#***************************************************************************
#                                  _   _ ____  _
#  Project                     ___| | | |  _ \| |
#                             / __| | | | |_) | |
#                            | (__| |_| |  _ <| |___
#                             \___|\___/|_| \_\_____|
#
# Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
#
# This software is licensed as described in the file COPYING, which
# you should have received as part of this distribution. The terms
# are also available at https://curl.haxx.se/docs/copyright.html.
#
# You may opt to use, copy, modify, merge, publish, distribute and/or sell
# copies of the Software, and permit persons to whom the Software is
# furnished to do so, under the terms of the COPYING file.
#
# This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
# KIND, either express or implied.
#
###########################################################################
# - Try to find the GSS Kerberos library
# Once done this will define
#
#  GSS_ROOT_DIR - Set this variable to the root installation of GSS
#
# Read-Only variables:
#  GSS_FOUND - system has the Heimdal library
#  GSS_FLAVOUR - "MIT" or "Heimdal" if anything found.
#  GSS_INCLUDE_DIR - the Heimdal include directory
#  GSS_LIBRARIES - The libraries needed to use GSS
#  GSS_LINK_DIRECTORIES - Directories to add to linker search path
#  GSS_LINKER_FLAGS - Additional linker flags
#  GSS_COMPILER_FLAGS - Additional compiler flags
#  GSS_VERSION - This is set to version advertised by pkg-config or read from manifest.
#                In case the library is found but no version info available it'll be set to "unknown"

set(_MIT_MODNAME mit-krb5-gssapi)
set(_HEIMDAL_MODNAME heimdal-gssapi)

include(CheckIncludeFile)
include(CheckIncludeFiles)
include(CheckTypeSize)

set(_GSS_ROOT_HINTS
    "${GSS_ROOT_DIR}"
    "$ENV{GSS_ROOT_DIR}"
)

# try to find library using system pkg-config if user didn't specify root dir
if(NOT GSS_ROOT_DIR AND NOT "$ENV{GSS_ROOT_DIR}")
  if(UNIX)
    find_package(PkgConfig QUIET)
    pkg_search_module(_GSS_PKG ${_MIT_MODNAME} ${_HEIMDAL_MODNAME})
    list(APPEND _GSS_ROOT_HINTS "${_GSS_PKG_PREFIX}")
  elseif(WIN32)
    list(APPEND _GSS_ROOT_HINTS "[HKEY_LOCAL_MACHINE\\SOFTWARE\\MIT\\Kerberos;InstallDir]")
  endif()
endif()

if(NOT _GSS_FOUND) #not found by pkg-config. Let's take more traditional approach.
  find_file(_GSS_CONFIGURE_SCRIPT
      NAMES
          "krb5-config"
      HINTS
          ${_GSS_ROOT_HINTS}
      PATH_SUFFIXES
          bin
      NO_CMAKE_PATH
      NO_CMAKE_ENVIRONMENT_PATH
  )

  # if not found in user-supplied directories, maybe system knows better
  find_file(_GSS_CONFIGURE_SCRIPT
      NAMES
          "krb5-config"
      PATH_SUFFIXES
          bin
  )

  if(_GSS_CONFIGURE_SCRIPT)
    execute_process(
          COMMAND ${_GSS_CONFIGURE_SCRIPT} "--cflags" "gssapi"
          OUTPUT_VARIABLE _GSS_CFLAGS
          RESULT_VARIABLE _GSS_CONFIGURE_FAILED
          OUTPUT_STRIP_TRAILING_WHITESPACE
      )
    message(STATUS "CFLAGS: ${_GSS_CFLAGS}")
    if(NOT _GSS_CONFIGURE_FAILED) # 0 means success
      # should also work in an odd case when multiple directories are given
      string(STRIP "${_GSS_CFLAGS}" _GSS_CFLAGS)
      string(REGEX REPLACE " +-I" ";" _GSS_CFLAGS "${_GSS_CFLAGS}")
      string(REGEX REPLACE " +-([^I][^ \\t;]*)" ";-\\1" _GSS_CFLAGS "${_GSS_CFLAGS}")

      foreach(_flag ${_GSS_CFLAGS})
        if(_flag MATCHES "^-I.*")
          string(REGEX REPLACE "^-I" "" _val "${_flag}")
          list(APPEND _GSS_INCLUDE_DIR "${_val}")
        else()
          list(APPEND _GSS_COMPILER_FLAGS "${_flag}")
        endif()
      endforeach()
    endif()

    execute_process(
        COMMAND ${_GSS_CONFIGURE_SCRIPT} "--libs" "gssapi"
        OUTPUT_VARIABLE _GSS_LIB_FLAGS
        RESULT_VARIABLE _GSS_CONFIGURE_FAILED
        OUTPUT_STRIP_TRAILING_WHITESPACE
    )
    message(STATUS "LDFLAGS: ${_GSS_LIB_FLAGS}")

