#!/usr/bin/env bash

. "$(dirname $0)/util/logging.bash"

read -d '' usage <<EOUSAGE
$0 - List C/C++ toolchain's #include paths.

Usage: $0 [clang|gcc|cc] OPTION

OPTIONS
      -c  Print C compiler's #include paths.
      -p  Print C++ compiler's #include paths.
      -P  Print C and C++ compilers' #include paths.

NOTE
      For a custom C/C++ compiler, set CC and CXX environment variables.
EOUSAGE

# Get C or C++ include paths
get-incl() {
  case "$1" in
    "cc") ;&
    "gcc") ;&
    "clang")
      xc='-xc'
      ;;
    "cxx") ;&
    "g++") ;&
    "clang++")
      xc='-xc++'
      ;;
  esac

  $1 -E -Wp,-v $xc /dev/null  2>&1 \
   | sed -e '1,/^\s*#include\s\+<\.\.\.>\s\+search\s\+starts\s\+here:\s*/d' \
   | sed -e '/^\s*End\s\+of\s\+search\s\+list.\s*$/,$d' \
   | sed -e 's/^\s\+//g; s/\s\+$//g'
}


cc=${CC:-cc}
cxx=${CXX:-cxx}

[ -z "$1" ] && errcat "$usage" && exit 1

case "$1" in
  'clang') ;&
  'clang++')
    cc='clang'
    cxx='clang++'
    shift
    ;;
  'gcc') ;&
  'g++')
    cc='gcc'
    cxx='g++'
    shift
    ;;
esac

get-both() { get-incl $cc; get-incl $cxx; }

while getopts 'cpP' opt; do
  case "${opt}" in
    c)
      get-incl $cc
      ;;
    p)
      get-incl $cxx
      ;;
    P)
      sort -u <<<$(get-both)
      ;;
    *)
      errcat "$usage"
      exit 1
      ;;
  esac
done

shift $((OPTIND-1))