include (ExternalProject)

set(PROTOBUF_INCLUDE_DIRS ${CMAKE_CURRENT_BINARY_DIR}/protobuf/src/protobuf/src)
set(PROTOBUF_URL https://github.com/google/protobuf/releases/download/v3.1.0/protobuf-cpp-3.1.0.zip)
set(PROTOBUF_HASH SHA256=0c18ccc99e921c407f359047f9b56cca196c3ab36eed79e5979df6c1f9e623b7)

if(WIN32)
  set(PROTOBUF_LIBRARIES ${CMAKE_CURRENT_BINARY_DIR}/protobuf/src/protobuf/${CMAKE_BUILD_TYPE}/libprotobuf.lib)
  set(PROTOBUF_PROTOC_EXECUTABLE ${CMAKE_CURRENT_BINARY_DIR}/protobuf/src/protobuf/${CMAKE_BUILD_TYPE}/protoc.exe)
else()
  set(PROTOBUF_LIBRARIES ${CMAKE_CURRENT_BINARY_DIR}/protobuf/src/protobuf/libprotobuf.a)
  set(PROTOBUF_PROTOC_EXECUTABLE ${CMAKE_CURRENT_BINARY_DIR}/protobuf/src/protobuf/protoc)
endif()

ExternalProject_Add(protobuf
    PREFIX protobuf
    URL ${PROTOBUF_URL}
    DOWNLOAD_DIR "${DOWNLOAD_LOCATION}"
    BUILD_IN_SOURCE 1
    SOURCE_DIR ${CMAKE_BINARY_DIR}/protobuf/src/protobuf
    CONFIGURE_COMMAND ${CMAKE_COMMAND} cmake/ -Dprotobuf_BUILD_TESTS=OFF -DCMAKE_POSITION_INDEPENDENT_CODE=ON -Dprotobuf_MSVC_STATIC_RUNTIME:BOOL=OFF
    INSTALL_COMMAND ""
    CMAKE_CACHE_ARGS
        -DCMAKE_BUILD_TYPE:STRING=Release
        -DCMAKE_VERBOSE_MAKEFILE:BOOL=OFF
        -Dprotobuf_MSVC_STATIC_RUNTIME:BOOL=OFF
        -DCMAKE_POSITION_INDEPENDENT_CODE:BOOL=ON
)