    if(NOT _GSS_CONFIGURE_FAILED) # 0 means success
      # this script gives us libraries and link directories. Blah. We have to deal with it.
      string(STRIP "${_GSS_LIB_FLAGS}" _GSS_LIB_FLAGS)
      string(REGEX REPLACE " +-(L|l)" ";-\\1" _GSS_LIB_FLAGS "${_GSS_LIB_FLAGS}")
      string(REGEX REPLACE " +-([^Ll][^ \\t;]*)" ";-\\1" _GSS_LIB_FLAGS "${_GSS_LIB_FLAGS}")

      foreach(_flag ${_GSS_LIB_FLAGS})
        if(_flag MATCHES "^-l.*")
          string(REGEX REPLACE "^-l" "" _val "${_flag}")
          list(APPEND _GSS_LIBRARIES "${_val}")
        elseif(_flag MATCHES "^-L.*")
          string(REGEX REPLACE "^-L" "" _val "${_flag}")
          list(APPEND _GSS_LINK_DIRECTORIES "${_val}")
        else()
          list(APPEND _GSS_LINKER_FLAGS "${_flag}")
        endif()
      endforeach()
    endif()

    execute_process(
        COMMAND ${_GSS_CONFIGURE_SCRIPT} "--version"
        OUTPUT_VARIABLE _GSS_VERSION
        RESULT_VARIABLE _GSS_CONFIGURE_FAILED
        OUTPUT_STRIP_TRAILING_WHITESPACE
    )

    # older versions may not have the "--version" parameter. In this case we just don't care.
    if(_GSS_CONFIGURE_FAILED)
      set(_GSS_VERSION 0)
    endif()

    execute_process(
        COMMAND ${_GSS_CONFIGURE_SCRIPT} "--vendor"
        OUTPUT_VARIABLE _GSS_VENDOR
        RESULT_VARIABLE _GSS_CONFIGURE_FAILED
        OUTPUT_STRIP_TRAILING_WHITESPACE
    )

    # older versions may not have the "--vendor" parameter. In this case we just don't care.
    if(_GSS_CONFIGURE_FAILED)
      set(GSS_FLAVOUR "Heimdal") # most probably, shouldn't really matter
    else()
      if(_GSS_VENDOR MATCHES ".*H|heimdal.*")
        set(GSS_FLAVOUR "Heimdal")
      else()
        set(GSS_FLAVOUR "MIT")
      endif()
    endif()

  else() # either there is no config script or we are on a platform that doesn't provide one (Windows?)

    find_path(_GSS_INCLUDE_DIR
        NAMES
            "gssapi/gssapi.h"
        HINTS
            ${_GSS_ROOT_HINTS}
        PATH_SUFFIXES
            include
            inc
    )

    if(_GSS_INCLUDE_DIR) #jay, we've found something
      set(CMAKE_REQUIRED_INCLUDES "${_GSS_INCLUDE_DIR}")
      check_include_files( "gssapi/gssapi_generic.h;gssapi/gssapi_krb5.h" _GSS_HAVE_MIT_HEADERS)

      if(_GSS_HAVE_MIT_HEADERS)
        set(GSS_FLAVOUR "MIT")
      else()
        # prevent compiling the header - just check if we can include it
        set(CMAKE_REQUIRED_DEFINITIONS "${CMAKE_REQUIRED_DEFINITIONS} -D__ROKEN_H__")
        check_include_file( "roken.h" _GSS_HAVE_ROKEN_H)

        check_include_file( "heimdal/roken.h" _GSS_HAVE_HEIMDAL_ROKEN_H)
        if(_GSS_HAVE_ROKEN_H OR _GSS_HAVE_HEIMDAL_ROKEN_H)
          set(GSS_FLAVOUR "Heimdal")
        endif()
        set(CMAKE_REQUIRED_DEFINITIONS "")
      endif()
    else()
      # I'm not convinced if this is the right way but this is what autotools do at the moment
      find_path(_GSS_INCLUDE_DIR
          NAMES
              "gssapi.h"
          HINTS
              ${_GSS_ROOT_HINTS}
          PATH_SUFFIXES
              include
              inc
      )

      if(_GSS_INCLUDE_DIR)
        set(GSS_FLAVOUR "Heimdal")
      endif()
    endif()

