from machine import Pin, time_pulse_us
from time import sleep, sleep_us
import network
import urequests
import time

# -------------------------------
# WIFI + THINGSPEAK
# -------------------------------

WIFI_SSID = "Wokwi-GUEST"
WIFI_PASSWORD = ""

WRITE_API_KEY = "QEHOL3OVDXGB4M2H"
THINGSPEAK_URL = "https://api.thingspeak.com/update"

last_upload_time = 0

def connect_wifi():
    wlan = network.WLAN(network.STA_IF)
    wlan.active(True)
    wlan.connect(WIFI_SSID, WIFI_PASSWORD)

    print("Connecting to WiFi", end="")
    while not wlan.isconnected():
        print(".", end="")
        sleep(0.3)

    print("\nConnected!")
    print("IP:", wlan.ifconfig()[0])

def send_to_thingspeak(value):
    global last_upload_time

    now = time.time()

    if now - last_upload_time < 15:
        print("ThingSpeak skipped - wait 15 seconds")
        return

    url = THINGSPEAK_URL + "?api_key=" + WRITE_API_KEY + "&field1=" + str(value)

    try:
        response = urequests.get(url)
        print("Sent to ThingSpeak:", value)
        print("ThingSpeak response:", response.text)
        response.close()
        last_upload_time = now
    except Exception as e:
        print("ThingSpeak upload failed:", e)

# -------------------------------
# LED SETUP (Traffic Lights)
# -------------------------------

red_a = Pin(0, Pin.OUT)
yellow_a = Pin(1, Pin.OUT)
green_a = Pin(2, Pin.OUT)

red_b = Pin(3, Pin.OUT)
yellow_b = Pin(4, Pin.OUT)
green_b = Pin(5, Pin.OUT)

# -------------------------------
# INPUTS (Buttons)
# -------------------------------

button_a = Pin(6, Pin.IN, Pin.PULL_UP)
button_b = Pin(12, Pin.IN, Pin.PULL_UP)

# -------------------------------
# OUTPUT (Buzzer)
# -------------------------------

buzzer = Pin(7, Pin.OUT)

# -------------------------------
# ULTRASONIC SENSORS
# -------------------------------

trig_a = Pin(8, Pin.OUT)
echo_a = Pin(9, Pin.IN)

trig_b = Pin(10, Pin.OUT)
echo_b = Pin(11, Pin.IN)

last_dist_a = 999
last_dist_b = 999

# -------------------------------
# TURN EVERYTHING OFF
# -------------------------------

def all_off():
    red_a.off()
    yellow_a.off()
    green_a.off()
    red_b.off()
    yellow_b.off()
    green_b.off()
    buzzer.off()

# -------------------------------
# TRAFFIC LIGHT STATES
# -------------------------------

def lane_a_green():
    red_a.off()
    yellow_a.off()
    green_a.on()
    red_b.on()
    yellow_b.off()
    green_b.off()

def lane_a_yellow():
    red_a.off()
    yellow_a.on()
    green_a.off()
    red_b.on()
    yellow_b.off()
    green_b.off()

def lane_b_green():
    red_a.on()
    yellow_a.off()
    green_a.off()
    red_b.off()
    yellow_b.off()
    green_b.on()

def lane_b_yellow():
    red_a.on()
    yellow_a.off()
    green_a.off()
    red_b.off()
    yellow_b.on()
    green_b.off()

# -------------------------------
# ULTRASONIC DISTANCE FUNCTION
# -------------------------------

def get_distance(trig, echo):
    trig.off()
    sleep_us(2)
    trig.on()
    sleep_us(10)
    trig.off()

    duration = time_pulse_us(echo, 1, 30000)

    if duration < 0:
        return 999

    return (duration * 0.0343) / 2

# -------------------------------
# SENSOR CHECK EVERY 5 SECONDS
# -------------------------------

def check_ultrasonic():
    dist_a = get_distance(trig_a, echo_a)
    dist_b = get_distance(trig_b, echo_b)

    print("---- Sensor Check ----")
    print("Lane A distance:", round(dist_a, 2), "cm")
    print("Lane B distance:", round(dist_b, 2), "cm")

    if dist_a < 25:
        print("Car detected in Lane A")

    if dist_b < 25:
        print("Car detected in Lane B")

    print("Next check in 5 seconds...\n")

    return dist_a, dist_b

# -------------------------------
# EMERGENCY MODE
# -------------------------------

def emergency_lane_a():
    print("\nEmergency button pressed in Lane A")
    print("Switching light in Lane A to GREEN to ensure the emergency vehicle can go through")
    print("ThingSpeak value: 100\n")

    all_off()
    green_a.on()
    red_b.on()

    send_to_thingspeak(100)
    sleep(1)

    for _ in range(6):
        buzzer.on()
        sleep(0.15)
        buzzer.off()
        sleep(0.15)

def emergency_lane_b():
    print("\nEmergency button pressed in Lane B")
    print("Switching light in Lane B to GREEN to ensure the emergency vehicle can go through")
    print("ThingSpeak value: 200\n")

    all_off()
    green_b.on()
    red_a.on()

    send_to_thingspeak(200)
    sleep(1)

    for _ in range(6):
        buzzer.on()
        sleep(0.15)
        buzzer.off()
        sleep(0.15)

# -------------------------------
# WAIT FUNCTION WITH CHECKS
# -------------------------------

def wait_with_button_check(seconds):
    global last_dist_a, last_dist_b

    elapsed = 0.0

    while elapsed < seconds:

        if int(elapsed) % 5 == 0 and abs(elapsed - int(elapsed)) < 0.01:
            last_dist_a, last_dist_b = check_ultrasonic()

        if button_a.value() == 0:
            emergency_lane_a()
            return True

        if button_b.value() == 0:
            emergency_lane_b()
            return True

        sleep(0.1)
        elapsed += 0.1

    return False

# -------------------------------
# STARTUP
# -------------------------------

print("System starting...")
connect_wifi()

# -------------------------------
# MAIN LOOP
# -------------------------------

while True:
    lane_a_green()
    if wait_with_button_check(6):
        continue

    lane_a_yellow()
    if wait_with_button_check(3):
        continue

    lane_b_green()
    if wait_with_button_check(6):
        continue

    lane_b_yellow()
    if wait_with_button_check(3):
        continue