From 477823b2f5ddcc861545992e7d60cc00043aa218 Mon Sep 17 00:00:00 2001
From: Olivier Gayot <olivier.gayot@sigexec.com>
Date: Mon, 21 Dec 2020 23:03:49 +0100
Subject: Handle collisions

Signed-off-by: Olivier Gayot <olivier.gayot@sigexec.com>
---
 cameltris.py | 87 +++++++++++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 75 insertions(+), 12 deletions(-)

(limited to 'cameltris.py')

diff --git a/cameltris.py b/cameltris.py
index eefd111..a5fd6e5 100755
--- a/cameltris.py
+++ b/cameltris.py
@@ -1,11 +1,16 @@
 #!/usr/bin/env python3
 
+import contextlib
 import sys
 import time
 
 import pygame
 
 
+class WouldCollide(Exception):
+    pass
+
+
 class Piece():
     def rotate(self):
         pass
@@ -95,6 +100,63 @@ def refresh_screen():
             if element is not None:
                 screen.blit(element, ((col_idx + current_piece_position[1]) * 50 + 1, (row_idx + current_piece_position[0]) * 50 + 1))
 
+
+def has_collision(y: int, x: int) -> bool:
+    try:
+        for row_id, row in enumerate(current_piece.elements):
+            for col_id, element in enumerate(row):
+                if element is None:
+                    continue
+
+                if col_id + x < 0:
+                    return True
+
+                if grid[row_id + y][col_id + x] is not None:
+                    return True
+
+    except IndexError:
+        return True
+
+    return False
+
+def move_piece_down():
+    if not has_collision(current_piece_position[0] + 1, current_piece_position[1]):
+        current_piece_position[0] += 1
+    else:
+        raise WouldCollide()
+
+def move_piece_up():
+    if not has_collision(current_piece_position[0] - 1, current_piece_position[1]):
+        current_piece_position[0] -= 1
+    else:
+        raise WouldCollide()
+
+def move_piece_left():
+    if not has_collision(current_piece_position[0], current_piece_position[1] - 1):
+        current_piece_position[1] -= 1
+    else:
+        raise WouldCollide()
+
+def move_piece_right():
+    if not has_collision(current_piece_position[0], current_piece_position[1] + 1):
+        current_piece_position[1] += 1
+    else:
+        raise WouldCollide()
+
+def rotate_piece_counter_clockwise():
+    current_piece.rotate_counter_clockwise()
+
+    if has_collision(current_piece_position[0], current_piece_position[1]):
+        current_piece.rotate_clockwise()
+        raise WouldCollide()
+
+def rotate_piece_clockwise():
+    current_piece.rotate_clockwise()
+
+    if has_collision(current_piece_position[0], current_piece_position[1]):
+        current_piece.rotate_counter_clockwise()
+        raise WouldCollide()
+
 pygame.init()
 
 black = (0, 0, 0)
@@ -142,18 +204,19 @@ while True:
         elif event.type == pygame.KEYDOWN:
             if event.key in (pygame.K_ESCAPE, pygame.K_q):
                 sys.exit()
-            if event.key in (pygame.K_DOWN, pygame.K_j):
-                current_piece_position[0] += 1
-            if event.key in (pygame.K_UP, pygame.K_k):
-                current_piece_position[0] -= 1
-            if event.key in (pygame.K_RIGHT, pygame.K_l):
-                current_piece_position[1] += 1
-            if event.key in (pygame.K_LEFT, pygame.K_h):
-                current_piece_position[1] -= 1
-            if event.key == pygame.K_s:
-                current_piece.rotate_clockwise()
-            if event.key == pygame.K_d:
-                current_piece.rotate_counter_clockwise()
+            with contextlib.suppress(WouldCollide):
+                if event.key in (pygame.K_DOWN, pygame.K_j):
+                    move_piece_down()
+                if event.key in (pygame.K_UP, pygame.K_k):
+                    move_piece_up()
+                if event.key in (pygame.K_RIGHT, pygame.K_l):
+                    move_piece_right()
+                if event.key in (pygame.K_LEFT, pygame.K_h):
+                    move_piece_left()
+                if event.key == pygame.K_s:
+                    rotate_piece_clockwise()
+                if event.key == pygame.K_d:
+                    rotate_piece_counter_clockwise()
 
     refresh_screen()
     pygame.display.flip()
-- 
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