Refactor message parsing things

7 files changed, 1053 insertions, 0 deletions

diff --git a/ui/messages/html/blockquote.go b/ui/messages/html/blockquote.go
new file mode 100644
index 0000000..30ce52e
--- /dev/null
+++ b/ui/messages/html/blockquote.go
@@ -0,0 +1,49 @@
+// 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 (
+	"fmt"
+
+	"maunium.net/go/mauview"
+)
+
+type BlockquoteEntity struct {
+	*BaseEntity
+}
+
+const BlockQuoteChar = '>'
+
+func NewBlockquoteEntity(children []Entity) *BlockquoteEntity {
+	return &BlockquoteEntity{&BaseEntity{
+		Tag:      "blockquote",
+		Children: children,
+		Block:    true,
+		Indent:   2,
+	}}
+}
+
+func (be *BlockquoteEntity) Draw(screen mauview.Screen) {
+	be.BaseEntity.Draw(screen)
+	for y := 0; y < be.height; y++ {
+		screen.SetContent(0, y, BlockQuoteChar, nil, be.Style)
+	}
+}
+
+func (be *BlockquoteEntity) String() string {
+	return fmt.Sprintf("&html.BlockquoteEntity{%s},\n", be.BaseEntity)
+}
diff --git a/ui/messages/html/break.go b/ui/messages/html/break.go
new file mode 100644
index 0000000..d400f00
--- /dev/null
+++ b/ui/messages/html/break.go
@@ -0,0 +1,28 @@
+// 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
+
+type BreakEntity struct {
+	*BaseEntity
+}
+
+func NewBreakEntity() *BreakEntity {
+	return &BreakEntity{&BaseEntity{
+		Tag:   "br",
+		Block: true,
+	}}
+}
diff --git a/ui/messages/html/codeblock.go b/ui/messages/html/codeblock.go
new file mode 100644
index 0000000..ec6181d
--- /dev/null
+++ b/ui/messages/html/codeblock.go
@@ -0,0 +1,48 @@
+// 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 (
+	"maunium.net/go/mauview"
+	"maunium.net/go/tcell"
+)
+
+type CodeBlockEntity struct {
+	*BaseEntity
+	Background tcell.Style
+}
+
+func NewCodeBlockEntity(children []Entity, background tcell.Style) *CodeBlockEntity {
+	return &CodeBlockEntity{
+		BaseEntity: &BaseEntity{
+			Tag:      "pre",
+			Block:    true,
+			Children: children,
+		},
+		Background: background,
+	}
+}
+
+func (ce *CodeBlockEntity) Draw(screen mauview.Screen) {
+	screen.Fill(' ', ce.Background)
+	ce.BaseEntity.Draw(screen)
+}
+
+func (ce *CodeBlockEntity) AdjustStyle(fn AdjustStyleFunc) Entity {
+	// Don't allow adjusting code block style.
