find_path(PYQT_SIP_DIR pyqt-gpl.sip
  PATH_SUFFIXES share/sip/PyQt4
)

macro(add_sip_bindings outputvar)
  # Work out what the SIP flags should be for PyQt4.  These would normally be
  # obtained from PyQt4.pyqtconfig.Configuration().pyqt_sip_flags, but we can't
  # call that when cross-compiling.
  set(PYQT_SIP_FLAGS
    "-x" "VendorID"
    "-x" "PyQt_NoPrintRangeBug"
    "-t" "Qt_${QT_VERSION_MAJOR}_${QT_VERSION_MINOR}_${QT_VERSION_PATCH}"
  )

  if(WIN32)
    list(APPEND PYQT_SIP_FLAGS "-t" "WS_WIN")
  elseif(APPLE)
    list(APPEND PYQT_SIP_FLAGS "-t" "WS_MAC")
  else(WIN32)
    list(APPEND PYQT_SIP_FLAGS "-t" "WS_X11")
  endif(WIN32)

  foreach(source ${ARGN})
    get_filename_component(source_directory ${source} PATH)
    get_filename_component(source_basename ${source} NAME)
    get_filename_component(source_module ${source} NAME_WE)

    set(outputs
      "${CMAKE_CURRENT_BINARY_DIR}/sip${source_module}cmodule.cpp"
      "${CMAKE_CURRENT_BINARY_DIR}/sipAPI${source_module}.h"
    )

    # Find any included files
    execute_process(
      COMMAND "awk" "/^%Include/ {ORS=\";\"; print \"${source_directory}/\" $2}"
              "${CMAKE_CURRENT_SOURCE_DIR}/${source}"
      OUTPUT_VARIABLE included_files
    )
    foreach(included_file ${included_files} ${source})
      # Sip creates 1 file per class... so we have to figure out what classes
      # it will generate
      execute_process(
        COMMAND "awk" "/^\\s*class +([A-Za-z0-9]+)/ {ORS=\";\"; print $2}"
                "${CMAKE_CURRENT_SOURCE_DIR}/${included_file}"
        OUTPUT_VARIABLE classes
      )
      foreach(class ${classes})
        list(APPEND outputs "${CMAKE_CURRENT_BINARY_DIR}/sip${source_module}${class}.cpp")
      endforeach(class)
    endforeach(included_file)

    add_custom_command(
      OUTPUT ${outputs}
      COMMAND "sip" ${PYQT_SIP_FLAGS}
        "-I${PYQT_SIP_DIR}"
        "-c" "${CMAKE_CURRENT_BINARY_DIR}"
        "${CMAKE_CURRENT_SOURCE_DIR}/${source}"
      DEPENDS ${included_files} "${source}"
    )

    list(APPEND ${outputvar} ${outputs})
  endforeach(source)
endmacro(add_sip_bindings)