include(ExternalProject)

set(LZ4_INCLUDE_DIR ${THIRD_PARTY_DIR}/lz4/include)
set(LZ4_LIBRARY_DIR ${THIRD_PARTY_DIR}/lz4/lib)

set(LZ4_URL https://github.com/lz4/lz4/archive/v1.9.2.tar.gz)
use_mirror(VARIABLE LZ4_URL URL ${LZ4_URL})
set(LZ4_BUILD_DIR ${CMAKE_CURRENT_BINARY_DIR}/lz4/src/lz4/lib)

set(LZ4_BUILD_LIBRARY_DIR ${LZ4_BUILD_DIR})
set(LZ4_LIBRARY_NAMES liblz4.a)

foreach(LIBRARY_NAME ${LZ4_LIBRARY_NAMES})
  list(APPEND LZ4_STATIC_LIBRARIES ${LZ4_LIBRARY_DIR}/${LIBRARY_NAME})
  list(APPEND LZ4_BUILD_STATIC_LIBRARIES ${LZ4_BUILD_LIBRARY_DIR}/${LIBRARY_NAME})
endforeach()

set(LZ4_HEADERS "${LZ4_BUILD_DIR}/lz4frame.h" "${LZ4_BUILD_DIR}/lz4frame_static.h"
                "${LZ4_BUILD_DIR}/lz4.h" "${LZ4_BUILD_DIR}/lz4hc.h" "${LZ4_BUILD_DIR}/xxhash.h")

set(LZ4_CFLAGS "-O3 -fPIC")

if(THIRD_PARTY)

  include(ProcessorCount)
  ProcessorCount(PROC_NUM)
  ExternalProject_Add(
    lz4
    PREFIX lz4
    URL ${LZ4_URL}
    URL_MD5 3898c56c82fb3d9455aefd48db48eaad
    UPDATE_COMMAND ""
    CONFIGURE_COMMAND ""
    BUILD_IN_SOURCE 1
    BUILD_COMMAND make -j ${PROC_NUM} lib CFLAGS=${LZ4_CFLAGS}
    INSTALL_COMMAND ""
    BUILD_BYPRODUCTS ${LZ4_STATIC_LIBRARIES})

  add_custom_target(lz4_create_header_dir COMMAND ${CMAKE_COMMAND} -E make_directory
                                                  ${LZ4_INCLUDE_DIR} DEPENDS lz4)

  add_custom_target(lz4_copy_headers_to_destination DEPENDS lz4_create_header_dir)

  foreach(header_file ${LZ4_HEADERS})
    add_custom_command(
      TARGET lz4_copy_headers_to_destination PRE_BUILD
      COMMAND ${CMAKE_COMMAND} -E copy_if_different ${header_file} ${LZ4_INCLUDE_DIR})
  endforeach()

  add_custom_target(lz4_create_library_dir COMMAND ${CMAKE_COMMAND} -E make_directory
                                                   ${LZ4_LIBRARY_DIR} DEPENDS lz4)

  message(STATUS ${LZ4_BUILD_STATIC_LIBRARIES})
  add_custom_target(
    lz4_copy_libs_to_destination COMMAND ${CMAKE_COMMAND} -E copy_if_different
                                         ${LZ4_BUILD_STATIC_LIBRARIES} ${LZ4_LIBRARY_DIR}
    DEPENDS lz4_create_library_dir)

endif(THIRD_PARTY)