import random
import pygame
import sys

pygame.init()

# Window Setup
WIDTH, HEIGHT = 1000, 700
screen = pygame.display.set_mode((WIDTH, HEIGHT))
pygame.display.set_caption("Traffic Simulation")

FPS = 60
clock = pygame.time.Clock()

# Colours
ROAD = (60, 60, 60)
CAR = (200, 40, 40)
GREEN = (0, 200, 0)
YELLOW= (255, 180, 0)
RED = (200, 0, 0)
WHITE = (255, 255, 255)
UI_BG = (30, 30, 30)

#Classes

#Traffic Light Class
class TrafficLight:
    def __init__(self, x, y):
        self.x = x
        self.y = y
        self.states = ["green", "yellow", "red"]
        self.current = "green"
        self.timer = 0
        self.cycle_time = 120

    def update(self):
        self.timer += 1
        if self.timer > self.cycle_time:
            self.timer = 0
            idx = self.states.index(self.current)
            self.current = self.states[(idx +1) % 3]

    def draw(self, surf):
        colour = GREEN if self.current == "green" else YELLOW if self.current == "yellow" else RED
        pygame.draw.circle(surf, colour, (self.x, self.y), 12)

#Vehicle Class
class Vehicle:
    def __init__(self, x, y, speed=2):
        self.x = x
        self.y = y
        self.speed = speed
        self.wait = 0

    def update(self, lights):
        #check if light ahead

        for light in lights:
            if abs(self.x - light.x) < 10 and self.y < light.y < self.y + 40:
                if light.current != "green":
                    self.wait += 1
                    return

        self.y += self.speed

    def draw(self, surf):
        pygame.draw.rect(surf, CAR, (self.x - 10, self.y - 20, 20, 40))




#sim state
vehicles = []
lights = []
intersections = []

spawn_timer = 0
SPAWN_RATE = 60 #every second spawn one


placing_mode = "intersection"

#loop

running = True
while running:
    clock.tick(FPS)
    screen.fill((40, 140, 40))

    #event handling
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
            pygame.quit()
            sys.exit()

        if event.type == pygame.MOUSEBUTTONDOWN:
            mx, my = pygame.mouse.get_pos()

            if mx < 800: #sim area

                if placing_mode == "intersection":
                    intersections.append((mx, my))
                elif placing_mode == "light":
                    lights.append(TrafficLight(mx, my))

        #switch placing mode
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_1:
                placing_mode = "intersection"
            if event.key == pygame.K_2:
                placing_mode = "light"


    #roads
    pygame.draw.rect(screen, ROAD, (380, 0, 240, HEIGHT))

    #veichles
    spawn_timer += 1
    if spawn_timer > SPAWN_RATE:
        spawn_timer = 0
        vehicles.append(Vehicle(500, -20))

    #update lights
    for light in lights:
        light.update()
        light.draw(screen)

    #update vehicles
    for v in vehicles:
        v.update(lights)
        v.draw(screen)

    #draw intersections
    for x, y in intersections:
         pygame.draw.rect(screen, WHITE, (x - 20, y - 20, 40, 40), 2)

    #ui
    pygame.draw.rect(screen, UI_BG, (800, 0, 200, HEIGHT))
    font = pygame.font.SysFont(None, 28)

    ui_text = [
        "Placement Mode:",
        f"{placing_mode.upper()}",
        "",
        "Press 1: Intersection",
        "Press 2: Traffic Light",
        "",
        f"Cars: {len(vehicles)}",
        f"Lights: {len(lights)}",
        f"Intersections: {len(intersections)}",
    ]

    y_offset = 20
    for line in ui_text:
        txt = font.render(line, True, WHITE)
        screen.blit(txt, (820, y_offset))
        y_offset += 30

    pygame.display.flip()