow changing theme
+	style := styles.SolarizedDark
+
+	tokens := iter.Tokens()
+	children := make([]Entity, len(tokens))
+	for i, token := range tokens {
+		if token.Value == "\n" {
+			children[i] = &BaseEntity{Block: true, Tag: "br"}
+		} else {
+			children[i] = &BaseEntity{
+				Tag:   token.Type.String(),
+				Text:  token.Value,
+				Style: styleEntryToStyle(style.Get(token.Type)),
+
+				DefaultHeight: 1,
+			}
+		}
+	}
+	return NewCodeBlockEntity(children, styleEntryToStyle(style.Get(chroma.Background)))
+}
+
+func (parser *htmlParser) codeblockToEntity(node *html.Node) Entity {
+	lang := "plaintext"
+	// TODO allow disabling syntax highlighting
+	if node.FirstChild.Type == html.ElementNode && node.FirstChild.Data == "code" {
+		node = node.FirstChild
+		attr := parser.getAttribute(node, "class")
+		for _, class := range strings.Split(attr, " ") {
+			if strings.HasPrefix(class, "language-") {
+				lang = class[len("language-"):]
+				break
+			}
+		}
+	}
+	parser.keepLinebreak = true
+	text := (&BaseEntity{
+		Children: parser.nodeToEntities(node.FirstChild),
+	}).PlainText()
+	parser.keepLinebreak = false
+	return parser.syntaxHighlight(text, lang)
+}
+
+func (parser *htmlParser) tagNodeToEntity(node *html.Node) Entity {
+	switch node.Data {
+	case "blockquote":
+		return parser.blockquoteToEntity(node)
+	case "ol", "ul":
+		return parser.listToEntity(node)
+	case "h1", "h2", "h3", "h4", "h5", "h6":
+		return parser.headerToEntity(node)
+	case "br":
+		return NewBreakEntity()
+	case "b", "strong", "i", "em", "s", "del", "u", "ins", "font":
+		return parser.basicFormatToEntity(node)
+	case "a":
+		return parser.linkToEntity(node)
+	case "img":
+		return parser.imageToEntity(node)
+	case "pre":
+		return parser.codeblockToEntity(node)
+	default:
+		return &BaseEntity{
+			Tag:      node.Data,
+			Children: parser.nodeToEntities(node.FirstChild),
+			Block:    parser.isBlockTag(node.Data),
+		}
+	}
+}
+
+func (parser *htmlParser) singleNodeToEntity(node *html.Node) Entity {
+	switch node.Type {
+	case html.TextNode:
+		if !parser.keepLinebreak {
+			node.Data = strings.ReplaceAll(node.Data, "\n", "")
+		}
+		return &BaseEntity{
+			Tag:  "text",
+			Text: node.Data,
+		}
+	case html.ElementNode:
+		return parser.tagNodeToEntity(node)
+	case html.DocumentNode:
+		if node.FirstChild.Data == "html" && node.FirstChild.NextSibling == nil {
+			return parser.singleNodeToEntity(node.FirstChild)
+		}
+		return &BaseEntity{
+			Tag:      "html",
+			Children: parser.nodeToEntities(node.FirstChild),
+			Block:    true,
+		}
+	default:
+		return nil
+	}
+}
+
+func (parser *htmlParser) nodeToEntities(node *html.Node) (entities []Entity) {
+	for ; node != nil; node = node.NextSibling {
+		if entity := parser.singleNodeToEntity(node); entity != nil {
+			entities = append(entities, entity)
+		}
+	}
+	return
+}
+
+var BlockTags = []string{"p", "h1", "h2", "h3", "h4", "h5", "h6", "ol", "ul", "li", "pre", "blockquote", "div", "hr", "table"}
+
+func (parser *htmlParser) isBlockTag(tag string) bool {
+	for _, blockTag := range BlockTags {
+		if tag == blockTag {
+			return true
+		}
+	}
+	return false
+}
+
+func (parser *htmlParser) Parse(htmlData string) Entity {
+	node, _ := html.Parse(strings.NewReader(htmlData))
+	return parser.singleNodeToEntity(node)
+}
+
+const TabLength = 4
+
+// Parse parses a HTML-formatted Matrix event into a UIMessage.
+func Parse(room *rooms.Room, evt *mautrix.Event, senderDisplayname string) Entity {
+	htmlData := evt.Content.FormattedBody
+	if evt.Content.Format != mautrix.FormatHTML {
+		htmlData = strings.ReplaceAll(html.EscapeString(evt.Content.Body), "\n", "<br/>")
+	}
+	htmlData = strings.Replace(htmlData, "\t", strings.Repeat(" ", TabLength), -1)
+
+	parser := htmlParser{room: room}
+	root := parser.Parse(htmlData)
+	root.(*BaseEntity).Block = false
+
+	if evt.Content.MsgType == mautrix.MsgEmote {
+		root = &BaseEntity{
+			Tag: "emote",
+			Children: []Entity{
+				NewTextEntity("* "),
+				NewTextEntity(senderDisplayname).AdjustStyle(AdjustStyleTextColor(widget.GetHashColor(evt.Sender))),
+				NewTextEntity(" "),
+				root,
+			},
+		}
+	}
+
+	return root
+}