move more ui logic into Collection

* Generalize hover detection and move it into ui.Collection
* Implement transparencu for the prompt banner

14 files changed, 374 insertions, 231 deletions

diff --git a/go/client/game.go b/go/client/game.go
index abd68378..8447e452 100644
--- a/go/client/game.go
+++ b/go/client/game.go
@@ -19,9 +19,7 @@ const (
 	RESOLVE_BUTTON_X   = 500
 	STACK_BUFFER_WIDTH = 300
 
-	HOVER_THRESHOLD   = 60
-	HOVER_CARD_WIDTH  = 500
-	HOVER_CARD_HEIGHT = 700
+	HOVER_THRESHOLD = 60
 
 	HAND_VIEW_WIDTH = 500
 
@@ -30,45 +28,8 @@ const (
 	POC_BUTTON_WIDTH = 150
 )
 
-// A simple structure to detect if the cursor has not moved for HOVER_THRESHOLD
-// ticks.
-// hoverDetector.update must be called during each Update invocation to track the
-// frame and the current cursor position.
-type hoverDetector struct {
-	last_x, last_y int
-	ticks          int
-	// ResetFunc is called when the cursor has moved.
-	// If resetFunc returns true the hoverDetector is reset
-	// otherwise the reset is skipped.
-	resetFunc func() bool
-}
-
-func (h *hoverDetector) update(x, y int) {
-	if x == h.last_x && y == h.last_y {
-		h.ticks++
-	} else {
-		h.last_x, h.last_y = x, y
-		h.reset()
-	}
-}
-
-func (h *hoverDetector) reset() {
-	if h.resetFunc != nil && !h.resetFunc() {
-		return
-	}
-	h.ticks = 0
-	h.resetFunc = nil
-}
-
-func (h *hoverDetector) startedHovering() bool {
-	return h.ticks == HOVER_THRESHOLD
-}
-
 type Game struct {
-	width, height int
-
 	selectedObject interface{}
-	hoverDetector  hoverDetector
 
 	handLayer         *ui.HandView
 	stateBar          *ui.StateBar
@@ -81,7 +42,7 @@ type Game struct {
 	storeButton       *ui.SimpleButton
 	stackBuffer       *ui.Buffer
 	prompt            *ui.Prompt
-	widgets           []ui.Widget
+	ui.Collection
 
 	activePlayer *game.Player
 
@@ -94,15 +55,16 @@ type Game struct {
 
 func newGame(app *app) *Game {
 	g := &Game{
-		width:  app.windowWidth,
-		height: app.windowHeight,
+		Collection: ui.Collection{
+			Width:  app.windowWidth,
+			Height: app.windowHeight,
+		},
 	}
 
-	g.widgets = []ui.Widget{}
 	g.gameState = game.NewState()
 
-	g.passButton = ui.NewSimpleButton(g.width-PASS_BUTTON_WIDTH,
-		g.height-DEFAULT_BUTTON_HEIGHT,
+	g.passButton = ui.NewSimpleButton(g.Width-PASS_BUTTON_WIDTH,
+		g.Height-DEFAULT_BUTTON_HEIGHT,
 		PASS_BUTTON_WIDTH,
 		DEFAULT_BUTTON_HEIGHT,
 		"Pass",
@@ -110,7 +72,7 @@ func newGame(app *app) *Game {
 			if g.prompt != nil {
 				a := g.prompt.Confirm()
 				g.declareAction(a)
-				g.removeWidget(g.prompt)
+				g.RemoveWidget(g.prompt)
 				g.prompt = nil
 
 			} else if g.hasPriority {
@@ -118,7 +80,7 @@ func newGame(app *app) *Game {
 			}
 		})
 
-	g.stackBuffer = ui.NewBuffer(g.width-STACK_BUFFER_WIDTH, g.passButton.Y-400,
+	g.stackBuffer = ui.NewBuffer(g.Width-STACK_BUFFER_WIDTH, g.passButton.Y-400,
 		STACK_BUFFER_WIDTH, 400)
 	return g
 }
@@ -130,6 +92,7 @@ func (g *Game) loadMap(mapName string) *Game {
 	}
 	g.gameState.Map = m
 	g.mapView = ui.NewMapView(g.gameState)
+	g.AddWidget(g.mapView)
 
 	storeTiles := m.FilterTiles(func(t *game.Tile) bool { return t.Type == game.TileTypes.Store })
 	g.storesOnMap = len(storeTiles) > 0
@@ -163,56 +126,56 @@ func (g *Game) initPlayerUi(player *game.Player) *Game {
 	g.handLayer = ui.NewHandView(0,
 		g.mapView.Height(),
 		HAND_VIEW_WIDTH,
-		g.height-g.mapView.Height()-DEFAULT_BUTTON_HEIGHT,
+		g.Height-g.mapView.Height()-DEFAULT_BUTTON_HEIGHT,
 		player.Hand,
 		true)
-	g.addWidget(g.handLayer)
+	g.AddWidget(g.handLayer)
 
 	g.stateBar = ui.NewStateBar(0,
-		g.height-DEFAULT_BUTTON_HEIGHT,
+		g.Height-DEFAULT_BUTTON_HEIGHT,
 		STATE_BAR_WIDTH,
 		DEFAULT_BUTTON_HEIGHT,
 		g.gameState,
 		player)
-	g.addWidget(g.stateBar)
+	g.AddWidget(g.stateBar)
 
