#!/bin/bash

system=$(lsb_release --description)
system_name=$(lsb_release --id --short)
system_version=$(lsb_release --release --short)
system_main_version=${system_version%%.*}

is_debian=false
is_ubuntu=false
is_mint=false
is_elementary=false
is_popos=false

if [ ! "${system/Pop!_OS}" = "$system" ] ; then
  is_popos=true
  is_ubuntu=true
elif [ ! "${system/Ubuntu}" = "$system" ] ; then
  is_ubuntu=true
elif [ ! "${system/Linux Mint}" = "$system" ] ; then
  is_mint=true
elif [ ! "${system/Debian}" = "$system" ] ; then
  is_debian=true
elif [ ! "${system/elementary}" = "$system" ] ; then
  is_elementary=true
else
  echo "this script is only for debian, ubuntu, mint and elementary. You're using ${system_name}."
  exit 1
fi

# make sure the firmware for intel sst audio device 808622A8 is installed
echo " -> Checking if the firmware for intels 808622A8 exists..."
if [ ! -f /lib/firmware/intel/fw_sst_22a8.bin ]; then
    # the firmware is not found where it is supposed to be, so install it
    package="firmware-intel-sound"
    package_source="deb http://ftp.de.debian.org/debian/ buster main non-free contrib"
    
    if [ "$is_ubuntu" = true ] || [ "$is_mint" = true ]; then
      package="linux-firmware"
      package_source="deb http://de.archive.ubuntu.com/ubuntu/ artful main"
    fi
    
    echo "     -> firmware not found, downloading ${package} to install it"
    
    install_from_newer_version=false
    if [ "$is_ubuntu" = true ] && [ "$system_main_version" -lt "16" ]; then
      install_from_newer_version=true
    fi

    if [ "$is_mint" = true ] && [ "$system_main_version" -lt "18" ]; then
      install_from_newer_version=true
    fi
    
    if [ "$is_debian" = true ] && [ "${system/stretch}" = "$system" ] && [ "${system/buster}" = "$system" ] && [ "${system/sid}" = "$system" ]; then
      install_from_newer_version=true
    fi
    
    if [ "$install_from_newer_version" = true ]; then
      echo "     -> Your version of ${system_name} is too old. Temporarily installing newer package source."
      sudo su -c "echo '${package_source}' >> /etc/apt/sources.list"
    fi
    
    sudo apt-get -qq update
    sudo apt-get -qq install $package
    
    if [ "$install_from_newer_version" = true ]; then
      echo "     -> Removing temporarily added package source."
      sudo sed -i '$d' /etc/apt/sources.list
      sudo apt-get -qq update
    fi
else
  echo "     -> firmware found."
fi

# Make sure alsa and pulseaudio are installed
echo ""
echo " -> Making sure pulseaudio is installed"
sudo apt-get -qq install pulseaudio

# configure pulseaudio to disable realtime-scheduling
echo " -> Disabling realtime scheduling in /etc/pulse.daemon.conf"
sudo sed --in-place --regexp-extended --expression='s/;?\s*realtime-scheduling\s*=\s*(yes|no)/realtime-scheduling = no/g' /etc/pulse/daemon.conf

# install alsa configuration files
echo " -> Downloading and installing alsa-ucm-configuration files"

sudo rm -rf /usr/share/alsa/ucm/chtcx2072x
sudo mkdir --parents /usr/share/alsa/ucm/bytcht-cx2072x/
sudo rm --force /usr/share/alsa/ucm/bytcht-cx2072x/HiFi.conf
sudo rm --force /usr/share/alsa/ucm/bytcht-cx2072x/bytcht-cx2072x.conf

sudo wget --quiet --show-progress  --output-document="/usr/share/alsa/ucm/bytcht-cx2072x/HiFi.conf" "https://raw.githubusercontent.com/heikomat/linux/cx2072x/cx2072x_fixes_and_manual/bytcht-cx2072x/HiFi.conf"
sudo wget --quiet --show-progress  --output-document="/usr/share/alsa/ucm/bytcht-cx2072x/bytcht-cx2072x.conf" "https://raw.githubusercontent.com/heikomat/linux/cx2072x/cx2072x_fixes_and_manual/bytcht-cx2072x/bytcht-cx2072x.conf"

# install the kernel
version=5.2
full_linux_version="${version}.0+"
headerfile="linux-headers-${version}_cx2072x_amd64.deb"
imagefile="linux-image-${version}_cx2072x_amd64.deb"

# download the kernel with cx2072x codec
echo ""
echo " -> Downloading Kernel with cx2072x support"
rm --force ${imagefile} ${headerfile}

wget --quiet --show-progress "https://github.com/heikomat/linux/releases/download/v${version}_cx2072x/${headerfile}"
wget --quiet --show-progress "https://github.com/heikomat/linux/releases/download/v${version}_cx2072x/${imagefile}"

# install the kernel
echo ""
echo " -> Installing the kernel"
sudo dpkg --install ${headerfile}
sudo dpkg --install ${imagefile}

# Pop!_OS uses systemd-boot instead of grub, and a tool called kernelstub to manage it
# Here we configure the efi-partition to boot with the new kernel
if [ "$is_popos" = true ]; then
  echo "     -> Pop!_OS detected. configuring efi-partition to use the new kernel"
  # make sure kernelstub is actually installed
  sudo apt-get -qq install kernelstub
  sudo kernelstub --kernel-path "/boot/vmlinuz-${full_linux_version}" --initrd-path "/boot/initrd.img-${full_linux_version}"
fi

# remove older kernels
echo " -> Removing old kernels"
sudo apt-get -qq autoremove 

# cleanup
echo " -> Cleaning up downloads"
rm --force ${imagefile} ${headerfile}

echo ""
echo ""
echo " -> All done. Please reboot! <-"
echo " If you still have no sound after rebooting, try the following: "
echo ""
echo " - Change the audio-output in your audio-control"
echo " - Set the default sink with:"
echo "      pacmd set-default-sink \$(pactl list short sinks | grep cx2072x | cut -c1)"
echo ""