+	return ce
+}
diff --git a/ui/messages/html/colormap.go b/ui/messages/html/colormap.go
new file mode 100644
index 0000000..305309c
--- /dev/null
+++ b/ui/messages/html/colormap.go
@@ -0,0 +1,156 @@
+// From https://github.com/golang/image/blob/master/colornames/colornames.go
+package html
+
+import (
+	"image/color"
+)
+
+var colorMap = map[string]color.RGBA{
+	"aliceblue":            {0xf0, 0xf8, 0xff, 0xff}, // rgb(240, 248, 255)
+	"antiquewhite":         {0xfa, 0xeb, 0xd7, 0xff}, // rgb(250, 235, 215)
+	"aqua":                 {0x00, 0xff, 0xff, 0xff}, // rgb(0, 255, 255)
+	"aquamarine":           {0x7f, 0xff, 0xd4, 0xff}, // rgb(127, 255, 212)
+	"azure":                {0xf0, 0xff, 0xff, 0xff}, // rgb(240, 255, 255)
+	"beige":                {0xf5, 0xf5, 0xdc, 0xff}, // rgb(245, 245, 220)
+	"bisque":               {0xff, 0xe4, 0xc4, 0xff}, // rgb(255, 228, 196)
+	"black":                {0x00, 0x00, 0x00, 0xff}, // rgb(0, 0, 0)
+	"blanchedalmond":       {0xff, 0xeb, 0xcd, 0xff}, // rgb(255, 235, 205)
+	"blue":                 {0x00, 0x00, 0xff, 0xff}, // rgb(0, 0, 255)
+	"blueviolet":           {0x8a, 0x2b, 0xe2, 0xff}, // rgb(138, 43, 226)
+	"brown":                {0xa5, 0x2a, 0x2a, 0xff}, // rgb(165, 42, 42)
+	"burlywood":            {0xde, 0xb8, 0x87, 0xff}, // rgb(222, 184, 135)
+	"cadetblue":            {0x5f, 0x9e, 0xa0, 0xff}, // rgb(95, 158, 160)
+	"chartreuse":           {0x7f, 0xff, 0x00, 0xff}, // rgb(127, 255, 0)
+	"chocolate":            {0xd2, 0x69, 0x1e, 0xff}, // rgb(210, 105, 30)
+	"coral":                {0xff, 0x7f, 0x50, 0xff}, // rgb(255, 127, 80)
+	"cornflowerblue":       {0x64, 0x95, 0xed, 0xff}, // rgb(100, 149, 237)
+	"cornsilk":             {0xff, 0xf8, 0xdc, 0xff}, // rgb(255, 248, 220)
+	"crimson":              {0xdc, 0x14, 0x3c, 0xff}, // rgb(220, 20, 60)
+	"cyan":                 {0x00, 0xff, 0xff, 0xff}, // rgb(0, 255, 255)
+	"darkblue":             {0x00, 0x00, 0x8b, 0xff}, // rgb(0, 0, 139)
+	"darkcyan":             {0x00, 0x8b, 0x8b, 0xff}, // rgb(0, 139, 139)
+	"darkgoldenrod":        {0xb8, 0x86, 0x0b, 0xff}, // rgb(184, 134, 11)
+	"darkgray":             {0xa9, 0xa9, 0xa9, 0xff}, // rgb(169, 169, 169)
+	"darkgreen":            {0x00, 0x64, 0x00, 0xff}, // rgb(0, 100, 0)
+	"darkgrey":             {0xa9, 0xa9, 0xa9, 0xff}, // rgb(169, 169, 169)
+	"darkkhaki":            {0xbd, 0xb7, 0x6b, 0xff}, // rgb(189, 183, 107)
+	"darkmagenta":          {0x8b, 0x00, 0x8b, 0xff}, // rgb(139, 0, 139)
+	"darkolivegreen":       {0x55, 0x6b, 0x2f, 0xff}, // rgb(85, 107, 47)
+	"darkorange":           {0xff, 0x8c, 0x00, 0xff}, // rgb(255, 140, 0)
+	"darkorchid":           {0x99, 0x32, 0xcc, 0xff}, // rgb(153, 50, 204)
+	"darkred":              {0x8b, 0x00, 0x00, 0xff}, // rgb(139, 0, 0)
+	"darksalmon":           {0xe9, 0x96, 0x7a, 0xff}, // rgb(233, 150, 122)
+	"darkseagreen":         {0x8f, 0xbc, 0x8f, 0xff}, // rgb(143, 188, 143)