 	g.discardPileButton = ui.NewSimpleButton(g.stateBar.Width,
-		g.height-DEFAULT_BUTTON_HEIGHT,
+		g.Height-DEFAULT_BUTTON_HEIGHT,
 		POC_BUTTON_WIDTH,
 		DEFAULT_BUTTON_HEIGHT,
 		"DiscardPile",
 		func(*ui.SimpleButton) {
-			if idx := g.findWidget(g.discardPileView); idx == -1 {
+			if idx := g.FindWidget(g.discardPileView); idx == -1 {
 				g.discardPileView.ForceRedraw()
-				g.addWidget(g.discardPileView)
+				g.AddWidget(g.discardPileView)
 			} else {
-				g.removeWidget(g.discardPileView)
+				g.RemoveWidget(g.discardPileView)
 			}
 		})
-	g.addWidget(g.discardPileButton)
+	g.AddWidget(g.discardPileButton)
 
 	x = g.discardPileButton.X + g.discardPileButton.Width/2
-	y = g.height - DEFAULT_BUTTON_HEIGHT
+	y = g.Height - DEFAULT_BUTTON_HEIGHT
 	g.discardPileView = ui.NewPocList(x, y, g.activePlayer.DiscardPile)
 
 	if !g.storesOnMap {
 		x = g.stateBar.Width + g.discardPileButton.Width
-		y = g.height - DEFAULT_BUTTON_HEIGHT
+		y = g.Height - DEFAULT_BUTTON_HEIGHT
 		g.storeButton = ui.NewSimpleButton(x, y,
 			POC_BUTTON_WIDTH,
 			DEFAULT_BUTTON_HEIGHT,
 			"Store",
 			func(*ui.SimpleButton) {
-				if idx := g.findWidget(g.storeView); idx == -1 {
+				if idx := g.FindWidget(g.storeView); idx == -1 {
 					g.showStore()
 				} else {
 					g.hideStore()
 				}
 			})
-		g.addWidget(g.storeButton)
+		g.AddWidget(g.storeButton)
 
 		x = g.storeButton.X + g.storeButton.Width/2
-		y = g.height - DEFAULT_BUTTON_HEIGHT
+		y = g.Height - DEFAULT_BUTTON_HEIGHT
 		g.storeView = ui.NewPocList(x, y, g.activePlayer.Store)
 	}
 
@@ -221,38 +184,11 @@ func (g *Game) initPlayerUi(player *game.Player) *Game {
 
 func (g *Game) showStore() {
 	g.storeView.ForceRedraw()
-	g.addWidget(g.storeView)
+	g.AddWidget(g.storeView)
 }
 
 func (g *Game) hideStore() {
-	g.removeWidget(g.storeView)
-}
-
-func (g *Game) addWidget(w ui.Widget) {
-	g.widgets = append(g.widgets, w)
-}
-
-func (g *Game) findWidget(widget ui.Widget) int {
-	for i, w := range g.widgets {
-		if w != widget {
-			continue
-		}
-		return i
-	}
-	return -1
-}
-
-func (g *Game) removeWidget(widget ui.Widget) {
-	idx := g.findWidget(widget)
-	if idx != -1 {
-		g.removeWidgetAt(idx)
-	}
-}
-
-func (g *Game) removeWidgetAt(idx int) {
-	nwidgets := len(g.widgets)
-	g.widgets[idx] = g.widgets[nwidgets-1]
-	g.widgets = g.widgets[:nwidgets-1]
+	g.RemoveWidget(g.storeView)
 }
 
 func (g *Game) addPermActionChoice(perm game.Permanent, x, y int) {
@@ -276,7 +212,7 @@ func (g *Game) addPermActionChoice(perm game.Permanent, x, y int) {
 			g.addActionChoice(p, x, y)
 		}
 		g.choice = ui.NewPermChoice(x, y, perms, onClick)
-		g.addWidget(g.choice)
+		g.AddWidget(g.choice)
 	} else {
 		g.selectedObject = perms[0]
 		g.addActionChoice(perms[0], x, y)
@@ -297,12 +233,12 @@ func (g *Game) addActionChoice(perm game.Permanent, x, y int) {
 			}
 		}
 		g.choice = ui.NewActionChoice(x, y, actions, onClick)
-		g.addWidget(g.choice)
+		g.AddWidget(g.choice)
 	}
 }
 
 func (g *Game) removeChoice() {
-	g.removeWidget(g.choice)
+	g.RemoveWidget(g.choice)
 	g.choice = nil
 }
 
@@ -337,11 +273,11 @@ func (g *Game) declareAction(a game.Action) {
 }
 
 func (g *Game) showPassButton() {
-	g.addWidget(g.passButton)
+	g.AddWidget(g.passButton)
 }
 
 func (g *Game) hidePassButton() {
-	g.removeWidget(g.passButton)
+	g.RemoveWidget(g.passButton)
 }
 
 func (g *Game) passPriority() {
@@ -363,10 +299,16 @@ func (g *Game) handlePlayerNotifications() {
 			}
 			a := n.Context.(game.Action)
 			g.stackBuffer.AddLine(a.String())
+			if !g.gameState.Stack.IsEmpty() && g.FindWidget(g.stackBuffer) == -1 {
+				g.AddWidget(g.stackBuffer)
+			}
 
 		case game.ResolvedActionNotification:
 			g.clearMapHighlights()
 			g.stackBuffer.RemoveLast()
+			if g.gameState.Stack.IsEmpty() {
+				g.RemoveWidget(g.stackBuffer)
+			}
 			g.mapView.ForceRedraw()
 
 		case game.TargetSelectionPrompt:
@@ -377,8 +319,8 @@ func (g *Game) handlePlayerNotifications() {
 				}
 			}
 
