gomuks/ui/messages/html/parser.go
2022-04-15 20:29:23 +03:00

486 lines
13 KiB
Go

// gomuks - A terminal Matrix client written in Go.
// Copyright (C) 2020 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 (
"fmt"
"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"
"go.mau.fi/tcell"
"maunium.net/go/mautrix/event"
"maunium.net/go/mautrix/id"
"maunium.net/go/gomuks/config"
"maunium.net/go/gomuks/matrix/rooms"
"maunium.net/go/gomuks/ui/widget"
)
var matrixToURL = regexp.MustCompile("^(?:https?://)?(?:www\\.)?matrix\\.to/#/([#@!].*)")
type htmlParser struct {
prefs *config.UserPreferences
room *rooms.Room
preserveWhitespace 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) maybeGetAttribute(node *html.Node, attribute string) (string, bool) {
for _, attr := range node.Attr {
if attr.Key == attribute {
return attr.Val, true
}
}
return "", false
}
func (parser *htmlParser) getAttribute(node *html.Node, attribute string) string {
val, _ := parser.maybeGetAttribute(node, attribute)
return val
}
func (parser *htmlParser) hasAttribute(node *html.Node, attribute string) bool {
_, ok := parser.maybeGetAttribute(node, attribute)
return ok
}
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 := &ContainerEntity{
BaseEntity: &BaseEntity{
Tag: node.Data,
},
Children: parser.nodeToEntities(node.FirstChild),
}
switch node.Data {
case "b", "strong":
entity.AdjustStyle(AdjustStyleBold, AdjustStyleReasonNormal)
case "i", "em":
entity.AdjustStyle(AdjustStyleItalic, AdjustStyleReasonNormal)
case "s", "del", "strike":
entity.AdjustStyle(AdjustStyleStrikethrough, AdjustStyleReasonNormal)
case "u", "ins":
entity.AdjustStyle(AdjustStyleUnderline, AdjustStyleReasonNormal)
case "font", "span":
fgColor, ok := parser.parseColor(node, "data-mx-color", "color")
if ok {
entity.AdjustStyle(AdjustStyleTextColor(fgColor), AdjustStyleReasonNormal)
}
bgColor, ok := parser.parseColor(node, "data-mx-bg-color", "background-color")
if ok {
entity.AdjustStyle(AdjustStyleBackgroundColor(bgColor), AdjustStyleReasonNormal)
}
spoilerReason, isSpoiler := parser.maybeGetAttribute(node, "data-mx-spoiler")
if isSpoiler {
return NewSpoilerEntity(entity, spoilerReason)
}
}
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 {
return (&ContainerEntity{
BaseEntity: &BaseEntity{
Tag: node.Data,
},
Children: append(
[]Entity{NewTextEntity(strings.Repeat("#", int(node.Data[1]-'0')) + " ")},
parser.nodeToEntities(node.FirstChild)...,
),
}).AdjustStyle(AdjustStyleBold, AdjustStyleReasonNormal)
}
func (parser *htmlParser) blockquoteToEntity(node *html.Node) Entity {
return NewBlockquoteEntity(parser.nodeToEntities(node.FirstChild))
}
func (parser *htmlParser) linkToEntity(node *html.Node) Entity {
sameURL := false
href := parser.getAttribute(node, "href")
entity := &ContainerEntity{
BaseEntity: &BaseEntity{
Tag: "a",
},
Children: parser.nodeToEntities(node.FirstChild),
}
if len(href) == 0 || parser.hasAttribute(node, "data-mautrix-exclude-plaintext") {
return entity
}
if len(entity.Children) == 1 {
entity, ok := entity.Children[0].(*TextEntity)
if ok && entity.Text == href {
sameURL = true
}
}
if !parser.prefs.DisableShowURLs && !parser.hasAttribute(node, "data-mautrix-no-link") && !sameURL {
entity.Children = append(entity.Children, NewTextEntity(fmt.Sprintf(" (%s)", href)))
}
match := matrixToURL.FindStringSubmatch(href)
if len(match) == 2 {
pillTarget := match[1]
text := NewTextEntity(pillTarget)
if pillTarget[0] == '@' {
if member := parser.room.GetMember(id.UserID(pillTarget)); member != nil {
text.Text = member.Displayname
text.Style = text.Style.Foreground(widget.GetHashColor(pillTarget))
}
entity.Children = []Entity{text}
/*} else if slash := strings.IndexRune(pillTarget, '/'); slash != -1 {
room := pillTarget[:slash]
event := pillTarget[slash+1:]*/
} else if pillTarget[0] == '#' {
entity.Children = []Entity{text}
}
}
// 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 := &TextEntity{
