package_r

#!/bin/bash

# fail fast
set -e

# debug
# set -x

# for checking which version of the build script was used, output to STDOUT
# so that it gets included in the build log output file
echo "#======================================================================"
echo "# $0"
cat $0
echo "#======================================================================"
echo "# Environment"
set
echo "#======================================================================"

R_VERSION="${1:-3.4.0}"
BUILD_NO="${2:-`date +%Y%m%d-%H%M`}"
STACK="${3:-cedar-14}"

# check arguments
if ([ -z "$R_VERSION" ] || [ -z "$BUILD_NO" ] || [ -z "$STACK" ]); then
  echo
  echo "USAGE: $0 VERSION [BUILD_NO] [STACK]"
  echo
  echo "  R_VERSION  Optionally, the R version for apt-get."
  echo "                 Defaults to 3.3.1-1trusty0"
  echo "                 Use \"apt-cache policy r-base\" to obtain valid versions."
  echo
  echo "  BUILD_NO       Optionally, the build number."
  echo "                 Defaults to todays date and current time, in the form \"YYYYMMDD-HHMM\"."
  echo
  echo "  STACK          Optionally, the Heroku stack."
  echo "                 Defaults to cedar-14"
  echo
  exit 1
fi

# helper functions
function topic() {
  echo "-----> $*"
}

function indent() {
  c='s/^/       /'
  case $(uname) in
    Darwin) sed -l "$c";;
    *)      sed -u "$c";;
  esac
}

function symlink_files() {

  # target $1 vs source $2
  echo "Comparing $1 -> $2"

  pushd "$1" > /dev/null
  count=0

  for f in *
  do

    # directory?
    if [[ -d "$f" ]]; then

      # skip symlinked directories
      if [[ ! -L "$f" ]]; then
        symlink_files "$1/$f" "$2/$f"
      fi

    # regular file, which exists in source directory?
    elif [[ ! -L "$f" ]] && [[ -f "$2/$f" ]]; then

      # get file sizes
      i=$(wc -c "$f"    | cut -d' ' -f1)
      j=$(wc -c "$2/$f" | cut -d' ' -f1)

      if [ $i -eq $j ]; then
        # echo "Linking $2/$f"
        count=$((count+1))
        ln -sf "$2/$f" "$f"
      fi

    fi

  done

  echo "Linked $count files"

  popd > /dev/null
}

ARCHIVE="R-$R_VERSION-binaries-$BUILD_NO.tar.gz"
SYMLINKS_VER=v1.4.3

APP_DIR="/app"
TOOLS_DIR="$APP_DIR/.tools"
CHROOT_DIR="$APP_DIR/.root"
DEBOOTSTRAP_BASE_DIR="$TOOLS_DIR/debootstrap"
DEBOOTSTRAP_DIR="$DEBOOTSTRAP_BASE_DIR/usr/share/debootstrap"
FAKECHROOT_DIR="$TOOLS_DIR/fakechroot"
PATH="$DEBOOTSTRAP_BASE_DIR/usr/sbin:$FAKECHROOT_DIR/sbin:$FAKECHROOT_DIR/bin:$PATH"

# export DEBIAN_FRONTEND=noninteractive
# export TERM=linux
export DEBOOTSTRAP_DIR
export PATH

pushd $APP_DIR > /dev/null

#======================================================================
topic 'Installing symlinks utility'
git clone -b "$SYMLINKS_VER" --single-branch --depth 1 https://github.com/brandt/symlinks.git
pushd symlinks > /dev/null
make
popd > /dev/null

#======================================================================
topic 'Packaging binaries'

# remove unneeded files to reduce slug size

rm -rf $CHROOT_DIR/usr/share/doc
rm -rf $CHROOT_DIR/usr/share/info
rm -rf $CHROOT_DIR/usr/share/man
rm -rf $CHROOT_DIR/var/lib/apt/lists/*

# convert all symlinks from absolute to relative to the /app/.root directory
pushd $CHROOT_DIR > /dev/null
/app/symlinks/symlinks -r -c bin etc lib lib64 opt run sbin usr var
popd > /dev/null

###
# these files are the same those in the "host", so convert to symlinks to save slug size
#  NOTE: will be absolute symlinks
##

symlink_files $CHROOT_DIR/bin /bin
symlink_files $CHROOT_DIR/lib /lib
symlink_files $CHROOT_DIR/usr /usr

#======================================================================
topic 'Compressing archive'

tar czf R-$R_VERSION-binaries-$BUILD_NO.tar.gz .root .tools

popd > /dev/null
exit 0