# SPDX-License-Identifier: BSD-3-Clause

# Module to find IlmBase
#
# This module will first look into the directories defined by the variables:
#   - ILMBASE_HOME, ILMBASE_VERSION, ILMBASE_LIB_AREA
#
# It also supports non-standard names for the library components.
#
# To use a custom IlmBase:
#   - Set the variable ILMBASE_CUSTOM to TRUE
#   - Set the variable ILMBASE_CUSTOM_LIBRARIES to a list of the libraries to
#     use, e.g. "SpiImath SpiHalf SpiIlmThread SpiIex"
#   - Optionally set the variable ILMBASE_CUSTOM_INCLUDE_DIR to any
#     particularly weird place that the OpenEXR/*.h files may be found
#   - Optionally set the variable ILMBASE_CUSTOM_LIB_DIR to any
#     particularly weird place that the libraries files may be found
#
# This module defines the following variables:
#
# ILMBASE_INCLUDE_DIR - where to find half.h, IlmBaseConfig.h, etc.
# ILMBASE_LIBRARIES   - list of libraries to link against when using IlmBase.
# ILMBASE_FOUND       - TRUE if IlmBase was found.

# Other standard issue macros
include(FindPackageHandleStandardArgs)
include(FindPackageMessage)
include(SelectLibraryConfigurations)


if(ILMBASE_USE_STATIC_LIBS)
  set(_ilmbase_ORIG_CMAKE_FIND_LIBRARY_SUFFIXES ${CMAKE_FIND_LIBRARY_SUFFIXES})
  if(WIN32)
    set(CMAKE_FIND_LIBRARY_SUFFIXES .lib .a ${CMAKE_FIND_LIBRARY_SUFFIXES})
  else()
    set(CMAKE_FIND_LIBRARY_SUFFIXES .a )
  endif()
endif()

# Macro to assemble a helper state variable
macro(SET_STATE_VAR varname)
  set(tmp_ilmbaselibs ${ILMBASE_CUSTOM_LIBRARIES})
  separate_arguments(tmp_ilmbaselibs)
  set(tmp_lst
    ${ILMBASE_CUSTOM} | ${tmp_ilmbaselibs} |
    ${ILMBASE_HOME} | ${ILMBASE_VERSION} | ${ILMBASE_LIB_AREA}
  )
  set(${varname} "${tmp_lst}")
  unset(tmp_ilmbaselibs)
  unset(tmp_lst)
endmacro()

# To enforce that find_* functions do not use inadvertently existing versions
if(ILMBASE_CUSTOM)
  set(ILMBASE_FIND_OPTIONS "NO_DEFAULT_PATH")
endif()

# Macro to search for an include directory
macro(PREFIX_FIND_INCLUDE_DIR prefix includefile libpath_var)
  string(TOUPPER ${prefix}_INCLUDE_DIR tmp_varname)
  find_path(${tmp_varname} ${includefile}
    HINTS ${${libpath_var}}
    PATH_SUFFIXES include
    ${ILMBASE_FIND_OPTIONS}
  )
  if(${tmp_varname})
    mark_as_advanced(${tmp_varname})
  endif()
  unset(tmp_varname)
endmacro()


# Macro to search for the given library and adds the cached
# variable names to the specified list
macro(PREFIX_FIND_LIB prefix libname libpath_var liblist_var cachelist_var)
  string(TOUPPER ${prefix}_${libname} tmp_prefix)
  # Handle new library names for OpenEXR 2.1 build via cmake
  string(REPLACE "." "_" _ILMBASE_VERSION ${ILMBASE_VERSION})
  string(SUBSTRING ${_ILMBASE_VERSION} 0 3 _ILMBASE_VERSION )

  find_library(${tmp_prefix}_LIBRARY_RELEASE
    NAMES ${libname} ${libname}-${_ILMBASE_VERSION}
    HINTS ${${libpath_var}}
    PATH_SUFFIXES lib
    ${ILMBASE_FIND_OPTIONS}
  )
  find_library(${tmp_prefix}_LIBRARY_DEBUG
    NAMES ${libname}d ${libname}_d ${libname}debug ${libname}_debug
    HINTS ${${libpath_var}}
    PATH_SUFFIXES lib
    ${ILMBASE_FIND_OPTIONS}
  )
  # Properly define ${tmp_prefix}_LIBRARY (cached) and ${tmp_prefix}_LIBRARIES
  select_library_configurations(${tmp_prefix})
  list(APPEND ${liblist_var} ${tmp_prefix}_LIBRARIES)

