Add support for loading more history

6 files changed, 189 insertions, 143 deletions

diff --git a/README.md b/README.md
index 854f65b..80ed3c6 100644
--- a/README.md
+++ b/README.md
@@ -3,8 +3,7 @@
 
 A terminal Matrix client written in Go using [gomatrix](https://github.com/matrix-org/gomatrix) and [tview](https://github.com/rivo/tview).
 
-Basic usage is possible, but many of the features you'd expect from a Matrix
-client (like proper chat history) haven't been implemented.
+Basic usage is possible, but expect bugs and missing features.
 
 ## Discussion
 
diff --git a/interface/ui.go b/interface/ui.go
index 406aa2f..088c2f4 100644
--- a/interface/ui.go
+++ b/interface/ui.go
@@ -48,7 +48,6 @@ type MainView interface {
 
 	SetTyping(roomID string, users []string)
 	AddServiceMessage(roomID string, message string)
-	GetHistory(room string)
 	ProcessMessageEvent(evt *gomatrix.Event) (*widget.RoomView, *types.Message)
 	ProcessMembershipEvent(evt *gomatrix.Event, new bool) (*widget.RoomView, *types.Message)
 }
diff --git a/matrix/matrix.go b/matrix/matrix.go
index 564dc81..f20825c 100644
--- a/matrix/matrix.go
+++ b/matrix/matrix.go
@@ -74,7 +74,7 @@ func (c *Container) InitClient() error {
 
 	c.stop = make(chan bool, 1)
 
-	if c.config.Session != nil {
+	if c.config.Session != nil && len(c.config.Session.AccessToken) > 0 {
 		go c.Start()
 	}
 	return nil
@@ -120,6 +120,11 @@ func (c *Container) Client() *gomatrix.Client {
 func (c *Container) UpdateRoomList() {
 	resp, err := c.client.JoinedRooms()
 	if err != nil {
+		respErr, _ := err.(gomatrix.HTTPError).WrappedError.(gomatrix.RespError)
+		if respErr.ErrCode == "M_UNKNOWN_TOKEN" {
+			c.OnLogout()
+			return
+		}
 		debug.Print("Error fetching room list:", err)
 		return
 	}
@@ -127,6 +132,11 @@ func (c *Container) UpdateRoomList() {
 	c.ui.MainView().SetRooms(resp.JoinedRooms)
 }
 
+func (c *Container) OnLogout() {
+	c.Stop()
+	c.ui.SetView(ifc.ViewLogin)
+}
+
 func (c *Container) OnLogin() {
 	c.client.Store = c.config.Session
 
@@ -145,6 +155,10 @@ func (c *Container) Start() {
 	c.ui.SetView(ifc.ViewMain)
 	c.OnLogin()
 
+	if c.client == nil {
+		return
+	}
+
 	debug.Print("Starting sync...")
 	c.running = true
 	for {
@@ -167,6 +181,7 @@ func (c *Container) HandleMessage(evt *gomatrix.Event) {
 	room, message := c.ui.MainView().ProcessMessageEvent(evt)
 	if room != nil {
 		room.AddMessage(message, widget.AppendMessage)
+		c.ui.Render()
 	}
 }
 
@@ -184,6 +199,7 @@ func (c *Container) HandleMembership(evt *gomatrix.Event) {
 		room.UpdateUserList()
 
 		room.AddMessage(message, widget.AppendMessage)
+		c.ui.Render()
 	}
 }
 
diff --git a/ui/view-main.go b/ui/view-main.go
index a2848e8..2cb8d60 100644
--- a/ui/view-main.go
+++ b/ui/view-main.go
@@ -175,7 +175,7 @@ func (view *MainView) HandleCommand(room, command string, args []string) {
 