    # if we have headers, check if we can link libraries
    if(GSS_FLAVOUR)
      set(_GSS_LIBDIR_SUFFIXES "")
      set(_GSS_LIBDIR_HINTS ${_GSS_ROOT_HINTS})
      get_filename_component(_GSS_CALCULATED_POTENTIAL_ROOT "${_GSS_INCLUDE_DIR}" PATH)
      list(APPEND _GSS_LIBDIR_HINTS ${_GSS_CALCULATED_POTENTIAL_ROOT})

      if(WIN32)
        if(CMAKE_SIZEOF_VOID_P EQUAL 8)
          list(APPEND _GSS_LIBDIR_SUFFIXES "lib/AMD64")
          if(GSS_FLAVOUR STREQUAL "MIT")
            set(_GSS_LIBNAME "gssapi64")
          else()
            set(_GSS_LIBNAME "libgssapi")
          endif()
        else()
          list(APPEND _GSS_LIBDIR_SUFFIXES "lib/i386")
          if(GSS_FLAVOUR STREQUAL "MIT")
            set(_GSS_LIBNAME "gssapi32")
          else()
            set(_GSS_LIBNAME "libgssapi")
          endif()
        endif()
      else()
        list(APPEND _GSS_LIBDIR_SUFFIXES "lib;lib64") # those suffixes are not checked for HINTS
        if(GSS_FLAVOUR STREQUAL "MIT")
          set(_GSS_LIBNAME "gssapi_krb5")
        else()
          set(_GSS_LIBNAME "gssapi")
        endif()
      endif()

      find_library(_GSS_LIBRARIES
          NAMES
              ${_GSS_LIBNAME}
          HINTS
              ${_GSS_LIBDIR_HINTS}
          PATH_SUFFIXES
              ${_GSS_LIBDIR_SUFFIXES}
      )

    endif()
  endif()
else()
  if(_GSS_PKG_${_MIT_MODNAME}_VERSION)
    set(GSS_FLAVOUR "MIT")
    set(_GSS_VERSION _GSS_PKG_${_MIT_MODNAME}_VERSION)
  else()
    set(GSS_FLAVOUR "Heimdal")
    set(_GSS_VERSION _GSS_PKG_${_MIT_HEIMDAL}_VERSION)
  endif()
endif()

set(GSS_INCLUDE_DIR ${_GSS_INCLUDE_DIR})
set(GSS_LIBRARIES ${_GSS_LIBRARIES})
set(GSS_LINK_DIRECTORIES ${_GSS_LINK_DIRECTORIES})
set(GSS_LINKER_FLAGS ${_GSS_LINKER_FLAGS})
set(GSS_COMPILER_FLAGS ${_GSS_COMPILER_FLAGS})
set(GSS_VERSION ${_GSS_VERSION})

if(GSS_FLAVOUR)
  if(NOT GSS_VERSION AND GSS_FLAVOUR STREQUAL "Heimdal")
    if(CMAKE_SIZEOF_VOID_P EQUAL 8)
      set(HEIMDAL_MANIFEST_FILE "Heimdal.Application.amd64.manifest")
    else()
      set(HEIMDAL_MANIFEST_FILE "Heimdal.Application.x86.manifest")
    endif()

    if(EXISTS "${GSS_INCLUDE_DIR}/${HEIMDAL_MANIFEST_FILE}")
      file(STRINGS "${GSS_INCLUDE_DIR}/${HEIMDAL_MANIFEST_FILE}" heimdal_version_str
           REGEX "^.*version=\"[0-9]\\.[^\"]+\".*$")

      string(REGEX MATCH "[0-9]\\.[^\"]+"
             GSS_VERSION "${heimdal_version_str}")
    endif()

    if(NOT GSS_VERSION)
      set(GSS_VERSION "Heimdal Unknown")
    endif()
  elseif(NOT GSS_VERSION AND GSS_FLAVOUR STREQUAL "MIT")
    get_filename_component(_MIT_VERSION "[HKEY_LOCAL_MACHINE\\SOFTWARE\\MIT\\Kerberos\\SDK\\CurrentVersion;VersionString]" NAME CACHE)
    if(WIN32 AND _MIT_VERSION)
      set(GSS_VERSION "${_MIT_VERSION}")
    else()
      set(GSS_VERSION "MIT Unknown")
    endif()
  endif()
endif()

include(FindPackageHandleStandardArgs)

set(_GSS_REQUIRED_VARS GSS_LIBRARIES GSS_FLAVOUR)

find_package_handle_standard_args(GSS
    REQUIRED_VARS
        ${_GSS_REQUIRED_VARS}
    VERSION_VAR
        GSS_VERSION
    FAIL_MESSAGE
        "Could NOT find GSS, try to set the path to GSS root folder in the system variable GSS_ROOT_DIR"
)

mark_as_advanced(GSS_INCLUDE_DIR GSS_LIBRARIES)