  # Add to the list of variables which should be reset
  list(APPEND ${cachelist_var}
    ${tmp_prefix}_LIBRARY
    ${tmp_prefix}_LIBRARY_RELEASE
    ${tmp_prefix}_LIBRARY_DEBUG)
  mark_as_advanced(
    ${tmp_prefix}_LIBRARY
    ${tmp_prefix}_LIBRARY_RELEASE
    ${tmp_prefix}_LIBRARY_DEBUG)
  unset(tmp_prefix)
endmacro()


# Encode the current state of the external variables into a string
SET_STATE_VAR(ILMBASE_CURRENT_STATE)

# If the state has changed, clear the cached variables
if(ILMBASE_CACHED_STATE AND
    NOT ILMBASE_CACHED_STATE STREQUAL ILMBASE_CURRENT_STATE)

  foreach(libvar ${ILMBASE_CACHED_VARS})
    unset(${libvar} CACHE)
  endforeach()
endif()


# Generic search paths
set(IlmBase_generic_include_paths
  ${ILMBASE_CUSTOM_INCLUDE_DIR}
  /usr/include
  /usr/include/${CMAKE_LIBRARY_ARCHITECTURE}
  /usr/local/include
  /opt/local/include
)
set(IlmBase_generic_library_paths
  ${ILMBASE_CUSTOM_LIB_DIR}
  /usr/lib
  /usr/lib/${CMAKE_LIBRARY_ARCHITECTURE}
  /usr/local/lib
  /usr/local/lib/${CMAKE_LIBRARY_ARCHITECTURE}
  /opt/local/lib
)

# Search paths for the IlmBase files
if(ILMBASE_HOME)
  if(ILMBASE_VERSION)
    set(IlmBase_include_paths
      ${ILMBASE_HOME}/ilmbase-${ILMBASE_VERSION}/include
      ${ILMBASE_HOME}/include/ilmbase-${ILMBASE_VERSION}
    )
    set(IlmBase_library_paths
      ${ILMBASE_HOME}/ilmbase-${ILMBASE_VERSION}/lib
      ${ILMBASE_HOME}/lib/ilmbase-${ILMBASE_VERSION}
    )
  endif()
  list(APPEND IlmBase_include_paths ${ILMBASE_HOME}/include)
  set(IlmBase_library_paths
    ${ILMBASE_HOME}/lib
    ${ILMBASE_HOME}/lib64
    ${ILMBASE_LIB_AREA}
    ${IlmBase_library_paths})
endif()
list(APPEND IlmBase_include_paths ${IlmBase_generic_include_paths})
list(APPEND IlmBase_library_paths ${IlmBase_generic_library_paths})

# Locate the header files
PREFIX_FIND_INCLUDE_DIR(IlmBase
  OpenEXR/IlmBaseConfig.h IlmBase_include_paths)

if(ILMBASE_INCLUDE_DIR)
  # Get the version from config file, if not already set.
  if(NOT ILMBASE_VERSION)
    FILE(STRINGS "${ILMBASE_INCLUDE_DIR}/OpenEXR/IlmBaseConfig.h" ILMBASE_BUILD_SPECIFICATION
         REGEX "^[ \t]*#define[ \t]+ILMBASE_VERSION_STRING[ \t]+\"[.0-9]+\".*$")

    if(ILMBASE_BUILD_SPECIFICATION)
      if(NOT IlmBase_FIND_QUIETLY)
        message(STATUS "${ILMBASE_BUILD_SPECIFICATION}")
      endif()
      string(REGEX REPLACE ".*#define[ \t]+ILMBASE_VERSION_STRING[ \t]+\"([.0-9]+)\".*"
             "\\1" XYZ ${ILMBASE_BUILD_SPECIFICATION})
      set("ILMBASE_VERSION" ${XYZ} CACHE STRING "Version of ILMBase lib")
    else()
      # Old versions (before 2.0?) do not have any version string,
      # just assuming 2.0 should be fine though.
      message(WARNING "Could not determine ILMBase library version, assuming 2.0.")
      set("ILMBASE_VERSION" "2.0" CACHE STRING "Version of ILMBase lib")
    endif()
  endif()
endif()