+	"darkslateblue":        {0x48, 0x3d, 0x8b, 0xff}, // rgb(72, 61, 139)
+	"darkslategray":        {0x2f, 0x4f, 0x4f, 0xff}, // rgb(47, 79, 79)
+	"darkslategrey":        {0x2f, 0x4f, 0x4f, 0xff}, // rgb(47, 79, 79)
+	"darkturquoise":        {0x00, 0xce, 0xd1, 0xff}, // rgb(0, 206, 209)
+	"darkviolet":           {0x94, 0x00, 0xd3, 0xff}, // rgb(148, 0, 211)
+	"deeppink":             {0xff, 0x14, 0x93, 0xff}, // rgb(255, 20, 147)
+	"deepskyblue":          {0x00, 0xbf, 0xff, 0xff}, // rgb(0, 191, 255)
+	"dimgray":              {0x69, 0x69, 0x69, 0xff}, // rgb(105, 105, 105)
+	"dimgrey":              {0x69, 0x69, 0x69, 0xff}, // rgb(105, 105, 105)
+	"dodgerblue":           {0x1e, 0x90, 0xff, 0xff}, // rgb(30, 144, 255)
+	"firebrick":            {0xb2, 0x22, 0x22, 0xff}, // rgb(178, 34, 34)
+	"floralwhite":          {0xff, 0xfa, 0xf0, 0xff}, // rgb(255, 250, 240)
+	"forestgreen":          {0x22, 0x8b, 0x22, 0xff}, // rgb(34, 139, 34)
+	"fuchsia":              {0xff, 0x00, 0xff, 0xff}, // rgb(255, 0, 255)
+	"gainsboro":            {0xdc, 0xdc, 0xdc, 0xff}, // rgb(220, 220, 220)
+	"ghostwhite":           {0xf8, 0xf8, 0xff, 0xff}, // rgb(248, 248, 255)
+	"gold":                 {0xff, 0xd7, 0x00, 0xff}, // rgb(255, 215, 0)
+	"goldenrod":            {0xda, 0xa5, 0x20, 0xff}, // rgb(218, 165, 32)
+	"gray":                 {0x80, 0x80, 0x80, 0xff}, // rgb(128, 128, 128)
+	"green":                {0x00, 0x80, 0x00, 0xff}, // rgb(0, 128, 0)
+	"greenyellow":          {0xad, 0xff, 0x2f, 0xff}, // rgb(173, 255, 47)
+	"grey":                 {0x80, 0x80, 0x80, 0xff}, // rgb(128, 128, 128)
+	"honeydew":             {0xf0, 0xff, 0xf0, 0xff}, // rgb(240, 255, 240)
+	"hotpink":              {0xff, 0x69, 0xb4, 0xff}, // rgb(255, 105, 180)
+	"indianred":            {0xcd, 0x5c, 0x5c, 0xff}, // rgb(205, 92, 92)
+	"indigo":               {0x4b, 0x00, 0x82, 0xff}, // rgb(75, 0, 130)
+	"ivory":                {0xff, 0xff, 0xf0, 0xff}, // rgb(255, 255, 240)
+	"khaki":                {0xf0, 0xe6, 0x8c, 0xff}, // rgb(240, 230, 140)
+	"lavender":             {0xe6, 0xe6, 0xfa, 0xff}, // rgb(230, 230, 250)
+	"lavenderblush":        {0xff, 0xf0, 0xf5, 0xff}, // rgb(255, 240, 245)
+	"lawngreen":            {0x7c, 0xfc, 0x00, 0xff}, // rgb(124, 252, 0)
+	"lemonchiffon":         {0xff, 0xfa, 0xcd, 0xff}, // rgb(255, 250, 205)
+	"lightblue":            {0xad, 0xd8, 0xe6, 0xff}, // rgb(173, 216, 230)
+	"lightcoral":           {0xf0, 0x80, 0x80, 0xff}, // rgb(240, 128, 128)
+	"lightcyan":            {0xe0, 0xff, 0xff, 0xff}, // rgb(224, 255, 255)
+	"lightgoldenrodyellow": {0xfa, 0xfa, 0xd2, 0xff}, // rgb(250, 250, 210)
+	"lightgray":            {0xd3, 0xd3, 0xd3, 0xff}, // rgb(211, 211, 211)
+	"lightgreen":           {0x90, 0xee, 0x90, 0xff}, // rgb(144, 238, 144)
+	"lightgrey":            {0xd3, 0xd3, 0xd3, 0xff}, // rgb(211, 211, 211)
