#!/usr/bin/env bash

bup_find_prog()
{
    # Prints prog path to stdout or nothing.
    local name="$1" result="$2"
    TLOGN "checking for $name"
    if ! [ "$result" ]; then
        result=`acLookFor "$name"`
    fi
    TLOG " ($result)"
    echo "$result"
}

bup_try_c_code()
{
    local code="$1" tmpdir rc cflags=''
    if test -z "$code"; then
        AC_FAIL "No code provided to test compile"
    fi
    case "$#" in
        1) ;;
        2) cflags="$2" ;;
        *)
            AC_FAIL "Invald call to bup_try_c_code" "$@"
            ;;
    esac
    tmpdir="$(mktemp -d "bup-try-c-compile-XXXXXXX")" || exit $?
    echo "$code" > "$tmpdir/test.c" || exit $?
    $AC_CC -Wall -Werror $cflags -c -o "$tmpdir/test" "$tmpdir/test.c"
    rc=$?
    rm -r "$tmpdir" || exit $?
    return $rc
}

TARGET=bup

. ./configure.inc

AC_INIT $TARGET

if ! AC_PROG_CC; then
    LOG " You need to have a functional C compiler to build $TARGET"
    exit 1
fi

MAKE="$(bup_find_prog make "$MAKE")"
if test -z "$MAKE"; then
    MAKE="$(bup_find_prog gmake "$GMAKE")"
fi

if test -z "$MAKE"; then
    AC_FAIL "ERROR: unable to find make"
fi

if ! ($MAKE --version | grep "GNU Make"); then
    AC_FAIL "ERROR: $MAKE is not GNU Make"
fi

MAKE_VERSION=`$MAKE --version | grep "GNU Make" | awk '{print $3}'`
if [ -z "$MAKE_VERSION" ]; then
    AC_FAIL "ERROR: $MAKE --version does not return sensible output?"
fi
expr "$MAKE_VERSION" '>=' '3.81' || AC_FAIL "ERROR: $MAKE must be >= version 3.81"

AC_SUB bup_make "$MAKE"

bup_python="$(type -p "$PYTHON")"
test -z "$bup_python" && bup_python="$(bup_find_prog python2.7 '')"
test -z "$bup_python" && bup_python="$(bup_find_prog python2.6 '')"
test -z "$bup_python" && bup_python="$(bup_find_prog python2 '')"
test -z "$bup_python" && bup_python="$(bup_find_prog python3.8 '')"
test -z "$bup_python" && bup_python="$(bup_find_prog python3.7 '')"
test -z "$bup_python" && bup_python="$(bup_find_prog python3.6 '')"
test -z "$bup_python" && bup_python="$(bup_find_prog python3 '')"
test -z "$bup_python" && bup_python="$(bup_find_prog python '')"
if test -z "$bup_python"; then
    AC_FAIL "ERROR: unable to find python"
else
    AC_SUB bup_python "$bup_python"
    bup_python_majver=$("$bup_python" -c 'import sys; print(sys.version_info[0])')
    bup_python_minver=$("$bup_python" -c 'import sys; print(sys.version_info[1])')
    AC_SUB bup_python_majver "$bup_python_majver"
fi

# May not be correct yet, i.e. actual requirement may be higher.
if test "$bup_python_majver" -gt 2 -a "$bup_python_minver" -lt 3; then
    # utime follow_symlinks >= 3.3
    bup_version_str=$("$bup_python" --version 2>&1)
    AC_FAIL "ERROR: found $bup_version_str (must be >= 3.3 if >= 3)"
fi

bup_git="$(bup_find_prog git '')"
if test -z "$bup_git"; then
    AC_FAIL "ERROR: unable to find git"
fi

