#!/bin/sh

usage() {
cat <<EOF
Usage: $0 [OPTION]... [VAR=VALUE]...

To assign environment variables (e.g., CC, CFLAGS...), specify them as
VAR=VALUE.

CC              C compiler command [detected]
CFLAGS          C compiler flags [-g, ...]
LDFLAGS         C linker flags

--prefix=<path> Set the install path
--debug         Flags for debug build, overrides CFLAGS

EOF
exit 0
}

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

prefix=/usr/local
CFLAGS="-std=c23"
LDFLAGS=
CC=

printf "checking for C compiler... "
trycc gcc
trycc clang
trycc cc
trycc icx
printf "%s\n" "$CC"

DEBUG=false
for arg; do
case "$arg" in
--help|-h) usage ;;
--prefix=*) prefix=${arg#*=} ;;
--debug) DEBUG=true ;;
CFLAGS=*) CFLAGS=${arg#*=} ;;
LDFLAGS=*) LDFLAGS=${arg#*=} ;;
CC=*) CC=${arg#*=} ;;
*) printf "Unrecognized option %s\n" "$arg" ;;
esac
done

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

GDEBUGCFLAGS="-std=c23 -O0 -g3 -Wall -Wextra -Wpedantic -Werror -Wshadow -Wdouble-promotion -Wformat=2 -Wnull-dereference -Wconversion -Wsign-conversion -Wcast-qual -Wcast-align=strict -Wpointer-arith -Wstrict-overflow=5 -Wstrict-aliasing=2 -Wundef -Wunreachable-code -Wswitch-enum -fanalyzer -fsanitize=undefined,address -fstack-protector-strong -D_FORTIFY_SOURCE=3"
CDEBUGCFLAGS="-std=gnu2x -O0 -g3 -Wall -Wextra -Wpedantic -Werror -Wshadow -Wdouble-promotion -Wformat=2 -Wnull-dereference -Wconversion -Wsign-conversion -Wcast-qual -Wcast-align=strict -Wpointer-arith -Wstrict-overflow=5 -Wstrict-aliasing=2 -Wundef -Wunreachable-code -Wswitch-enum -fanalyzer -fsanitize=undefined,address -fstack-protector-strong -D_FORTIFY_SOURCE=3"

if [ -z "$DEBUG" ]; then
case "$CC" in
gcc) CFLAGS="$GDEBUGFLAGS";;
clang) CFLAGS="$CDEBUGFLAGS";;
*) ;;
esac
else
case "$CC" in
gcc) ;;
clang) ;;
*) ;;
esac
fi

case "$OSTYPE" in
cygwin|msys) 
echo "enabling windows specific flags"
CFLAGS="-v $CFLAGS"
;;
esac

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