1 files changed, 260 insertions, 0 deletions
diff --git a/message-view.go b/message-view.go
new file mode 100644
index 0000000..633c551
--- /dev/null
+++ b/message-view.go
@@ -0,0 +1,260 @@
+// 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 main
+
+import (
+	"regexp"
+	"strings"
+	"time"
+
+	"github.com/gdamore/tcell"
+	"github.com/mattn/go-runewidth"
+	"maunium.net/go/tview"
+)
+
+type Message struct {
+	ID           string
+	Sender       string
+	Text         string
+	Timestamp    string
+	RenderSender bool
+
+	buffer      []string
+	senderColor tcell.Color
+}
+
+var (
+	boundaryPattern = regexp.MustCompile("([[:punct:]]\\s*|\\s+)")
+	spacePattern    = regexp.MustCompile(`\s+`)
+)
+
+func (message *Message) calculateBuffer(width int) {
+	if width < 1 {
+		return
+	}
+	message.buffer = []string{}
+	forcedLinebreaks := strings.Split(message.Text, "\n")
+	newlines := 0
+	for _, str := range forcedLinebreaks {
+		if len(str) == 0 && newlines < 1 {
+			message.buffer = append(message.buffer, "")
+			newlines++
+		} else {
+			newlines = 0
+		}
+		// From tview/textview.go#reindexBuffer()
+		for len(str) > 0 {
+			extract := runewidth.Truncate(str, width, "")
+			if len(extract) < len(str) {
+				if spaces := spacePattern.FindStringIndex(str[len(extract):]); spaces != nil && spaces[0] == 0 {
+					extract = str[:len(extract)+spaces[1]]
+				}
+
+				matches := boundaryPattern.FindAllStringIndex(extract, -1)
+				if len(matches) > 0 {
+					extract = extract[:matches[len(matches)-1][1]]
+				}
+			}
+			message.buffer = append(message.buffer, extract)
+			str = str[len(extract):]
+		}
+	}
+}
+
+type MessageView struct {
+	*tview.Box
+
+	ScrollOffset    int
+	MaxSenderWidth  int
+	TimestampFormat string
+	TimestampWidth  int
+	Separator       rune
+
+	widestSender        int
+	prevWidth           int
+	prevHeight          int
+	prevScrollOffset    int
+	firstDisplayMessage int
+	lastDisplayMessage  int
+	totalHeight         int
+
+	messages []*Message
+
+	debug DebugPrinter
+}
+
+func NewMessageView(debug DebugPrinter) *MessageView {
+	return &MessageView{
+		Box:             tview.NewBox(),
+		MaxSenderWidth:  20,
+		TimestampFormat: "15:04:05",
+		TimestampWidth:  8,
+		Separator:       '|',
+		ScrollOffset:    0,
+
+		widestSender:        5,
+		prevWidth:           -1,
+		prevHeight:          -1,
+		prevScrollOffset:    -1,
+		firstDisplayMessage: -1,
+		lastDisplayMessage:  -1,
+		totalHeight:         -1,
+
+		debug: debug,
+	}
+}
+
+func (view *MessageView) recalculateBuffers(width int) {
+	width -= view.TimestampWidth + TimestampSenderGap + view.widestSender + SenderMessageGap
+	for _, message := range view.messages {
+		message.calculateBuffer(width)
+	}
+	view.prevWidth = width
+}
+
+func (view *MessageView) AddMessage(id, sender, text string, timestamp time.Time) {
+	if len(sender) > view.widestSender {
+		view.widestSender = len(sender)
+		if view.widestSender > view.MaxSenderWidth {
+			view.widestSender = view.MaxSenderWidth
+		}
+	}
+	message := &Message{
+		ID:           id,
+		Sender:       sender,
+		RenderSender: true,
+		Text:         text,
+		Timestamp:    timestamp.Format(view.TimestampFormat),
+		senderColor:  getColor(sender),
+	}
+	_, _, width, height := view.GetInnerRect()
+	width -= view.TimestampWidth + TimestampSenderGap + view.widestSender + SenderMessageGap
+	message.calculateBuffer(width)
