#!/usr/bin/env bash
set -o pipefail -o errtrace -o nounset -o errexit

# Experimental script, please consult with dmarion@me.com before
# submitting any changes

# defaults
build_dir=.
install_dir=/usr/local
build_type=release
src_dir="$(dirname "$(readlink -f "$0")")"
host_arch=$(uname -m)
arch=${host_arch}
wipe=no
args=()

help()
{
  cat << __EOF__
VPP Build Configuration Script

USAGE: ${0} [options]

OPTIONS:
  --help, -h              This help
  --arch, -a              Cross-compile for specified target architecture (aarch64, riscv64, i386, ...)
  --build-dir, -b         Build directory
  --install-dir, -i       Install directory
  --build-type, -t        Build type (release, debug, ...)
  --wipe, -w              Wipe whole repo (except startup.* files)
__EOF__
}

while (( "$#" )); do
  case "$1" in
    -h|--help)
      help
      exit 1
      ;;
    -b|--build-dir)
      if [ -n "$2" ] && [ ${2:0:1} != "-" ]; then
        build_dir=$2
        shift 2
      else
        echo "Error: Argument for $1 is missing" >&2
        exit 1
      fi
      ;;
    -a|--arch)
      if [ -n "$2" ] && [ ${2:0:1} != "-" ]; then
	arch=$2
        shift 2
      else
        echo "Error: Argument for $1 is missing" >&2
        exit 1
      fi
      ;;
    -i|--install-dir)
      if [ -n "$2" ] && [ ${2:0:1} != "-" ]; then
        install_dir=$2
        shift 2
      else
        echo "Error: Argument for $1 is missing" >&2
        exit 1
      fi
      ;;
    -t|--build-type)
      if [ -n "$2" ] && [ ${2:0:1} != "-" ]; then
        build_type=$2
        shift 2
      else
        echo "Error: Argument for $1 is missing" >&2
        exit 1
      fi
      ;;
    -w|--wipe)
      wipe=yes
      shift 1
      ;;
    -*|--*=) # unsupported flags
      echo "Error: Unsupported flag $1" >&2
      exit 1
      ;;
    *) # preserve positional arguments
      PARAMS="$PARAMS $1"
      shift
      ;;
  esac
done

if [ "${arch}" != "${host_arch}" ] ; then
  args+=("-DCMAKE_SYSTEM_NAME=Linux")
  args+=("-DCMAKE_SYSTEM_PROCESSOR=${arch}")
  args+=("-DCMAKE_C_COMPILER=clang")
  args+=("-DCMAKE_C_COMPILER_TARGET=${arch}-linux-gnu")
  args+=("-DCMAKE_ASM_COMPILER_TARGET=${arch}-linux-gnu")
  args+=("-DCMAKE_FIND_ROOT_PATH=/usr/${arch}-linux-gnu")
  args+=("-DCMAKE_FIND_ROOT_PATH_MODE_PROGRAM=NEVER")
  args+=("-DCMAKE_FIND_ROOT_PATH_MODE_LIBRARY=BOTH")
  args+=("-DCMAKE_FIND_ROOT_PATH_MODE_INCLUDE=BOTH")
  args+=("-DCMAKE_FIND_ROOT_PATH_MODE_PACKAGE=ONLY")
fi

args+=("-DCMAKE_PREFIX_PATH=/opt/vpp/external/${arch}")
args+=("-DCMAKE_EXPORT_COMPILE_COMMANDS:BOOL=ON")
args+=("-DCMAKE_INSTALL_PREFIX=${install_dir}")
args+=("-DCMAKE_BUILD_TYPE:STRING=${build_type}")

[ "${wipe}" == "yes" ] && git clean -fdx --exclude=startup.\*

cmake ${args[@]} -G Ninja -S ${src_dir}/src -B ${build_dir}

cat << __EOF__

  Useful build commands:

  ninja                   Build VPP
  ninja set-build-type-*  Change build type to <debug|release|gcov|...>
  ninja config            Start build configuration TUI
  ninja run               Runs VPP using startup.conf in the build directory
  ninja debug             Runs VPP inside GDB using startup.conf in the build directory
  ninja pkg-deb           Create .deb packages
  ninja install           Install VPP to $install_dir

__EOF__