#!/usr/bin/env bash

# Download build dependencies for the build, notably:
#
# - required git submodules
# - host packages
#
# Only needs to be run once before each type of build per-system.

set -eux
all=false
apt_get=true
baremetal=false
baremetal_given=false
buildroot=true
buildroot_given=false
linux=true
linux_given=false
interactive_pkgs=libsdl2-dev
parsec_benchmark_given=false
gem5=false
gem5_given=false
qemu=true
qemu_given=false
submodules_dir=submodules
submodules=
y=
while [ $# -gt 0 ]; do
  case "$1" in
    --all)
      all=true
      shift
    ;;
    --baremetal)
      baremetal_given=true
      shift
    ;;
    --buildroot)
      buildroot_given=true
      shift
    ;;
    --gem5)
      gem5_given=true
      shift
    ;;
    --parsec-benchmark)
      parsec_benchmark_given=true
      shift
    ;;
    --qemu)
      qemu_given=true
      shift
    ;;
    --no-apt-get)
      apt_get=false
      shift
    ;;
    --travis)
      interactive_pkgs=
      y=-y
      shift
    ;;
    *)
      echo 'unknown option' 1>&2
      exit 2
    ;;
  esac
done
if ! "$all" && "$gem5_given" && ! "$qemu_given"; then
  qemu=false
fi
if "$all" || "$gem5_given"; then
  gem5=true
fi
if "$all" || "$baremetal_given"; then
  baremetal=true
fi
if ! "$all" && "$baremetal_given" && ! "$buildroot_given"; then
  buildroot=false
fi
if "$all" || "$parsec_benchmark_given"; then
  submodules="${submodules} parsec-benchmark"
fi

if "$apt_get"; then
  pkgs="\
automake \
bc \
bison \
build-essential \
coreutils \
cpio \
expect \
flex \
gcc-aarch64-linux-gnu \
gcc-arm-linux-gnueabi \
git \
libguestfs-tools \
moreutils \
rsync \
tmux \
unzip \
vinagre \
wget \
"
  if "$gem5"; then
    pkgs="${pkgs} \
ccache \
diod \
libgoogle-perftools-dev \
protobuf-compiler \
python-dev \
python-pip \
scons \
"
  fi
  if "$baremetal"; then
    pkgs="${pkgs} \
docbook2x \
libtool-bin \
"
  fi
  command -v apt-get >/dev/null 2>&1 || {
    cat <<EOF
apt-get not found. You're on your own for installing dependencies.

On Ubuntu they are:

$pkgs
EOF
    exit 0
  }

  # Without this started failing in kernel 4.15 with:
  # Makefile:932: *** "Cannot generate ORC metadata for CONFIG_UNWINDER_ORC=y, please install libelf-dev, libelf-devel or elfutils-libelf-devel".  Stop.
  pkgs="$pkgs libelf-dev"

  # https://stackoverflow.com/questions/20010199/determining-if-a-process-runs-inside-lxc-docker
  if [ -f /.dockerenv ]; then
    # https://askubuntu.com/questions/909277/avoiding-user-interaction-with-tzdata-when-installing-certbot-in-a-docker-contai
    export DEBIAN_FRONTEND=noninteractive
    mysudo=
    # https://askubuntu.com/questions/496549/error-you-must-put-some-source-uris-in-your-sources-list
    sed -Ei 's/^# deb-src/deb-src/' /etc/apt/sources.list
    y=-y
  else
    mysudo=sudo
  fi
  $mysudo apt-get update $y
  # Building SDL for QEMU in Buildroot was rejected upstream because it adds many dependencies:
  # https://patchwork.ozlabs.org/patch/770684/
  # We are just using the host SDL for now, if it causes too much problems we might remove it.
  # libsdl2-dev needs to be installed separatedly from sudo apt-get build-dep qemu
  # because Ubuntu 16.04's QEMU uses SDL 1.
  $mysudo apt-get install $y \
    $pkgs \
    $interactive_pkgs \
  ;
  if "$qemu"; then
    $mysudo apt-get build-dep $y qemu
  fi
  if "$gem5"; then
    # Generate graphs of config.ini under m5out.
    # Not with pip directly:
    # https://stackoverflow.com/questions/49836676/error-after-upgrading-pip-cannot-import-name-main/51846054#51846054
    python -m pip install --user pydot
  fi
fi

## Submodules

if "$baremetal"; then
  submodules="${submodules} crosstool-ng"
fi
if "$buildroot"; then
  submodules="${submodules} buildroot"
fi
if "$qemu"; then
  submodules="${submodules} qemu"
fi
if "$gem5"; then
  submodules="${submodules} gem5"
fi
submodules="$(for submodule in ${submodules}; do printf "${submodules_dir}/${submodule} "; done)"

# == Shallow cloning.
#
# TODO Ideally we should shallow clone --depth 1 all of them.
#
# However, most git servers out there are crap or craply configured
# and don't allow shallow cloning except for branches.
#
# So for now, let's shallow clone only the Linux kernel, which has by far
# the largest .git repo history, and full clone the others.
#
# Then we will maintain a GitHub Linux kernel mirror / fork that always has a
# lkmc branch, and point to it, so that it will always succeed.
#
# See also:
#
# * https://stackoverflow.com/questions/3489173/how-to-clone-git-repository-with-specific-revision-changeset
# * https://stackoverflow.com/questions/2144406/git-shallow-submodules/47374702#47374702
# * https://unix.stackexchange.com/questions/338578/why-is-the-git-clone-of-the-linux-kernel-source-code-much-larger-than-the-extrac
#
# == Other nice git options for when distros move to newer Git
#
# Currently not on Ubuntu 16.04:
#
# `--progress`: added on Git 2.10:
#
# * https://stackoverflow.com/questions/32944468/how-to-show-progress-for-submodule-fetching
# * https://stackoverflow.com/questions/4640020/progress-indicator-for-git-clone
#
# `--jobs"`: https://stackoverflow.com/questions/26957237/how-to-make-git-clone-faster-with-multiple-threads/52327638#52327638
#
git submodule update --init --recursive -- ${submodules}
if "$linux"; then
  git submodule update --depth 1 --init --recursive -- "${submodules_dir}/linux"
fi