# For stat.
AC_CHECK_HEADERS sys/stat.h
AC_CHECK_HEADERS sys/types.h

# For stat and mincore.
AC_CHECK_HEADERS unistd.h

# For mincore.
AC_CHECK_HEADERS sys/mman.h

# For FS_IOC_GETFLAGS and FS_IOC_SETFLAGS.
AC_CHECK_HEADERS linux/fs.h
AC_CHECK_HEADERS sys/ioctl.h

if test "$bup_python_majver" -gt 2; then
    AC_DEFINE BUP_USE_PYTHON_UTIME 1
else # Python 2
    # On GNU/kFreeBSD utimensat is defined in GNU libc, but won't work.
    if [ -z "$OS_GNU_KFREEBSD" ]; then
        AC_CHECK_FUNCS utimensat
    fi
    AC_CHECK_FUNCS utimes
    AC_CHECK_FUNCS lutimes
fi

builtin_mul_overflow_code="
#include <stddef.h>
int main(int argc, char **argv)
{
    size_t n = 0, size = 0, total;
    __builtin_mul_overflow(n, size, &total);
    return 0;
}
"

TLOGN "checking for __builtin_mul_overflow"
if bup_try_c_code "$builtin_mul_overflow_code"; then
    AC_DEFINE BUP_HAVE_BUILTIN_MUL_OVERFLOW 1
    TLOG ' (found)'
else
    TLOG ' (not found)'
fi


AC_CHECK_FUNCS mincore

mincore_incore_code="
#if 0$ac_defined_HAVE_UNISTD_H
#include <unistd.h>
#endif
#if 0$ac_defined_HAVE_SYS_MMAN_H
#include <sys/mman.h>
#endif
int main(int argc, char **argv)
{
    if (MINCORE_INCORE)
      return 0;
}
"

mincore_buf_type_code()
{
    local vec_type="$1"
    echo "
#include <sys/mman.h>
int main(int argc, char **argv)
{
    void *x = 0;
    $vec_type *buf = 0;
    return mincore(x, 0, buf);
}" || exit $?
}

if test "$ac_defined_HAVE_MINCORE"; then
    TLOGN "checking for MINCORE_INCORE"
    if bup_try_c_code "$mincore_incore_code"; then
        AC_DEFINE BUP_HAVE_MINCORE_INCORE 1
        TLOG ' (found)'
    else
        TLOG ' (not found)'
    fi

    TLOGN "checking mincore buf type"
    if bup_try_c_code "$(mincore_buf_type_code char)"; then
        AC_DEFINE BUP_MINCORE_BUF_TYPE 'char'
        TLOG ' (char)'
    elif bup_try_c_code "$(mincore_buf_type_code 'unsigned char')"; then
        AC_DEFINE BUP_MINCORE_BUF_TYPE 'unsigned char'
        TLOG ' (unsigned char)'
    else
        AC_FAIL "ERROR: unexpected mincore definition; please notify bup-list@googlegroups.com"
    fi
fi


TLOGN "checking for readline"
bup_have_readline=''
bup_readline_includes_in_subdir=''
bup_readline_via_pkg_config=''
# We test this specific thing because it should work everywhere and it was
# a particulary problem on macos (we'd get the wrong includes if we just
# tested that the includes work).
readline_test_code='
  static char *on_completion_entry(const char *text, int state) { return NULL; }
  void bup_test(void) { rl_completion_entry_function = on_completion_entry; }
'
if pkg-config readline; then
    bup_readline_cflags="$(pkg-config readline --cflags)" || exit $?
    bup_readline_ldflags="$(pkg-config readline --libs)" || exit $?
    # It looks like it's not uncommon for pkg-config to provide a -I
    # that doesn't support the documentation's specified #include
    # <readline/readline.h>.  See what's really going on.
    if bup_try_c_code "#include <readline/readline.h> $readline_test_code" \
                      "$bup_readline_cflags"
    then
        bup_have_readline=1
        bup_readline_includes_in_subdir=1
    elif bup_try_c_code "#include <readline.h> $readline_test_code" \
                        "$bup_readline_cflags"
    then
        bup_have_readline=1
    fi
    if test "$bup_have_readline"; then
        bup_readline_via_pkg_config=1
    else
        bup_readline_cflags=''
        bup_readline_ldflags=''
    fi
fi
if ! test "$bup_have_readline"; then
    if bup_try_c_code "#include <readline/readline.h> $readline_test_code"; then
        bup_readline_ldflags=-lreadline
        bup_have_readline=1
        bup_readline_includes_in_subdir=1
    elif bup_try_c_code "#include <readline.h> $readline_test_code"; then
        bup_readline_ldflags=-lreadline
        bup_have_readline=1
    fi
fi
if test "$bup_have_readline"; then
    AC_DEFINE BUP_HAVE_READLINE 1
    if test "$bup_readline_includes_in_subdir"; then
        AC_DEFINE BUP_READLINE_INCLUDES_IN_SUBDIR 1
    fi
    if test "$bup_readline_via_pkg_config"; then
        TLOG ' (yes, pkg-config)'
    else
        TLOG ' (yes)'
    fi
fi


