1 files changed, 360 insertions, 0 deletions
diff --git a/ui/message-view.go b/ui/message-view.go
new file mode 100644
index 0000000..f9d477b
--- /dev/null
+++ b/ui/message-view.go
@@ -0,0 +1,360 @@
+// 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 ui
+
+import (
+	"encoding/gob"
+	"fmt"
+	"math"
+	"os"
+	"time"
+
+	"github.com/gdamore/tcell"
+	"maunium.net/go/gomuks/debug"
+	"maunium.net/go/gomuks/interface"
+	"maunium.net/go/gomuks/ui/messages"
+	"maunium.net/go/gomuks/ui/widget"
+	"maunium.net/go/tview"
+)
+
+type MessageView struct {
+	*tview.Box
+
+	ScrollOffset    int
+	MaxSenderWidth  int
+	DateFormat      string
+	TimestampFormat string
+	TimestampWidth  int
+	LoadingMessages bool
+
+	widestSender int
+	prevWidth    int
+	prevHeight   int
+	prevMsgCount int
+
+	messageIDs map[string]messages.UIMessage
+	messages   []messages.UIMessage
+
+	textBuffer []string
+	metaBuffer []ifc.MessageMeta
+}
+
+func NewMessageView() *MessageView {
+	return &MessageView{
+		Box:             tview.NewBox(),
+		MaxSenderWidth:  15,
+		DateFormat:      "January _2, 2006",
+		TimestampFormat: "15:04:05",
+		TimestampWidth:  8,
+		ScrollOffset:    0,
+
+		messages:   make([]messages.UIMessage, 0),
+		messageIDs: make(map[string]messages.UIMessage),
+		textBuffer: make([]string, 0),
+		metaBuffer: make([]ifc.MessageMeta, 0),
+
+		widestSender: 5,
+		prevWidth:    -1,
+		prevHeight:   -1,
+		prevMsgCount: -1,
+	}
+}
+
+func (view *MessageView) NewMessage(id, sender, msgtype, text string, timestamp time.Time) messages.UIMessage {
+	return messages.NewMessage(id, sender, msgtype, text,
+		timestamp.Format(view.TimestampFormat),
+		timestamp.Format(view.DateFormat),
+		widget.GetHashColor(sender))
+}
+
+func (view *MessageView) SaveHistory(path string) error {
+	file, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE, 0600)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	enc := gob.NewEncoder(file)
+	err = enc.Encode(view.messages)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (view *MessageView) LoadHistory(path string) (int, error) {
+	file, err := os.OpenFile(path, os.O_RDONLY, 0600)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return 0, nil
+		}
+		return -1, err
+	}
+	defer file.Close()
+
+	dec := gob.NewDecoder(file)
+	err = dec.Decode(&view.messages)
+	if err != nil {
+		return -1, err
+	}
+
+	for _, message := range view.messages {
+		view.updateWidestSender(message.Sender())
+	}
+
+	return len(view.messages), nil
+}
+
+func (view *MessageView) updateWidestSender(sender string) {
+	if len(sender) > view.widestSender {
+		view.widestSender = len(sender)
+		if view.widestSender > view.MaxSenderWidth {
+			view.widestSender = view.MaxSenderWidth
+		}
+	}
+}
+
+func (view *MessageView) UpdateMessageID(ifcMessage ifc.Message, newID string) {
+	message, ok := ifcMessage.(messages.UIMessage)
+	if !ok {
+		debug.Print("[Warning] Passed non-UIMessage ifc.Message object to UpdateMessageID().")
+		debug.PrintStack()
+		return
+	}
+	delete(view.messageIDs, message.ID())
+	message.SetID(newID)
+	view.messageIDs[message.ID()] = message
+}
+
+func (view *MessageView) AddMessage(ifcMessage ifc.Message, direction ifc.MessageDirection) {
+	if ifcMessage == nil {
+		return
+	}
+	message, ok := ifcMessage.(messages.UIMessage)
+	if !ok {
+		debug.Print("[Warning] Passed non-UIMessage ifc.Message object to AddMessage().")