+	"lightpink":            {0xff, 0xb6, 0xc1, 0xff}, // rgb(255, 182, 193)
+	"lightsalmon":          {0xff, 0xa0, 0x7a, 0xff}, // rgb(255, 160, 122)
+	"lightseagreen":        {0x20, 0xb2, 0xaa, 0xff}, // rgb(32, 178, 170)
+	"lightskyblue":         {0x87, 0xce, 0xfa, 0xff}, // rgb(135, 206, 250)
+	"lightslategray":       {0x77, 0x88, 0x99, 0xff}, // rgb(119, 136, 153)
+	"lightslategrey":       {0x77, 0x88, 0x99, 0xff}, // rgb(119, 136, 153)
+	"lightsteelblue":       {0xb0, 0xc4, 0xde, 0xff}, // rgb(176, 196, 222)
+	"lightyellow":          {0xff, 0xff, 0xe0, 0xff}, // rgb(255, 255, 224)
+	"lime":                 {0x00, 0xff, 0x00, 0xff}, // rgb(0, 255, 0)
+	"limegreen":            {0x32, 0xcd, 0x32, 0xff}, // rgb(50, 205, 50)
+	"linen":                {0xfa, 0xf0, 0xe6, 0xff}, // rgb(250, 240, 230)
+	"magenta":              {0xff, 0x00, 0xff, 0xff}, // rgb(255, 0, 255)
+	"maroon":               {0x80, 0x00, 0x00, 0xff}, // rgb(128, 0, 0)
+	"mediumaquamarine":     {0x66, 0xcd, 0xaa, 0xff}, // rgb(102, 205, 170)
+	"mediumblue":           {0x00, 0x00, 0xcd, 0xff}, // rgb(0, 0, 205)
+	"mediumorchid":         {0xba, 0x55, 0xd3, 0xff}, // rgb(186, 85, 211)
+	"mediumpurple":         {0x93, 0x70, 0xdb, 0xff}, // rgb(147, 112, 219)
+	"mediumseagreen":       {0x3c, 0xb3, 0x71, 0xff}, // rgb(60, 179, 113)
+	"mediumslateblue":      {0x7b, 0x68, 0xee, 0xff}, // rgb(123, 104, 238)
+	"mediumspringgreen":    {0x00, 0xfa, 0x9a, 0xff}, // rgb(0, 250, 154)
+	"mediumturquoise":      {0x48, 0xd1, 0xcc, 0xff}, // rgb(72, 209, 204)
+	"mediumvioletred":      {0xc7, 0x15, 0x85, 0xff}, // rgb(199, 21, 133)
+	"midnightblue":         {0x19, 0x19, 0x70, 0xff}, // rgb(25, 25, 112)
+	"mintcream":            {0xf5, 0xff, 0xfa, 0xff}, // rgb(245, 255, 250)
+	"mistyrose":            {0xff, 0xe4, 0xe1, 0xff}, // rgb(255, 228, 225)
+	"moccasin":             {0xff, 0xe4, 0xb5, 0xff}, // rgb(255, 228, 181)
+	"navajowhite":          {0xff, 0xde, 0xad, 0xff}, // rgb(255, 222, 173)
+	"navy":                 {0x00, 0x00, 0x80, 0xff}, // rgb(0, 0, 128)
+	"oldlace":              {0xfd, 0xf5, 0xe6, 0xff}, // rgb(253, 245, 230)
+	"olive":                {0x80, 0x80, 0x00, 0xff}, // rgb(128, 128, 0)
+	"olivedrab":            {0x6b, 0x8e, 0x23, 0xff}, // rgb(107, 142, 35)
+	"orange":               {0xff, 0xa5, 0x00, 0xff}, // rgb(255, 165, 0)
+	"orangered":            {0xff, 0x45, 0x00, 0xff}, // rgb(255, 69, 0)
+	"orchid":               {0xda, 0x70, 0xd6, 0xff}, // rgb(218, 112, 214)
+	"palegoldenrod":        {0xee, 0xe8, 0xaa, 0xff}, // rgb(238, 232, 170)
+	"palegreen":            {0x98, 0xfb, 0x98, 0xff}, // rgb(152, 251, 152)
+	"paleturquoise":        {0xaf, 0xee, 0xee, 0xff}, // rgb(175, 238, 238)
+	"palevioletred":        {0xdb, 0x70, 0x93, 0xff}, // rgb(219, 112, 147)
+	"papayawhip":           {0xff, 0xef, 0xd5, 0xff}, // rgb(255, 239, 213)
+	"peachpuff":            {0xff, 0xda, 0xb9, 0xff}, // rgb(255, 218, 185)
