From cf591dbb95ae35ca43f99c4a9a529399efbf9d61 Mon Sep 17 00:00:00 2001
From: Junwei Zhao <wahyd4@gmail.com>
Date: Sun, 15 Mar 2020 23:36:39 +1100
Subject: [PATCH] code refactoring

---
 app.go        | 32 ++++++++++++++++++++------------
 parse.go      |  6 +++---
 parse_test.go |  2 +-
 3 files changed, 24 insertions(+), 16 deletions(-)

diff --git a/app.go b/app.go
index eee07d8..95fe9ef 100644
--- a/app.go
+++ b/app.go
@@ -7,33 +7,37 @@ import (
 
 // Application presents the actual the runner
 type Application struct {
-	GridSize  int
-	Zombie    *models.Zombie
-	Creatures []*models.Creature
-	Commands  []MoveCommand
-
+	GridSize        int
+	Creatures       []*models.Creature
+	Commands        []MoveCommand
+	CurrentZombie   *models.Zombie
 	NextZombie      *TransformedZombie
 	FinishedZombies []*models.Zombie
 	Score           int
 }
 
+// TransformedZombie defines the zombies transformed from creatures,
+// and these type of zombies are linked one by one
 type TransformedZombie struct {
 	Zombie *models.Zombie
 	Next   *TransformedZombie
 }
 
+// Run starts zombie with movements
 func (app *Application) Run() {
 	for _, command := range app.Commands {
-		command.Execute(app.Zombie)
+		command.Execute(app.CurrentZombie)
+
 		collided, creature := app.checkCollisionWithCreature()
 		if collided {
 			app.transformCreatureToZombie(creature)
 			app.IncreaseScore()
 		}
 	}
-	app.updateFinishedZombies()
 
-	if app.NextZombie != nil {
+	app.recordedFinishedZombies()
+
+	if app.hasTransformedZombie() {
 		app.updateCurrentZombie()
 		app.updateNextZombie()
 		app.Run()
@@ -53,7 +57,7 @@ func (app *Application) Stats() {
 
 func (app *Application) checkCollisionWithCreature() (bool, *models.Creature) {
 	for _, creature := range app.Creatures {
-		if app.Zombie.Coordinate == creature.Coordinate {
+		if app.CurrentZombie.Coordinate == creature.Coordinate {
 			return true, creature
 		}
 	}
@@ -100,8 +104,8 @@ func (app *Application) IncreaseScore() {
 	app.Score++
 }
 
-func (app *Application) updateFinishedZombies() {
-	app.FinishedZombies = append(app.FinishedZombies, app.Zombie)
+func (app *Application) recordedFinishedZombies() {
+	app.FinishedZombies = append(app.FinishedZombies, app.CurrentZombie)
 }
 
 func (app *Application) updateNextZombie() {
@@ -109,5 +113,9 @@ func (app *Application) updateNextZombie() {
 }
 
 func (app *Application) updateCurrentZombie() {
-	app.Zombie = app.NextZombie.Zombie
+	app.CurrentZombie = app.NextZombie.Zombie
+}
+
+func (app *Application) hasTransformedZombie() bool {
+	return app.NextZombie != nil
 }
diff --git a/parse.go b/parse.go
index 77f608d..5f65a52 100644
--- a/parse.go
+++ b/parse.go
@@ -30,7 +30,7 @@ func Init(input string) (*Application, error) {
 	defer file.Close()
 
 	application := Application{
-		Zombie: &models.Zombie{},
+		CurrentZombie: &models.Zombie{},
 	}
 	scanner := bufio.NewScanner(file)
 	for lineIndex := 0; scanner.Scan(); lineIndex++ {
@@ -39,10 +39,10 @@ func Init(input string) (*Application, error) {
 		case 0:
 			gridSize, _ := strconv.Atoi(text)
 			application.GridSize = gridSize
-			application.Zombie.GridSize = gridSize
+			application.CurrentZombie.GridSize = gridSize
 		case 1:
 			coordinate := parseCoordinate(text)
-			application.Zombie.Coordinate = coordinate
+			application.CurrentZombie.Coordinate = coordinate
 		case 2:
 			creatures := parseCreatures(text)
 			application.Creatures = creatures
diff --git a/parse_test.go b/parse_test.go
index 781b7b9..2cfe506 100644
--- a/parse_test.go
+++ b/parse_test.go
@@ -21,7 +21,7 @@ func TestInit(t *testing.T) {
 			args{input: "test_data/input_test.txt"},
 			&Application{
 				GridSize: 4,
-				Zombie: &models.Zombie{
+				CurrentZombie: &models.Zombie{
 					GridSize: 4,
 					Coordinate: models.Coordinate{
 						XAxis: 2,