power-beeps

#!/bin/python3
from collections import namedtuple
from contextlib import contextmanager
import math
import re
import os
import struct
import subprocess
from time import sleep

TONE = {
    0: 500,
    1: 600,
    2: 700,
}
rate = 48000 # Hz
vol = 1 # As a percentage

Status = namedtuple("Status", ["battery", "status", "percent"])
class Monitor():
    def __init__(self):
        self.state = None

    def play(self, s):
        if os.path.exists("/bin/paplay"):
            command = ['paplay', '--raw', "--channels", "1", "--rate", str(rate), "--format"        , "s16le"]
        else:
            command = ['aplay', '-r', str(rate), '-f', 's16']

        p = subprocess.Popen(command, stdin=subprocess.PIPE, stderr=subprocess.DEVNULL)
        bytes_ = struct.pack(f"<{str(len(s))}h", *[int(32000 * x * vol) for x in s])
        p.stdin.write(bytes_)
        p.stdin.close()
        p.wait()
    
    @staticmethod
    def silence(sec):
        samples = int(sec * rate)
        return [0]*samples

    @staticmethod
    def tone(freq, sec):
        #ms = randExp(200,600)
        #freq = randExp(220, 900)
        samples = int(sec * rate)
        r = [math.sin(t*freq/rate*math.pi) for t in range(samples)]
        for x in range(100):
            r[x] *= (x/100)
            r[-x] *= (x/100)
        return r

    def acpi(self):
        # Battery 0: Not charging, 0%
        # Battery 1: Not charging, 99%
        # Battery 1: Discharging, 99%, 03:51:12 remaining
        # Battery 1: Discharging, 99%, discharging at zero rate - will never fully discharge.
        # Battery 1: Charging, 91%, charging at zero rate - will never fully charge.
        # Battery 1: Charging, 91%, 00:06:17 until charged

        pattern = "Battery ([0-9]): (.*), ([0-9]+)%(?:, .*)?"
        out = subprocess.check_output("acpi").decode('utf8').rstrip().split("\n")
        s = []
        for line in out:
            if m := re.match(pattern, line):
                battery = int(m.group(1))
                status = m.group(2)
                percent = int(m.group(3))
                s.append(Status(battery, status, percent))
            else:
                raise Exception(f"re.match({repr(pattern)}, {repr(line)})")
                assert re.match(pattern, line)
        return s

    @contextmanager
    def unmuted(self):
        isPulse = os.path.exists("/bin/paplay")
        if isPulse:
            isMuted = {"[off]": False, "[on]": True}[subprocess.check_output(["amixer", "get", "Master"]).decode("utf8").rstrip().split()[-1]]
            mute = unmute = lambda: subprocess.run(["amixer", "-D", "pulse", "sset", "Master", "toggle"])
        else: # Alsa
            isMuted = {"[off]": False, "[on]": True}[subprocess.check_output(["amixer", "get", "Master"]).decode("utf8").rstrip().split()[-1]]
            mute = unmute = lambda: subprocess.run(["amixer", "set", "Master", "toggle"])

        if not isMuted: unmute()
        try:
            yield
        finally:
            if not isMuted: mute()

    def beep(self, *tones):
        #print("Beeps", tones)
        samples = []
        for i, tone in enumerate(tones):
            if i != 0:
                samples.extend(self.silence(.1))
            samples.extend(self.tone(TONE[tone], .2))
        with self.unmuted():
            self.play(samples)

    def change_power(self, old, new):
        oldAC = not any(batt.status == "Discharging" for batt in old)
        newAC = not any(batt.status == "Discharging" for batt in new)
        if not oldAC and newAC:
            self.beep(0, 1) # Connected to power
        if oldAC and not newAC:
            self.beep(1, 0) # Disconnected from power

        if not newAC and all(batt.percent <= 10 for batt in new) and any(batt.percent > 10 for batt in old):
            self.beep(2, 2) # Warning! Power low!
        if not newAC and all(batt.percent <= 5 for batt in new) and any(batt.percent > 5 for batt in old):
            self.beep(2, 2, 2) # Warning! Power critically low!

    def check_power(self):
        old_state, self.state = self.state, self.acpi()
        if old_state is not None:
            self.change_power(old_state, self.state)
        

def every(time, action):
    while True:
        sleep(time)
        action()

if __name__ == "__main__":
    monitor = Monitor()
    every(1, monitor.check_power)