from calculate.variables.datavars import Variable, Namespace, Dependence, \
    StringType, BooleanType, HashType, ListType, Calculate, Copy
from calculate.vars.main.os.func import get_arch_gentoo

from calculate.utils.package import PackageAtomParser

def get_available_audio_system():
    audio_systems = (
        ('alsa', None),
        ('pulseaudio', 'media-sound/pulseaudio')
    )
    package_db = PackageAtomParser()
    return [
        audio_system
        for audio_system, pkg in audio_systems
        if pkg is None or package_db.is_package_exists(pkg)
    ]

def get_audio_selected(available_systems, cmdline_audio):
    available_systems = available_systems.value

    if 'pulseaudio' in available_systems:
        cmdline_audio = cmdline_audio.value
        if cmdline_audio and cmdline_audio == 'alsa':
            return 'alsa'
        else:
            return 'pulseaudio'
    return 'alsa'

with Namespace("arch"):
    Variable("machine", type=StringType,
        source=Copy("main.os.arch.machine"))
    Variable("gentoo", type=StringType,
        source=Calculate(get_arch_gentoo, ".machine"))

with Namespace("audio"):
    Variable("available", type=ListType,
        source=Calculate(get_available_audio_system))
    Variable("selected", type=StringType, 
        source=Calculate(get_audio_selected, ".available", "main.cl.cmdline.calculate.audio"))