+	"peru":                 {0xcd, 0x85, 0x3f, 0xff}, // rgb(205, 133, 63)
+	"pink":                 {0xff, 0xc0, 0xcb, 0xff}, // rgb(255, 192, 203)
+	"plum":                 {0xdd, 0xa0, 0xdd, 0xff}, // rgb(221, 160, 221)
+	"powderblue":           {0xb0, 0xe0, 0xe6, 0xff}, // rgb(176, 224, 230)
+	"purple":               {0x80, 0x00, 0x80, 0xff}, // rgb(128, 0, 128)
+	"red":                  {0xff, 0x00, 0x00, 0xff}, // rgb(255, 0, 0)
+	"rosybrown":            {0xbc, 0x8f, 0x8f, 0xff}, // rgb(188, 143, 143)
+	"royalblue":            {0x41, 0x69, 0xe1, 0xff}, // rgb(65, 105, 225)
+	"saddlebrown":          {0x8b, 0x45, 0x13, 0xff}, // rgb(139, 69, 19)
+	"salmon":               {0xfa, 0x80, 0x72, 0xff}, // rgb(250, 128, 114)
+	"sandybrown":           {0xf4, 0xa4, 0x60, 0xff}, // rgb(244, 164, 96)
+	"seagreen":             {0x2e, 0x8b, 0x57, 0xff}, // rgb(46, 139, 87)
+	"seashell":             {0xff, 0xf5, 0xee, 0xff}, // rgb(255, 245, 238)
+	"sienna":               {0xa0, 0x52, 0x2d, 0xff}, // rgb(160, 82, 45)
+	"silver":               {0xc0, 0xc0, 0xc0, 0xff}, // rgb(192, 192, 192)
+	"skyblue":              {0x87, 0xce, 0xeb, 0xff}, // rgb(135, 206, 235)
+	"slateblue":            {0x6a, 0x5a, 0xcd, 0xff}, // rgb(106, 90, 205)
+	"slategray":            {0x70, 0x80, 0x90, 0xff}, // rgb(112, 128, 144)
+	"slategrey":            {0x70, 0x80, 0x90, 0xff}, // rgb(112, 128, 144)
+	"snow":                 {0xff, 0xfa, 0xfa, 0xff}, // rgb(255, 250, 250)
+	"springgreen":          {0x00, 0xff, 0x7f, 0xff}, // rgb(0, 255, 127)
+	"steelblue":            {0x46, 0x82, 0xb4, 0xff}, // rgb(70, 130, 180)
+	"tan":                  {0xd2, 0xb4, 0x8c, 0xff}, // rgb(210, 180, 140)
+	"teal":                 {0x00, 0x80, 0x80, 0xff}, // rgb(0, 128, 128)
+	"thistle":              {0xd8, 0xbf, 0xd8, 0xff}, // rgb(216, 191, 216)
+	"tomato":               {0xff, 0x63, 0x47, 0xff}, // rgb(255, 99, 71)
+	"turquoise":            {0x40, 0xe0, 0xd0, 0xff}, // rgb(64, 224, 208)
+	"violet":               {0xee, 0x82, 0xee, 0xff}, // rgb(238, 130, 238)
+	"wheat":                {0xf5, 0xde, 0xb3, 0xff}, // rgb(245, 222, 179)
+	"white":                {0xff, 0xff, 0xff, 0xff}, // rgb(255, 255, 255)
+	"whitesmoke":           {0xf5, 0xf5, 0xf5, 0xff}, // rgb(245, 245, 245)
+	"yellow":               {0xff, 0xff, 0x00, 0xff}, // rgb(255, 255, 0)
+	"yellowgreen":          {0x9a, 0xcd, 0x32, 0xff}, // rgb(154, 205, 50)
+}
diff --git a/ui/messages/html/entity.go b/ui/messages/html/entity.go
new file mode 100644
index 0000000..2ce37a8
--- /dev/null
+++ b/ui/messages/html/entity.go
@@ -0,0 +1,312 @@
+// 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 (
+	"fmt"
+	"regexp"
+	"strings"
+
+	"github.com/mattn/go-runewidth"
+
+	"maunium.net/go/gomuks/ui/widget"
+	"maunium.net/go/mauview"
+	"maunium.net/go/tcell"
+)
+
+// AdjustStyleFunc is a lambda function type to edit an existing tcell Style.