+		debug.PrintStack()
+		return
+	}
+
+	msg, messageExists := view.messageIDs[message.ID()]
+	if msg != nil && messageExists {
+		msg.CopyFrom(message)
+		message = msg
+		direction = ifc.IgnoreMessage
+	}
+
+	view.updateWidestSender(message.Sender())
+
+	_, _, width, _ := view.GetInnerRect()
+	width -= view.TimestampWidth + TimestampSenderGap + view.widestSender + SenderMessageGap
+	message.CalculateBuffer(width)
+
+	if direction == ifc.AppendMessage {
+		if view.ScrollOffset > 0 {
+			view.ScrollOffset += message.Height()
+		}
+		view.messages = append(view.messages, message)
+		view.appendBuffer(message)
+	} else if direction == ifc.PrependMessage {
+		view.messages = append([]messages.UIMessage{message}, view.messages...)
+	}
+
+	view.messageIDs[message.ID()] = message
+}
+
+func (view *MessageView) appendBuffer(message messages.UIMessage) {
+	if len(view.metaBuffer) > 0 {
+		prevMeta := view.metaBuffer[len(view.metaBuffer)-1]
+		if prevMeta != nil && prevMeta.Date() != message.Date() {
+			view.textBuffer = append(view.textBuffer, fmt.Sprintf("Date changed to %s", message.Date()))
+			view.metaBuffer = append(view.metaBuffer, &messages.BasicMeta{BTextColor: tcell.ColorGreen})
+		}
+	}
+
+	view.textBuffer = append(view.textBuffer, message.Buffer()...)
+	for range message.Buffer() {
+		view.metaBuffer = append(view.metaBuffer, message)
+	}
+	view.prevMsgCount++
+}
+
+func (view *MessageView) recalculateBuffers() {
+	_, _, width, height := view.GetInnerRect()
+
+	width -= view.TimestampWidth + TimestampSenderGap + view.widestSender + SenderMessageGap
+	recalculateMessageBuffers := width != view.prevWidth
+	if height != view.prevHeight || recalculateMessageBuffers || len(view.messages) != view.prevMsgCount {
+		view.textBuffer = []string{}
+		view.metaBuffer = []ifc.MessageMeta{}
+		view.prevMsgCount = 0
+		for _, message := range view.messages {
+			if recalculateMessageBuffers {
+				message.CalculateBuffer(width)
+			}
+			view.appendBuffer(message)
+		}
+		view.prevHeight = height
+		view.prevWidth = width
+	}
+}
+
+const PaddingAtTop = 5
+
+func (view *MessageView) AddScrollOffset(diff int) {
+	_, _, _, height := view.GetInnerRect()
+
+	totalHeight := len(view.textBuffer)
+	if diff >= 0 && view.ScrollOffset+diff >= totalHeight-height+PaddingAtTop {
+		view.ScrollOffset = totalHeight - height + PaddingAtTop
+	} else {
+		view.ScrollOffset += diff
+	}
+
+	if view.ScrollOffset > totalHeight-height+PaddingAtTop {
+		view.ScrollOffset = totalHeight - height + PaddingAtTop
+	}
+	if view.ScrollOffset < 0 {
+		view.ScrollOffset = 0
+	}
+}
+
+func (view *MessageView) Height() int {
+	_, _, _, height := view.GetInnerRect()
+	return height
+}
+
+func (view *MessageView) TotalHeight() int {
+	return len(view.textBuffer)
+}
+
+func (view *MessageView) IsAtTop() bool {
+	_, _, _, height := view.GetInnerRect()
+	totalHeight := len(view.textBuffer)
+	return view.ScrollOffset >= totalHeight-height+PaddingAtTop
+}
+
+const (
+	TimestampSenderGap = 1
+	SenderSeparatorGap = 1
+	SenderMessageGap   = 3
+)
