# - Configures C++14 compiler, setting TDLib-specific compilation options.

function(td_set_up_compiler)
  set(CMAKE_EXPORT_COMPILE_COMMANDS 1 PARENT_SCOPE)

  set(CMAKE_POSITION_INDEPENDENT_CODE ON PARENT_SCOPE)

  include(illumos)

  if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
    set(GCC 1)
    set(GCC 1 PARENT_SCOPE)
  elseif (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
    set(CLANG 1)
    set(CLANG 1 PARENT_SCOPE)
  elseif (CMAKE_CXX_COMPILER_ID STREQUAL "Intel")
    set(INTEL 1)
    set(INTEL 1 PARENT_SCOPE)
  elseif (NOT MSVC)
    message(FATAL_ERROR "Compiler isn't supported")
  endif()

  include(CheckCXXCompilerFlag)

  if (GCC OR CLANG OR INTEL)
    if (WIN32 AND INTEL)
      set(STD14_FLAG /Qstd=c++14)
    else()
      set(STD14_FLAG -std=c++14)
    endif()
    check_cxx_compiler_flag(${STD14_FLAG} HAVE_STD14)
    if (NOT HAVE_STD14)
      string(REPLACE "c++14" "c++1y" STD14_FLAG "${STD14_FLAG}")
      check_cxx_compiler_flag(${STD14_FLAG} HAVE_STD1Y)
      set(HAVE_STD14 ${HAVE_STD1Y})
    endif()
  elseif (MSVC)
    set(HAVE_STD14 MSVC_VERSION>=1900)
  endif()

  if (NOT HAVE_STD14)
    message(FATAL_ERROR "No C++14 support in the compiler. Please upgrade the compiler.")
  endif()

  if (MSVC)
    if (CMAKE_CXX_FLAGS_DEBUG MATCHES "/RTC1")
      string(REPLACE "/RTC1" " " CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG}")
    endif()
    add_definitions(-D_SCL_SECURE_NO_WARNINGS -D_CRT_SECURE_NO_WARNINGS)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /utf-8 /GR- /W4 /wd4100 /wd4127 /wd4324 /wd4505 /wd4814 /wd4702 /bigobj")
  elseif (CLANG OR GCC)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${STD14_FLAG} -fno-omit-frame-pointer -fno-exceptions -fno-rtti")
    if (APPLE)
      set(TD_LINKER_FLAGS "-Wl,-dead_strip")
      if (NOT CMAKE_BUILD_TYPE MATCHES "Deb")
        set(TD_LINKER_FLAGS "${TD_LINKER_FLAGS},-x,-S")
      endif()
    else()
      set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -ffunction-sections -fdata-sections")
      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -ffunction-sections -fdata-sections")
      if (CMAKE_SYSTEM_NAME STREQUAL "SunOS")
        set(TD_LINKER_FLAGS "-Wl,-z,ignore")
      elseif (EMSCRIPTEN)
        set(TD_LINKER_FLAGS "-Wl,--gc-sections")
      else()
        set(TD_LINKER_FLAGS "-Wl,--gc-sections -Wl,--exclude-libs,ALL")
      endif()
    endif()
    set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} ${TD_LINKER_FLAGS}")
    set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${TD_LINKER_FLAGS}")

    if (WIN32 OR CYGWIN)
      if (GCC)
        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wa,-mbig-obj")
      endif()
    endif()
  elseif (INTEL)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${STD14_FLAG}")
  endif()

  if (WIN32)
    add_definitions(-DNTDDI_VERSION=0x06020000 -DWINVER=0x0602 -D_WIN32_WINNT=0x0602 -DPSAPI_VERSION=1 -DNOMINMAX -DUNICODE -D_UNICODE -DWIN32_LEAN_AND_MEAN)
  endif()
  if (CYGWIN)
    add_definitions(-D_DEFAULT_SOURCE=1 -DFD_SETSIZE=4096)
  endif()

  # _FILE_OFFSET_BITS is broken in Android NDK r15, r15b and r17 and doesn't work prior to Android 7.0
  add_definitions(-D_FILE_OFFSET_BITS=64)

