# @HEADER
# *****************************************************************************
#            TriBITS: Tribal Build, Integrate, and Test System
#
# Copyright 2013-2016 NTESS and the TriBITS contributors.
# SPDX-License-Identifier: BSD-3-Clause
# *****************************************************************************
# @HEADER


# @FUNCTION: tribits_get_package_enable_status()
#
# Function that determines a given external or internal package's enable
# status (e.g. 'ON' or 'OFF' or any valid CMake bool)
#
# Usage::
#
#   tribits_get_package_enable_status(<packageName>  <packageEnableOut>
#     <packageEnableVarNameOut>)
#
# On return, if non-empty, the variable ``<packageEnableOut>`` will contain
# the actual value of ``${${PROJECT_NAME}_ENABLE_<packageName>}`` or
# ``${TPL_ENABLE_<packageName>}`` or will return empty "".  If
# ``${packageName}_PACKAGE_BUILD_STATUS == "INTERNAL"``, then only the value
# of ``${PROJECT_NAME}_ENABLE_<packageName>`` will be considered.
#
# On return, if non-empty, the variable ``<packageEnableVarNameOut>`` will be
# either ``${${PROJECT_NAME}_ENABLE_<packageName>}`` or
# ``${TPL_ENABLE_<packageName>}``, depending on which one is used to obtain
# the value ``<packageEnableOut>``.
#
# This works for both external packages/TPLs and internal packages.
#
function(tribits_get_package_enable_status  packageName  packageEnableOut
    packageEnableVarNameOut
  )
  tribits_get_package_enable_status_assert_args("${packageName}"
    "${packageEnableOut}" "${packageEnableVarNameOut}")
  tribits_assert_package_enable_status(${packageName})
  # Determine which variable, if any, to extract enable status from
  set(packageEnableVarName "")
  if (NOT "${${PROJECT_NAME}_ENABLE_${packageName}}" STREQUAL "")
    set(packageEnableVarName  ${PROJECT_NAME}_ENABLE_${packageName})
  elseif (NOT "${TPL_ENABLE_${packageName}}" STREQUAL "")
    set(packageEnableVarName  TPL_ENABLE_${packageName})
  elseif (${packageName}_PACKAGE_BUILD_STATUS  STREQUAL  "INTERNAL")
    set(packageEnableVarName  ${PROJECT_NAME}_ENABLE_${packageName})
  elseif (${packageName}_PACKAGE_BUILD_STATUS  STREQUAL  "EXTERNAL")
    set(packageEnableVarName  TPL_ENABLE_${packageName})
  else()
    message(FATAL_ERROR "Could not determine status of package ${packageName}")
  endif()
  # Extract the enable status, set output args
  set(packageEnable ${${packageEnableVarName}})
  if (packageEnableOut)
    set(${packageEnableOut} ${packageEnable} PARENT_SCOPE)
  endif()
  if (packageEnableVarNameOut)
    set(${packageEnableVarNameOut} ${packageEnableVarName} PARENT_SCOPE)
  endif()
endfunction()


# @FUNCTION: tribits_package_is_enabled_or_unset()
#
# Function that determines if a package's enable variable evaluates to true or
# is unset.
#
# Usage::
#
#   tribits_package_is_enabled_or_unset((<packageEnableVarName>
#     <packageIsEnabledOrUnsetOut>)
#
# On return, the value of ``<packageIsEnabledOrUnsetOut>`` will set to
# ``TRUE`` if the variable ``<packageEnableVarName>`` evaluates to true and
# or is empty "".  Otherwise, ``<packageIsEnabledOrUnsetOut>`` will set
# to ``FALSE`` on return.
#
function(tribits_package_is_enabled_or_unset  packageEnableVarName
    packageIsEnabledOrUnsetOut
  )
  if (${packageEnableVarName} OR ("${${packageEnableVarName}}" STREQUAL ""))
    set(packageIsEnabledOrUnset TRUE)
  else()
    set(packageIsEnabledOrUnset FALSE)
  endif()
  set(${packageIsEnabledOrUnsetOut} ${packageIsEnabledOrUnset}
    PARENT_SCOPE)
endfunction()


# @FUNCTION: tribits_package_is_explicitly_disabled()
#
# Function that determines if a package's enable variable is
# explicitly disabled (i.e. evaluates to false but is not emapty).
#
# Usage::
#
#   tribits_package_is_explicitly_disabled((<packageEnableVarName>
#     <packageIsExplicitlyDisabledOut>)
#
# On return, the value of ``<packageIsExplicitlyDisabledOut>`` will set to
# ``TRUE`` if the variable ``<packageEnableVarName>`` evaluates to false and
# is not empty "".  Otherwise, ``<packageIsExplicitlyDisabledOut>`` will set
# to ``FALSE`` on return.
#
function(tribits_package_is_explicitly_disabled  packageEnableVarName
    packageIsExplicitlyDisabledOut
  )
  if ((NOT ${packageEnableVarName}) AND (NOT "${${packageEnableVarName}}" STREQUAL ""))
    set(packageIsExplicitlyDisabled TRUE)
  else()
    set(packageIsExplicitlyDisabled FALSE)
  endif()
  set(${packageIsExplicitlyDisabledOut} ${packageIsExplicitlyDisabled}
    PARENT_SCOPE)
endfunction()


# @FUNCTION: tribits_assert_package_enable_status()
#
# Function that asserts that if both ``${PROJECT_NAME}_ENABLE_${packageName}``
# and ``TPL_ENABLE_${packageName}`` are both set to non-empty, then they must
# be the same value or this is an error.
#
# Usage::
#
#   tribits_assert_package_enable_status(<packageName>)
#
function(tribits_assert_package_enable_status  packageName)
  if ( (NOT "${${PROJECT_NAME}_ENABLE_${packageName}}" STREQUAL "")
      AND (NOT "${TPL_ENABLE_${packageName}}" STREQUAL "")
      AND (NOT "${${PROJECT_NAME}_ENABLE_${packageName}}" STREQUAL
        "${TPL_ENABLE_${packageName}}")
      )
  message(SEND_ERROR "Error, ${PROJECT_NAME}_ENABLE_${packageName}="
    "'${${PROJECT_NAME}_ENABLE_${packageName}}' !="
    " TPL_ENABLE_${packageName} = '${TPL_ENABLE_${packageName}}'")
  endif()
endfunction()
# ToDo: Create a cache var for the mode of message() above in case the user
# wants to disable the warning.


function(tribits_get_package_enable_status_assert_args  packageName  packageEnableOut
    packageEnableVarNameOut
  )
  if ("${packageName}" STREQUAL "")
    message(FATAL_ERROR "Error, packageName='' is not allowed!")
  endif()
  if ("${packageEnableOut}" STREQUAL "" AND "${packageEnableVarNameOut}" STREQUAL "")
    message(FATAL_ERROR "Error, both packageEnableOut='' and"
      " packageEnableVarNameOut='' is not allowed!")
  endif()
endfunction()