cmake_minimum_required(VERSION 2.8.8)

#options
option (USE_PRECOMPILED_HEADERS "Use precompiled headers" ON)
option (USE_OBJECT_BUNDLES "Use object bundles" ON)
if ((USE_OBJECT_BUNDLES)AND(USE_PRECOMPILED_HEADERS)AND(MSVC))
  message( WARNING "you selected the buggy combination: MSVC + USE_OBJECT_BUNDLES + USE_PRECOMPILED_HEADERS" )
else ()
  message( WARNING "you selected a non-buggy combination" )
endif()

##my files
include_directories(${CMAKE_SOURCE_DIR})
set(INCS ${INCS} "${CMAKE_CURRENT_SOURCE_DIR}/lib.hpp")
set(SOURCE_FILES ${SOURCE_FILES} "${CMAKE_CURRENT_SOURCE_DIR}/lib.cpp")

##Precompiled header
MACRO(ADD_PRECOMPILED_HEADER _targetName _input)
  GET_FILENAME_COMPONENT(_inputWe ${_input} NAME_WE)
  SET(pch_source ${_inputWe}.cpp)
  FOREACH(arg ${ARGN})
    IF(arg STREQUAL FORCEINCLUDE)
      SET(FORCEINCLUDE ON)
    ELSE(arg STREQUAL FORCEINCLUDE)
      SET(FORCEINCLUDE OFF)
    ENDIF(arg STREQUAL FORCEINCLUDE)
  ENDFOREACH(arg)
  IF(MSVC)
    #message("precompile project " ${_targetName})
    GET_TARGET_PROPERTY(sources ${_targetName} SOURCES)
    SET(_sourceFound FALSE)
    FOREACH(_source ${sources})
      SET(PCH_COMPILE_FLAGS "")
      IF(_source MATCHES \\.\(cc|cxx|cpp\)$)
        #message("  precompile " ${_source})
        GET_FILENAME_COMPONENT(_sourceWe ${_source} NAME_WE)
        IF(_sourceWe STREQUAL ${_inputWe})
            #message("    precompile creation")
            SET(PCH_COMPILE_FLAGS "${PCH_COMPILE_FLAGS} /Yc${_input}")
            SET(_sourceFound TRUE)
        ELSE(_sourceWe STREQUAL ${_inputWe})
            #message("    precompile utilization")
            SET(PCH_COMPILE_FLAGS "${PCH_COMPILE_FLAGS} /Yu${_input}")
            IF(FORCEINCLUDE)
                SET(PCH_COMPILE_FLAGS "${PCH_COMPILE_FLAGS} /FI${_input}")
            ENDIF(FORCEINCLUDE)
        ENDIF(_sourceWe STREQUAL ${_inputWe})
        #message("  precompile flags " ${PCH_COMPILE_FLAGS})
        SET_SOURCE_FILES_PROPERTIES(${_source} PROPERTIES COMPILE_FLAGS "${PCH_COMPILE_FLAGS}")
      ENDIF(_source MATCHES \\.\(cc|cxx|cpp\)$)
    ENDFOREACH()
    IF(NOT _sourceFound)
      MESSAGE(FATAL_ERROR "A source file for ${_input} was not found. Required for MSVC builds.")
    ENDIF(NOT _sourceFound)
  ELSEIF((CMAKE_COMPILER_IS_GNUCXX)OR("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang"))
    GET_FILENAME_COMPONENT(_name ${_input} NAME)
    SET(_source "${CMAKE_CURRENT_SOURCE_DIR}/${_input}")
    SET(_output "${CMAKE_CURRENT_BINARY_DIR}/${_name}.pch")
    SET(_compiler_FLAGS ${CMAKE_CXX_FLAGS})
    GET_DIRECTORY_PROPERTY(_directory_flags INCLUDE_DIRECTORIES)
    FOREACH(item ${_directory_flags})
      LIST(APPEND _compiler_FLAGS "-I${item}")
    ENDFOREACH(item)
    GET_DIRECTORY_PROPERTY(_directory_flags DEFINITIONS)
    LIST(APPEND _compiler_FLAGS ${_directory_flags})
    SEPARATE_ARGUMENTS(_compiler_FLAGS)
    ADD_CUSTOM_COMMAND(
      OUTPUT ${_output}
      COMMAND ${CMAKE_CXX_COMPILER} ${_compiler_FLAGS} -x c++-header -o ${_output} ${_source}
      DEPENDS ${_source} )
    ADD_CUSTOM_TARGET(${_targetName}_gch DEPENDS ${_output})
    ADD_DEPENDENCIES(${_targetName} ${_targetName}_gch)
    if (CMAKE_COMPILER_IS_GNUCXX)
      SET_TARGET_PROPERTIES(${_targetName} PROPERTIES COMPILE_FLAGS "-include ${_name} -Winvalid-pch")
    else()
      SET_TARGET_PROPERTIES(${_targetName} PROPERTIES COMPILE_FLAGS "-Winvalid-pch")
    endif()
  ENDIF()
ENDMACRO()
set (COMMON_HEADER "common-header.hpp")
if (USE_PRECOMPILED_HEADERS)
  if (MSVC)
    set(OPTIONAL_PRECOMPILATION_DEPENDENCIES common-header.cpp) #only MSVC requires a fake source file
  else()
    set(OPTIONAL_PRECOMPILATION_DEPENDENCIES "") #only MSVC requires a fake source file
  endif()
else ()
  set(INCS ${INCS} "${CMAKE_CURRENT_SOURCE_DIR}/${COMMON_HEADER}")
endif()

##Object libraries
if (USE_OBJECT_BUNDLES)
    FOREACH(_object ${SOURCE_FILES})
        GET_FILENAME_COMPONENT(_rootname ${_object} NAME_WE)
        set(_bundle_name "bundle_${_rootname}")
        add_library("${_bundle_name}" OBJECT "${_object}" ${OPTIONAL_PRECOMPILATION_DEPENDENCIES})
        if (USE_PRECOMPILED_HEADERS)
          add_precompiled_header("${_bundle_name}" ${COMMON_HEADER} FORCEINCLUDE)
        endif()
        set(INCS ${INCS} "$<TARGET_OBJECTS:${_bundle_name}>")
    ENDFOREACH()
else ()
    set(INCS ${INCS} ${SOURCE_FILES})
endif ()

##Executable
add_executable (main main.cpp ${OPTIONAL_PRECOMPILATION_DEPENDENCIES} ${INCS})
if (USE_PRECOMPILED_HEADERS)
  add_precompiled_header(main ${COMMON_HEADER} FORCEINCLUDE)
endif()