 func (view *MainView) InputCapture(key *tcell.EventKey) *tcell.EventKey {
 	k := key.Key()
-	if key.Modifiers() == tcell.ModCtrl {
+	if key.Modifiers() == tcell.ModCtrl || key.Modifiers() == tcell.ModAlt {
 		if k == tcell.KeyDown {
 			view.SwitchRoom(view.currentRoomIndex + 1)
 			view.roomList.SetCurrentItem(view.currentRoomIndex)
@@ -185,13 +185,18 @@ func (view *MainView) InputCapture(key *tcell.EventKey) *tcell.EventKey {
 		} else {
 			return key
 		}
-	} else if k == tcell.KeyPgUp || k == tcell.KeyPgDn {
+	} else if k == tcell.KeyPgUp || k == tcell.KeyPgDn || k == tcell.KeyUp || k == tcell.KeyDown {
 		msgView := view.rooms[view.CurrentRoomID()].MessageView()
-		if k == tcell.KeyPgUp {
-			msgView.PageUp()
+		if k == tcell.KeyPgUp || k == tcell.KeyUp {
+			if msgView.IsAtTop() {
+				go view.LoadMoreHistory(view.CurrentRoomID())
+			} else {
+				msgView.MoveUp(k == tcell.KeyPgUp)
+			}
 		} else {
-			msgView.PageDown()
+			msgView.MoveDown(k == tcell.KeyPgDn)
 		}
+		view.parent.Render()
 	} else {
 		return key
 	}
@@ -225,11 +230,11 @@ func (view *MainView) addRoom(index int, room string) {
 		view.SwitchRoom(index)
 	})
 	if !view.roomView.HasPage(room) {
-		roomView := widget.NewRoomView(view, roomStore)
+		roomView := widget.NewRoomView(roomStore)
 		view.rooms[room] = roomView
 		view.roomView.AddPage(room, roomView, true, false)
 		roomView.UpdateUserList()
-		view.GetHistory(room)
+		go view.LoadInitialHistory(room)
 	}
 }
 
@@ -269,7 +274,7 @@ func (view *MainView) RemoveRoom(room string) {
 	view.roomIDs = append(view.roomIDs[:removeIndex], view.roomIDs[removeIndex+1:]...)
 	view.roomView.RemovePage(room)
 	delete(view.rooms, room)
-	view.Render()
+	view.parent.Render()
 }
 
 func (view *MainView) SetRooms(rooms []string) {
@@ -294,24 +299,52 @@ func (view *MainView) SetTyping(room string, users []string) {
 func (view *MainView) AddServiceMessage(room, message string) {
 	roomView, ok := view.rooms[room]
 	if ok {
-		messageView := roomView.MessageView()
-		message := messageView.NewMessage("", "*", message, time.Now())
-		messageView.AddMessage(message, widget.AppendMessage)
+		message := roomView.NewMessage("", "*", message, time.Now())
+		roomView.AddMessage(message, widget.AppendMessage)
 		view.parent.Render()
 	}
 }
 
-func (view *MainView) Render() {
-	view.parent.Render()
+func (view *MainView) LoadMoreHistory(room string) {
+	view.UpdateLogs(room, false)
+}
+
+func (view *MainView) LoadInitialHistory(room string) {
+	view.UpdateLogs(room, true)
 }
 
-func (view *MainView) GetHistory(room string) {
+func (view *MainView) UpdateLogs(room string, initial bool) {
+	defer view.gmx.Recover()
 	roomView := view.rooms[room]
-	history, _, err := view.matrix.GetHistory(roomView.Room.ID, view.config.Session.NextBatch, 50)
+
+	batch := roomView.Room.PrevBatch
+	lockTime := time.Now().Unix() + 1
+
+	roomView.FetchHistoryLock.Lock()
+	roomView.MessageView().LoadingMessages = true
+	defer func() {
+		roomView.FetchHistoryLock.Unlock()
+		roomView.MessageView().LoadingMessages = false
+	}()
+
+	// There's no clean way to try to lock a mutex, so we just check if we still
+	// want to continue after we get the lock. This function should always be ran
+	// in a goroutine, so the blocking doesn't matter.
+	if time.Now().Unix() >= lockTime || batch != roomView.Room.PrevBatch {
+		return
+	}
+
+	if initial {
+		batch = view.config.Session.NextBatch
+	}
+	debug.Print("Loading history for", room, "starting from", batch, "(initial:", initial, ")")
+	history, prevBatch, err := view.matrix.GetHistory(roomView.Room.ID, batch, 50)
 	if err != nil {
+		view.AddServiceMessage(room, "Failed to fetch history")
 		debug.Print("Failed to fetch history for", roomView.Room.ID, err)
 		return
 	}
+	roomView.Room.PrevBatch = prevBatch
 	for _, evt := range history {
 		var room *widget.RoomView
 		var message *types.Message
@@ -324,6 +357,7 @@ func (view *MainView) GetHistory(room string) {
 			room.AddMessage(message, widget.PrependMessage)
 		}
 	}
+	view.parent.Render()
 }
 