+type AdjustStyleFunc func(tcell.Style) tcell.Style
+
+type Entity interface {
+	// AdjustStyle recursively changes the style of the entity and all its children.
+	AdjustStyle(AdjustStyleFunc) Entity
+	// Draw draws the entity onto the given mauview Screen.
+	Draw(screen mauview.Screen)
+	// IsBlock returns whether or not it's a block-type entity.
+	IsBlock() bool
+	// GetTag returns the HTML tag of the entity.
+	GetTag() string
+	// PlainText returns the plaintext content in the entity and all its children.
+	PlainText() string
+	// String returns a string representation of the entity struct.
+	String() string
+	// Clone creates a deep copy of the entity.
+	Clone() Entity
+
+	// Height returns the render height of the entity.
+	Height() int
+	// CalculateBuffer prepares the entity and all its children for rendering with the given parameters
+	CalculateBuffer(width, startX int, bare bool) int
+
+	getStartX() int
+}
+
+type BaseEntity struct {
+	// The HTML tag of this entity.
+	Tag string
+	// Text in this entity.
+	Text string
+	// Style for this entity.
+	Style tcell.Style
+	// Child entities.
+	Children []Entity
+	// Whether or not this is a block-type entity.
+	Block bool
+	// Number of cells to indent children.
+	Indent int
+
+	// Height to use for entity if both text and children are empty.
+	DefaultHeight int
+
+	buffer    []string
+	prevWidth int
+	startX    int
+	height    int
+}
+
+// NewTextEntity creates a new text-only Entity.
+func NewTextEntity(text string) *BaseEntity {
+	return &BaseEntity{
+		Tag:  "text",
+		Text: text,
+	}
+}
+
+// AdjustStyle recursively changes the style of this entity and all its children.
+func (he *BaseEntity) AdjustStyle(fn AdjustStyleFunc) Entity {
+	for _, child := range he.Children {
+		child.AdjustStyle(fn)
+	}
+	he.Style = fn(he.Style)
+	return he
+}
+
+// IsBlock returns whether or not this is a block-type entity.
+func (he *BaseEntity) IsBlock() bool {
+	return he.Block
+}
+
+// GetTag returns the HTML tag of this entity.
+func (he *BaseEntity) GetTag() string {
+	return he.Tag
+}
+
+// Height returns the render height of this entity.
+func (he *BaseEntity) Height() int {
+	return he.height
+}
+
+func (he *BaseEntity) getStartX() int {
+	return he.startX
+}
+
+// Clone creates a deep copy of this entity.
+func (he *BaseEntity) Clone() Entity {
+	children := make([]Entity, len(he.Children))
+	for i, child := range he.Children {
+		children[i] = child.Clone()
+	}
+	return &BaseEntity{
+		Tag:           he.Tag,
+		Text:          he.Text,
+		Style:         he.Style,
+		Children:      children,
+		Block:         he.Block,
+		Indent:        he.Indent,
+		DefaultHeight: he.DefaultHeight,
+	}
+}
+
+// String returns a textual representation of this BaseEntity struct.
