#! /bin/sh
curdir="$(dirname "$0")"

# parse options, they can be specified by the build system (for .deb or .rpm), such as:
# deb:
# --build=x86_64-linux-gnu --prefix=/usr --includedir=\${prefix}/include --mandir=\${prefix}/share/man --infodir=\${prefix}/share/info --sysconfdir=/etc --localstatedir=/var --disable-silent-rules --libdir=\${prefix}/lib/x86_64-linux-gnu --libexecdir=\${prefix}/lib/x86_64-linux-gnu --disable-maintainer-mode --disable-dependency-tracking
# rpm:
# --host=x86_64-pc-linux-gnu --build=x86_64-pc-linux-gnu --program-prefix= --disable-dependency-tracking --prefix=/usr --exec-prefix=/usr --bindir=/usr/bin --sbindir=/usr/sbin --sysconfdir=/etc --datadir=/usr/share --includedir=/usr/include --libdir=/usr/lib64 --libexecdir=/usr/lib/x86_64-linux-gnu --localstatedir=/var --sharedstatedir=/usr/com --mandir=/usr/share/man --infodir=/usr/share/info

MKCONF="$curdir/config.mk"
rm -f "$MKCONF"
touch "$MKCONF"
while [ -n "$1" ]; do
    value=$(echo "$1" | cut -d= -f2- | sed -e "s/\${prefix}/\$(PREFIX)/g")
    case "$1" in
        --prefix=*) echo "PREFIX ?= $value" >> "$MKCONF";
                        echo "Will use PREFIX=$value";;
        --mandir=*) echo "MANDIR ?= $value" >> "$MKCONF";
                        echo "Will use MANDIR=$value";;
        --bindir=*) echo "BINDIR ?= $value" >> "$MKCONF";
                        echo "Will use BINDIR=$value";;
    esac
    shift
done

echo '#ifndef CONFIGURE_H' >"$curdir/configure.h"
echo '#define CONFIGURE_H' >>"$curdir/configure.h"

printf "%b" "Looking for compiler... "
[ -z "$CC" ] && CC=gcc
command -v $CC >/dev/null 2>&1 || CC=clang
command -v $CC >/dev/null 2>&1 || CC=cc
echo "$CC"

LDLIBS=''
DEFINES_STR='uses:'
CFLAGS='-std=c99'
PTHREAD=''
COMPRESS_ZSTD=''

if [ "$STATIC" = 1 ]; then
    CFLAGS="$CFLAGS -static"
fi

os=$(uname -s)
if [ "$os" = Linux ]; then
    CFLAGS="$CFLAGS -D_XOPEN_SOURCE=600 -D_XOPEN_SOURCE_EXTENDED -D_GNU_SOURCE -pipe"
elif [ "$os" = NetBSD ]; then
    true
elif [ "$os" = FreeBSD ]; then
    true
elif [ "$os" = OpenBSD ]; then
    true
elif [ "$os" = DragonFly ]; then
    true
elif [ "$os" = Darwin ]; then
    true
elif [ "$os" = SunOS ]; then
    CFLAGS="$CFLAGS -D__EXTENSIONS__"
elif [ "$os" = Haiku ]; then
    true
fi

srcfile=$(mktemp)
mv "$srcfile" "$srcfile.c"
# shellcheck disable=SC2064
trap "rm -f $srcfile.c" INT HUP EXIT

printf "%b" "Checking if compiler can create executables... "
cat >"$srcfile.c" <<EOF
int main(void) { return 0; }
EOF
if $CC "$srcfile.c" -o /dev/null >/dev/null 2>&1; then
    echo "yes"
else
    echo "no"
    echo
    echo "Please ensure you have a working C compiler and relaunch configure."
    exit 1
fi

printf "%b" "Checking how to get pthread support... "
cat >"$srcfile.c" <<EOF
int main(void) { return 0; }
EOF
if $CC -pthread "$srcfile.c" -o /dev/null >/dev/null 2>&1; then
    echo "-pthread"
    PTHREAD='-pthread'
else
    echo "-lpthread"
    PTHREAD='-lpthread'
fi


