# Serval Project Swift language support
#
# SYNOPSIS
#
#   AX_PROG_SWIFT_BUILD_WORKS
#
# DESCRIPTION
#
#   AX_PROG_SWIFT_BUILD_WORKS tests whether the Swift package manager "build"
#   command works.
#
#   Requires the SWIFT shell variable to contain the path of the Swift package
#   manager executable (not the Swift compiler!), either relative to $PATH or
#   absolute; this will usually be just "swift".  Expands the SWIFTCFLAGS shell
#   variable on the build command-line with -Xswiftc preceding each word.
#
#   Sets the SWIFT_BUILD variable to the command to invoke the build-package
#   command, usually "$SWIFT build".
#
#   To force a specific swift executable, either:
#
#   - in configure.ac, set SWIFT=yourswift before calling
#     AX_PROG_SWIFT_PACKAGE_MANAGER, or
#
#   - before invoking ./configure, export SWIFT=yourswift
#
# LICENSE
#
#   Copyright (C) 2016 Flinders University
#
#   This program is free software; you can redistribute it and/or modify it
#   under the terms of the GNU General Public License as published by the
#   Free Software Foundation; either version 2 of the License, or (at your
#   option) any later version.
#
#   This program is distributed in the hope that it will be useful, but
#   WITHOUT ANY WARRANTY; without even the implied warranty of
#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
#   Public License for more details.
#
#   You should have received a copy of the GNU General Public License along
#   with this program. If not, see <http://www.gnu.org/licenses/>.
#
#   As a special exception, the respective Autoconf Macro's copyright owner
#   gives unlimited permission to copy, distribute and modify the configure
#   scripts that are the output of Autoconf when processing the Macro. You
#   need not follow the terms of the GNU General Public License when using
#   or distributing such scripts, even though portions of the text of the
#   Macro appear in them. The GNU General Public License (GPL) does govern
#   all other use of the material that constitutes the Autoconf Macro.
#
#   This special exception to the GPL applies to versions of the Autoconf
#   Macro released by the Autoconf Archive. When you make and distribute a
#   modified version of the Autoconf Macro, you may extend this special
#   exception to the GPL to apply to your modified version as well.

AU_ALIAS([AC_PROG_SWIFT_BUILD_WORKS], [AX_PROG_SWIFT_BUILD_WORKS])
AC_DEFUN([AX_PROG_SWIFT_BUILD_WORKS],[
    AC_REQUIRE([AX_TMPDIR_SWIFT])
    SWIFT_BUILD="$SWIFT build"
    AC_CACHE_CHECK([if $SWIFT_BUILD works], ac_cv_prog_swift_build_works, [
        AS_MKDIR_P(["$ax_tmpdir_swift/swift_package/Sources"])
        cat << EOF > "$ax_tmpdir_swift/swift_package/Package.swift"
/* [#]line __oline__ "configure" */
import PackageDescription
let package = Package(name: "test")
EOF
        cat << EOF > "$ax_tmpdir_swift/swift_package/Sources/test.swift"
/* [#]line __oline__ "configure" */
public func test() {
    test1()
}
fileprivate func test1() {}
EOF
        ac_cv_prog_swift_build_works=no
        SWIFTBUILDFLAGS=
        for flag in $SWIFTCFLAGS; do
            AS_VAR_APPEND([SWIFTBUILDFLAGS], [" -Xswiftc $flag"])
        done
        AS_IF([AC_TRY_COMMAND(cd "$ax_tmpdir_swift/swift_package" && $SWIFT_BUILD $SWIFTBUILDFLAGS) >/dev/null 2>&1], [
            AS_IF([test -e "$ax_tmpdir_swift/swift_package/.build/debug/test.swiftmodule"], [
                ac_cv_prog_swift_build_works=yes
            ])
        ])
        AS_IF([test "x$ac_cv_prog_swift_build_works" != xyes], [
          echo "Package.swift:" >&AS_MESSAGE_LOG_FD
          cat "$ax_tmpdir_swift/swift_package/Package.swift" >&AS_MESSAGE_LOG_FD
          echo "failed program was:" >&AS_MESSAGE_LOG_FD
          cat "$ax_tmpdir_swift/swift_package/Sources/test.swift" >&AS_MESSAGE_LOG_FD
        ])
    ])
    AS_IF([test "x$ac_cv_prog_swift_build_works" != xyes], [
        AS_UNSET([SWIFT_BUILD])
    ])
    AC_PROVIDE([$0])dnl
])