+func (he *BaseEntity) String() string {
+	var buf strings.Builder
+	buf.WriteString("&html.BaseEntity{\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")
+		_, _ = fmt.Fprintf(&buf, `    Text="%s"`, he.Text)
+	}
+	if len(he.Children) > 0 {
+		buf.WriteString(",\n")
+		buf.WriteString("    Children={")
+		for _, child := range he.Children {
+			buf.WriteString("\n        ")
+			buf.WriteString(strings.Join(strings.Split(strings.TrimRight(child.String(), "\n"), "\n"), "\n        "))
+		}
+		buf.WriteString("\n    },")
+	}
+	buf.WriteString("\n},\n")
+	return buf.String()
+}
+
+// PlainText returns the plaintext content in this entity and all its children.
+func (he *BaseEntity) 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.IsBlock() && !newlined {
+			buf.WriteRune('\n')
+		}
+		newlined = false
+		buf.WriteString(child.PlainText())
+		if child.IsBlock() {
+			buf.WriteRune('\n')
+			newlined = true
+		}
+	}
+	return buf.String()
+}
+
+// Draw draws this entity onto the given mauview Screen.
+func (he *BaseEntity) Draw(screen mauview.Screen) {
+	width, _ := screen.Size()
+	if len(he.buffer) > 0 {
+		x := he.startX
+		for y, line := range he.buffer {
+			widget.WriteLine(screen, mauview.AlignLeft, line, x, y, width, he.Style)
+			x = 0
+		}
+	}
+	if len(he.Children) > 0 {
+		prevBreak := false
+		proxyScreen := &mauview.ProxyScreen{Parent: screen, OffsetX: he.Indent, Width: width - he.Indent, Style: he.Style}
+		for i, entity := range he.Children {
+			if i != 0 && entity.getStartX() == 0 {
+				proxyScreen.OffsetY++
+			}
+			proxyScreen.Height = entity.Height()
+			entity.Draw(proxyScreen)
+			proxyScreen.SetStyle(he.Style)
+			proxyScreen.OffsetY += entity.Height() - 1
+			_, isBreak := entity.(*BreakEntity)
+			if prevBreak && isBreak {
+				proxyScreen.OffsetY++
+			}
+			prevBreak = isBreak
+		}
+	}
+}
+
+// CalculateBuffer prepares this entity and all its children for rendering with the given parameters
+func (he *BaseEntity) CalculateBuffer(width, startX int, bare bool) int {
+	he.startX = startX
+	if he.Block {
+		he.startX = 0
+	}
+	he.height = 0
+	if len(he.Children) > 0 {
+		childStartX := he.startX
+		prevBreak := false
+		for _, entity := range he.Children {
+			if entity.IsBlock() || childStartX == 0 || he.height == 0 {
+				he.height++
+			}
+			childStartX = entity.CalculateBuffer(width-he.Indent, childStartX, bare)
+			he.height += entity.Height() - 1
+			_, isBreak := entity.(*BreakEntity)
+			if prevBreak && isBreak {
+				he.height++
+			}
+			prevBreak = isBreak
+		}
+		if len(he.Text) == 0 && !he.Block {
+			return childStartX
+		}
+	}
+	if len(he.Text) > 0 {
+		he.prevWidth = width
+		if he.buffer == nil {
+			he.buffer = []string{}
+		}
+		bufPtr := 0
+		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 {
+				if bufPtr < len(he.buffer) {
+					he.buffer[bufPtr] = ""
+				} else {
+					he.buffer = append(he.buffer, "")
+				}
+				bufPtr++
+				textStartX = 0
+				continue
+			}
+			if bufPtr < len(he.buffer) {
+				he.buffer[bufPtr] = extract
+			} else {
+				he.buffer = append(he.buffer, extract)
+			}
+			bufPtr++
+			text = text[len(extract):]
