# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
# file Copyright.txt or https://cmake.org/licensing for details.

include(${CMAKE_CURRENT_LIST_DIR}/FindPackageMessage.cmake)

# internal helper macro
macro(_FPHSA_FAILURE_MESSAGE _msg)
  set (__msg "${_msg}")
  if (FPHSA_REASON_FAILURE_MESSAGE)
    string(APPEND __msg "\n    Reason given by package: ${FPHSA_REASON_FAILURE_MESSAGE}\n")
  endif()
  if (${_NAME}_FIND_REQUIRED)
    message(FATAL_ERROR "${__msg}")
  else ()
    if (NOT ${_NAME}_FIND_QUIETLY)
      message(STATUS "${__msg}")
    endif ()
  endif ()
endmacro()


# internal helper macro to generate the failure message when used in CONFIG_MODE:
macro(_FPHSA_HANDLE_FAILURE_CONFIG_MODE)
  # <PackageName>_CONFIG is set, but FOUND is false, this means that some other of the REQUIRED_VARS was not found:
  if(${_NAME}_CONFIG)
    _FPHSA_FAILURE_MESSAGE("${FPHSA_FAIL_MESSAGE}: missing:${MISSING_VARS} (found ${${_NAME}_CONFIG} ${VERSION_MSG})")
  else()
    # If _CONSIDERED_CONFIGS is set, the config-file has been found, but no suitable version.
    # List them all in the error message:
    if(${_NAME}_CONSIDERED_CONFIGS)
      set(configsText "")
      list(LENGTH ${_NAME}_CONSIDERED_CONFIGS configsCount)
      math(EXPR configsCount "${configsCount} - 1")
      foreach(currentConfigIndex RANGE ${configsCount})
        list(GET ${_NAME}_CONSIDERED_CONFIGS ${currentConfigIndex} filename)
        list(GET ${_NAME}_CONSIDERED_VERSIONS ${currentConfigIndex} version)
        string(APPEND configsText "\n    ${filename} (version ${version})")
      endforeach()
      if (${_NAME}_NOT_FOUND_MESSAGE)
        if (FPHSA_REASON_FAILURE_MESSAGE)
          string(PREPEND FPHSA_REASON_FAILURE_MESSAGE "${${_NAME}_NOT_FOUND_MESSAGE}\n    ")
        else()
          set(FPHSA_REASON_FAILURE_MESSAGE "${${_NAME}_NOT_FOUND_MESSAGE}")
        endif()
      else()
        string(APPEND configsText "\n")
      endif()
      _FPHSA_FAILURE_MESSAGE("${FPHSA_FAIL_MESSAGE} ${VERSION_MSG}, checked the following files:${configsText}")

    else()
      # Simple case: No Config-file was found at all:
      _FPHSA_FAILURE_MESSAGE("${FPHSA_FAIL_MESSAGE}: found neither ${_NAME}Config.cmake nor ${_NAME_LOWER}-config.cmake ${VERSION_MSG}")
    endif()
  endif()
endmacro()


function(FIND_PACKAGE_HANDLE_STANDARD_ARGS _NAME _FIRST_ARG)

# Set up the arguments for `cmake_parse_arguments`.
  set(options  CONFIG_MODE  HANDLE_COMPONENTS)
  set(oneValueArgs  FAIL_MESSAGE  REASON_FAILURE_MESSAGE VERSION_VAR  FOUND_VAR)
  set(multiValueArgs REQUIRED_VARS)

# Check whether we are in 'simple' or 'extended' mode:
  set(_KEYWORDS_FOR_EXTENDED_MODE  ${options} ${oneValueArgs} ${multiValueArgs} )
  list(FIND _KEYWORDS_FOR_EXTENDED_MODE "${_FIRST_ARG}" INDEX)

  if(${INDEX} EQUAL -1)
    set(FPHSA_FAIL_MESSAGE ${_FIRST_ARG})
    set(FPHSA_REQUIRED_VARS ${ARGN})
    set(FPHSA_VERSION_VAR)
  else()
    cmake_parse_arguments(FPHSA "${options}" "${oneValueArgs}" "${multiValueArgs}"  ${_FIRST_ARG} ${ARGN})

    if(FPHSA_UNPARSED_ARGUMENTS)
      message(FATAL_ERROR "Unknown keywords given to FIND_PACKAGE_HANDLE_STANDARD_ARGS(): \"${FPHSA_UNPARSED_ARGUMENTS}\"")
    endif()

    if(NOT FPHSA_FAIL_MESSAGE)
      set(FPHSA_FAIL_MESSAGE  "DEFAULT_MSG")
    endif()

