#!/bin/bash

function fail {
  >&2 echo "$*"
  exit -1
}

PRE_RUN=()
POST_RUN=()
RUN=
for arg in "${@}"; do
  [[ "${arg}" == "run" ]] && {
    RUN=1
    continue
  }
  (( ! RUN )) && {
    PRE_RUN+=("${arg}")
  } || {
    POST_RUN+=("${arg}")
  }
done

function usage {
  cat << EOF
usage: scripts/intel-docker [DOCKER-OPTIONS]

intel-docker adds the following docker parameters to your
DOCKER-OPTIONS, based on the host configuration:

  --device=/dev/dri
  --group-add \${VIDEO}
  --group-add \${RENDER}

The group id used for VIDEO and RENDER is
based on the 'video' and 'render' group definitions used
for ownership of /dev/dri/* entries. Typically card* is 
owned by 'video' and render* is owned by 'render'. To
find the group id, 'stat' is used:

  VIDEO=\$(stat -c '%g' /dev/dri/card*)
  RENDER=\$(stat -c '%g' /dev/dri/render*)

If /dev/dri entries do not exist, no group add lines are added to
the docker option.
EOF
}

if test -e /dev/dri/card*; then
  VIDEO=$(stat -c '%g' /dev/dri/card*)
fi
if test -e /dev/dri/render*; then
  RENDER=$(stat -c '%g' /dev/dri/render*)
fi
if [ "${RENDER}" == "${VIDEO}" ]; then
  unset RENDER
fi
if [ "${RENDER}" == "" ] && [ "${VIDEO}" == "" ]; then
  fail "No /dev/dri/* entries found on host. Does your kernel have the GPU driver loaded?"
fi

cat << EOF
-------------------------------------------------------------------------------
Intel Xe graphics container script
EOF

(( RUN )) && {
  PRE_RUN+=("run")
  POST_RUN=(--device=/dev/dri ${POST_RUN[@]})

  [[ "${VIDEO}" != "" ]] || fail "No group ownership of /dev/dri/card* found."
  POST_RUN=("--group-add ${VIDEO}" ${POST_RUN[@]})

  [[ "${RENDER}" != "" ]] && POST_RUN=("--group-add ${RENDER}" ${POST_RUN[@]})
  true
} || {
  cat << EOF

NOTE: intel-docker is intended to be executed with the same arguments as you
would pass to docker, including the 'run' command.

EOF
}

cat << EOF
Adding the following options to the docker command line after 'run' and before
user options:

  --device=/dev/dri
  --group-add ${VIDEO}$( [[ "${RENDER}" != "" ]] && echo -e "\n  --group-add ${RENDER}\n" )

-------------------------------------------------------------------------------
EOF

echo -e "Running:\ndocker ${PRE_RUN[@]} ${POST_RUN[@]}"
docker ${PRE_RUN[@]} ${POST_RUN[@]}