-			g.prompt = ui.NewPrompt(g.height/2, g.width, ctx.Action, ctx.Prompt)
-			g.addWidget(g.prompt)
+			g.prompt = ui.NewPrompt(g.Height/2, g.Width, ctx.Action, ctx.Prompt)
+			g.AddWidget(g.prompt)
 			g.showPassButton()
 		}
 
@@ -392,8 +334,9 @@ func (g *Game) handlePlayerNotifications() {
 func (g *Game) findObjectAt(x, y int) interface{} {
 	// Iterate the widget in reverse order to ensure that objects are found
 	// in the newer widget possibly drawn over older ones
-	for i := len(g.widgets) - 1; i >= 0; i-- {
-		w := g.widgets[i]
+	widgets := g.Widgets()
+	for i := len(widgets) - 1; i >= 0; i-- {
+		w := widgets[i]
 		if obj := w.FindObjectAt(x, y); obj != nil {
 			return obj
 		}
@@ -428,9 +371,6 @@ func (g *Game) handleSelection(obj interface{}, x, y int) {
 		g.handleTargetSelection(obj)
 	} else {
 		switch obj := obj.(type) {
-		case ui.Button:
-			obj.Click(x, y)
-
 		case *game.Tile:
 			if g.storesOnMap && obj.Type == game.TileTypes.Store && g.activePlayer.KnowsStore(obj.Position) {
 				if g.storeView != nil {
@@ -467,72 +407,17 @@ func (g *Game) highlightTargets() {
 	}
 }
 
-func (g *Game) handleHover(obj interface{}, x, y int) {
-	var hoverHint ui.Widget
-	switch obj := obj.(type) {
-	case *game.Card:
-		wx, wy := x, y
-		if x+HOVER_CARD_WIDTH > g.width || y+HOVER_CARD_HEIGHT > g.height {
-			wx = x - HOVER_CARD_WIDTH
-			wy = y - HOVER_CARD_HEIGHT
-		}
-		if wx < 0 {
-			wx = 0
-		}
-		if wy < 0 {
-			wy = 0
-		}
-		hoverHint = ui.NewScaledCardView(wx, wy, HOVER_CARD_WIDTH, HOVER_CARD_HEIGHT, obj.Path())
-	case *game.Unit:
-		hoverHint = ui.NewUnitInfo(x+ui.TILE_WIDTH, y, obj)
-	case game.Permanent:
-		hoverHint = ui.NewPermInfo(x+ui.TILE_WIDTH, y, obj)
-		// case *game.Tile:
-		// if g.storesOnMap && obj.Type == game.TileTypes.Store {
-		// poc := g.gameState.Map.StoreOn(obj.Position)
-		// hoverHint = ui.NewPocList(x, y, poc)
-		// // Set a special hoverDetector resetFunc keeping the hovering store
-		// // around and allow card selection until the cursor leaves the store widget.
-		// g.hoverDetector.resetFunc = func() bool {
-		// x, y := ebiten.CursorPosition()
-		// if hoverHint.Contains(x, y) {
-		// return false
-		// }
-		// g.removeWidget(hoverHint)
-		// return true
-		// }
-		// }
-	}
-
-	if hoverHint != nil {
-		g.addWidget(hoverHint)
-		// Set the default reset function removing the hoverHint
-		if g.hoverDetector.resetFunc == nil {
-			g.hoverDetector.resetFunc = func() bool {
-				g.removeWidget(hoverHint)
-				return true
-			}
-		}
-	}
-}
-
 func (g *Game) Update() error {
 	g.handlePlayerNotifications()
 
+	if err := g.Collection.Update(); err != nil {
+		return nil
+	}
+
 	x, y := ebiten.CursorPosition()
-	g.hoverDetector.update(x, y)
 
 	obj := g.findObjectAt(x, y)
 
-	scrollX, scrollY := ebiten.Wheel()
-	if scrollX != 0 || scrollY != 0 {
-		for _, w := range g.widgets {
-			if scrollable, ok := w.(ui.Scrollable); ok && w.Contains(x, y) {
-				scrollable.Scroll(int(scrollX), int(scrollY))
-			}
-		}
-	}
-
 	g.highlightTargets()
 
 	if inpututil.IsMouseButtonJustPressed(ebiten.MouseButtonLeft) {
@@ -546,36 +431,31 @@ func (g *Game) Update() error {
 		} else {
 			g.handleSelection(obj, x, y)
 		}
-	} else if g.hoverDetector.startedHovering() && g.selectedObject == nil && obj != nil {
-		g.handleHover(obj, x, y)
 	} else if inpututil.IsKeyJustPressed(ebiten.KeySpace) {
 		g.passButton.Click(0, 0)
 	} else if inpututil.IsKeyJustPressed(ebiten.KeyEscape) {
 		g.removeChoice()
 		g.selectedObject = nil
-		g.hoverDetector.reset()
+		g.ResetHover()
 		g.clearMapHighlights()
 		g.handLayer.ClearHighlights()
 		g.hideStore()
-		g.removeWidget(g.discardPileView)
+		g.RemoveWidget(g.discardPileView)
+		if g.prompt != nil {
+			g.prompt.ClearSelections()
+		}
 	}
 	return nil
 }
 
