from array import array

import micropython
from machine import Pin, Timer, disable_irq, enable_irq
from time import sleep_ms


PRIMARY_LED_PIN = 2
SECONDARY_LED_PIN = 4

PRIMARY_TIMER_ID = 0
SECONDARY_TIMER_ID = 1

PRIMARY_PERIOD_MS = 1000
SECONDARY_PERIOD_MS = 500

MAX_TIMER_EVENTS = 20

micropython.alloc_emergency_exception_buf(100)

primary_led = Pin(PRIMARY_LED_PIN, Pin.OUT)
secondary_led = Pin(SECONDARY_LED_PIN, Pin.OUT)

primary_led.off()
secondary_led.off()

primary_timer = Timer(PRIMARY_TIMER_ID)
secondary_timer = Timer(SECONDARY_TIMER_ID)

timer_count = array("I", [0])


def primary_timer_callback(timer):
    if timer_count[0] < MAX_TIMER_EVENTS:
        timer_count[0] += 1
        primary_led.value(1 - primary_led.value())


def secondary_timer_callback(timer):
    secondary_led.value(1 - secondary_led.value())


def read_timer_count():

    irq_state = disable_irq()

    count = timer_count[0]

    enable_irq(irq_state)

    return count


def stop_timers():
    primary_timer.deinit()
    secondary_timer.deinit()

    primary_led.off()
    secondary_led.off()


def main():

    timer_count[0] = 0

    primary_led.off()
    secondary_led.off()
    primary_timer.init(
        period=PRIMARY_PERIOD_MS,
        mode=Timer.PERIODIC,
        callback=primary_timer_callback
    )
    secondary_timer.init(
        period=SECONDARY_PERIOD_MS,
        mode=Timer.PERIODIC,
        callback=secondary_timer_callback
    )

    print("Hardware timers started")
    print("Timer 0 period: 1000 ms")
    print("Timer 1 period: 500 ms")

    last_reported_count = 0

    try:

        while True:

            count = read_timer_count()

            # Print every Timer 0 event
            while last_reported_count < count:

                last_reported_count += 1

                print(
                    "Timer count:",
                    last_reported_count
                )

                # Every 5 seconds
                if last_reported_count % 5 == 0:

                    print(
                        "5-second interval reached"
                    )

            # Stop after 20 events
            if count >= MAX_TIMER_EVENTS:

                print("Timer stopped.")

                break

            sleep_ms(10)

    finally:

        stop_timers()


if __name__ == "__main__":

    try:

        main()

    except KeyboardInterrupt:

        stop_timers()

        print("Exercise 2 stopped by user")