commit be88e9cdccc0ee122411698dd61c10e21b96adae
Author: Nhân <hi@imnhan.com>
Date:   Sun Sep 17 14:11:20 2023 +0700

    implement walk states

diff --git a/main.go b/main.go
index 024d63f..ba19b37 100644
--- a/main.go
+++ b/main.go
@@ -49,6 +49,7 @@ type Anim struct {
 type Position struct{ x, y int }
 
 var DurationTillHungry time.Duration
+var WalkChance, StopChance int
 
 type Game struct {
 	CurrentAnim      *Anim
@@ -60,8 +61,6 @@ type Game struct {
 	MouseStartPos    Vector
 	Size             int
 	LastFed          time.Time
-	WalkChance       int
-	StopChance       int
 	X                int
 	Y                int
 	MaxX             int
@@ -145,7 +144,7 @@ func (g *Game) Update() error {
 		}
 
 		if g.CurrentAnim == Idle {
-			if randBool(g.WalkChance) {
+			if randBool(WalkChance) {
 				if randBool(50) {
 					g.CurrentAnim = WalkLeft
 				} else {
@@ -153,7 +152,7 @@ func (g *Game) Update() error {
 				}
 			}
 		} else if g.CurrentAnim == WalkLeft || g.CurrentAnim == WalkRight {
-			if randBool(g.StopChance) {
+			if randBool(StopChance) {
 				g.CurrentAnim = Idle
 			}
 		}
@@ -268,8 +267,8 @@ func main() {
 	game.LastFed = time.Now()
 	DurationTillHungry = time.Duration(secondsUntilHungryFlag) * 1_000_000_000
 	game.Size = sizeFlag
-	game.WalkChance = walkChanceFlag
-	game.StopChance = stopChanceFlag
+	WalkChance = walkChanceFlag
+	StopChance = stopChanceFlag
 	game.X = xFlag
 	game.Y = yFlag
 
diff --git a/states.go b/states.go
index 36e6bce..d886778 100644
--- a/states.go
+++ b/states.go
@@ -40,6 +40,8 @@ func (sm *StateMachine) SetState(s State) {
 func (sm *StateMachine) Update() error {
 	now := time.Now()
 
+	// If enough time has passed, force enter hungry state,
+	// otherwise process state-specific logic as usual.
 	if now.Sub(sm.lastFed) >= DurationTillHungry {
 		sm.SetState(&StateHungry{})
 		sm.lastFed = now
@@ -78,9 +80,6 @@ type State interface {
 	EndAnimHook(sm *StateMachine)
 }
 
-type StateWalkL struct{}
-type StateWalkR struct{}
-
 type StateIdle struct{}
 
 func (s *StateIdle) Enter(sm *StateMachine) { sm.SetAnim(Idle) }
@@ -94,7 +93,16 @@ func (s *StateIdle) Update(sm *StateMachine) {
 		return
 	}
 }
-func (s *StateIdle) EndAnimHook(sm *StateMachine) {}
+func (s *StateIdle) EndAnimHook(sm *StateMachine) {
+	if randBool(WalkChance) {
+		if randBool(50) {
+			sm.SetState(&StateWalkL{})
+		} else {
+			sm.SetState(&StateWalkR{})
+		}
+		return
+	}
+}
 
 type StateDrag struct {
 	PreviousMousePos Vector
@@ -150,3 +158,23 @@ func (s *StateFeed) Update(sm *StateMachine) {}
 func (s *StateFeed) EndAnimHook(sm *StateMachine) {
 	sm.SetState(&StateIdle{})
 }
+
+type StateWalkL struct{}
+
+func (s *StateWalkL) Enter(sm *StateMachine)  { sm.SetAnim(WalkLeft) }
+func (s *StateWalkL) Update(sm *StateMachine) {}
+func (s *StateWalkL) EndAnimHook(sm *StateMachine) {
+	if randBool(StopChance) {
+		sm.SetState(&StateIdle{})
+	}
+}
+
+type StateWalkR struct{}
+
+func (s *StateWalkR) Enter(sm *StateMachine)  { sm.SetAnim(WalkRight) }
+func (s *StateWalkR) Update(sm *StateMachine) {}
+func (s *StateWalkR) EndAnimHook(sm *StateMachine) {
+	if randBool(StopChance) {
+		sm.SetState(&StateIdle{})
+	}
+}