 func (view *MainView) ProcessMessageEvent(evt *gomatrix.Event) (room *widget.RoomView, message *types.Message) {
diff --git a/ui/widget/message-view.go b/ui/widget/message-view.go
index 3503a5f..953dd7d 100644
--- a/ui/widget/message-view.go
+++ b/ui/widget/message-view.go
@@ -18,7 +18,6 @@ package widget
 
 import (
 	"fmt"
-	"strings"
 	"time"
 
 	"github.com/gdamore/tcell"
@@ -36,17 +35,17 @@ type MessageView struct {
 	TimestampFormat string
 	TimestampWidth  int
 	Separator       rune
+	LoadingMessages bool
 
-	widestSender        int
-	prevWidth           int
-	prevHeight          int
-	prevScrollOffset    int
-	firstDisplayMessage int
-	lastDisplayMessage  int
-	totalHeight         int
+	widestSender int
+	prevWidth    int
+	prevHeight   int
 
 	messageIDs map[string]bool
 	messages   []*types.Message
+
+	metaBuffer []*types.Message
+	textBuffer []string
 }
 
 func NewMessageView() *MessageView {
@@ -61,14 +60,12 @@ func NewMessageView() *MessageView {
 
 		messages:   make([]*types.Message, 0),
 		messageIDs: make(map[string]bool),
+		textBuffer: make([]string, 0),
+		metaBuffer: make([]*types.Message, 0),
 
-		widestSender:        5,
-		prevWidth:           -1,
-		prevHeight:          -1,
-		prevScrollOffset:    -1,
-		firstDisplayMessage: -1,
-		lastDisplayMessage:  -1,
-		totalHeight:         -1,
+		widestSender: 5,
+		prevWidth:    -1,
+		prevHeight:   -1,
 	}
 }
 
@@ -79,17 +76,6 @@ func (view *MessageView) NewMessage(id, sender, text string, timestamp time.Time
 		GetHashColor(sender))
 }
 
-func (view *MessageView) recalculateBuffers() {
-	_, _, width, _ := view.GetInnerRect()
-	width -= view.TimestampWidth + TimestampSenderGap + view.widestSender + SenderMessageGap
-	if width != view.prevWidth {
-		for _, message := range view.messages {
-			message.CalculateBuffer(width)
-		}
-		view.prevWidth = width
-	}
-}
-
 func (view *MessageView) updateWidestSender(sender string) {
 	if len(sender) > view.widestSender {
 		view.widestSender = len(sender)
@@ -100,7 +86,7 @@ func (view *MessageView) updateWidestSender(sender string) {
 }
 
 const (
-	AppendMessage  int = iota
+	AppendMessage  = iota
 	PrependMessage
 )
 
@@ -126,53 +112,87 @@ func (view *MessageView) AddMessage(message *types.Message, direction int) {
 	}
 
 	view.messageIDs[message.ID] = true
-	view.recalculateHeight()
+	view.appendBuffer(message)
 }
 
-func (view *MessageView) recalculateHeight() {
-	_, _, width, height := view.GetInnerRect()
-	if height != view.prevHeight || width != view.prevWidth || view.ScrollOffset != view.prevScrollOffset {
-		view.firstDisplayMessage = -1
-		view.lastDisplayMessage = -1
-		view.totalHeight = 0
-		prevDate := ""
-		for i := len(view.messages) - 1; i >= 0; i-- {
-			prevTotalHeight := view.totalHeight
-			message := view.messages[i]
-			view.totalHeight += len(message.Buffer)
-			if message.Date != prevDate {
-				if len(prevDate) != 0 {
-					view.totalHeight++
-				}
-				prevDate = message.Date
-			}
+func (view *MessageView) recalculateMessageBuffers() {
+	_, _, width, _ := view.GetInnerRect()
+	width -= view.TimestampWidth + TimestampSenderGap + view.widestSender + SenderMessageGap
+	if width != view.prevWidth {
+		for _, message := range view.messages {
+			message.CalculateBuffer(width)
+		}
+		view.prevWidth = width
+	}
+}
 