 func (g *Game) Draw(screen *ebiten.Image) {
-	g.mapView.Draw(screen)
-	if !g.gameState.Stack.IsEmpty() {
-		g.stackBuffer.Draw(screen)
-	}
-	for _, b := range g.widgets {
-		b.Draw(screen)
-	}
+	g.Collection.Draw(screen)
 	ebitenutil.DebugPrint(screen,
 		fmt.Sprintf("TPS: %0.2f FPS: %0.2f", ebiten.ActualTPS(), ebiten.ActualFPS()))
 }
 
 func (g *Game) Layout(outsideWidth, outsideHeight int) (int, int) {
-	return g.width, g.height
+	return g.Width, g.Height
 }
 
 func (g *Game) Start() *Game {
diff --git a/go/client/main.go b/go/client/main.go
index 2b7496ad..82b60a40 100644
--- a/go/client/main.go
+++ b/go/client/main.go
@@ -70,7 +70,7 @@ func main() {
 	ebiten.SetWindowSize(app.windowWidth, app.windowHeight)
 	ebiten.SetWindowTitle("Muhq's Game")
 
-	startMenu.width, startMenu.height = app.windowWidth, app.windowHeight
+	startMenu.Width, startMenu.Height = app.windowWidth, app.windowHeight
 
 	if startDeckPath != "" {
 		file, err := os.Open(startDeckPath)
diff --git a/go/client/sealed.go b/go/client/sealed.go
index ab0f0296..c219dbf6 100644
--- a/go/client/sealed.go
+++ b/go/client/sealed.go
@@ -3,6 +3,9 @@ package main
 import (
 	"strings"
 
+	"github.com/hajimehoshi/ebiten/v2"
+	"github.com/hajimehoshi/ebiten/v2/inpututil"
+
 	"muhq.space/muhqs-game/go/game"
 	"muhq.space/muhqs-game/go/ui"
 )
@@ -13,27 +16,29 @@ const (
 
 type Sealed struct {
 	ui.Collection
-	app           *app
-	width, height int
+	app *app
 
 	pool game.PileOfCards
 	deck game.PileOfCards
 }
 
 func NewSealed(width, height int, app *app) *Sealed {
-	s := &Sealed{app: app, width: width, height: height}
+	s := &Sealed{
+		app:        app,
+		Collection: ui.Collection{Width: width, Height: height},
+	}
 
 	s.AddWidget(ui.NewFixedTextBox(
-		(s.width-START_BUTTON_WIDTH)/2-START_BUTTON_WIDTH,
-		(s.height-START_BUTTON_HEIGHT)/2-START_BUTTON_HEIGHT,
+		(s.Width-START_BUTTON_WIDTH)/2-START_BUTTON_WIDTH,
+		(s.Height-START_BUTTON_HEIGHT)/2-START_BUTTON_HEIGHT,
 		START_BUTTON_WIDTH,
 		START_BUTTON_HEIGHT,
 		"sets:",
 	).Centering(true))
 
 	setInput := ui.NewTextInput(
-		(s.width-START_BUTTON_WIDTH)/2,
-		(s.height-START_BUTTON_HEIGHT)/2-START_BUTTON_HEIGHT,
+		(s.Width-START_BUTTON_WIDTH)/2,
+		(s.Height-START_BUTTON_HEIGHT)/2-START_BUTTON_HEIGHT,
 		START_BUTTON_WIDTH,
 		START_BUTTON_HEIGHT,
 		"set list",
@@ -41,8 +46,8 @@ func NewSealed(width, height int, app *app) *Sealed {
 	s.AddWidget(setInput)
 
 	s.AddWidget(ui.NewSimpleButton(
-		(s.width-START_BUTTON_WIDTH)/2,
-		(s.height-START_BUTTON_HEIGHT)/2,
+		(s.Width-START_BUTTON_WIDTH)/2,
+		(s.Height-START_BUTTON_HEIGHT)/2,
 		START_BUTTON_WIDTH,
 		START_BUTTON_HEIGHT,
 		"Start",
@@ -53,8 +58,20 @@ func NewSealed(width, height int, app *app) *Sealed {
 	return s
 }
 
+func (s *Sealed) Update() error {
+	if err := s.Collection.Update(); err != nil {
+		return err
+	}
+
+	if inpututil.IsKeyJustPressed(ebiten.KeyEscape) {
+		s.app.popActivity()
+	}
+
+	return nil
+}
+
 func (s *Sealed) Layout(width, height int) (int, int) {
-	return s.width, s.height
+	return s.Width, s.Height
 }
 
 func (s *Sealed) startSealed(_sets string) {
@@ -75,11 +92,11 @@ func (s *Sealed) startSealed(_sets string) {
 		setDeck.MoveInto(s.pool)
 	}
 