+
+func getScrollbarStyle(scrollbarHere, isTop, isBottom bool) (char rune, style tcell.Style) {
+	char = '│'
+	style = tcell.StyleDefault
+	if scrollbarHere {
+		style = style.Foreground(tcell.ColorGreen)
+	}
+	if isTop {
+		if scrollbarHere {
+			char = '╥'
+		} else {
+			char = '┬'
+		}
+	} else if isBottom {
+		if scrollbarHere {
+			char = '╨'
+		} else {
+			char = '┴'
+		}
+	} else if scrollbarHere {
+		char = '║'
+	}
+	return
+}
+
+func (view *MessageView) Draw(screen tcell.Screen) {
+	view.Box.Draw(screen)
+
+	x, y, _, height := view.GetInnerRect()
+	view.recalculateBuffers()
+
+	if len(view.textBuffer) == 0 {
+		widget.WriteLineSimple(screen, "It's quite empty in here.", x, y+height)
+		return
+	}
+
+	usernameX := x + view.TimestampWidth + TimestampSenderGap
+	messageX := usernameX + view.widestSender + SenderMessageGap
+	separatorX := usernameX + view.widestSender + SenderSeparatorGap
+
+	indexOffset := len(view.textBuffer) - view.ScrollOffset - height
+	if indexOffset <= -PaddingAtTop {
+		message := "Scroll up to load more messages."
+		if view.LoadingMessages {
+			message = "Loading more messages..."
+		}
+		widget.WriteLineSimpleColor(screen, message, messageX, y, tcell.ColorGreen)
+	}
+
+	if len(view.textBuffer) != len(view.metaBuffer) {
+		debug.Printf("Unexpected text/meta buffer length mismatch: %d != %d.", len(view.textBuffer), len(view.metaBuffer))
+		return
+	}
+
+	var scrollBarHeight, scrollBarPos int
+	// Black magic (aka math) used to figure out where the scroll bar should be put.
+	{
+		viewportHeight := float64(height)
+		contentHeight := float64(len(view.textBuffer))
+
+		scrollBarHeight = int(math.Ceil(viewportHeight / (contentHeight / viewportHeight)))
+
+		scrollBarPos = height - int(math.Round(float64(view.ScrollOffset)/contentHeight*viewportHeight))
+	}
+
+	var prevMeta ifc.MessageMeta
+	firstLine := true
+	skippedLines := 0
+
+	for line := 0; line < height; line++ {
+		index := indexOffset + line
+		if index < 0 {
+			skippedLines++
+			continue
+		} else if index >= len(view.textBuffer) {
+			break
+		}
+
+		showScrollbar := line-skippedLines >= scrollBarPos-scrollBarHeight && line-skippedLines < scrollBarPos
+		isTop := firstLine && view.ScrollOffset+height >= len(view.textBuffer)
+		isBottom := line == height-1 && view.ScrollOffset == 0
+
+		borderChar, borderStyle := getScrollbarStyle(showScrollbar, isTop, isBottom)
+
+		firstLine = false
+
+		screen.SetContent(separatorX, y+line, borderChar, nil, borderStyle)
+
+		text, meta := view.textBuffer[index], view.metaBuffer[index]
+		if meta != prevMeta {
+			if len(meta.Timestamp()) > 0 {
+				widget.WriteLineSimpleColor(screen, meta.Timestamp(), x, y+line, meta.TimestampColor())
+			}
+			if prevMeta == nil || meta.Sender() != prevMeta.Sender() {
+				widget.WriteLineColor(
+					screen, tview.AlignRight, meta.Sender(),
+					usernameX, y+line, view.widestSender,
+					meta.SenderColor())
+			}
+			prevMeta = meta
+		}
+		widget.WriteLineSimpleColor(screen, text, messageX, y+line, meta.TextColor())
+	}
+}