AC_INIT([utun],[2.0.0],[https://github.com/anomalyco/utun3/issues])
AC_CONFIG_SRCDIR([src/utun.c])
AC_CONFIG_HEADERS([config.h])
AC_CONFIG_AUX_DIR([build-aux])
AC_CONFIG_MACRO_DIR([m4])

# Required programs
AC_PROG_CC
AC_PROG_RANLIB
AM_PROG_AR
AM_INIT_AUTOMAKE([foreign subdir-objects -Wall])

# Checks for programs
AC_PROG_INSTALL
AC_PROG_MAKE_SET

# Option to use OpenSSL instead of TinyCrypt for secure_channel
AC_ARG_WITH([openssl],
    AS_HELP_STRING([--with-openssl], [Use OpenSSL for cryptography (default: yes)]),
    [with_openssl=$withval],
    [with_openssl=yes])

if test "x$with_openssl" = "xyes"; then
    # For Windows cross-compilation, check MSYS2 paths
    case "$host" in
        *mingw* | *msys* | *cygwin* | *win*)
            # Try MSYS2 UCRT64 paths
            if test -d "/c/msys64/ucrt64/include/openssl"; then
                OPENSSL_CFLAGS="-I/c/msys64/ucrt64/include"
                OPENSSL_LIBS="-L/c/msys64/ucrt64/lib -lcrypto"
                CFLAGS="$CFLAGS $OPENSSL_CFLAGS"
                LDFLAGS="$LDFLAGS $OPENSSL_LIBS"
                AC_MSG_NOTICE([Using MSYS2 UCRT64 OpenSSL: /c/msys64/ucrt64])
            elif test -d "/ucrt64/include/openssl"; then
                OPENSSL_CFLAGS="-I/ucrt64/include"
                OPENSSL_LIBS="-L/ucrt64/lib -lcrypto"
                CFLAGS="$CFLAGS $OPENSSL_CFLAGS"
                LDFLAGS="$LDFLAGS $OPENSSL_LIBS"
                AC_MSG_NOTICE([Using MSYS2 UCRT64 OpenSSL: /ucrt64])
            elif test -d "/mingw64/include/openssl"; then
                OPENSSL_CFLAGS="-I/mingw64/include"
                OPENSSL_LIBS="-L/mingw64/lib -lcrypto"
                CFLAGS="$CFLAGS $OPENSSL_CFLAGS"
                LDFLAGS="$LDFLAGS $OPENSSL_LIBS"
                AC_MSG_NOTICE([Using MSYS2 MINGW64 OpenSSL: /mingw64])
            fi
            ;;
    esac
    
    # Save original LIBS
    save_LIBS="$LIBS"
    # Add crypto library to LIBS for the check
    LIBS="-lcrypto $LIBS"
    
    AC_CHECK_LIB([crypto], [SHA256_Init], 
        [
            AC_DEFINE([USE_OPENSSL], [1], [Define to use OpenSSL for cryptography])
        ], 
        [
            AC_MSG_ERROR([OpenSSL crypto library required. Use --without-openssl to use TinyCrypt instead.])
        ])
    
    # Restore LIBS (the actual linking will use the flags we set)
    LIBS="$save_LIBS"
fi

AM_CONDITIONAL([USE_OPENSSL], [test "x$with_openssl" = "xyes"])

# Detect Windows for TUN implementation
AC_MSG_CHECKING([for Windows])
case $host_os in
  *mingw* | *msys* | *cygwin* | *win*)
    os_windows=yes
    ;;
  *)
    # Also check $host for cross-compilation case
    case $host in
      *mingw* | *msys* | *cygwin* | *win*)
        os_windows=yes
        ;;
      *)
        os_windows=no
        ;;
    esac
    ;;
esac
AC_MSG_RESULT([$os_windows])
AM_CONDITIONAL([OS_WINDOWS], [test "x$os_windows" = "xyes"])

# Checks for header files
AC_CHECK_HEADERS([arpa/inet.h fcntl.h limits.h netinet/in.h stdlib.h string.h sys/ioctl.h sys/socket.h unistd.h])

# Checks for typedefs, structures, and compiler characteristics
AC_TYPE_SIZE_T
AC_TYPE_SSIZE_T
AC_TYPE_UINT16_T
AC_TYPE_UINT32_T
AC_TYPE_UINT64_T
AC_TYPE_UINT8_T
AC_C_INLINE

# Checks for library functions
AC_FUNC_MALLOC
AC_CHECK_FUNCS([gettimeofday memset socket strchr strdup strerror strstr])

# Check for TUN/TAP support
AC_MSG_CHECKING([for TUN/TAP support])
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
#include <linux/if_tun.h>
]], [[
int fd = open("/dev/net/tun", O_RDWR);
]])], [
  AC_MSG_RESULT([yes])
  AC_DEFINE([HAVE_TUN_TAP], [1], [Define if TUN/TAP is available])
], [
  AC_MSG_RESULT([no])
])

# Output files
AC_CONFIG_FILES([
  Makefile
  src/Makefile
  tests/Makefile
  lib/Makefile
])

AC_OUTPUT

# Summary
echo "
Configuration summary:
----------------------
  Prefix:       ${prefix}
  Compiler:     ${CC}
  CFLAGS:       ${CFLAGS}
  
  Features:
    TUN/TAP:    ${have_tun_tap}
"