# Copyright (c) 2016 Gang Liao <gangliao@umd.edu> All Rights Reserve.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

INCLUDE(ExternalProject)

SET(GFLAGS_SOURCES_DIR ${BAZEL_THIRD_PARTY_DIR}/gflags)
SET(GFLAGS_INSTALL_DIR ${CMAKE_CURRENT_BINARY_DIR}/third_party/gflags)
SET(GFLAGS_INCLUDE_DIR "${GFLAGS_INSTALL_DIR}/include" CACHE PATH "gflags include directory." FORCE)
IF(WIN32)
    set(GFLAGS_LIBRARIES "${GFLAGS_INSTALL_DIR}/lib/gflags_static.lib" CACHE FILEPATH "GFLAGS_LIBRARIES" FORCE)
ELSE(WIN32)
    set(GFLAGS_LIBRARIES "${GFLAGS_INSTALL_DIR}/lib/libgflags.a" CACHE FILEPATH "GFLAGS_LIBRARIES" FORCE)
ENDIF(WIN32)

INCLUDE_DIRECTORIES(${GFLAGS_INCLUDE_DIR})

ExternalProject_Add(
    extern_gflags
    ${EXTERNAL_PROJECT_LOG_ARGS}
    SOURCE_DIR       ${GFLAGS_SOURCES_DIR}
    DOWNLOAD_COMMAND ""
    UPDATE_COMMAND   ""
    ${EXTERNAL_PROJECT_CMAKE_ARGS}
    CMAKE_ARGS      -DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}
    CMAKE_ARGS      -DCMAKE_C_COMPILER=${CMAKE_C_COMPILER}
    CMAKE_ARGS      -DCMAKE_AR=${CMAKE_AR}
    CMAKE_ARGS      -DCMAKE_RANLIB=${CMAKE_RANLIB}
    CMAKE_ARGS      -DCMAKE_CXX_FLAGS=${CMAKE_CXX_FLAGS}
    CMAKE_ARGS      -DCMAKE_C_FLAGS=${CMAKE_C_FLAGS}
    CMAKE_ARGS      -DCMAKE_INSTALL_PREFIX=${GFLAGS_INSTALL_DIR}
    CMAKE_ARGS      -DCMAKE_INSTALL_LIBDIR=${GFLAGS_INSTALL_DIR}/lib
    CMAKE_ARGS      -DCMAKE_POSITION_INDEPENDENT_CODE=ON
    CMAKE_ARGS      -DBUILD_TESTING=OFF
    CMAKE_ARGS      -DCMAKE_BUILD_TYPE=Release
    CMAKE_CACHE_ARGS -DCMAKE_INSTALL_PREFIX:PATH=${GFLAGS_INSTALL_DIR}
                     -DCMAKE_POSITION_INDEPENDENT_CODE:BOOL=ON
                     -DCMAKE_BUILD_TYPE:STRING=Release
)

ADD_LIBRARY(gflags STATIC IMPORTED GLOBAL)
SET_PROPERTY(TARGET gflags PROPERTY IMPORTED_LOCATION ${GFLAGS_LIBRARIES})
ADD_DEPENDENCIES(gflags extern_gflags)

IF(WIN32)
    # https://groups.google.com/forum/#!topic/google-gflags/cM4DuGOS_GI
    LINK_LIBRARIES("shlwapi.lib")
ENDIF(WIN32)

MESSAGE(STATUS "Google/gflags library: ${GFLAGS_LIBRARIES}")
