from machine import PWM, UART, Pin, Timer
from micropython import const
import time

_PWM_MAX = const(65535)
_PWM_FREQ = const(2000)

_PIN_EN_MOTOR_VERT = const(0)
_PIN_A_MOTOR_VERT = const(0)
_PIN_B_MOTOR_VERT = const(0)

_PIN_EN_MOTOR_HOR = const(0)
_PIN_A_MOTOR_HOR = const(0)
_PIN_B_MOTOR_HOR = const(0)

_PIN_EN_BACKLIGHT = const(0)
_PIN_EN_FRONTLIGHT = const(0)

_PIN_LED_RED_BTN = const(0)
_PIN_LED_BLU_BTN = const(0)

_PIN_RED_BTN = const(0)
_PIN_BLU_BTN = const(0)

_PIN_SENS_END_VERT = const(0)
_PIN_SENS_CNT_VERT = const(0)
_PIN_SENS_END_HOR = const(0)
_PIN_SENS_CNT_HOR = const(0)

CMD_MOT_V = 'V'     # run vertical motor
CMD_MOT_H = 'H'     # run horizontal motor
CMD_BL = 'B'        # backlight
CMD_FL = 'F'        # frontlight
CMD_UI = 'U'        # user interaction
CMD_RC = 'C'        # recording
CMD_RW = 'R'        # rewind

LED = PWM(Pin(25))
LED.freq(_PWM_FREQ)

class Scroll:
    def __init__(self, cnt_pin:Pin, end_pin:Pin, en_pin:PWM, a_pin:Pin, b_pin:Pin) -> None:
        self.c = 0
        self._dir = 0
        self._speed = 0
        self.en_pin = en_pin
        self.a_pin = a_pin
        self.b_pin = b_pin
        self.c_pin = cnt_pin
        self.c_pin.irq(self._count, Pin.IRQ_RISING | Pin.IRQ_FALLING)
        self.e_pin = end_pin
        self.e_pin.irq(self._stop, Pin.IRQ_RISING)        
    
    def _count(self, pin):
        self.c += self._dir

    def _stop(self, pin):
        self.a_pin.value(0)
        self.b_pin.value(0)

    @property
    def dir(self):
        return self._dir
    
    @dir.setter
    def dir(self, d):
        self.a_pin.value(1 if d > 0 else 0)
        self.b_pin.value(1 if d < 0 else 0)
        self._dir = d

    @property
    def speed(self):
        return self._speed * self._dir

    @speed.setter
    def speed(self, speed):
        self._speed = speed
        self.en_pin.duty_u16(speed * (_PWM_MAX // 100))
        self.dir = (1 if speed > 0 else
                    (-1 if speed < 0 else 0))

pwm_bl = PWM(Pin(_PIN_EN_BACKLIGHT))
pwm_bl.freq(_PWM_FREQ)
pwm_fl = PWM(Pin(_PIN_EN_FRONTLIGHT))
pwm_fl.freq(_PWM_FREQ)
pwm_mv = PWM(Pin(_PIN_EN_MOTOR_VERT))
pwm_mv.freq(_PWM_FREQ)
pwm_mh = PWM(Pin(_PIN_EN_MOTOR_HOR))
pwm_mh.freq(_PWM_FREQ)

pin_mv_a = Pin(_PIN_A_MOTOR_VERT, Pin.OUT)
pin_mv_b = Pin(_PIN_B_MOTOR_VERT, Pin.OUT)
pin_mh_a = Pin(_PIN_A_MOTOR_HOR, Pin.OUT)
pin_mh_b = Pin(_PIN_B_MOTOR_HOR)

led_blu = Pin(_PIN_LED_BLU_BTN, Pin.OUT)
led_red = Pin(_PIN_LED_RED_BTN, Pin.OUT)

btn_blu = Pin(_PIN_BLU_BTN, Pin.IN, Pin.PULL_UP)
btn_red = Pin(_PIN_RED_BTN, Pin.IN, Pin.PULL_UP)

cnt_v = Pin(_PIN_SENS_CNT_VERT, Pin.IN)
cnt_h = Pin(_PIN_SENS_CNT_HOR, Pin.IN)
end_v = Pin(_PIN_SENS_END_VERT, Pin.IN)
end_h = Pin(_PIN_SENS_END_HOR, Pin.IN)

uart0 = UART(0, baudrate=9600, tx=Pin(0), rx=Pin(1))

scroll_h = Scroll(cnt_h, end_h, pwm_mh, pin_mh_a, pin_mh_b)
scroll_v = Scroll(cnt_v, end_v, pwm_mv, pin_mv_a, pin_mv_b)

def motor_vert(*opts):
    _motorctrl(scroll_v, *opts)
    return 'OK'

def motor_hor(*opts):
    _motorctrl(scroll_h, *opts)
    return 'OK'

def _motorctrl(scroll: Scroll, steps: int, *opts):
    end = scroll.c + steps
    while True:
        err = end - scroll.c
        if abs(err) > 4:
            speed = (err / (2 * steps)) + 0.5
            scroll.speed = int(100 * speed)
        else:
            scroll.speed = 0
            break
        time.sleep_ms(5)   

def backlight(*opts):
    _fade_led(pwm_bl, *opts)
    return 'OK'

def frontlight(*opts):
    _fade_led(pwm_fl, *opts)
    return 'OK'

def _fade_led(led_pin: PWM, intensity: int, fade_ms: int, steps: int):
    intensity = intensity * (_PWM_MAX // 100)
    if fade_ms == 0:
        led_pin.duty_u16(intensity)
        return
    
    cur_intensity = led_pin.duty_u16()
    step = (intensity - cur_intensity) // steps
    wait = fade_ms // steps
    print(f'{cur_intensity} -> {intensity}, step={step}, wait={wait}')

    if step != 0:
        for i in range(steps):
            cur_intensity += step
            led_pin.duty_u16(cur_intensity)
            time.sleep_ms(wait)

    led_pin.duty_u16(intensity)

def user_interaction(timeout):
    def _toggle_leds(timer):
        led_blu.toggle()
        led_red.toggle()
    tmr = Timer()
    tmr.init(freq=2, mode=Timer.PERIODIC, callback=_toggle_leds)
    startime = time.ticks_ms()
    timeout *= 1000
    while time.ticks_diff(time.ticks_ms(), startime) < timeout:
        b, r = btn_blu.value(), btn_red.value()
        if (b + r) < 2:
            tmr.deinit()
            return 'B' if not b else 'R'
    tmr.deinit()
    led_blu.value(0)
    led_red.value(0)
    return 'T'   # Timeout

def recording(timeout):
    pass

def rewind(*opts):
    print(f'rewind({opts})')

###############################################################################

choice_map = {
    CMD_MOT_V: motor_vert,
    CMD_MOT_H: motor_hor,
    CMD_BL: backlight, 
    CMD_FL: frontlight,
    CMD_UI: user_interaction,
    CMD_RW: rewind
}

def parseCmd(cmd_str: str):
    cmd, parm_str = cmd_str.split(':')
    parms = []
    if len(parm_str) != 0:
        parms = [int(x) for x in parm_str.split('+')]
    resp = choice_map[cmd](*parms)
    uart0.write(f'{resp}\n'.encode('utf-8'))


if __name__ == '__main__':
    rxData = ''
    while True:
        rxBuf = uart0.read(1)
        if rxBuf is not None:
            rxData += rxBuf.decode('utf-8')
            if rxData.endswith('\n'):
                parseCmd(rxData.strip())
                rxData = ''