+			if len(text) == 0 {
+				he.buffer = he.buffer[:bufPtr]
+				he.height += len(he.buffer)
+				// This entity is over, return the startX for the next entity
+				if he.Block {
+					// ...except if it's a block entity
+					return 0
+				}
+				return textStartX + runewidth.StringWidth(extract)
+			}
+			textStartX = 0
+		}
+	}
+	if len(he.Text) == 0 && len(he.Children) == 0 {
+		he.height = he.DefaultHeight
+	}
+	return he.startX
+}
+
+var (
+	boundaryPattern     = regexp.MustCompile(`([[:punct:]]\s*|\s+)`)
+	bareBoundaryPattern = regexp.MustCompile(`(\s+)`)
+	spacePattern        = regexp.MustCompile(`\s+`)
+)
+
+func trim(extract, full string, bare bool) (string, bool) {
+	if len(extract) == len(full) {
+		return extract, true
+	}
+	if spaces := spacePattern.FindStringIndex(full[len(extract):]); spaces != nil && spaces[0] == 0 {
+		extract = full[:len(extract)+spaces[1]]
+	}
+	regex := boundaryPattern
+	if bare {
+		regex = bareBoundaryPattern
+	}
+	matches := regex.FindAllStringIndex(extract, -1)
+	if len(matches) > 0 {
+		if match := matches[len(matches)-1]; len(match) >= 2 {
+			if until := match[1]; until < len(extract) {
+				extract = extract[:until]
+				return extract, true
+			}
+		}
+	}
+	return extract, len(extract) > 0 && extract[len(extract)-1] == ' '
+}
diff --git a/ui/messages/html/list.go b/ui/messages/html/list.go
new file mode 100644
index 0000000..9f45b92
--- /dev/null
+++ b/ui/messages/html/list.go
@@ -0,0 +1,80 @@
+// 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 (
+	"fmt"
+	"math"
+	"strings"
+
+	"maunium.net/go/gomuks/ui/widget"
+	"maunium.net/go/mauview"
+)
+
+type ListEntity struct {
+	*BaseEntity
+	Ordered bool
+	Start   int
+}
+
+func digits(num int) int {
+	if num <= 0 {
+		return 0
+	}
+	return int(math.Floor(math.Log10(float64(num))) + 1)
+}
+
+func NewListEntity(ordered bool, start int, children []Entity) *ListEntity {
+	entity := &ListEntity{
+		BaseEntity: &BaseEntity{
+			Tag:      "ul",
+			Children: children,
+			Block:    true,
+			Indent:   2,
+		},
+		Ordered: ordered,
+		Start:   start,
+	}
+	if ordered {
+		entity.Tag = "ol"
+		entity.Indent += digits(start + len(children) - 1)
+	}
+	return entity
+}
+
+func (le *ListEntity) Draw(screen mauview.Screen) {
+	width, _ := screen.Size()
+
+	proxyScreen := &mauview.ProxyScreen{Parent: screen, OffsetX: le.Indent, Width: width - le.Indent, Style: le.Style}
+	for i, entity := range le.Children {
+		proxyScreen.Height = entity.Height()
+		if le.Ordered {
+			number := le.Start + i
+			line := fmt.Sprintf("%d. %s", number, strings.Repeat(" ", le.Indent-2-digits(number)))
+			widget.WriteLine(screen, mauview.AlignLeft, line, 0, proxyScreen.OffsetY, le.Indent, le.Style)
+		} else {
+			screen.SetContent(0, proxyScreen.OffsetY, '●', nil, le.Style)
+		}
+		entity.Draw(proxyScreen)
+		proxyScreen.SetStyle(le.Style)
+		proxyScreen.OffsetY += entity.Height()
+	}
+}
+
+func (le *ListEntity) String() string {
+	return fmt.Sprintf("&html.ListEntity{Ordered=%t, Start=%d, Base=%s},\n", le.Ordered, le.Start, le.BaseEntity)
+}
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
+}