Demo Inline Chat

class Car:
    def update(self, light_state, cars_ahead):
        """Update the car's position.
        - Check if the car is approaching the intersection's stop line.
        - Stop if the light is red or yellow and the car is not in the intersection.
        - Maintain safe distance from the car ahead.
        """
        move = True  # assume car can move

        # Determine when to stop at the light for northbound traffic
        if self.direction == 'north':
            front = self.rect.bottom
            if front + CAR_SPEED >= STOP_LINE['north'] and light_state != 'green':
                move = False

        # Enforce safe gap from cars ahead
        for other in cars_ahead:
            if other.rect.top <= self.rect.bottom:
                continue
            if other.rect.top < self.rect.bottom + SAFE_GAP:
                move = False
                break

        # Move the car if permitted
        if move:
            self.rect.y += CAR_SPEED

LIGHT_COLORS = {
    'green': (0, 255, 0),
    'yellow': (255, 255, 0),
    'red': (255, 0, 0)
}

import json

def load_config(path):
    with open(path) as f:
        return json.load(f)

config = load_config('config.json')
LIGHT_COLORS = config['light_colors']

import pygame
import json

# ---------------- Configuration Constants ----------------
WINDOW_WIDTH, WINDOW_HEIGHT = 800, 800
ROAD_WIDTH = 100
CENTER_X = WINDOW_WIDTH // 2
CENTER_Y = WINDOW_HEIGHT // 2

VERT_ROAD_RECT = pygame.Rect(CENTER_X - ROAD_WIDTH/2, 0, ROAD_WIDTH, WINDOW_HEIGHT)
HORZ_ROAD_RECT = pygame.Rect(0, CENTER_Y - ROAD_WIDTH/2, WINDOW_WIDTH, ROAD_WIDTH)

STOP_LINE = {
    'north': CENTER_Y - ROAD_WIDTH/2,
    'south': CENTER_Y + ROAD_WIDTH/2,
    'east':  CENTER_X + ROAD_WIDTH/2,
    'west':  CENTER_X - ROAD_WIDTH/2
}

CAR_SPEED = 3                 # pixels per frame
CAR_SIZE = {'vertical': (20, 40), 'horizontal': (40, 20)}
SAFE_GAP = 10                 # pixels between cars
SPAWN_INTERVAL = 60           # frames between spawns
LIGHT_OFFSET = 30
LIGHT_RADIUS = 8

def get_light_state(direction, cycle_timer):
    """
    Determine traffic light state based on timer.
    - NS group: 'north'/'south'
    - EW group: 'east'/'west'
    """
    t = cycle_timer % CYCLE_LENGTH
    if direction in ('north', 'south'):
        if t < NS_GREEN_DURATION:
            return 'green'
        if t < NS_GREEN_DURATION + NS_YELLOW_DURATION:
            return 'yellow'
        return 'red'
    else:
        if t < NS_GREEN_DURATION + NS_YELLOW_DURATION:
            return 'red'
        if t < CYCLE_LENGTH:
            return 'green'
        return 'yellow'

import pytest
from main2 import get_light_state, CYCLE_LENGTH, NS_GREEN_DURATION, NS_YELLOW_DURATION

@pytest.mark.parametrize("t", range(NS_GREEN_DURATION))
def test_ns_green_light(t):
    assert get_light_state('north', t) == 'green'
    assert get_light_state('south', t) == 'green'

@pytest.mark.parametrize("t", range(NS_GREEN_DURATION, NS_GREEN_DURATION + NS_YELLOW_DURATION))
def test_ns_yellow_light(t):
    assert get_light_state('north', t) == 'yellow'
    assert get_light_state('south', t) == 'yellow'