Refactor message parsing things

1 files changed, 312 insertions, 0 deletions

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] == ' '
+}