#-----------------------------------------------------------------------------
# Private helper macros.

# _vtk_module_config_recurse(<namespace> <module>)
#
# Internal macro to recursively load module information into the supplied
# namespace, this is called from vtk_module_config. It should be noted that
# _${ns}_${mod}_USED must be cleared if this macro is to work correctly on
# subsequent invocations. The macro will load the module files using the
# vtk_module_load, making all of its variables available in the local scope.
macro(_vtk_module_config_recurse ns mod)
  if(NOT _${ns}_${mod}_USED)
    set(_${ns}_${mod}_USED 1)
    list(APPEND _${ns}_USED_MODULES ${mod})
    vtk_module_load("${mod}")
    list(APPEND ${ns}_LIBRARIES ${${mod}_LIBRARIES})
    list(APPEND ${ns}_INCLUDE_DIRS ${${mod}_INCLUDE_DIRS})
    list(APPEND ${ns}_LIBRARY_DIRS ${${mod}_LIBRARY_DIRS})
    list(APPEND ${ns}_RUNTIME_LIBRARY_DIRS ${${mod}_RUNTIME_LIBRARY_DIRS})
    foreach(iface IN LISTS ${mod}_IMPLEMENTS)
      list(APPEND _${ns}_AUTOINIT_${iface} ${mod})
      list(APPEND _${ns}_AUTOINIT ${iface})
    endforeach()
    foreach(dep IN LISTS ${mod}_DEPENDS)
      _vtk_module_config_recurse("${ns}" "${dep}")
    endforeach()
  endif()
endmacro()

#-----------------------------------------------------------------------------
# Public interface macros.

# vtk_module_load(<module>)
#
# Loads variables describing the given module, these include custom variables
# set by the module along with the standard ones listed below:
#  <module>_LOADED         = True if the module has been loaded
#  <module>_DEPENDS        = List of dependencies on other modules
#  <module>_LIBRARIES      = Libraries to link
#  <module>_INCLUDE_DIRS   = Header search path
#  <module>_LIBRARY_DIRS   = Library search path (for outside dependencies)
#  <module>_RUNTIME_LIBRARY_DIRS = Runtime linker search path
macro(vtk_module_load mod)
  if(NOT ${mod}_LOADED)
    include("${VTK_MODULES_DIR}/${mod}.cmake" OPTIONAL RESULT_VARIABLE _found)
    if(NOT _found)
      # When building applications outside VTK, they can provide extra module
      # config files by simply adding the corresponding locations to the
      # CMAKE_MODULE_PATH
      include(${mod} OPTIONAL)
    endif()
    if(NOT ${mod}_LOADED)
      message(FATAL_ERROR "No such module: \"${mod}\"")
    endif()
    # Include the targets file if it has been defined. Targets files other
    # than VTKTargets.cmake are created when modules are built externally. Do not
    # include the targets file inside the module itself -- which occurs in a module's
    # test configuration.
    if(EXISTS "${${mod}_TARGETS_FILE}" AND NOT vtk-module STREQUAL mod)
      include("${${mod}_TARGETS_FILE}")
    endif()
  endif()
endmacro()

# vtk_module_dep_includes(<module>)
#
# Loads the <module>_DEPENDS_INCLUDE_DIRS variable.
macro(vtk_module_dep_includes mod)
  vtk_module_load("${mod}")
  vtk_module_config(_dep_${mod} ${${mod}_DEPENDS})
  if(_dep_${mod}_INCLUDE_DIRS)
    set(${mod}_DEPENDS_INCLUDE_DIRS ${_dep_${mod}_INCLUDE_DIRS})
  endif()
endmacro()

# vtk_module_headers_load(<module>)
#
# Loads variables describing the headers/API of the given module, this is not
# loaded by vtk_module_config, and is mainly useful for wrapping generation:
#  <module>_HEADERS_LOADED      = True if the module header info has been loaded
#  <module>_HEADERS             = List of headers
#  <module>_HEADER_<header>_EXISTS
#  <module>_HEADER_<header>_ABSTRACT
#  <module>_HEADER_<header>_WRAP_EXCLUDE
#  <module>_HEADER_<header>_WRAP_EXCLUDE_PYTHON
macro(vtk_module_headers_load mod)
  if(NOT ${mod}_HEADERS_LOADED)
    include("${VTK_MODULES_DIR}/${mod}-Headers.cmake"
      OPTIONAL RESULT_VARIABLE _found)
    if(NOT _found)
      # When building applications outside VTK, they can provide extra module
      # config files by simply adding the corresponding locations to the
      # CMAKE_MODULE_PATH
      include(${mod}-Headers OPTIONAL)
    endif()
    if(NOT ${mod}_HEADERS_LOADED)
      message(FATAL_ERROR "No such module: \"${mod}\"")
    endif()
  endif()
endmacro()

