import os
import subprocess
from functools import reduce
from operator import and_
import re
from distutils.version import LooseVersion

import logging
logger = logging.getLogger(__name__)


class UnknownFeatureException(Exception):
    pass

class FeatureDetector(object):
    features = {
        "core": [ "csdr", "nmux", "nc" ],
        "rtl_sdr": [ "rtl_sdr" ],
        "sdrplay": [ "rx_tools" ],
        "hackrf": [ "hackrf_transfer" ],
        "airspy": [ "airspy_rx" ],
        "digital_voice_digiham": [ "digiham", "sox" ],
        "digital_voice_dsd": [ "dsd", "sox", "digiham" ]
    }

    def feature_availability(self):
        return {name: self.is_available(name) for name in FeatureDetector.features}

    def is_available(self, feature):
        return self.has_requirements(self.get_requirements(feature))

    def get_requirements(self, feature):
        try:
            return FeatureDetector.features[feature]
        except KeyError:
            raise UnknownFeatureException("Feature \"{0}\" is not known.".format(feature))

    def has_requirements(self, requirements):
        passed = True
        for requirement in requirements:
            methodname = "has_" + requirement
            if hasattr(self, methodname) and callable(getattr(self, methodname)):
                passed = passed and getattr(self, methodname)()
            else:
                logger.error("detection of requirement {0} not implement. please fix in code!".format(requirement))
        return passed

    def command_is_runnable(self, command):
        return os.system("{0} 2>/dev/null >/dev/null".format(command)) != 32512

    def has_csdr(self):
        return self.command_is_runnable("csdr")

    def has_nmux(self):
        return self.command_is_runnable("nmux --help")

    def has_nc(self):
        return self.command_is_runnable('nc --help')

    def has_rtl_sdr(self):
        return self.command_is_runnable("rtl_sdr --help")

    def has_rx_tools(self):
        return self.command_is_runnable("rx_sdr --help")

    """
    To use a HackRF, compile the HackRF host tools from its "stdout" branch:
     git clone https://github.com/mossmann/hackrf/
     cd hackrf
     git fetch
     git checkout origin/stdout
     cd host
     mkdir build
     cd build
     cmake .. -DINSTALL_UDEV_RULES=ON
     make
     sudo make install
    """
    def has_hackrf_transfer(self):
        # TODO i don't have a hackrf, so somebody doublecheck this.
        # TODO also check if it has the stdout feature
        return self.command_is_runnable("hackrf_transfer --help")

    def command_exists(self, command):
        return os.system("which {0}".format(command)) == 0

    """
    To use DMR and YSF, the digiham package is required. You can find the package and installation instructions here:
    https://github.com/jketterl/digiham
    
    Please note: there is close interaction between digiham and openwebrx, so older versions will probably not work.
    If you have an older verison of digiham installed, please update it along with openwebrx.
    As of now, we require version 0.2 of digiham.
    """
    def has_digiham(self):
        required_version = LooseVersion("0.2")

        digiham_version_regex = re.compile('^digiham version (.*)$')
        def check_digiham_version(command):
            try:
                process = subprocess.Popen([command, "--version"], stdout=subprocess.PIPE)
                version = LooseVersion(digiham_version_regex.match(process.stdout.readline().decode())[1])
                process.wait(1)
                return version >= required_version
            except FileNotFoundError:
                return False
        return reduce(and_,
                      map(
                          check_digiham_version,
                          ["rrc_filter", "ysf_decoder", "dmr_decoder", "mbe_synthesizer", "gfsk_demodulator",
                           "digitalvoice_filter"]
                      ),
                      True)

    def has_dsd(self):
        return self.command_is_runnable("dsd")

    def has_sox(self):
        return self.command_is_runnable("sox")

    def has_airspy_rx(self):
        return self.command_is_runnable("airspy_rx --help 2> /dev/null")