+	if view.ScrollOffset > 0 {
+		view.ScrollOffset += len(message.buffer)
+	}
+	if len(view.messages) > 0 && view.messages[len(view.messages)-1].Sender == message.Sender {
+		message.RenderSender = false
+	}
+	view.messages = append(view.messages, message)
+	view.recalculateHeight(height)
+}
+
+func (view *MessageView) recalculateHeight(height int) {
+	view.firstDisplayMessage = -1
+	view.lastDisplayMessage = -1
+	view.totalHeight = 0
+	for i := len(view.messages) - 1; i >= 0; i-- {
+		prevTotalHeight := view.totalHeight
+		view.totalHeight += len(view.messages[i].buffer)
+
+		if view.totalHeight < view.ScrollOffset {
+			continue
+		} else if view.firstDisplayMessage == -1 {
+			view.lastDisplayMessage = i
+			view.firstDisplayMessage = i
+		}
+
+		if prevTotalHeight < height+view.ScrollOffset {
+			view.lastDisplayMessage = i
+		}
+	}
+	view.prevScrollOffset = view.ScrollOffset
+}
+
+func (view *MessageView) PageUp() {
+	_, _, _, height := view.GetInnerRect()
+	view.ScrollOffset += height / 2
+	if view.ScrollOffset > view.totalHeight-height {
+		view.ScrollOffset = view.totalHeight - height + 5
+	}
+}
+
+func (view *MessageView) PageDown() {
+	_, _, _, height := view.GetInnerRect()
+	view.ScrollOffset -= height / 2
+	if view.ScrollOffset < 0 {
+		view.ScrollOffset = 0
+	}
+}
+
+func (view *MessageView) writeLine(screen tcell.Screen, line string, x, y int, color tcell.Color) {
+	offsetX := 0
+	for _, ch := range line {
+		chWidth := runewidth.RuneWidth(ch)
+		if chWidth == 0 {
+			continue
+		}
+
+		for localOffset := 0; localOffset < chWidth; localOffset++ {
+			screen.SetContent(x+offsetX+localOffset, y, ch, nil, tcell.StyleDefault.Foreground(color))
+		}
+		offsetX += chWidth
+	}
+}
+
+const (
+	TimestampSenderGap = 1
+	SenderSeparatorGap = 1
+	SenderMessageGap   = 3
+)
+
+func (view *MessageView) Draw(screen tcell.Screen) {
+	view.Box.Draw(screen)
+
+	x, y, width, height := view.GetInnerRect()
+	if width != view.prevWidth {
+		view.recalculateBuffers(width)
+	}
+	if height != view.prevHeight || width != view.prevWidth || view.ScrollOffset != view.prevScrollOffset {
+		view.recalculateHeight(height)
+	}
+	usernameOffsetX := view.TimestampWidth + TimestampSenderGap
+	messageOffsetX := usernameOffsetX + view.widestSender + SenderMessageGap
+
+	separatorX := x + usernameOffsetX + view.widestSender + SenderSeparatorGap
+	for separatorY := y; separatorY < y+height; separatorY++ {
+		screen.SetContent(separatorX, separatorY, view.Separator, nil, tcell.StyleDefault)
+	}
+
+	if view.firstDisplayMessage == -1 || view.lastDisplayMessage == -1 {
+		return
+	}
+
+	writeOffset := 0
+	for i := view.firstDisplayMessage; i >= view.lastDisplayMessage; i-- {
+		message := view.messages[i]
+		messageHeight := len(message.buffer)
+
+		senderAtLine := y + height - writeOffset - messageHeight
+		if senderAtLine < y {
+			senderAtLine = y
+		}
+		view.writeLine(screen, message.Timestamp, x, senderAtLine, tcell.ColorDefault)
+		if message.RenderSender || i == view.lastDisplayMessage {
+			view.writeLine(screen, message.Sender, x+usernameOffsetX, senderAtLine, message.senderColor)
+		}
+
+		for num, line := range message.buffer {
+			offsetY := height - messageHeight - writeOffset + num
+			if offsetY >= 0 {
+				view.writeLine(screen, line, x+messageOffsetX, y+offsetY, tcell.ColorDefault)
+			}
+		}
+		writeOffset += messageHeight
+	}
+}