#!/bin/bash

if [[ ! -d /tmp/output/${OS_IDENTIFIER} ]]; then
  mkdir -p "/tmp/output/${OS_IDENTIFIER}"
fi

# R 3.x requires PCRE1. On RHEL 9, R 3.x also requires PCRE2 for Pango support.
pcre_libs='- pcre2-devel'
if [[ "${R_VERSION}" =~ ^3 ]]; then
  pcre_libs='- pcre2-devel
- pcre-devel'
fi

# On RHEL and SUSE, we link R against the internal shared BLAS to make the
# R binaries more portable and allow users to switch BLAS implementations without
# having to recompile R. We default to OpenBLAS, but users may prefer other implementations.
# 
# Binary packages built against the shared BLAS are also more portable and may be used
# with the default R distributed by RHEL/SUSE, or other R installations using
# shared BLAS and configured with a different BLAS (such as Microsoft R Open with MKL).
# This is especially important for Posit Package Manager's binary packages.
#
# However, EPEL 9's R now links externally against FlexiBLAS, which provides a
# native BLAS switching mechanism for Fedora/RHEL. Starting with R 4.3.0, we also
# link to external FlexiBLAS for compatibility.
# https://fedoraproject.org/wiki/Changes/FlexiBLAS_as_BLAS/LAPACK_manager
#
# On Ubuntu/Debian, we link R against the external BLAS instead (--with-blas/--with-lapack),
# as those distributions use the alternatives system to swap BLAS libraries at runtime.
# The default R distributions on Ubuntu/Debian use the external BLAS, so we do as well
# for portability.
#
# https://cran.r-project.org/doc/manuals/r-release/R-admin.html#Shared-BLAS
if [[ "$("${R_INSTALL_PATH}/bin/R" CMD config BLAS_LIBS)" == "-lflexiblas" ]]; then
  blas_lib='flexiblas-devel'

  # Create postremove script to remove empty directories, as nFPM doesn't include them in the RPM files.
  cat <<EOF >> /after-remove.sh
  if [ -d ${R_INSTALL_PATH} ]; then
    rm -r ${R_INSTALL_PATH}
  fi
EOF

  scripts="scripts:
  postremove: /after-remove.sh
"
else
  blas_lib='openblas-devel'

  # Create post-install script required for OpenBLAS.
  cat <<EOF >> /post-install.sh
  mv ${R_INSTALL_PATH}/lib/R/lib/libRblas.so ${R_INSTALL_PATH}/lib/R/lib/libRblas.so.keep
  ln -s /usr/lib64/libopenblasp.so ${R_INSTALL_PATH}/lib/R/lib/libRblas.so
EOF

  # Create after-remove script to remove internal BLAS, which won't be cleaned up automatically.
  cat <<EOF >> /after-remove.sh
  if [ -d ${R_INSTALL_PATH} ]; then
    rm -r ${R_INSTALL_PATH}
  fi
EOF

  scripts="scripts:
  postinstall: /post-install.sh
  postremove: /after-remove.sh
"
fi

if [ "$(arch)" == "aarch64" ]; then echo arm64; else echo amd64; fi > /tmp/arch

cat <<EOF > /tmp/nfpm.yml
name: R-${R_VERSION}
version: 1
version_schema: none
arch: $(cat /tmp/arch)
release: 1
maintainer: Posit Software, PBC <https://github.com/rstudio/r-builds>
description: |
  GNU R statistical computation and graphics system
vendor: Posit Software, PBC
homepage: https://www.r-project.org
license: GPLv2+
depends:
- bzip2-devel
- gcc
- gcc-c++
- gcc-gfortran
- libcurl-devel
- libicu-devel
- libSM
- libtiff
- libXmu
- libXt
- make
- ${blas_lib}
- pango
${pcre_libs}
- tcl
- tk
- unzip
- which
- xz-devel
- zip
- zlib-devel
contents:
- src: ${R_INSTALL_PATH}
  dst: ${R_INSTALL_PATH}
${scripts}
EOF

nfpm package \
  -f /tmp/nfpm.yml \
  -p rpm \
  -t "/tmp/output/${OS_IDENTIFIER}"

export PKG_FILE=$(ls /tmp/output/${OS_IDENTIFIER}/R-${R_VERSION}*.rpm | head -1)