    # In config-mode, we rely on the variable <PackageName>_CONFIG, which is set by find_package()
    # when it successfully found the config-file, including version checking:
    if(FPHSA_CONFIG_MODE)
      list(INSERT FPHSA_REQUIRED_VARS 0 ${_NAME}_CONFIG)
      list(REMOVE_DUPLICATES FPHSA_REQUIRED_VARS)
      set(FPHSA_VERSION_VAR ${_NAME}_VERSION)
    endif()

    if(NOT FPHSA_REQUIRED_VARS)
      message(FATAL_ERROR "No REQUIRED_VARS specified for FIND_PACKAGE_HANDLE_STANDARD_ARGS()")
    endif()
  endif()

# now that we collected all arguments, process them

  if("x${FPHSA_FAIL_MESSAGE}" STREQUAL "xDEFAULT_MSG")
    set(FPHSA_FAIL_MESSAGE "Could NOT find ${_NAME}")
  endif()

  list(GET FPHSA_REQUIRED_VARS 0 _FIRST_REQUIRED_VAR)

  string(TOUPPER ${_NAME} _NAME_UPPER)
  string(TOLOWER ${_NAME} _NAME_LOWER)

  if(FPHSA_FOUND_VAR)
    if(FPHSA_FOUND_VAR MATCHES "^${_NAME}_FOUND$"  OR  FPHSA_FOUND_VAR MATCHES "^${_NAME_UPPER}_FOUND$")
      set(_FOUND_VAR ${FPHSA_FOUND_VAR})
    else()
      message(FATAL_ERROR "The argument for FOUND_VAR is \"${FPHSA_FOUND_VAR}\", but only \"${_NAME}_FOUND\" and \"${_NAME_UPPER}_FOUND\" are valid names.")
    endif()
  else()
    set(_FOUND_VAR ${_NAME_UPPER}_FOUND)
  endif()

  # collect all variables which were not found, so they can be printed, so the
  # user knows better what went wrong (#6375)
  set(MISSING_VARS "")
  set(DETAILS "")
  # check if all passed variables are valid
  set(FPHSA_FOUND_${_NAME} TRUE)
  foreach(_CURRENT_VAR ${FPHSA_REQUIRED_VARS})
    if(NOT ${_CURRENT_VAR})
      set(FPHSA_FOUND_${_NAME} FALSE)
      string(APPEND MISSING_VARS " ${_CURRENT_VAR}")
    else()
      string(APPEND DETAILS "[${${_CURRENT_VAR}}]")
    endif()
  endforeach()
  if(FPHSA_FOUND_${_NAME})
    set(${_NAME}_FOUND TRUE)
    set(${_NAME_UPPER}_FOUND TRUE)
  else()
    set(${_NAME}_FOUND FALSE)
    set(${_NAME_UPPER}_FOUND FALSE)
  endif()

  # component handling
  unset(FOUND_COMPONENTS_MSG)
  unset(MISSING_COMPONENTS_MSG)

  if(FPHSA_HANDLE_COMPONENTS)
    foreach(comp ${${_NAME}_FIND_COMPONENTS})
      if(${_NAME}_${comp}_FOUND)

        if(NOT DEFINED FOUND_COMPONENTS_MSG)
          set(FOUND_COMPONENTS_MSG "found components:")
        endif()
        string(APPEND FOUND_COMPONENTS_MSG " ${comp}")

      else()

        if(NOT DEFINED MISSING_COMPONENTS_MSG)
          set(MISSING_COMPONENTS_MSG "missing components:")
        endif()
        string(APPEND MISSING_COMPONENTS_MSG " ${comp}")

        if(${_NAME}_FIND_REQUIRED_${comp})
          set(${_NAME}_FOUND FALSE)
          string(APPEND MISSING_VARS " ${comp}")
        endif()

      endif()
    endforeach()
    set(COMPONENT_MSG "${FOUND_COMPONENTS_MSG} ${MISSING_COMPONENTS_MSG}")
    string(APPEND DETAILS "[c${COMPONENT_MSG}]")
  endif()

