#!/bin/bash
set -e

export CRAN=${CRAN-"https://cran.rstudio.com"}
export S3_BUCKET_PREFIX=${S3_BUCKET_PREFIX-""}
export OS_IDENTIFIER=${OS_IDENTIFIER-"unknown"}
export TARBALL_NAME="R-${R_VERSION}-${OS_IDENTIFIER}.tar.gz"

# Some Dockerfiles may copy a `/env.sh` to set up environment variables
# that require command substitution. If this file exists, source it.
if [[ -f /env.sh ]]; then
    echo "Sourcing environment variables"
    source /env.sh
fi

# upload_r()
upload_r() {
  baseName="r/${OS_IDENTIFIER}"
  if [ -n "$S3_BUCKET" ] && [ "$S3_BUCKET" != "" ]; then
    echo "Storing artifact on s3: ${S3_BUCKET}, tarball: ${TARBALL_NAME}"
    aws s3 cp /tmp/${TARBALL_NAME} s3://${S3_BUCKET}/${S3_BUCKET_PREFIX}${baseName}/${TARBALL_NAME}
  fi
  if [ -n "$LOCAL_STORE" ] && [ "$LOCAL_STORE" != '' ]; then
    echo "Storing artifact locally: ${LOCAL_STORE}, tarball: ${TARBALL_NAME}"
    mkdir -p ${LOCAL_STORE}/${baseName}
    cp /tmp/${TARBALL_NAME} ${LOCAL_STORE}/${baseName}/${TARBALL_NAME}
  fi
}

# archive_r() - $1 as r version
archive_r() {
  tar czf /tmp/${TARBALL_NAME} --directory=/opt/R ${1} --owner=0 --group=0
}

fetch_r_source() {
  echo "Downloading R-${1}"
  wget -q ${CRAN}/src/base/R-3/R-${1}.tar.gz -O /tmp/R-${1}.tar.gz
  echo "Extracting R-${1}"
  tar xf /tmp/R-${1}.tar.gz -C /tmp
  rm /tmp/R-${1}.tar.gz
}

# On CentOS 6, we need to clean up references to the static library and header paths.
clean_r() {
  if [[ -f /clean.sh ]]; then
    echo "Cleaning R build on CentOS 6"
    source /clean.sh
  fi
}

# compile_r() - $1 as r version
compile_r() {
  cd /tmp/R-${1}

  # tools/config.guess in R versions older than 3.2.2 guess 'unknown' instead of 'pc'
  # test the version and properly set the flag.
  build_flag='--build=x86_64-pc-linux-gnu'
  if _version_is_greater_than ${R_VERSION} 3.2.2; then
    build_flag=''
  fi

  # Default configure options. Some Dockerfiles override this with an ENV directive.
  default_configure_options="\
    --enable-R-shlib \
    --with-tcltk \
    --enable-memory-profiling \
    --with-x \
    --with-blas \
    --with-lapack"

  CONFIGURE_OPTIONS=${CONFIGURE_OPTIONS:-$default_configure_options}

  # set some common environment variables for the configure step
  AWK=/usr/bin/awk \
  LIBnn=lib \
  PERL=/usr/bin/perl \
  R_PDFVIEWER=xdg-open \
  R_BROWSER=xdg-open \
  R_PAPERSIZE=letter \
  R_PRINTCMD=/usr/bin/lpr \
  R_UNZIPCMD=/usr/bin/unzip \
  R_ZIPCMD=/usr/bin/zip \
  ./configure \
    --prefix=/opt/R/${1} \
    ${CONFIGURE_OPTIONS} \
    ${build_flag}
  make clean
  make
  make install
}

set_up_environment() {
  mkdir -p /opt/R
}

_version_is_greater_than() {
  test "$(printf '%s\n' "$@" | sort -V | head -n 1)" != "$1"
}

###### RUN R COMPILE PROCEDURE ######
set_up_environment
fetch_r_source $R_VERSION
compile_r $R_VERSION
clean_r
archive_r $R_VERSION
upload_r $R_VERSION