#!/bin/bash

# We don't support srcdir != builddir
echo \#buildapi-variable-no-builddir > /dev/null

prefix=/usr

enable_documentation=yes
enable_dracut_cpio=no

CC="${CC:-cc}"
PKG_CONFIG="${PKG_CONFIG:-pkg-config}"

# Little helper function for reading args from the commandline.
# it automatically handles -a b and -a=b variants, and returns 1 if
# we need to shift $3.
read_arg() {
    # $1 = arg name
    # $2 = arg value
    # $3 = arg parameter
    local rematch='^[^=]*=(.*)$'
    if [[ $2 =~ $rematch ]]; then
        read -r "$1" <<< "${BASH_REMATCH[1]}"
    else
        read -r "$1" <<< "$3"
        # There is no way to shift our callers args, so
        # return 1 to indicate they should do it instead.
        return 1
    fi
    return 0
}

while (($# > 0)); do
    case "${1%%=*}" in
        --prefix) read_arg prefix "$@" || shift ;;
        --libdir) read_arg libdir "$@" || shift ;;
        --datadir) read_arg datadir "$@" || shift ;;
        --sysconfdir) read_arg sysconfdir "$@" || shift ;;
        --sbindir) read_arg sbindir "$@" || shift ;;
        --mandir) read_arg mandir "$@" || shift ;;
        --disable-documentation) enable_documentation=no ;;
        --program-prefix) read_arg programprefix "$@" || shift ;;
        --exec-prefix) read_arg execprefix "$@" || shift ;;
        --bindir) read_arg bindir "$@" || shift ;;
        --includedir) read_arg includedir "$@" || shift ;;
        --libexecdir) read_arg libexecdir "$@" || shift ;;
        --localstatedir) read_arg localstatedir "$@" || shift ;;
        --sharedstatedir) read_arg sharedstatedir "$@" || shift ;;
        --infodir) read_arg infodir "$@" || shift ;;
        --systemdsystemunitdir) read_arg systemdsystemunitdir "$@" || shift ;;
        --bashcompletiondir) read_arg bashcompletiondir "$@" || shift ;;
        --enable-dracut-cpio) enable_dracut_cpio=yes ;;
        *) echo "Ignoring unknown option '$1'" ;;
    esac
    shift
done

if ! ${PKG_CONFIG} --exists --print-errors " libkmod >= 23 "; then
    echo "dracut needs pkg-config and libkmod >= 23." >&2
    exit 1
fi

if ! command -v "${CC}" > /dev/null; then
    echo "dracut needs a C compiler (${CC} not found)." >&2
    exit 1
fi

cat << EOF > conftest.c
#include <fts.h>
int main() {
	return 0;
}
EOF

# shellcheck disable=SC2086
${CC} $CFLAGS $LDFLAGS conftest.c > /dev/null 2>&1
ret=$?
rm -f conftest.c a.out

# musl doesn't have fts.h included
if test $ret -ne 0; then
    echo "dracut needs fts development files." >&2
    exit 1
fi

cat << EOF > conftest.c
#include <fts.h>
int main(void) {
	fts_open(0, 0, 0);
	return 0;
}
EOF

found=no
for lib in "-lc" "-lfts"; do
    # shellcheck disable=SC2086
    ${CC} $CFLAGS $LDFLAGS conftest.c -Wl,$lib > /dev/null 2>&1
    ret=$?
    if test $ret -eq 0; then
        FTS_LIBS="$lib"
        found=yes
        break
    fi
done
rm -f conftest.c a.out

if test $found = no; then
    echo "dracut couldn't find usable fts library" >&2
    exit 1
fi

cat << EOF > conftest.c
#include <stdio.h>
#include <unistd.h>
#include <sys/syscall.h>

#ifndef SYS_gettid
#error "SYS_gettid unavailable on this system"
#endif

#define gettid()    ((pid_t) syscall(SYS_gettid))

int main(void) {
  return getpid() == gettid() ? 0 : -1;
}
EOF

# shellcheck disable=SC2086
${CC} $CFLAGS $LDFLAGS conftest.c > /dev/null 2>&1
ret=$?
rm -f conftest.c a.out

if test $ret -ne 0; then
    echo "dracut needs SYS_gettid support." >&2
    exit 1
fi

if test "$enable_dracut_cpio" = "yes"; then
    cargo --version > /dev/null
    ret=$?
    if test $ret -ne 0; then
        echo "dracut couldn't find cargo for dracut-cpio build"
        exit 1
    fi
fi

cat > Makefile.inc.$$ << EOF
prefix ?= ${prefix}
libdir ?= ${libdir:-${prefix}/lib}
datadir ?= ${datadir:-${prefix}/share}
sysconfdir ?= ${sysconfdir:-${prefix}/etc}
sbindir ?= ${sbindir:-${prefix}/sbin}
mandir ?= ${mandir:-${prefix}/share/man}
enable_documentation ?= ${enable_documentation:-yes}
enable_dracut_cpio ?= ${enable_dracut_cpio}
bindir ?= ${bindir:-${prefix}/bin}
KMOD_CFLAGS ?= $(${PKG_CONFIG} --cflags " libkmod >= 23 ")
KMOD_LIBS ?= $(${PKG_CONFIG} --libs " libkmod >= 23 ")
FTS_LIBS ?= ${FTS_LIBS}
EOF

{
    [[ $programprefix ]] && echo "programprefix ?= ${programprefix}"
    [[ $execprefix ]] && echo "execprefix ?= ${execprefix}"
    [[ $includedir ]] && echo "includedir ?= ${includedir}"
    [[ $libexecdir ]] && echo "libexecdir ?= ${libexecdir}"
    [[ $localstatedir ]] && echo "localstatedir ?= ${localstatedir}"
    [[ $sharedstatedir ]] && echo "sharedstatedir ?= ${sharedstatedir}"
    [[ $infodir ]] && echo "infodir ?= ${infodir}"
    [[ $systemdsystemunitdir ]] && echo "systemdsystemunitdir ?= ${systemdsystemunitdir}"
    [[ $bashcompletiondir ]] && echo "bashcompletiondir ?= ${bashcompletiondir}"
} >> Makefile.inc.$$

mv Makefile.inc.$$ Makefile.inc