BaseEntity: &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 tokenToTextEntity(style *chroma.Style, token *chroma.Token) *TextEntity {
return &TextEntity{
BaseEntity: &BaseEntity{
Tag: token.Type.String(),
Style: styleEntryToStyle(style.Get(token.Type)),
DefaultHeight: 1,
},
Text: token.Value,
}
}
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()
var children []Entity
for _, token := range tokens {
if token.Value == "\n" {
children = append(children, NewBreakEntity())
} else if token.Type.String() == "CommentSingle" {
children = append(children, tokenToTextEntity(style, &token))
children = append(children, NewBreakEntity())
} else if token.Type.String() == "CommentMultiline" {
lines := strings.Split(token.Value, "\n")
for i, line := range lines {
t := token.Clone()
t.Value = line
children = append(children, tokenToTextEntity(style, &t))
if i < len(lines)-1 {
children = append(children, NewBreakEntity())
}
}
} else {
children = append(children, tokenToTextEntity(style, &token))
}
}
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 != nil && 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.preserveWhitespace = true
text := (&ContainerEntity{
Children: parser.nodeToEntities(node.FirstChild),
}).PlainText()
parser.preserveWhitespace = 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", "strike", "del", "u", "ins", "font", "span":
return parser.basicFormatToEntity(node)
case "a":
return parser.linkToEntity(node)
case "img":
return parser.imageToEntity(node)
case "pre":
return parser.codeblockToEntity(node)
case "hr":
return NewHorizontalLineEntity()
case "mx-reply":
return nil
default:
return &ContainerEntity{
BaseEntity: &BaseEntity{
Tag: node.Data,
Block: parser.isBlockTag(node.Data),
},
Children: parser.nodeToEntities(node.FirstChild),
}
}
}
var spaces = regexp.MustCompile("\\s+")
func (parser *htmlParser) singleNodeToEntity(node *html.Node) Entity {
switch node.Type {
case html.TextNode:
if !parser.preserveWhitespace {
node.Data = strings.ReplaceAll(node.Data, "\n", "")
node.Data = spaces.ReplaceAllLiteralString(node.Data, " ")
}
if len(node.Data) == 0 {
return nil
}
return NewTextEntity(node.Data)
case html.ElementNode:
parsed := parser.tagNodeToEntity(node)
if parsed != nil && !parsed.IsBlock() && parsed.IsEmpty() {
return nil
}
return parsed
case html.DocumentNode:
if node.FirstChild.Data == "html" && node.FirstChild.NextSibling == nil {
return parser.singleNodeToEntity(node.FirstChild)
}
return &ContainerEntity{
BaseEntity: &BaseEntity{
Tag: "html",
Block: true,
},
Children: parser.nodeToEntities(node.FirstChild),
}
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))
bodyNode := node.FirstChild.FirstChild
for bodyNode != nil && (bodyNode.Type != html.ElementNode || bodyNode.Data != "body") {
bodyNode = bodyNode.NextSibling
}
if bodyNode != nil {
return parser.singleNodeToEntity(bodyNode)
}
return parser.singleNodeToEntity(node)
}
const TabLength = 4
// Parse parses a HTML-formatted Matrix event into a UIMessage.
func Parse(prefs *config.UserPreferences, room *rooms.Room, content *event.MessageEventContent, sender id.UserID, senderDisplayname string) Entity {
htmlData := content.FormattedBody
if content.Format != event.FormatHTML {
htmlData = strings.Replace(html.EscapeString(content.Body), "\n", "<br/>", -1)
}
htmlData = strings.Replace(htmlData, "\t", strings.Repeat(" ", TabLength), -1)
parser := htmlParser{room: room, prefs: prefs}
root := parser.Parse(htmlData)
beRoot := root.(*ContainerEntity)
beRoot.Block = false
if len(beRoot.Children) > 0 {
beChild, ok := beRoot.Children[0].(*ContainerEntity)
if ok && beChild.Tag == "p" {
// Hacky fix for m.emote
beChild.Block = false
}
}
if content.MsgType == event.MsgEmote {
root = &ContainerEntity{
BaseEntity: &BaseEntity{
Tag: "emote",
},
Children: []Entity{
NewTextEntity("* "),
NewTextEntity(senderDisplayname).AdjustStyle(AdjustStyleTextColor(widget.GetHashColor(sender)), AdjustStyleReasonNormal),
NewTextEntity(" "),
root,
},
}
}
return root
}