  # _GNU_SOURCE might not be defined by g++
  add_definitions(-D_GNU_SOURCE)

  if (CMAKE_SYSTEM_NAME STREQUAL "SunOS")
    set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -lsocket -lnsl")
    if (ILLUMOS)
      add_definitions(-DTD_ILLUMOS=1)
    endif()
  endif()

  include(AddCXXCompilerFlag)
  if (NOT MSVC)
    add_cxx_compiler_flag("-Wall")
    add_cxx_compiler_flag("-Wextra")
    add_cxx_compiler_flag("-Wimplicit-fallthrough=2")
    add_cxx_compiler_flag("-Wpointer-arith")
    add_cxx_compiler_flag("-Wcast-qual")
    add_cxx_compiler_flag("-Wsign-compare")
    add_cxx_compiler_flag("-Wduplicated-branches")
    add_cxx_compiler_flag("-Wduplicated-cond")
    add_cxx_compiler_flag("-Walloc-zero")
    add_cxx_compiler_flag("-Wlogical-op")
    add_cxx_compiler_flag("-Wno-tautological-compare")
    add_cxx_compiler_flag("-Wpointer-arith")
    add_cxx_compiler_flag("-Wvla")
    add_cxx_compiler_flag("-Wnon-virtual-dtor")
    add_cxx_compiler_flag("-Wno-unused-parameter")
    add_cxx_compiler_flag("-Wconversion")
    add_cxx_compiler_flag("-Wno-sign-conversion")
    add_cxx_compiler_flag("-Wc++14-compat-pedantic")
    add_cxx_compiler_flag("-Wdeprecated")
    add_cxx_compiler_flag("-Wno-unused-command-line-argument")
    add_cxx_compiler_flag("-Qunused-arguments")
    add_cxx_compiler_flag("-Wodr")
    add_cxx_compiler_flag("-flto-odr-type-merging")

  #  add_cxx_compiler_flag("-Werror")

  #  add_cxx_compiler_flag("-Wcast-align")

  #std::int32_t <-> int and off_t <-> std::size_t/std::int64_t
  #  add_cxx_compiler_flag("-Wuseless-cast")

  #external headers like openssl
  #  add_cxx_compiler_flag("-Wzero-as-null-pointer-constant")
  endif()

  if (GCC AND NOT (CMAKE_CXX_COMPILER_VERSION VERSION_LESS 7.0))
    add_cxx_compiler_flag("-Wno-maybe-uninitialized")  # too many false positives
  endif()
  if (WIN32 AND GCC AND NOT (CMAKE_CXX_COMPILER_VERSION VERSION_LESS 8.0))
    # warns about casts of function pointers returned by GetProcAddress
    add_cxx_compiler_flag("-Wno-cast-function-type")
  endif()
  if (GCC AND NOT (CMAKE_CXX_COMPILER_VERSION VERSION_LESS 9.0))
    # warns about a lot of "return std::move", which are not redundant for compilers without fix for DR 1579, i.e. GCC 4.9 or clang 3.8
    # see http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#1579
    add_cxx_compiler_flag("-Wno-redundant-move")
  endif()
  if (GCC AND NOT (CMAKE_CXX_COMPILER_VERSION VERSION_LESS 12.0))
    add_cxx_compiler_flag("-Wno-stringop-overflow")  # some false positives
  endif()
  if (CLANG AND (CMAKE_CXX_COMPILER_VERSION VERSION_LESS 3.5))
    # https://stackoverflow.com/questions/26744556/warning-returning-a-captured-reference-from-a-lambda
    add_cxx_compiler_flag("-Wno-return-stack-address")
  endif()

  #set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -isystem /usr/include/c++/v1")
  #set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -stdlib=libc++")
  #set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fsanitize=thread")
  #set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fsanitize=address")
  #set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fsanitize=undefined")
  #set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fsanitize=leak")

  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}" PARENT_SCOPE)
  set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG}" PARENT_SCOPE)
  set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS}" PARENT_SCOPE)
  set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS}" PARENT_SCOPE)
  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS}" PARENT_SCOPE)
endfunction()