printf "%b" "Looking for libzstd... "
cat >"$srcfile.c" <<EOF
#include <zstd.h>
int main(void) { ZSTD_CStream *c = ZSTD_createCStream(); ZSTD_initCStream(c, 3); ZSTD_freeCStream(c); return 0; }
EOF
if [ "$NO_ZSTD" != 1 ] && $CC "$srcfile.c" -L/usr/local/lib -I/usr/local/include -lzstd -o /dev/null >/dev/null 2>&1; then
    echo "yes"
    echo '#define HAVE_zstd' >>"$curdir/configure.h"
    COMPRESS_ZSTD='compress_zstd.o'
    printf "%b" "Checking whether we can link zstd statically... "
    for dir in $($CC -print-search-dirs | awk '/^libraries:/ {$1=""; print}' | tr : "\n") /usr/local/lib
    do
        test -f "$dir/libzstd.a" && libzstda="$dir/libzstd.a"
    done
    if [ -n "$libzstda" ] && [ -f "$libzstda" ] && [ "$NO_STATIC_ZSTD" != 1 ]; then
        echo "yes ($libzstda)"
        DEFINES_STR="$DEFINES_STR zstd[static]"
        LDLIBS="$LDLIBS $libzstda"
    else
        echo "no"
        DEFINES_STR="$DEFINES_STR zstd"
        LDLIBS="$LDLIBS -lzstd"
    fi
else
    echo "no"
fi

printf "%b" "Looking for inotify(7)... "
cat >"$srcfile.c" <<EOF
#include <sys/inotify.h>
int main(void) { return inotify_init1(IN_NONBLOCK); }
EOF
if $CC "$srcfile.c" -o /dev/null >/dev/null 2>&1; then
    echo "yes"
    echo '#define HAVE_inotify' >>"$curdir/configure.h"
    DEFINES_STR="$DEFINES_STR inotify"
else
    echo "no"
fi

printf "%b" "Looking for isastream()... "
cat >"$srcfile.c" <<EOF
#include <stropts.h>
int main(void) { return isastream(0); }
EOF
if $CC "$srcfile.c" -o /dev/null >/dev/null 2>&1; then
    echo "yes"
    echo '#define HAVE_isastream' >>"$curdir/configure.h"
    DEFINES_STR="$DEFINES_STR isastream"
else
    echo "no"
fi

printf "%b" "Looking for cfmakeraw()... "
cat >"$srcfile.c" <<EOF
#include <termios.h>
#include <unistd.h>
int main(void) { cfmakeraw(0); return 0; }
EOF
if $CC "$srcfile.c" -o /dev/null >/dev/null 2>&1; then
    echo "yes"
    echo '#define HAVE_cfmakeraw' >>"$curdir/configure.h"
    DEFINES_STR="$DEFINES_STR cfmakeraw"
else
    echo "no"
fi

printf "%b" "Looking for getpt()... "
cat >"$srcfile.c" <<EOF
#include <stdlib.h>
int main(void) { return getpt(); }
EOF
if $CC "$srcfile.c" -o /dev/null >/dev/null 2>&1; then
    echo "yes"
    echo '#define HAVE_getpt' >>"$curdir/configure.h"
    DEFINES_STR="$DEFINES_STR getpt"
else
    echo "no"
fi

printf "%b" "Looking for posix_openpt()... "
cat >"$srcfile.c" <<EOF
#include <stdlib.h>
#include <fcntl.h>
int main(void) { return posix_openpt(0); }
EOF
if $CC "$srcfile.c" -o /dev/null >/dev/null 2>&1; then
    echo "yes"
    echo '#define HAVE_posix_openpt' >>"$curdir/configure.h"
    DEFINES_STR="$DEFINES_STR posix_openpt"
else
    echo "no"
fi

printf "%b" "Looking for grantpt()... "
cat >"$srcfile.c" <<EOF
#include <stdlib.h>
int main(void) { (void)ptsname(0); return grantpt(0) + unlockpt(0); }
EOF
if $CC "$srcfile.c" -o /dev/null >/dev/null 2>&1; then
    echo "yes"
    echo '#define HAVE_grantpt' >>"$curdir/configure.h"
    DEFINES_STR="$DEFINES_STR grantpt"
else
    echo "no"
fi

