configure

#!/bin/bash

ABS_SRCDIR="$( cd "$( dirname \
        "${BASH_SOURCE[0]}" )"&> /dev/null && pwd )" || exit

SRCDIR=$("${REALPATH:-realpath}" --relative-to="." "$ABS_SRCDIR") || \
        fail 'Unable to deduce relative path to source'

BUILDDIR=.
ABS_BUILDDIR=$(pwd)

# These are the programs that have an environment 
# variable that differs from the executable names,
# that might be -posix or -win32 suffixed,
# and always have the cross-compiler host prefix
declare -A namedtools=(
  [CC]=gcc
  [CXX]=g++
)

# These are the programs that are named the same
# as the name here, converted to uppercase, 
# and might be gcc- prefixed,
# and might be -posix or -win32 suffixed, 
# and always have the cross-compiler host prefix
declare -a hosttoolnames=(
  "cpp"
  "ar"
  "nm"
  "ranlib"
  "gcov-dump"
  "gcov"
  "gcov-tool"
  "nm"
  "objdump"
  "objcopy"
  "ld"
  "addr2line"
  "as"
  "gprof"
)

# These are tools that are not cross-compilation related
declare -a buildtoolnames=(
  "rm"
  "mkdir"
  "grep"
  "find"
  "sed"
  "awk"
)

# Use the HOST environment variable if there is one,
# otherwise, begin with the assumption that it is
# a windows host
host=${HOST:-x86_64-w64-mingw32}
suffix=posix

# -h overrides the host compiler name prefix
# -s overrides the host compiler name suffix
while getopts "h:s:?" opt; do
  case $opt in
    h) host="$OPTARG"
    ;;
    s) suffix="$OPTARG"
    ;;
    \?) 
    echo Produces a config.mak for the Makefile, for cross-compiler selection
    echo and to allow out-of-source builds.
    echo Usage:
    echo   configure [-h prefix] [-s suffix]
    echo example:
    echo   configure -h x86_64-w64-mingw32 -s posix
    exit 1
    ;;
  esac
done

CONFIGFILE=config.mak

if [[ -n $host ]]; then
  host=${host}-
fi

function envvar_name() {
  local name="$1"
  name="${name//-/_}"
  name="${name^^}"
  echo -n "$name"
}

function work {
  echo "# This file is automatically generated!"
  echo "# This is meant to be included by the main Makefile"
  echo "# Running configure in the source tree, " 
  echo "# from the build directory should update this file"
  echo "HOST=${host}"
  echo "ABS_BUILDDIR=${ABS_BUILDDIR}"
  echo "ABS_SRCDIR=${ABS_SRCDIR}"
  echo "SRCDIR=${SRCDIR}"
  echo "BUILDDIR=${BUILDDIR}"
  for name in "${!namedtools[@]}"; do
    name=$(envvar_name "$name")
    program="${namedtools[$name]}"
    selected=""
    if [[ "$suffix" == "posix" ]] && \
        which "${host}${program}-posix" >/dev/null; then
      selected="\$(HOST)${program}-posix"
    elif [[ "$suffix" == "" ]] && \
        which "${host}${program}" >/dev/null; then
      selected="\$(HOST)${program}"
    elif [[ "$suffix" == "win32" ]] && \
        which "${host}${program}-win32" >/dev/null; then
      selected="\$(HOST)${program}-win32"
    else
      echo "Can't find ${host}${program}" >&2
      exit 1
    fi
    echo "Found ${selected} for ${name}" >&2
    echo "${name}=${selected}"
  done
  for name in "${hosttoolnames[@]}"; do
    program="$name"
    name=$(envvar_name "$name")
    selected=
    if [[ "$suffix" == "posix" ]] && \
        which "${host}gcc-${program}-posix" >/dev/null; then
      selected="\$(HOST)gcc-${program}-posix"
    elif [[ "$suffix" != "win32" ]] &&  \
        which "${host}gcc-${program}" >/dev/null; then
      selected="\$(HOST)gcc-${program}"
    elif which "${host}gcc-${program}-win32" >/dev/null; then
      selected="\$(HOST)gcc-${program}-win32"
    elif [[ "$suffix" == "posix" ]] && \
        which "${host}${program}-posix" >/dev/null; then
      selected="\$(HOST)${program}-posix"
    elif [[ "$suffix" != "win32" ]] && \
        which "${host}${program}" >/dev/null; then
      selected="\$(HOST)${program}"
    elif which "${host}${program}-win32" >/dev/null; then
      selected="\$(HOST)${program}-win32"
    elif which "${host}${program}-win32" >/dev/null; then
      selected="\$(HOST)${program}-win32"
    elif which "${program}" >/dev/null; then
      selected="${program}"
    else
      echo "Can't find ${program}" >&2
      exit 1
    fi
    echo "Found ${selected} for ${name}" >&2
    echo "${name}=${selected}"
  done
  for name in "${buildtoolnames[@]}"; do
    program="$name"
    name="$(envvar_name "$name")"
    selected=
    if which "${program}" >/dev/null; then
      selected="${program}"
    else
      echo "Can't find ${program}" >&2
      exit 1
    fi
    echo "Found ${selected} for ${name}" >&2
    echo "${name}=${selected}"
  done

  WINHEADERS=${WINHEADERS:-/usr/share/mingw-w64/include}
  echo "WINHEADERS=${WINHEADERS}"

  if [[ ! -f Makefile ]]; then
    echo need a makefile >&2
    ln -rs "${SRCDIR}/Makefile" . || exit
  fi
}

( work ) >"$CONFIGFILE" || exit