howwwwwwww do you put objects DOWN

internal/app/game_view.go

@@ -51,6 +51,9 @@ func (v *gameView) walkHandler(e *tcell.EventKey) change {
 		case 'p':
 			v.keyHandler = v.pickupHandler
 			v.statusLine = "(pickup)"
+		case 'P':
+			v.keyHandler = v.putdownHandler
+			v.statusLine = "(put down)"
 		}
 	}
 	return nil
@@ -116,6 +119,12 @@ func (v *gameView) pickupHandler(e *tcell.EventKey) change {
 	return nil
 }
 
+func (v *gameView) putdownHandler(e *tcell.EventKey) change {
+	v.keyHandler = v.walkHandler
+	v.statusLine = "(walk)"
+	return nil
+}
+
 func (v *gameView) draw(img canvas, st *state) {
 	fill(img, tcell.StyleDefault.Background(tcell.NewRGBColor(0, 0, 12)))
 	v.drawHeader(img, st)

internal/app/inventory.go

@@ -16,11 +16,27 @@ type item struct {
 }
 
 type inventoryView struct {
+	highlight int
+	*inventory
 }
 
 func (v *inventoryView) handleEvent(e tcell.Event) change {
-	if k, ok := e.(*tcell.EventKey); ok {
+	switch t := e.(type) {
-		if k.Key() == tcell.KeyESC {
+	case *tcell.EventKey:
+		key := t.Key()
+		switch key {
+		case tcell.KeyEnter:
+		case tcell.KeyDown:
+			if len(v.items) > 0 {
+				v.highlight = (v.highlight + 1) % len(v.items)
+			}
+
+		case tcell.KeyUp:
+			if len(v.items) > 0 {
+				v.highlight = (v.highlight - 1 + len(v.items)) % len(v.items)
+			}
+
+		case tcell.KeyESC:
 			return changeFn(func(ui *UI) {
 				if ui.root == inGameView {
 					inGameView.focus(0)
@@ -28,13 +44,18 @@ func (v *inventoryView) handleEvent(e tcell.Event) change {
 			})
 		}
 	}
+
 	return nil
 }
 
 func (v *inventoryView) draw(img canvas, st *state) {
+	v.inventory = &st.inventory
 	writeString(img, "Inventory", math.Vec{0, 0}, tcell.StyleDefault)
 	for i, item := range st.inventory.items {
 		line := fmt.Sprintf("- %s", item.name)
+		if i == v.highlight {
+			line = fmt.Sprintf("+ %s", item.name)
+		}
 		writeString(img, line, math.Vec{0, i + 2}, tcell.StyleDefault)
 	}
 }

internal/math/vec.go

@@ -45,3 +45,6 @@ func (v Vec) Unit() Vec {
 	}
 	return out
 }
+
+// MDist calculates the manhattan distance between two vectors.
+func (v Vec) MDist(v2 Vec) int { return Abs(v.X-v2.X) + Abs(v.Y-v2.Y) }

internal/sim/door.go

@@ -13,7 +13,7 @@ type door struct {
 	arrived int
 }
 
-func (d *door) update(time.Duration) {}
+func (d *door) update(*entity, time.Duration) {}
 
 func (d *door) exec(w *world, r *room, p *player, seq int) result {
 	p.Info("executing door to %q for player %s", d.to, p.name)

internal/sim/entity.go

@@ -79,9 +79,9 @@ func (e *entity) stopOverlap(e2 *entity) {
 
 type behavior interface {
 	// update is the standard tick function
-	update(time.Duration)
+	update(*entity, time.Duration)
 }
 
 type doNothing struct{}
 
-func (d doNothing) update(time.Duration) {}
+func (d doNothing) update(*entity, time.Duration) {}

internal/sim/player.go

@@ -165,7 +165,26 @@ func sendResponse(conn *websocket.Conn, res wire.Response) error {
 	return nil
 }
 
-func (p *player) update(dt time.Duration) {}
+func (p *player) removeItem(id int) *entity {
+	for i, e := range p.inventory {
+		if e.ID == id {
+			p.inventory = append(p.inventory[:i], p.inventory[i+1:]...)
+			return e
+		}
+	}
+	return nil
+}
+
+func (p *player) peekItem(id int) *entity {
+	for _, e := range p.inventory {
+		if e.ID == id {
+			return e
+		}
+	}
+	return nil
+}
+
+func (p *player) update(*entity, time.Duration) {}
 
 type spawnPlayer struct{}
 
@@ -179,6 +198,16 @@ func (s spawnPlayer) exec(w *world, r *room, p *player, seq int) result {
 	}
 	p.avatar = &e
 