# vtk_module_config(<namespace> [modules...])
#
# Configures variables describing the given modules and their dependencies:
#  <namespace>_DEFINITIONS  = Preprocessor definitions
#  <namespace>_LIBRARIES    = Libraries to link
#  <namespace>_INCLUDE_DIRS = Header search path
#  <namespace>_LIBRARY_DIRS = Library search path (for outside dependencies)
#  <namespace>_RUNTIME_LIBRARY_DIRS = Runtime linker search path
#
# Calling this macro also recursively calls vtk_module_load for all modules
# explicitly named, and their dependencies, making them available in the local
# scope. This means that module level information can be accessed once this
# macro has been called.
#
# Do not name a module as the namespace.
macro(vtk_module_config ns)

  # Sanity check
  if(NOT DEFINED VTK_MODULES_DIR)
    message(FATAL_ERROR "VTK_MODULES_DIR is not defined !")
  endif()

  # Determine list of available VTK-modules by scanning the VTK_MODULES_DIR.
  set(VTK_MODULES_AVAILABLE)
  file(GLOB config_files RELATIVE "${VTK_MODULES_DIR}" "${VTK_MODULES_DIR}/*.cmake")
  foreach (_file ${config_files})
    if (NOT "${_file}" MATCHES "[^\\-]+-[a-zA-Z]+\\.cmake")
      string(REGEX REPLACE "\\.cmake$" "" _${ns}_module "${_file}")
      list(APPEND VTK_MODULES_AVAILABLE "${_${ns}_module}")
    endif()
  endforeach()

  set(_${ns}_MISSING ${ARGN})
  if(_${ns}_MISSING)
    list(REMOVE_ITEM _${ns}_MISSING ${VTK_MODULES_AVAILABLE})
  endif()
  if(_${ns}_MISSING)
    set(msg "")
    foreach(mod ${_${ns}_MISSING})
      set(msg "${msg}\n  ${mod}")
    endforeach()
    message(FATAL_ERROR "Requested modules not available:${msg}")
  endif()

  set(${ns}_DEFINITIONS "")
  set(${ns}_LIBRARIES "")
  set(${ns}_INCLUDE_DIRS "")
  set(${ns}_LIBRARY_DIRS "")
  set(${ns}_RUNTIME_LIBRARY_DIRS "")
  set(_${ns}_AUTOINIT "")

  set(_${ns}_USED_MODULES "")
  foreach(mod ${ARGN})
    _vtk_module_config_recurse("${ns}" "${mod}")
  endforeach()
  foreach(mod ${_${ns}_USED_MODULES})
    unset(_${ns}_${mod}_USED)
  endforeach()
  unset(_${ns}_USED_MODULES)

  foreach(v ${ns}_LIBRARIES ${ns}_INCLUDE_DIRS ${ns}_LIBRARY_DIRS
            ${ns}_RUNTIME_LIBRARY_DIRS _${ns}_AUTOINIT)
    if(${v})
      list(REMOVE_DUPLICATES ${v})
    endif()
  endforeach()

  list(SORT _${ns}_AUTOINIT) # Deterministic order.
  foreach(mod ${_${ns}_AUTOINIT})
    list(SORT _${ns}_AUTOINIT_${mod}) # Deterministic order.
    list(REMOVE_DUPLICATES _${ns}_AUTOINIT_${mod})
    list(LENGTH _${ns}_AUTOINIT_${mod} _ai_len)
    string(REPLACE ";" "," _ai "${_ai_len}(${_${ns}_AUTOINIT_${mod}})")
    if(${_ai_len} GREATER 1 AND "${CMAKE_GENERATOR}" MATCHES "Visual Studio")
      # VS IDE project files cannot handle a comma (,) in a
      # preprocessor definition value outside a quoted string.
      # Generate a header file to do the definition and define
      # ${mod}_INCLUDE to tell ${mod}Module.h to include it.
      # Name the file after its content to guarantee uniqueness.
      string(REPLACE ";" "_" _inc
        "${CMAKE_BINARY_DIR}/CMakeFiles/${mod}_AUTOINIT_${_${ns}_AUTOINIT_${mod}}.h")
      set(CMAKE_CONFIGURABLE_FILE_CONTENT "#define ${mod}_AUTOINIT ${_ai}")
      configure_file(${CMAKE_ROOT}/Modules/CMakeConfigurableFile.in ${_inc})
      list(APPEND ${ns}_DEFINITIONS "${mod}_INCLUDE=\"${_inc}\"")
    else()
      # Directly define ${mod}_AUTOINIT.
      list(APPEND ${ns}_DEFINITIONS "${mod}_AUTOINIT=${_ai}")
    endif()
    unset(_${ns}_AUTOINIT_${mod})
  endforeach()
  unset(_${ns}_AUTOINIT)
endmacro()

# vtk_add_to_module_search_path(<source> <build>)
#
# Call to add a single module to the module search path.
macro(vtk_add_to_module_search_path src bld)
  list(APPEND vtk_module_search_path "${src},${bld}")
endmacro()