  # version handling:
  set(VERSION_MSG "")
  set(VERSION_OK TRUE)

  # check with DEFINED here as the requested or found version may be "0"
  if (DEFINED ${_NAME}_FIND_VERSION)
    if(DEFINED ${FPHSA_VERSION_VAR})
      set(_FOUND_VERSION ${${FPHSA_VERSION_VAR}})

      if(${_NAME}_FIND_VERSION_EXACT)       # exact version required
        # count the dots in the version string
        string(REGEX REPLACE "[^.]" "" _VERSION_DOTS "${_FOUND_VERSION}")
        # add one dot because there is one dot more than there are components
        string(LENGTH "${_VERSION_DOTS}." _VERSION_DOTS)
        if (_VERSION_DOTS GREATER ${_NAME}_FIND_VERSION_COUNT)
          # Because of the C++ implementation of find_package() ${_NAME}_FIND_VERSION_COUNT
          # is at most 4 here. Therefore a simple lookup table is used.
          if (${_NAME}_FIND_VERSION_COUNT EQUAL 1)
            set(_VERSION_REGEX "[^.]*")
          elseif (${_NAME}_FIND_VERSION_COUNT EQUAL 2)
            set(_VERSION_REGEX "[^.]*\\.[^.]*")
          elseif (${_NAME}_FIND_VERSION_COUNT EQUAL 3)
            set(_VERSION_REGEX "[^.]*\\.[^.]*\\.[^.]*")
          else ()
            set(_VERSION_REGEX "[^.]*\\.[^.]*\\.[^.]*\\.[^.]*")
          endif ()
          string(REGEX REPLACE "^(${_VERSION_REGEX})\\..*" "\\1" _VERSION_HEAD "${_FOUND_VERSION}")
          unset(_VERSION_REGEX)
          if (NOT ${_NAME}_FIND_VERSION VERSION_EQUAL _VERSION_HEAD)
            set(VERSION_MSG "Found unsuitable version \"${_FOUND_VERSION}\", but required is exact version \"${${_NAME}_FIND_VERSION}\"")
            set(VERSION_OK FALSE)
          else ()
            set(VERSION_MSG "(found suitable exact version \"${_FOUND_VERSION}\")")
          endif ()
          unset(_VERSION_HEAD)
        else ()
          if (NOT ${_NAME}_FIND_VERSION VERSION_EQUAL _FOUND_VERSION)
            set(VERSION_MSG "Found unsuitable version \"${_FOUND_VERSION}\", but required is exact version \"${${_NAME}_FIND_VERSION}\"")
            set(VERSION_OK FALSE)
          else ()
            set(VERSION_MSG "(found suitable exact version \"${_FOUND_VERSION}\")")
          endif ()
        endif ()
        unset(_VERSION_DOTS)

      else()     # minimum version specified:
        if (${_NAME}_FIND_VERSION VERSION_GREATER _FOUND_VERSION)
          set(VERSION_MSG "Found unsuitable version \"${_FOUND_VERSION}\", but required is at least \"${${_NAME}_FIND_VERSION}\"")
          set(VERSION_OK FALSE)
        else ()
          set(VERSION_MSG "(found suitable version \"${_FOUND_VERSION}\", minimum required is \"${${_NAME}_FIND_VERSION}\")")
        endif ()
      endif()

    else()

      # if the package was not found, but a version was given, add that to the output:
      if(${_NAME}_FIND_VERSION_EXACT)
         set(VERSION_MSG "(Required is exact version \"${${_NAME}_FIND_VERSION}\")")
      else()
         set(VERSION_MSG "(Required is at least version \"${${_NAME}_FIND_VERSION}\")")
      endif()

    endif()
  else ()
    # Check with DEFINED as the found version may be 0.
    if(DEFINED ${FPHSA_VERSION_VAR})
      set(VERSION_MSG "(found version \"${${FPHSA_VERSION_VAR}}\")")
    endif()
  endif ()

  if(VERSION_OK)
    string(APPEND DETAILS "[v${${FPHSA_VERSION_VAR}}(${${_NAME}_FIND_VERSION})]")
  else()
    set(${_NAME}_FOUND FALSE)
  endif()


  # print the result:
  if (${_NAME}_FOUND)
    FIND_PACKAGE_MESSAGE(${_NAME} "Found ${_NAME}: ${${_FIRST_REQUIRED_VAR}} ${VERSION_MSG} ${COMPONENT_MSG}" "${DETAILS}")
  else ()

    if(FPHSA_CONFIG_MODE)
      _FPHSA_HANDLE_FAILURE_CONFIG_MODE()
    else()
      if(NOT VERSION_OK)
        _FPHSA_FAILURE_MESSAGE("${FPHSA_FAIL_MESSAGE}: ${VERSION_MSG} (found ${${_FIRST_REQUIRED_VAR}})")
      else()
        _FPHSA_FAILURE_MESSAGE("${FPHSA_FAIL_MESSAGE} (missing:${MISSING_VARS}) ${VERSION_MSG}")
      endif()
    endif()

  endif ()

  set(${_NAME}_FOUND ${${_NAME}_FOUND} PARENT_SCOPE)
  set(${_NAME_UPPER}_FOUND ${${_NAME}_FOUND} PARENT_SCOPE)
endfunction()