+	p.inventory = append(p.inventory, &entity{
+		ID:          <-w.nextID,
+		Glyph:       'p',
+		solid:       false,
+		name:        "a potato",
+		description: "it's a potato, what more information could you need?",
+		pickupable:  true,
+		behavior:    &potato{},
+	})
+
 	for n, _ := range r.tiles {
 		t := &r.tiles[n]
 		x, y := n%r.Width, n/r.Width
@@ -277,6 +306,41 @@ type Pickedup struct {
 
 func (p Pickedup) NetTag() string { return "pickedup" }
 
+type Putdown struct {
+	ID       int      `json:"id"`
+	Location math.Vec `json:"loc"`
+}
+
+func (pd *Putdown) exec(w *world, r *room, pl *player, seq int) result {
+	pos := pl.avatar.Position
+	if pos.MDist(pd.Location) > 1 {
+		return result{reply: wire.Errorf("destination tile %v is too far from your current location at %v", pd.Location, pos)}
+	}
+
+	nextTile := r.getTile(pd.Location)
+	if nextTile == nil {
+		return result{reply: wire.Errorf("no tile at location %v", pd.Location)}
+	}
+
+	item := pl.peekItem(pd.ID)
+	if item == nil {
+		return result{reply: wire.Errorf("you're not holding an item with ID %d", pd.ID)}
+	}
+
+	if item.solid {
+		for _, e := range nextTile.here {
+			if e.solid {
+				return result{reply: wire.Errorf("you can't put a %s on top of a %s", item.name, e.name)}
+			}
+		}
+	}
+
+	nextTile.addEntity(pl.removeItem(pd.ID))
+	return result{reply: wire.OK{}}
+}
+
+func (Putdown) NetTag() string { return "put-down" }
+
 var lastEntityID = 0
 
 func init() {
@@ -285,4 +349,5 @@ func init() {
 	wire.Register(func() wire.Value { return new(LookAt) })
 	wire.Register(func() wire.Value { return new(Pickup) })
 	wire.Register(func() wire.Value { return new(Pickedup) })
+	wire.Register(func() wire.Value { return new(Putdown) })
 }

internal/sim/potato.go

@@ -0,0 +1,38 @@
+package sim
+
+import (
+	"time"
+)
+
+type stageOfGrowth int
+
+const (
+	unborn stageOfGrowth = iota
+	planted
+	sapling
+	unripe
+	ripe
+	overripe
+	rotting
+	dead
+)
+
+type potato struct {
+	planted time.Duration
+	stage   stageOfGrowth
+}
+
+func (p *potato) update(e *entity, dt time.Duration) {
+	if p.stage > unborn {
+		p.planted += dt
+	}
+}
+
+type percent int
+
+func (p *potato) progress() percent {
+	if p.stage <= unborn {
+		return 0
+	}
+	return 100
+}

internal/sim/tile.go

@@ -62,7 +62,7 @@ func (t *tile) isOccupied() bool {
 
 func (t *tile) update(d time.Duration) {
 	for _, e := range t.here {
-		e.update(d)
+		e.update(e, d)
 	}
 }
 

internal/sim/world.go

@@ -49,6 +49,26 @@ func newWorld(log *blammo.Log) *world {
 		behavior:   doNothing{},
 	})
 
+	foyer.addEntity(&entity{
+		ID:         -2,
+		Position:   math.Vec{5, 5},
+		Glyph:      'o',
+		solid:      true,
+		pickupable: true,
+		name:       "another rock",
+		behavior:   doNothing{},
+	})
+
+	foyer.addEntity(&entity{
+		ID:         -3,
+		Position:   math.Vec{5, 6},
+		Glyph:      'o',
+		solid:      true,
+		pickupable: true,
+		name:       "yet another rock (YAR)",
+		behavior:   doNothing{},
+	})
+
 	foyer.addEntity(&entity{
 		ID:       -4,
 		Position: math.Vec{9, 5},