-	deckList := ui.NewPocList(s.width-SIDEBARD_WIDTH/2, s.height-START_BUTTON_HEIGHT-20, s.deck)
+	deckList := ui.NewPocList(s.Width-SIDEBARD_WIDTH/2, s.Height-START_BUTTON_HEIGHT-20, s.deck)
 	deckList.Bg(ui.Gray)
 	s.AddWidget(deckList)
 
-	grid := ui.NewCardGrid(0, 0, s.width-SIDEBARD_WIDTH, s.height, 0.5, s.pool).Columns(3)
+	grid := ui.NewCardGrid(0, 0, s.Width-SIDEBARD_WIDTH, s.Height, 0.5, s.pool).Columns(3)
 	selectCard := func(x, y int) {
 		_card := grid.FindObjectAt(x, y)
 		if _card == nil {
@@ -94,8 +111,8 @@ func (s *Sealed) startSealed(_sets string) {
 	s.AddWidget(ui.NewClickWrapper(grid, selectCard))
 
 	s.AddWidget(ui.NewSimpleButton(
-		s.width-SIDEBARD_WIDTH/2-START_BUTTON_WIDTH/2,
-		s.height-START_BUTTON_HEIGHT,
+		s.Width-SIDEBARD_WIDTH/2-START_BUTTON_WIDTH/2,
+		s.Height-START_BUTTON_HEIGHT,
 		START_BUTTON_WIDTH,
 		START_BUTTON_HEIGHT,
 		"Done",
diff --git a/go/client/startMenu.go b/go/client/startMenu.go
index 29a4a18c..94ec3aef 100644
--- a/go/client/startMenu.go
+++ b/go/client/startMenu.go
@@ -17,8 +17,7 @@ const (
 
 type StartMenu struct {
 	ui.Collection
-	app           *app
-	width, height int
+	app *app
 
 	deckInput *ui.TextInput
 
@@ -36,8 +35,8 @@ func NewStartMenu(app *app) *StartMenu {
 
 func (m *StartMenu) build() {
 	deckInput := ui.NewTextInput(
-		(m.width-DECK_LIST_WIDTH)/2,
-		(m.height-DECK_LIST_HEIGHT)/2,
+		(m.Width-DECK_LIST_WIDTH)/2,
+		(m.Height-DECK_LIST_HEIGHT)/2,
 		DECK_LIST_WIDTH,
 		DECK_LIST_HEIGHT,
 		"deck",
@@ -52,7 +51,7 @@ func (m *StartMenu) build() {
 	m.AddWidget(deckInput)
 
 	m.AddWidget(ui.NewFixedTextBox(
-		(m.width-START_BUTTON_WIDTH)/2-START_BUTTON_WIDTH,
+		(m.Width-START_BUTTON_WIDTH)/2-START_BUTTON_WIDTH,
 		deckInput.Y-START_BUTTON_HEIGHT,
 		START_BUTTON_WIDTH,
 		START_BUTTON_HEIGHT,
@@ -60,7 +59,7 @@ func (m *StartMenu) build() {
 	).Centering(true))
 
 	mapInput := ui.NewTextInput(
-		(m.width-START_BUTTON_WIDTH)/2,
+		(m.Width-START_BUTTON_WIDTH)/2,
 		deckInput.Y-START_BUTTON_HEIGHT,
 		START_BUTTON_WIDTH,
 		START_BUTTON_HEIGHT,
@@ -74,7 +73,7 @@ func (m *StartMenu) build() {
 	m.AddWidget(mapInput)
 
 	m.AddWidget(ui.NewFixedTextBox(
-		(m.width-START_BUTTON_WIDTH)/2-START_BUTTON_WIDTH,
+		(m.Width-START_BUTTON_WIDTH)/2-START_BUTTON_WIDTH,
 		mapInput.Y-START_BUTTON_HEIGHT,
 		START_BUTTON_WIDTH,
 		START_BUTTON_HEIGHT,
@@ -82,7 +81,7 @@ func (m *StartMenu) build() {
 	).Centering(true))
 
 	playerInput := ui.NewTextInput(
-		(m.width-START_BUTTON_WIDTH)/2,
+		(m.Width-START_BUTTON_WIDTH)/2,
 		mapInput.Y-START_BUTTON_HEIGHT,
 		START_BUTTON_WIDTH,
 		START_BUTTON_HEIGHT,
@@ -96,18 +95,18 @@ func (m *StartMenu) build() {
 	m.AddWidget(playerInput)
 
 	m.AddWidget(ui.NewSimpleButton(
-		(m.width-START_BUTTON_WIDTH)/2+START_BUTTON_WIDTH/2,
+		(m.Width-START_BUTTON_WIDTH)/2+START_BUTTON_WIDTH/2,
 		deckInput.Y+deckInput.Height,
 		START_BUTTON_WIDTH,
 		START_BUTTON_HEIGHT,
 		"Sealed",
 		func(*ui.SimpleButton) {
-			sealed := NewSealed(m.width, m.height, m.app)
+			sealed := NewSealed(m.Width, m.Height, m.app)
 			m.app.pushActivity(sealed)
 		}))
 
 	m.AddWidget(ui.NewSimpleButton(
-		(m.width-START_BUTTON_WIDTH)/2-START_BUTTON_WIDTH/2,
+		(m.Width-START_BUTTON_WIDTH)/2-START_BUTTON_WIDTH/2,
 		deckInput.Y+deckInput.Height,
 		START_BUTTON_WIDTH,
 		START_BUTTON_HEIGHT,
@@ -129,7 +128,7 @@ func (m *StartMenu) Update() error {
 }
 
 func (m *StartMenu) Layout(width, height int) (int, int) {
-	return m.width, m.height
+	return m.Width, m.Height
 }
 
 func (m *StartMenu) startGame() {
diff --git a/go/ui/button.go b/go/ui/button.go
index 78ab459f..eac3c2e4 100644
--- a/go/ui/button.go
+++ b/go/ui/button.go
@@ -41,13 +41,6 @@ func (b *SimpleButton) render() *ebiten.Image {
 	return img
 }
 
