Refactor code structure for improved readability and maintainability

Entities/Units/marine.py

@@ -0,0 +1,43 @@
+import random
+from Entities.entity import Entity
+
+class Marine(Entity):
+
+    next_cell = (1,1)
+    movement = 0
+    
+
+    def update(self):
+        self.move()
+        super().update()
+    
+    def select_unit(self):
+        self.selected = True
+        # Play a random voice response when selected
+        sound_file = f"marine/tmawht0{random.randint(0, 4)}.wav"
+        print(f"Playing sound: {sound_file}")
+        self.graphics.play_sound(sound_file)
+        
+    def move(self):
+        if (self.x, self.y) != self.next_cell:
+            # Set walking animation and direction
+            self.action = "walk"
+            self.direction = self.graphics.get_direction((self.x, self.y), self.next_cell)
+            self.moving = True
+            
+            # Calculate target coordinates
+            target_x, target_y = self.graphics.iso_transform(self.next_cell[0], self.next_cell[1])
+            
+            # Increment movement counter
+            self.movement += 0.01
+            
+            # Calculate how far we've moved (0.0 to 1.0)
+            move_progress = min(self.movement, 1.0)
+            # Calculate new position based on progress between cells
+            self.iso_x = self.iso_x + (target_x - self.iso_x) * move_progress
+            self.iso_y = self.iso_y + (target_y - self.iso_y) * move_progress
+            print(f"Moving to {self.iso_x}, {self.iso_y} with progress {move_progress}")
+            if self.movement >= 1.0:
+                # Reset movement and set to idle
+                self.movement = 0
+                self.iso_x, self.iso_y = self.graphics.iso_transform(self.x, self.y)

Entities/entity.py

@@ -0,0 +1,29 @@
+class Entity:
+    def __init__(self, asset, x, y, action, direction, speed, engine):
+        self.asset = asset
+        
+        self.graphics = engine.graphics
+        self.x = x
+        self.y = y
+        self.iso_x, self.iso_y = self.graphics.iso_transform(self.x, self.y)
+        self.action = action
+        self.direction = direction
+        self.speed = speed
+        self.frame = 0
+        self.engine = engine
+        self.selected = True
+        self.movement = 0
+
+    def update(self):
+        x, y = self.graphics.iso_transform(self.x, self.y)
+        occlusion = self.graphics.get_distance((self.x, self.y), self.engine.cursor_pos) / 4
+        
+        # Set color based on selection status
+        color = (255, 255, 0, 255) if self.selected else (0, 255, 0, 255)
+        self.graphics.draw_square(self.x, self.y, color=color, margin=4)
+        
+        if occlusion >= 0.8:
+            return
+        
+        self.frame = self.graphics.render_sprite(f"{self.asset}_{self.action}_dir{self.direction}", self.iso_x, self.iso_y, self.frame, occlusion)
+