# Set a default build type if none was specified
# Override the default by specifying default_build_type
if(NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
  if( NOT default_build_type )
    set( default_build_type "RelWithDebInfo" )
  endif()
  message(
    STATUS "Setting build type to '${default_build_type}' as none was specified.")
  set(CMAKE_BUILD_TYPE
      ${default_build_type}
      CACHE STRING "Choose the type of build." FORCE)
  # Set the possible values of build type for cmake-gui, ccmake
  set_property(CACHE CMAKE_BUILD_TYPE PROPERTY STRINGS "Debug" "Release"
                                               "MinSizeRel" "RelWithDebInfo")
else()
    message( STATUS "Current CMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}" )
endif()

if(CMAKE_INSTALL_PREFIX_INITIALIZED_TO_DEFAULT)
  SET(CMAKE_INSTALL_PREFIX "/usr/" CACHE PATH "Common prefix for all installed files." FORCE)
endif(CMAKE_INSTALL_PREFIX_INITIALIZED_TO_DEFAULT)


find_program(CCACHE ccache)
if(CCACHE)
  message("using ccache")
  set(CMAKE_CXX_COMPILER_LAUNCHER ${CCACHE})
else()
#  message("ccache not found cannot use")
endif()

# Generate compile_commands.json to make it easier to work with clang based
# tools
set(CMAKE_EXPORT_COMPILE_COMMANDS ON)

option(ENABLE_IPO
       "Enable Iterprocedural Optimization, aka Link Time Optimization (LTO)"
       OFF)

if(ENABLE_IPO)
  include(CheckIPOSupported)
  check_ipo_supported(RESULT result OUTPUT output)
  if(result)
    set(CMAKE_INTERPROCEDURAL_OPTIMIZATION TRUE)
  else()
    message(SEND_ERROR "IPO is not supported: ${output}")
  endif()
endif()


if(MSVC)
    option(MSVC_STATIC_CRT "Statically link MSVC CRT" OFF)
    
    if(MSVC_STATIC_CRT)
        message(STATUS "Using static MSVC CRT")

        # http://stackoverflow.com/a/32128977/486990
        add_compile_options(
            "$<$<CONFIG:Debug>:/MTd>"
            "$<$<CONFIG:RelWithDebInfo>:/MT>"
            "$<$<CONFIG:Release>:/MT>"
            "$<$<CONFIG:MinSizeRel>:/MT>"
        )

        foreach(flag_var
            CMAKE_CXX_FLAGS CMAKE_CXX_FLAGS_DEBUG CMAKE_CXX_FLAGS_RELEASE
            CMAKE_CXX_FLAGS_MINSIZEREL CMAKE_CXX_FLAGS_RELWITHDEBINFO)
            if(${flag_var} MATCHES "/MD")
                string(REGEX REPLACE "/MD" "/MT" ${flag_var} "${${flag_var}}")
            endif(${flag_var} MATCHES "/MD")
            if(${flag_var} MATCHES "/W3")
                string(REGEX REPLACE "/W3" "/W4" ${flag_var} "${${flag_var}}")
            endif(${flag_var} MATCHES "/W3")
        endforeach(flag_var)
        
    else()
        # Turn off a duplicate LIBCMT linker warning
        set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} /NODEFAULTLIB:libcmt.lib")
        set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} /NODEFAULTLIB:libcmt.lib")
    endif()
endif()