-func (b *SimpleButton) FindObjectAt(x, y int) interface{} {
-	if b.Contains(x, y) {
-		return b
-	}
-	return nil
-}
-
 func (b *SimpleButton) Click(x, y int) {
 	b.OnClick(b)
 }
diff --git a/go/ui/choice.go b/go/ui/choice.go
index bacc6657..28878604 100644
--- a/go/ui/choice.go
+++ b/go/ui/choice.go
@@ -51,16 +51,8 @@ func (c *Choice) Contains(x, y int) bool {
 	return x >= c.X && x <= c.X+c.Width && y >= c.Y && y <= c.Y+height
 }
 
-func (c *Choice) FindObjectAt(x, y int) interface{} {
-	if c.Contains(x, y) {
-		return c
-	}
-	return nil
-}
-
-func (c *Choice) Render() *ebiten.Image {
-	return nil
-}
+func (c *Choice) FindObjectAt(x, y int) interface{} { return nil }
+func (c *Choice) Render() *ebiten.Image             { return nil }
 
 func NewObjectChoice(x, y int, objs []interface{}, onClick func(*Choice, int, int)) *Choice {
 	// TODO: use dynamic with width and height
diff --git a/go/ui/collection.go b/go/ui/collection.go
index ac53ba8c..d75e3267 100644
--- a/go/ui/collection.go
+++ b/go/ui/collection.go
@@ -1,12 +1,20 @@
 package ui
 
 import (
+	"log"
+
 	"github.com/hajimehoshi/ebiten/v2"
 	"github.com/hajimehoshi/ebiten/v2/inpututil"
 )
 
 type Collection struct {
-	widgets []Widget
+	Width, Height int
+	hoverDetector hoverDetector
+	widgets       []Widget
+}
+
+func (c *Collection) Layout() (int, int) {
+	return c.Width, c.Height
 }
 
 func (c *Collection) Widgets() []Widget {
@@ -17,10 +25,40 @@ func (c *Collection) Clear() {
 	c.widgets = []Widget{}
 }
 
+func (c *Collection) ResetHover() {
+	c.hoverDetector.reset(0, 0)
+}
+
 func (c *Collection) AddWidget(w Widget) {
+	if w == nil {
+		log.Panicf("Adding nil widget to collection")
+	}
 	c.widgets = append(c.widgets, w)
 }
 
+func (c *Collection) FindWidget(toFind Widget) int {
+	for i, w := range c.widgets {
+		if w != toFind {
+			continue
+		}
+		return i
+	}
+	return -1
+}
+
+func (c *Collection) RemoveWidget(widget Widget) {
+	idx := c.FindWidget(widget)
+	if idx != -1 {
+		c.RemoveWidgetAt(idx)
+	}
+}
+
+func (c *Collection) RemoveWidgetAt(idx int) {
+	nwidgets := len(c.widgets)
+	c.widgets[idx] = c.widgets[nwidgets-1]
+	c.widgets = c.widgets[:nwidgets-1]
+}
+
 func (c *Collection) Draw(screen *ebiten.Image) {
 	for _, w := range c.widgets {
 		w.Draw(screen)
@@ -39,6 +77,8 @@ func (c *Collection) Update() error {
 		break
 	}
 
+	c.hoverDetector.update(c, x, y, activeWidget)
+
 	if activeWidget == nil {
 		return nil
 	}
@@ -61,7 +101,7 @@ func (c *Collection) Update() error {
 	}
 
