""" HW Mixer module """

import alsaaudio

class HwMixer():

    saved_volume = -1

    def __init__(self):
        self.mixerid = ''
        self.cardindex = None
        for ci in alsaaudio.card_indexes():
            if "seeed" in alsaaudio.cards()[ci]:
                self.cardindex = ci
        if self.cardindex is None:
            # We don't run a seeed card, use the default mixer
            self.cardindex = 0
            self.mixerid = alsaaudio.mixers(self.cardindex)[0]
        else:
            for i in alsaaudio.mixers(self.cardindex):
                if i == 'Master' or i == 'PCM' or i == 'Speaker' or i == 'Playback':
                    self.mixerid = i
            if self.mixerid == '':
                raise Exception('Cannot find mixer')
        self.mixer = alsaaudio.Mixer(cardindex=self.cardindex, control=self.mixerid)

    def svol(self):
        vols = self.mixer.getvolume()
        return int(sum(vols)/len(vols))

    def volume(self, val):
        if (val is None):
            return self.svol()
        elif (val == 'up'):
            self.mixer.setvolume(min(100, self.svol() + 10))
        elif (val == 'dn'):
            self.mixer.setvolume(max(0, self.svol() - 10))
        elif ((isinstance(val, int) or val.isdigit()) and (int(val) <= 100) and (int(val) >= 0)):
            self.mixer.setvolume(int(val))
        else:
            raise Exception('Unknown volume control')

    def save_volume(self):
        self.saved_volume = self.svol()

    def restore_volume(self):
        if (self.saved_volume > 0):
            self.mixer.setvolume(self.saved_volume)

mixer = HwMixer()