AC_SUB bup_readline_cflags "$bup_readline_cflags"
AC_SUB bup_readline_ldflags "$bup_readline_ldflags"
AC_SUB bup_have_readline "$bup_have_readline"


AC_CHECK_FIELD stat st_atim sys/types.h sys/stat.h unistd.h
AC_CHECK_FIELD stat st_mtim sys/types.h sys/stat.h unistd.h
AC_CHECK_FIELD stat st_ctim sys/types.h sys/stat.h unistd.h

AC_CHECK_FIELD stat st_atimensec sys/types.h sys/stat.h unistd.h
AC_CHECK_FIELD stat st_mtimensec sys/types.h sys/stat.h unistd.h
AC_CHECK_FIELD stat st_ctimensec sys/types.h sys/stat.h unistd.h

AC_CHECK_FIELD tm tm_gmtoff time.h


orig_ac_cc="$AC_CC"
orig_libs="$LIBS"
TLOGN "checking for libacl"
if pkg-config libacl; then
    bup_libacl_cflags="$(pkg-config libacl --cflags)"
    bup_libacl_ldflags="$(pkg-config libacl --libs)"
    TLOG ' (yes, pkg-config)'
else
    bup_libacl_cflags=
    bup_libacl_ldflags='-lacl'
    TLOG ' (yes)'
fi
AC_CC="$AC_CC${bup_libacl_cflags:+ $bup_libacl_cflags}"
LIBS="$bup_libacl_ldflags"
AC_CHECK_HEADERS sys/acl.h
AC_CHECK_HEADERS acl/libacl.h
AC_CHECK_FUNCS acl_get_file
AC_CHECK_FUNCS acl_from_text
AC_CHECK_FUNCS acl_set_file
# Note: These are linux specific, but we need them (for now?)
AC_CHECK_FUNCS acl_extended_file
AC_CHECK_FUNCS acl_to_any_text
TLOGN "checking for complete acl support"
if test "$ac_defined_HAVE_ACL_EXTENDED_FILE"; then
    bup_have_libacl=1
    AC_SUB bup_libacl_cflags "$bup_libacl_cflags"
    AC_SUB bup_libacl_ldflags "$bup_libacl_ldflags"
    TLOG ' (yes)'
else
    bup_have_libacl=
    AC_SUB bup_have_libacl ''
    TLOG ' (no)'
fi
AC_SUB bup_have_libacl "$bup_have_libacl"
AC_CC="$orig_ac_cc"
LIBS="$orig_libs"


AC_OUTPUT config.vars

if test -e config.var; then rm -r config.var; fi
mkdir -p config.var
echo -n "$MAKE" > config.var/bup-make
echo -n "$bup_python" > config.var/bup-python

if test -e bin; then rm -r bin; fi
mkdir -p bin
(cd bin && ln -s "$bup_python" python)

printf "
found: python (%q, $("$bup_python" --version 2>&1))
found: git (%q, ($("$bup_git" --version))
" \
       "$bup_python" \
       "$bup_git" \
       1>&5

summarize()
{
    local found="$1"
    shift
    if test "$found"; then
        TLOG found: "$@"
    else
        TLOG not found: "$@"
    fi
}
summarize "$bup_have_readline" 'readline support (e.g. bup ftp)'
summarize "$bup_have_libacl" 'POSIX ACL support'
TLOG