 	if inpututil.IsMouseButtonJustPressed(ebiten.MouseButtonLeft) {
-		if btn, ok := activeWidget.(Button); ok {
+		if btn, ok := activeWidget.(Clickable); ok {
 			btn.Click(x, y)
 		}
 	}
diff --git a/go/ui/hoverDetector.go b/go/ui/hoverDetector.go
new file mode 100644
index 00000000..49161f4f
--- /dev/null
+++ b/go/ui/hoverDetector.go
@@ -0,0 +1,41 @@
+package ui
+
+// A simple structure to detect if the cursor has not moved or started moving again.
+// hoverDetector.update must be called during each Update invocation to track the
+// frame and the current cursor position.
+type hoverDetector struct {
+	last_x, last_y int
+	ticks          int
+	hovering       Hoverable
+}
+
+func (h *hoverDetector) update(collection *Collection, x, y int, w Widget) {
+	if x == h.last_x && y == h.last_y {
+		h.hover(collection, x, y, w)
+	} else {
+		h.reset(x, y)
+		h.last_x, h.last_y = x, y
+	}
+}
+
+func (h *hoverDetector) hover(collection *Collection, x, y int, w Widget) {
+	h.ticks++
+
+	if w == nil || h.hovering != nil {
+		return
+	}
+
+	if hoverable, ok := w.(Hoverable); ok && hoverable.onHover(h.ticks, x, y, collection) {
+		h.hovering = hoverable
+	}
+}
+
+func (h *hoverDetector) reset(x, y int) {
+	if h.hovering != nil {
+		if !h.hovering.stopHover(h.ticks, x, y) {
+			return
+		}
+		h.hovering = nil
+	}
+	h.ticks = 0
+}
diff --git a/go/ui/hoverable.go b/go/ui/hoverable.go
new file mode 100644
index 00000000..54d4ec15
--- /dev/null
+++ b/go/ui/hoverable.go
@@ -0,0 +1,120 @@
+package ui
+
+import (
+	"muhq.space/muhqs-game/go/game"
+)
+
+const (
+	HOVER_THRESHOLD = 60
+
+	HOVER_CARD_WIDTH  = 500
+	HOVER_CARD_HEIGHT = 700
+)
+
+type Hoverable interface {
+	onHover(ticks int, x, y int, c *Collection) bool
+	stopHover(ticks int, x, y int) bool
+}
+
+type hoverWidget struct {
+	createHint func(x, y int) Widget
+	reset      func()
+	xMax, yMax int
+}
+
+func (h *hoverWidget) showHint(x, y int, c *Collection) {
+	hint := h.createHint(x, y)
+	if hint == nil {
+		return
+	}
+
+	c.AddWidget(hint)
+	h.reset = func() {
+		c.RemoveWidget(hint)
+	}
+}
+
+func (h *hoverWidget) onHover(ticks int, x, y int, c *Collection) bool {
+	if h.xMax == 0 || h.yMax == 0 {
+		width, height := c.Layout()
+		h.xMax = width
+		h.yMax = height
+	}
+
+	if ticks == HOVER_THRESHOLD {
+		h.showHint(x, y, c)
+		return true
+	}
+
+	return false
+}
+
+func (h *hoverWidget) stopHover(ticks int, x, y int) bool {
+	if h.reset != nil {
+		h.reset()
+	}
+	return true
+}
+
+type hoverCardView struct {
+	hoverWidget
+}
+
+func (h *hoverCardView) init(w Widget) {
+	h.createHint = func(x, y int) Widget {
+		card := w.FindObjectAt(x, y).(*game.Card)
+		if card == nil {
+			return nil
+		}
+
+		wx, wy := x, y
+		if x+HOVER_CARD_WIDTH > h.xMax || y+HOVER_CARD_HEIGHT > h.yMax {
+			wx = x - HOVER_CARD_WIDTH
+			wy = y - HOVER_CARD_HEIGHT
+		}
+		if wx < 0 {
+			wx = 0
+		}
+		if wy < 0 {
+			wy = 0
+		}
+
+		return NewScaledCardView(wx, wy, HOVER_CARD_WIDTH, HOVER_CARD_HEIGHT, card.Path())
+	}
+}
+
+type hoverPermInfo struct {
+	hoverWidget
+}
+
+func (h *hoverPermInfo) init(w Widget) {
+	h.createHint = func(x, y int) Widget {
+		obj := w.FindObjectAt(x, y)
+		if obj == nil {
+			return nil
+		}
+
+		perm, ok := obj.(game.Permanent)
+		if !ok {
+			return nil
+		}
+
+		hint := NewPermInfo(x+TILE_WIDTH, y, perm)
+
+		wx, wy := x, y
+		if hint.X+hint.Width > h.xMax || y+hint.Height > h.yMax {
+			wx = x - hint.Width
+			wy = y - hint.Height
+		}
+		if wx < 0 {
+			wx = 0
+		}
+		if wy < 0 {
+			wy = 0
+		}
+
+		hint.X, hint.Y = wx, wy
+
+		return hint
+	}
+}
diff --git a/go/ui/mapView.go b/go/ui/mapView.go
index 155750b4..0553b348 100644
--- a/go/ui/mapView.go
+++ b/go/ui/mapView.go
@@ -23,6 +23,7 @@ const (
 )
 
 type MapView struct {
+	hoverPermInfo
 	gameState            *game.State
 	mapLayer             *ebiten.Image
 	permanentsLayer      *ebiten.Image
@@ -31,14 +32,25 @@ type MapView struct {
 }
 
 func NewMapView(g *game.State) *MapView {
-	vw := MapView{g, nil, nil, []game.Position{}, []game.Permanent{}}
-	return &vw
+	vw := &MapView{gameState: g}
+	vw.hoverPermInfo.init(vw)
+	return vw
 }
 
 func (mv *MapView) Height() int {
 	return len(mv.gameState.Map.Tiles) * TILE_HEIGHT
 }
 
+func (mv *MapView) Width() int {
+	maxWidth := 0
+	for _, row := range mv.gameState.Map.Tiles {
+		if n := len(row); n > maxWidth {
+			maxWidth = n
+		}
+	}
+	return maxWidth * TILE_WIDTH
+}
+
 func rotateStreetImg(x, y int, radian float64, op *ebiten.DrawImageOptions) {
 	// Move the image's center to the screen's upper-left corner.
 	// This is a preparation for rotating. When geometry matrices are applied,
@@ -278,6 +290,12 @@ func (vw *MapView) ClearPermanentsHighlights() {
 	vw.HighlightPermanents([]game.Permanent{})
 }
 