if(ILMBASE_CUSTOM)
  if(NOT ILMBASE_CUSTOM_LIBRARIES)
    message(FATAL_ERROR "Custom IlmBase libraries requested but ILMBASE_CUSTOM_LIBRARIES is not set.")
  endif()
  set(IlmBase_Libraries ${ILMBASE_CUSTOM_LIBRARIES})
  separate_arguments(IlmBase_Libraries)
else()
# elseif(${ILMBASE_VERSION} VERSION_LESS "2.1")
  set(IlmBase_Libraries Half Iex Imath IlmThread)
# else()
  # string(REGEX REPLACE "([0-9]+)[.]([0-9]+).*" "\\1_\\2" _ilmbase_libs_ver ${ILMBASE_VERSION})
  # set(IlmBase_Libraries
  #   Half
  #   Iex-${_ilmbase_libs_ver}
  #   Imath-${_ilmbase_libs_ver}
  #   IlmThread-${_ilmbase_libs_ver}
  # )
endif()


# Locate the IlmBase libraries
set(IlmBase_libvars "")
set(IlmBase_cachevars "")
foreach(ilmbase_lib ${IlmBase_Libraries})
  PREFIX_FIND_LIB(IlmBase ${ilmbase_lib}
    IlmBase_library_paths IlmBase_libvars IlmBase_cachevars)
endforeach()
# Create the list of variables that might need to be cleared
set(ILMBASE_CACHED_VARS
  ILMBASE_INCLUDE_DIR ${IlmBase_cachevars}
  CACHE INTERNAL "Variables set by FindIlmBase.cmake" FORCE)

# Store the current state so that variables might be cleared if required
set(ILMBASE_CACHED_STATE ${ILMBASE_CURRENT_STATE}
  CACHE INTERNAL "State last seen by FindIlmBase.cmake" FORCE)

# Link with pthreads if required
if(NOT WIN32 AND EXISTS ${ILMBASE_INCLUDE_DIR}/OpenEXR/IlmBaseConfig.h)
  file(STRINGS ${ILMBASE_INCLUDE_DIR}/OpenEXR/IlmBaseConfig.h
    ILMBASE_HAVE_PTHREAD
    REGEX "^[ \\t]*#define[ \\t]+HAVE_PTHREAD[ \\t]1[ \\t]*\$"
  )
  if(ILMBASE_HAVE_PTHREAD)
    find_package(Threads)
    if(CMAKE_USE_PTHREADS_INIT)
      set(ILMBASE_PTHREADS ${CMAKE_THREAD_LIBS_INIT})
    endif()
  endif()
endif()

# Use the standard function to handle ILMBASE_FOUND
FIND_PACKAGE_HANDLE_STANDARD_ARGS(IlmBase DEFAULT_MSG
  ILMBASE_INCLUDE_DIR ${IlmBase_libvars})

if(ILMBASE_FOUND)
  set(ILMBASE_LIBRARIES "")
  foreach(tmplib ${IlmBase_libvars})
    list(APPEND ILMBASE_LIBRARIES ${${tmplib}})
  endforeach()
  list(APPEND ILMBASE_LIBRARIES ${ILMBASE_PTHREADS})
  if(NOT IlmBase_FIND_QUIETLY)
    FIND_PACKAGE_MESSAGE(ILMBASE
      "Found IlmBase: ${ILMBASE_LIBRARIES}"
      "[${ILMBASE_INCLUDE_DIR}][${ILMBASE_LIBRARIES}][${ILMBASE_CURRENT_STATE}]"
      )
  endif()
endif()

# Restore the original find library ordering
if(ILMBASE_USE_STATIC_LIBS )
  set(CMAKE_FIND_LIBRARY_SUFFIXES ${_ilmbase_ORIG_CMAKE_FIND_LIBRARY_SUFFIXES})
endif()

# Unset the helper variables to avoid pollution
unset(ILMBASE_CURRENT_STATE)
unset(IlmBase_include_paths)
unset(IlmBase_library_paths)
unset(IlmBase_generic_include_paths)
unset(IlmBase_generic_library_paths)
unset(IlmBase_libvars)
unset(IlmBase_cachevars)
unset(ILMBASE_PTHREADS)