-			if view.totalHeight < view.ScrollOffset {
-				continue
-			} else if view.firstDisplayMessage == -1 {
-				view.lastDisplayMessage = i
-				view.firstDisplayMessage = i
-			}
+func (view *MessageView) appendBuffer(message *types.Message) {
+	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, nil)
+		}
+	}
 
-			if prevTotalHeight < height+view.ScrollOffset {
-				view.lastDisplayMessage = i
-			}
+	view.textBuffer = append(view.textBuffer, message.Buffer...)
+	for range message.Buffer {
+		view.metaBuffer = append(view.metaBuffer, message)
+	}
+}
+
+func (view *MessageView) recalculateBuffer() {
+	_, _, width, height := view.GetInnerRect()
+	view.textBuffer = make([]string, 0)
+	view.metaBuffer = make([]*types.Message, 0)
+
+	if height != view.prevHeight || width != view.prevWidth {
+		for _, message := range view.messages {
+			view.appendBuffer(message)
 		}
-		view.prevScrollOffset = view.ScrollOffset
+		view.prevHeight = height
 	}
 }
 
-func (view *MessageView) PageUp() {
+const PaddingAtTop = 5
+
+func (view *MessageView) MoveUp(page bool) {
 	_, _, _, height := view.GetInnerRect()
-	view.ScrollOffset += height / 2
-	if view.ScrollOffset > view.totalHeight-height {
-		view.ScrollOffset = view.totalHeight - height + 5
+
+	totalHeight := len(view.textBuffer)
+	if view.ScrollOffset >= totalHeight-height {
+		// If the user is at the top and presses page up again, add a bit of blank space.
+		if page {
+			view.ScrollOffset = totalHeight - height + PaddingAtTop
+		} else if view.ScrollOffset < totalHeight-height+PaddingAtTop {
+			view.ScrollOffset++
+		}
+		return
+	}
+
+	if page {
+		view.ScrollOffset += height / 2
+	} else {
+		view.ScrollOffset++
 	}
+	if view.ScrollOffset > totalHeight-height {
+		view.ScrollOffset = totalHeight - height
+	}
+}
+
+func (view *MessageView) IsAtTop() bool {
+	_, _, _, height := view.GetInnerRect()
+	totalHeight := len(view.textBuffer)
+	return view.ScrollOffset >= totalHeight-height+PaddingAtTop
 }
 
-func (view *MessageView) PageDown() {
+func (view *MessageView) MoveDown(page bool) {
 	_, _, _, height := view.GetInnerRect()
-	view.ScrollOffset -= height / 2
+	if page {
+		view.ScrollOffset -= height / 2
+	} else {
+		view.ScrollOffset--
+	}
 	if view.ScrollOffset < 0 {
 		view.ScrollOffset = 0
 	}
@@ -224,10 +244,10 @@ func (view *MessageView) Draw(screen tcell.Screen) {
 	view.Box.Draw(screen)
 
 	x, y, _, height := view.GetInnerRect()
-	view.recalculateBuffers()
-	view.recalculateHeight()
+	view.recalculateMessageBuffers()
+	view.recalculateBuffer()
 
-	if view.firstDisplayMessage == -1 || view.lastDisplayMessage == -1 {
+	if len(view.textBuffer) == 0 {
 		view.writeLine(screen, "It's quite empty in here.", x, y+height, tcell.ColorDefault)
 		return
 	}
@@ -239,55 +259,37 @@ func (view *MessageView) Draw(screen tcell.Screen) {
 		screen.SetContent(separatorX, separatorY, view.Separator, nil, tcell.StyleDefault)
 	}
 
