import psutil
import sys
import signal

from gpiozero import Button
from signal import pause
from subprocess import check_call
from time import sleep
from unicornhatmini import UnicornHATMini, BUTTON_A

POWER_BUTTON_HOLD_TIME_IN_SECONDS = 1
TEMP_COLOR = [64, 0, 0]
CPU_COLOR = [0, 16, 32]
MAX_TEMP = 80
MIN_TEMP = 40
BLACK = [0, 0, 0]


class SystemStatus:
    def __init__(self, hat):
        self.hat = hat
        self.hat.set_brightness(0.1)
        self.hat.set_rotation(270)
        self.width, self.height = self.hat.get_shape()
        self.tempStartColumn = 0
        self.tempEndColumn = int(self.width / 2)
        self.cpuStartColumn = int(self.width / 2)
        self.cpuEndColumn = self.width - 1

    def display(self):
        self.displayTemp()
        self.displayCpu()
        self.hat.show()

    def displayTemp(self):
        self.displayField(
            start=self.tempStartColumn,
            end=self.tempEndColumn,
            value=self.getTempValue(),
            color=TEMP_COLOR
        )

    def displayCpu(self):
        self.displayField(
            start=self.cpuStartColumn,
            end=self.cpuEndColumn,
            value=self.getCpuValue(),
            color=CPU_COLOR
        )

    def displayField(self, start, end, value, color):
        for x in range(start, end):
            for y in range(value):
                self.hat.set_pixel(x, y, *color)
            for y in range(value, self.height):
                self.hat.set_pixel(x, y, BLACK)

    def getTempValue(self):
        temp = psutil.sensors_temperatures()['cpu_thermal'][0].current
        adjusted = max(0, temp - MIN_TEMP)
        percent = min(1, adjusted / (MAX_TEMP - MIN_TEMP))

        return int(self.height * percent)

    def getCpuValue(self):
        return int(self.height * (psutil.cpu_percent() / 100))

    def exit(self):
        self.hat.set_all(0, 0, 0)
        self.hat.show()

    def terminate(self):
        for _ in range(3):
            self.hat.set_all(0, 0, 0)
            self.hat.show()
            sleep(0.25)
            self.hat.set_all(255, 127, 0)
            self.hat.show()
            sleep(0.25)


def cleanExit(systemStatus, button):
    def exit(signum, frame):
        button.close()
        systemStatus.exit()
        sys.exit(0)

    return exit


def poweroff(systemStatus):
    def terminate():
        systemStatus.terminate()
        check_call(['sudo', 'poweroff'])

    return terminate


def main():
    systemStatus = SystemStatus(UnicornHATMini())
    powerButton = Button(BUTTON_A, hold_time=POWER_BUTTON_HOLD_TIME_IN_SECONDS)
    signal.signal(signal.SIGTERM, cleanExit(systemStatus, powerButton))

    powerButton.when_held = poweroff(systemStatus)

    while True:
        systemStatus.display()
        sleep(2)


if __name__ == '__main__':
    main()