include(CMakeParseArguments)

function(precondition var)
  cmake_parse_arguments(
    PRECONDITION # prefix
    "NEGATE" # options
    "MESSAGE" # single-value args
    "" # multi-value args
    ${ARGN})

  if (PRECONDITION_NEGATE)
    if (${var})
      if (PRECONDITION_MESSAGE)
        message(FATAL_ERROR "Error! ${PRECONDITION_MESSAGE}")
      else()
        message(FATAL_ERROR "Error! Variable ${var} is true or not empty. The value of ${var} is ${${var}}.")
      endif()
    endif()
  else()
    if (NOT ${var})
      if (PRECONDITION_MESSAGE)
        message(FATAL_ERROR "Error! ${PRECONDITION_MESSAGE}")
      else()
        message(FATAL_ERROR "Error! Variable ${var} is false, empty or not set.")
      endif()
    endif()
  endif()
endfunction()

# Assert is 'NOT ${LHS} ${OP} ${RHS}' is true.
function(precondition_binary_op OP LHS RHS)
  cmake_parse_arguments(
    PRECONDITIONBINOP # prefix
    "NEGATE" # options
    "MESSAGE" # single-value args
    "" # multi-value args
    ${ARGN})

  if (PRECONDITIONBINOP_NEGATE)
    if (${LHS} ${OP} ${RHS})
      if (PRECONDITIONBINOP_MESSAGE)
        message(FATAL_ERROR "Error! ${PRECONDITIONBINOP_MESSAGE}")
      else()
        message(FATAL_ERROR "Error! ${LHS} ${OP} ${RHS} is true!")
      endif()
    endif()
  else()
    if (NOT ${LHS} ${OP} ${RHS})
      if (PRECONDITIONBINOP_MESSAGE)
        message(FATAL_ERROR "Error! ${PRECONDITIONBINOP_MESSAGE}")
      else()
        message(FATAL_ERROR "Error! ${LHS} ${OP} ${RHS} is false!")
      endif()
    endif()
  endif()
endfunction()

# Translate a yes/no variable to the presence of a given string in a
# variable.
#
# Usage:
#   translate_flag(is_set flag_name var_name)
#
# If is_set is true, sets ${var_name} to ${flag_name}. Otherwise,
# unsets ${var_name}.
function(translate_flag is_set flag_name var_name)
  if(${is_set})
    set("${var_name}" "${flag_name}" PARENT_SCOPE)
  else()
    set("${var_name}" "" PARENT_SCOPE)
  endif()
endfunction()

macro(translate_flags prefix options)
  foreach(var ${options})
    translate_flag("${${prefix}_${var}}" "${var}" "${prefix}_${var}_keyword")
  endforeach()
endmacro()

# Set ${outvar} to ${${invar}}, asserting if ${invar} is not set.
function(precondition_translate_flag invar outvar)
  precondition(${invar})
  set(${outvar} "${${invar}}" PARENT_SCOPE)
endfunction()

function(is_build_type_optimized build_type result_var_name)
  if("${build_type}" STREQUAL "Debug")
    set("${result_var_name}" FALSE PARENT_SCOPE)
  elseif("${build_type}" STREQUAL "RelWithDebInfo" OR
         "${build_type}" STREQUAL "Release" OR
         "${build_type}" STREQUAL "MinSizeRel")
    set("${result_var_name}" TRUE PARENT_SCOPE)
  else()
    message(FATAL_ERROR "Unknown build type: ${build_type}")
  endif()
endfunction()

function(is_build_type_with_debuginfo build_type result_var_name)
  if("${build_type}" STREQUAL "Debug" OR
     "${build_type}" STREQUAL "RelWithDebInfo")
    set("${result_var_name}" TRUE PARENT_SCOPE)
  elseif("${build_type}" STREQUAL "Release" OR
         "${build_type}" STREQUAL "MinSizeRel")
    set("${result_var_name}" FALSE PARENT_SCOPE)
  else()
    message(FATAL_ERROR "Unknown build type: ${build_type}")
  endif()
endfunction()

# Set variable to value if value is not null or false. Otherwise set variable to
# default_value.
function(set_with_default variable value)
  cmake_parse_argument(
    SWD
    ""
    "DEFAULT"
    "" ${ARGN})
  precondition(SWD_DEFAULT
    MESSAGE "Must specify a default argument")
  if (value)
    set(${variable} ${value} PARENT_SCOPE)
  else()
    set(${variable} ${SWD_DEFAULT} PARENT_SCOPE)
  endif()
endfunction()

function(swift_create_post_build_symlink target)
  set(options IS_DIRECTORY)
  set(oneValueArgs SOURCE DESTINATION WORKING_DIRECTORY COMMENT)
  cmake_parse_arguments(CS
    "${options}"
    "${oneValueArgs}"
    ""
    ${ARGN})

  if("${CMAKE_SYSTEM_NAME}" STREQUAL "Windows")
    if(CS_IS_DIRECTORY)
      set(cmake_symlink_option "copy_directory")
    else()
      set(cmake_symlink_option "copy_if_different")
    endif()
  else()
      set(cmake_symlink_option "create_symlink")
  endif()

  add_custom_command(TARGET "${target}" POST_BUILD
    COMMAND
      "${CMAKE_COMMAND}" "-E" "${cmake_symlink_option}"
      "${CS_SOURCE}"
      "${CS_DESTINATION}"
    WORKING_DIRECTORY "${CS_WORKING_DIRECTORY}"
    COMMENT "${CS_COMMENT}")
endfunction()

function(dump_swift_vars)
  set(SWIFT_STDLIB_GLOBAL_CMAKE_CACHE)
  get_cmake_property(variableNames VARIABLES)
  foreach(variableName ${variableNames})
    if(variableName MATCHES "^SWIFT")
      set(SWIFT_STDLIB_GLOBAL_CMAKE_CACHE "${SWIFT_STDLIB_GLOBAL_CMAKE_CACHE}set(${variableName} \"${${variableName}}\")\n")
      message("set(${variableName} \"${${variableName}}\")")
    endif()
  endforeach()
endfunction()

function(is_sdk_requested name result_var_name)
  if("${SWIFT_HOST_VARIANT_SDK}" STREQUAL "${name}")
    set("${result_var_name}" "TRUE" PARENT_SCOPE)
  else()
    if("${name}" IN_LIST SWIFT_SDKS)
      set("${result_var_name}" "TRUE" PARENT_SCOPE)
    else()
      set("${result_var_name}" "FALSE" PARENT_SCOPE)
    endif()
  endif()
endfunction()