-	writeOffset := 0
-	prevDate := ""
-	prevSender := ""
-	prevSenderLine := -1
-	for i := view.firstDisplayMessage; i >= view.lastDisplayMessage; i-- {
-		message := view.messages[i]
-		messageHeight := len(message.Buffer)
-
-		// Show message when the date changes.
-		if message.Date != prevDate {
-			if len(prevDate) > 0 {
-				writeOffset++
-				view.writeLine(
-					screen, fmt.Sprintf("Date changed to %s", prevDate),
-					x+messageOffsetX, y+height-writeOffset, tcell.ColorGreen)
-			}
-			prevDate = message.Date
+	var prevMeta *types.Message
+	var prevSender string
+	indexOffset := len(view.textBuffer) - view.ScrollOffset - height
+	if indexOffset <= -PaddingAtTop {
+		message := "Scroll up to load more messages."
+		if view.LoadingMessages {
+			message = "Loading more messages..."
 		}
-
-		senderAtLine := y + height - writeOffset - messageHeight
-		// The message may be only partially on screen, so we need to make sure the sender
-		// is on screen even when the message is not shown completely.
-		if senderAtLine < y {
-			senderAtLine = y
-		}
-
-		view.writeLine(screen, message.Timestamp, x, senderAtLine, tcell.ColorDefault)
-		view.writeLineRight(screen, message.Sender,
-			x+usernameOffsetX, senderAtLine,
-			view.widestSender, message.SenderColor)
-
-		if message.Sender == prevSender {
-			// Sender is same as previous. We're looping from bottom to top, and we want the
-			// sender name only on the topmost message, so clear out the duplicate sender name
-			// below.
-			view.writeLineRight(screen, strings.Repeat(" ", view.widestSender),
-				x+usernameOffsetX, prevSenderLine,
-				view.widestSender, message.SenderColor)
+		view.writeLine(screen, message, x+messageOffsetX, y, tcell.ColorGreen)
+	}
+	for line := 0; line < height; line++ {
+		index := indexOffset + line
+		if index < 0 {
+			continue
+		} else if index > len(view.textBuffer) {
+			break
 		}
-		prevSender = message.Sender
-		prevSenderLine = senderAtLine
-
-		for num, line := range message.Buffer {
-			offsetY := height - messageHeight - writeOffset + num
-			// Only render message if it's within the message view.
-			if offsetY >= 0 {
-				view.writeLine(screen, line, x+messageOffsetX, y+offsetY, tcell.ColorDefault)
+		text, meta := view.textBuffer[index], view.metaBuffer[index]
+		if meta != prevMeta {
+			if meta != nil {
+				view.writeLine(screen, meta.Timestamp, x, y+line, tcell.ColorDefault)
+				if meta.Sender != prevSender {
+					view.writeLineRight(
+						screen, meta.Sender,
+						x+usernameOffsetX, y+line,
+						view.widestSender, meta.SenderColor)
+					prevSender = meta.Sender
+				}
 			}
+			prevMeta = meta
 		}
-		writeOffset += messageHeight
+		view.writeLine(screen, text, x+messageOffsetX, y+line, tcell.ColorDefault)
 	}
 }
diff --git a/ui/widget/room-view.go b/ui/widget/room-view.go
index eeab7b2..1fb19c7 100644
--- a/ui/widget/room-view.go
+++ b/ui/widget/room-view.go
@@ -19,6 +19,7 @@ package widget
 import (
 	"fmt"
 	"strings"
+	"sync"
 	"time"
 
 	"github.com/gdamore/tcell"
@@ -27,10 +28,6 @@ import (
 	"maunium.net/go/tview"
 )
 
-type Renderable interface {
-	Render()
-}
-
 type RoomView struct {
 	*tview.Box
 
@@ -40,18 +37,18 @@ type RoomView struct {
 	userList *tview.TextView
 	Room     *rooms.Room
 
-	parent Renderable
+	FetchHistoryLock *sync.Mutex
 }
 
-func NewRoomView(parent Renderable, room *rooms.Room) *RoomView {
+func NewRoomView(room *rooms.Room) *RoomView {
 	view := &RoomView{
-		Box:      tview.NewBox(),
-		topic:    tview.NewTextView(),
-		content:  NewMessageView(),
-		status:   tview.NewTextView(),
-		userList: tview.NewTextView(),
-		Room:     room,
-		parent:   parent,
+		Box:              tview.NewBox(),
+		topic:            tview.NewTextView(),
+		content:          NewMessageView(),
+		status:           tview.NewTextView(),
+		userList:         tview.NewTextView(),
+		FetchHistoryLock: &sync.Mutex{},
+		Room:             room,
 	}
 	view.topic.
 		SetText(strings.Replace(room.GetTopic(), "\n", " ", -1)).
@@ -148,5 +145,4 @@ func (view *RoomView) NewMessage(id, sender, text string, timestamp time.Time) *
 
 func (view *RoomView) AddMessage(message *types.Message, direction int) {
 	view.content.AddMessage(message, direction)
-	view.parent.Render()
 }