printf "%b" "Looking for openpty()... "
cat >"$srcfile.c" <<EOF
#include <pty.h>
int main(void) { return openpty(0, 0, 0, 0, 0); }
EOF
if $CC "$srcfile.c" -lutil -o /dev/null >/dev/null 2>&1; then
    echo "yes (pty.h, libutil)"
    LDLIBS="$LDLIBS -lutil"
    echo '#define HAVE_openpty' >>"$curdir/configure.h"
    echo '#define HAVE_openpty_pty_h' >>"$curdir/configure.h"
    DEFINES_STR="$DEFINES_STR openpty[pty.h]"
else
    cat >"$srcfile.c" <<EOF
#include <util.h>
int main(void) { return openpty(0, 0, 0, 0, 0); }
EOF
    if $CC "$srcfile.c" -lutil -o /dev/null >/dev/null 2>&1; then
        echo "yes (util.h, libutil)"
        LDLIBS="$LDLIBS -lutil"
        echo '#define HAVE_openpty' >>"$curdir/configure.h"
        echo '#define HAVE_openpty_util_h' >>"$curdir/configure.h"
        DEFINES_STR="$DEFINES_STR openpty[util.h]"
    else
        cat >"$srcfile.c" <<EOF
#include <libutil.h>
int main(void) { return openpty(0, 0, 0, 0, 0); }
EOF
        if $CC "$srcfile.c" -lutil -o /dev/null >/dev/null 2>&1; then
            echo "yes (libutil.h, libutil)"
            LDLIBS="$LDLIBS -lutil"
            echo '#define HAVE_openpty' >>"$curdir/configure.h"
            echo '#define HAVE_openpty_libutil_h' >>"$curdir/configure.h"
            DEFINES_STR="$DEFINES_STR openpty[libutil.h]"
        else
        cat >"$srcfile.c" <<EOF
#include <pty.h>
int main(void) { return openpty(0, 0, 0, 0, 0); }
EOF
            if $CC "$srcfile.c" -lbsd -o /dev/null >/dev/null 2>&1; then
                echo "yes (pty.h, libbsd)"
                echo '#define HAVE_openpty' >>"$curdir/configure.h"
                echo '#define HAVE_openpty_pty_h' >>"$curdir/configure.h"
                DEFINES_STR="$DEFINES_STR openpty[pty.h/libbsd]"
                LDLIBS="$LDLIBS -lbsd"
            else
                echo "no"
            fi
        fi
    fi
fi

echo "Checking for supported compiler options..."
for w in -Wall -Wextra -pedantic -Wno-unused-result -Wbad-function-cast -Wmissing-declarations \
    -Wmissing-prototypes -Wnested-externs -Wold-style-definition -Wstrict-prototypes \
    -Wpointer-sign -Wmissing-parameter-type -Wold-style-declaration -Wl,--as-needed \
    -Wno-unused-command-line-argument
do
    echo 'int main(void) { return 0; }' >"$srcfile.c"
    if [ "$($CC "$srcfile.c" $w -o /dev/null 2>&1 | wc -l)" = 0 ]; then
        echo "... OK $w"
        if echo "$w" | grep -q -- '-Wl,'; then
            LDFLAGS="$LDFLAGS $w"
        else
            CFLAGS="$CFLAGS $w"
        fi
    else
        echo "... unsupported $w"
    fi
done

cat "$(dirname "$0")"/Makefile.in > "$(dirname "$0")"/Makefile.tmp
for i in CC LDLIBS CFLAGS COMPRESS_ZSTD PTHREAD
do
    replace=$(eval printf "%b" "\"\$$i\"")
    sed "s:%$i%:$replace:g" "$(dirname "$0")"/Makefile.tmp > "$(dirname "$0")"/Makefile
    cat "$(dirname "$0")"/Makefile > "$(dirname "$0")"/Makefile.tmp
done
rm -f "$(dirname "$0")"/Makefile.tmp

cat >>"$curdir/configure.h" <<EOF
#define DEFINES_STR "$DEFINES_STR"
#define COMPILER_NAME "$CC"
#define MACHINE_STR "$($CC -dumpmachine)"
#endif
EOF

echo
if [ "$(uname -s)" = Linux ]; then
    echo "You may run make now"
else
    echo "You may run gmake now"
fi