#!/bin/sh
#   gck.configure - Prepares the build system for GCK distributions
#   FEATURES:
#       - Generate config.mak
#       - Sets C Flags
#
#    COMPILATION (Linux - POSIX):
#        ./configure
#
#
#   LICENSE: BSD-3-Clause
#
#   Copyright (c) 2025 GCK
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
# 
# 1. Redistributions of source code must retain the above copyright notice, this
#    list of conditions and the following disclaimer.
# 
# 2. Redistributions in binary form must reproduce the above copyright notice,
#    this list of conditions and the following disclaimer in the documentation
#    and/or other materials provided with the distribution.
# 
# 3. Neither the name of the copyright holder nor the names of its
#    contributors may be used to endorse or promote products derived from
#    this software without specific prior written permission.
# 
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#

me=$0
scriptversion="1.0.1"

version="make $scriptversion

Copyright (C) 2025 GCK.

This is free software; you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law."

usage="\
Usage: $me [OPTION]...
Prepares the build system for GCK distributions

Options:
   --release        enable release flags
   --enable-debug   enable debugging options
   --prefix PREFIX  set installation prefix

   --help     print this help and exit
   --version  output version information

Environment variables:

   CC      C compiler command
   CFLAGS  C compiler flags

Use these variables to override the choices made by 'configure'."

release=false
debug=false
prefix=/usr/local
CFLAGS=-pedantic
CC=
args_old=$@

while [ $# -gt 0 ]; do
  case $1 in
    --help) echo "$usage"; exit 0 ;;
    --version) echo "$version"; exit 0 ;;
    --release) release=true ;;
    --enable-debug) debug=true ;;
    --prefix) shift; prefix=${1:?missing prefix argument} ;;
    --strict) CFLAGS+="-Werror" ;;
    CC=*) CC=${1#*=} ;;
    CFLAGS=*) CFLAGS=${1#*=} ;;
    -*)
      echo "$0: Unknown option '$1'." >&2
      echo "$0: Try '--help' for more information." >&2
      exit 1 ;;
  esac
  shift
done

if [ "$release" = true ] && [ "$debug" = true ]; then
  echo "$0: Can't set both '--release' and '--debug'." >&2
  echo "$0: Try '--help' for more information." >&2
  exit 1
fi

cmdexists() { command -v "$1" >/dev/null 2>&1 ; }
trycc() { [ -z "$CC" ] && cmdexists "$1" && CC=$1 ; }

if [ -z "$CC" ]; then
  printf "checking for C compiler... "
  trycc gcc
  trycc clang
  trycc cc
  if [ -z "$CC" ]; then
    echo "none found"
    exit 1
  fi
  printf "%s\n" "$CC"
fi

printf "checking for git... "
if cmdexists git; then
  echo "yes"
else
  echo "no"
  exit 1
fi

printf "checking whether C compiler works... "
tmpcdir="$(mktemp -d)"
tmpc="$tmpcdir/test.c"
echo "typedef int x;" > "$tmpc"
if output=$($CC $CFLAGS -c -o /dev/null "$tmpc" 2>&1); then
  printf "yes\n"
else
  printf "no; %s\n" "$output"
  rm -rf "$tmpcdir"
  exit 1
fi
rm -rf "$tmpcdir"

if [ "$release" = true ]; then
  CFLAGS="$CFLAGS -O3 -pipe -DNDEBUG -march=native -flto -s -fdata-sections -ffunction-sections -Wl,--gc-sections"
elif [ "$debug" = true ]; then
  CFLAGS="$CFLAGS -O0 -ggdb -Wall -Wextra -Wpedantic -fno-omit-frame-pointer -DDEBUG"
fi

echo "creating config.status"
cat <<EOF > config.status
#!/bin/sh
#   DO NOT MODIFY. THIS IS A AUTOGENERATED SCRIPT FROM 'configure'
#
#    COMPILATION (Linux - POSIX):
#        ./config.status
#
#
#   LICENSE: BSD-3-Clause
#
#   Copyright (c) 2025 GCK
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
# 
# 1. Redistributions of source code must retain the above copyright notice, this
#    list of conditions and the following disclaimer.
# 
# 2. Redistributions in binary form must reproduce the above copyright notice,
#    this list of conditions and the following disclaimer in the documentation
#    and/or other materials provided with the distribution.
# 
# 3. Neither the name of the copyright holder nor the names of its
#    contributors may be used to endorse or promote products derived from
#    this software without specific prior written permission.
# 
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#

printf "config.status: recreating config.mak... "
{
  printf "PREFIX=%s\\n" "$prefix"
  printf "CFLAGS=%s\\n" "$CFLAGS"
  printf "CC=%s\\n" "$CC"
} > config.status
printf "done\n"
EOF
chmod u+x config.status

printf "configure: creating config.mak... "
{
  printf "PREFIX=%s\n" "$prefix"
  printf "CFLAGS=%s\n" "$CFLAGS"
  printf "CC=%s\n" "$CC"
} > config.mak
printf "done\n"

# End: configure