+func (mv *MapView) Contains(x, y int) bool {
+	w := mv.Width()
+	h := mv.Height()
+	return x >= 0 && y >= 0 && x <= w && y <= h
+}
+
 func (*MapView) Render(Widget) *ebiten.Image {
 	return nil
 }
diff --git a/go/ui/prompt.go b/go/ui/prompt.go
index b8d60a49..93c4b4cd 100644
--- a/go/ui/prompt.go
+++ b/go/ui/prompt.go
@@ -1,6 +1,8 @@
 package ui
 
 import (
+	"image/color"
+
 	"github.com/hajimehoshi/ebiten/v2"
 
 	"muhq.space/muhqs-game/go/game"
@@ -42,6 +44,10 @@ func (p *Prompt) Height() int {
 	return PROMPT_HEIGHT
 }
 
+func (p *Prompt) ClearSelections() {
+	p.action.Targets().ClearSelections()
+}
+
 func (p *Prompt) Draw(screen *ebiten.Image) {
 	for _, comp := range p.components {
 		comp.Draw(screen)
@@ -54,3 +60,34 @@ func (p *Prompt) Contains(x, y int) bool {
 
 func (p *Prompt) FindObjectAt(screenX, screenY int) interface{} { return nil }
 func (*Prompt) Render(Widget) *ebiten.Image                     { return nil }
+
+func (p *Prompt) setTextBgAlpha(alpha uint8) {
+	for _, comp := range p.components {
+		textBox, ok := comp.(*TextBox)
+		if !ok {
+			continue
+		}
+		bg := color.RGBAModel.Convert(textBox.bg).(color.RGBA)
+		bg.A = alpha
+		textBox.Bg(bg)
+		textBox.ForceRedraw()
+	}
+}
+
+func (p *Prompt) onHover(ticks int, x int, y int, c *Collection) bool {
+	if ticks == 1 {
+		p.setTextBgAlpha(0x7f)
+		return true
+	}
+
+	return false
+}
+
+func (p *Prompt) stopHover(ticks int, x, y int) bool {
+	if p.Contains(x, y) {
+		return false
+	}
+
+	p.setTextBgAlpha(0xff)
+	return true
+}
diff --git a/go/ui/stateBar.go b/go/ui/stateBar.go
index 93de9af9..1686b5e1 100644
--- a/go/ui/stateBar.go
+++ b/go/ui/stateBar.go
@@ -44,9 +44,7 @@ func (sb *StateBar) Draw(screen *ebiten.Image) {
 	sb.phaseView.Draw(screen)
 }
 
-func (sb *StateBar) FindObjectAt(x, y int) interface{} {
-	return nil
-}
+func (sb *StateBar) FindObjectAt(x, y int) interface{} { return nil }
 
 func (sb *StateBar) ForceRedraw() {
 	if sb.resourceView != nil {
diff --git a/go/ui/textBox.go b/go/ui/textBox.go
index 2635535c..66b90698 100644
--- a/go/ui/textBox.go
+++ b/go/ui/textBox.go
@@ -84,11 +84,20 @@ func NewUnitInfo(x, y int, u *game.Unit) *TextBox {
 	return NewAutoTextBox(x, y, info)
 }
 
-func NewPermInfo(x, y int, p game.Permanent) *TextBox {
+func NewGenericPermInfo(x, y int, p game.Permanent) *TextBox {
 	info := fmt.Sprintf("%s\nDamage: %d", p.String(), p.Damage())
 	return NewAutoTextBox(x, y, info)
 }
 
+func NewPermInfo(x, y int, p game.Permanent) *TextBox {
+	switch p := p.(type) {
+	case *game.Unit:
+		return NewUnitInfo(x, y, p)
+	default:
+		return NewGenericPermInfo(x, y, p)
+	}
+}
+
 func (tb *TextBox) render() *ebiten.Image {
 	var x, y int
 	b := text.BoundString(font.Font24, tb.text)
@@ -115,6 +124,7 @@ func (tb *TextBox) render() *ebiten.Image {
 
 type PocList struct {
 	TextBox
+	hoverCardView
 	centerX int
 	bottomY int
 	poc     game.PileOfCards
@@ -128,6 +138,8 @@ func NewPocList(centerX, bottomY int, poc game.PileOfCards) *PocList {
 		poc:     poc,
 	}
 
+	w.hoverCardView.init(w)
+
 	w.renderImpl = func() *ebiten.Image {
 		w.setText()
 		return w.render()
diff --git a/go/ui/widget.go b/go/ui/widget.go
index cfcdd766..4ee0caac 100644
--- a/go/ui/widget.go
+++ b/go/ui/widget.go
@@ -17,12 +17,8 @@ type WidgetBase struct {
 	renderImpl    func() *ebiten.Image
 }
 
-func renderDummy() *ebiten.Image {
-	return nil
-}
-
 func NewWidgetBase(x, y, width, height int) WidgetBase {
-	return WidgetBase{x, y, width, height, nil, renderDummy}
+	return WidgetBase{X: x, Y: y, Width: width, Height: height}
 }
 
 func (w *WidgetBase) Draw(screen *ebiten.Image) {