#.rst:
# ECMFindModuleHelpers
# --------------------
#
# Helper macros for find modules: ecm_find_package_version_check(),
# ecm_find_package_parse_components() and
# ecm_find_package_handle_library_components().
#
# ::
#
#   ecm_find_package_version_check(<name>)
#
# Prints warnings if the CMake version or the project's required CMake version
# is older than that required by extra-cmake-modules.
#
# ::
#
#   ecm_find_package_parse_components(<name>
#       RESULT_VAR <variable>
#       KNOWN_COMPONENTS <component1> [<component2> [...]]
#       [SKIP_DEPENDENCY_HANDLING])
#
# This macro will populate <variable> with a list of components found in
# <name>_FIND_COMPONENTS, after checking that all those components are in the
# list of KNOWN_COMPONENTS; if there are any unknown components, it will print
# an error or warning (depending on the value of <name>_FIND_REQUIRED) and call
# return().
#
# The order of components in <variable> is guaranteed to match the order they
# are listed in the KNOWN_COMPONENTS argument.
#
# If SKIP_DEPENDENCY_HANDLING is not set, for each component the variable
# <name>_<component>_component_deps will be checked for dependent components.
# If <component> is listed in <name>_FIND_COMPONENTS, then all its (transitive)
# dependencies will also be added to <variable>.
#
# ::
#
#   ecm_find_package_handle_library_components(<name>
#       COMPONENTS <component> [<component> [...]]
#       [SKIP_DEPENDENCY_HANDLING])
#       [SKIP_PKG_CONFIG])
#
# Creates an imported library target for each component.  The operation of this
# macro depends on the presence of a number of CMake variables.
#
# The <name>_<component>_lib variable should contain the name of this library,
# and <name>_<component>_header variable should contain the name of a header
# file associated with it (whatever relative path is normally passed to
# '#include').  ecm_find_package_components() will then search for the library
# and include directory (creating appropriate cache variables) and create an
# imported library target named <name>::<component>.
#
# Additional variables can be used to provide additional information:
#
# If SKIP_PKG_CONFIG, the <name>_<component>_pkg_config variable is set, and
# pkg-config is found, the pkg-config module given by
# <name>_<component>_pkg_config will be searched for and used to help locate the
# library and header file.  It will also be used to set
# <name>_<component>_VERSION.
#
# Note that if version information is found via pkg-config,
# <name>_<component>_FIND_VERSION can be set to require a particular version
# for each component.
#
# If SKIP_DEPENDENCY_HANDLING is not set, the INTERFACE_LINK_LIBRARIES property
# of the imported target for <component> will be set to contain the imported
# targets for the components listed in <name>_<component>_component_deps.
# <component>_FOUND will also be set to false if any of the compoments in
# <name>_<component>_component_deps are not found.  This requires the components
# in <name>_<component>_component_deps to be listed before <component> in the
# COMPONENTS argument.
#
# The following variables will be set:
#
# ``<name>_TARGETS``
#   the imported targets
# ``<name>_LIBRARIES``
#   the found libraries
# ``<name>_INCLUDE_DIRS``
#   the combined required include directories for the components
# ``<name>_DEFINITIONS``
#   the "other" CFLAGS provided by pkg-config, if any
# ``<name>_VERSION``
#   the value of ``<name>_<component>_VERSION`` for the first component that
#   has this variable set (note that components are searched for in the order
#   they are passed to the macro), although if it is already set, it will not
#   be altered
#
# Note that these variables are never cleared, so if
# ecm_find_package_handle_library_components() is called multiple times with
# different components (typically because of multiple find_package() calls) then
# ``<name>_TARGETS``, for example, will contain all the targets found in any
# call (although no duplicates).
#
# Since pre-1.0.0.

#=============================================================================
# Copyright 2014 Alex Merry <alex.merry@kde.org>
#
# Distributed under the OSI-approved BSD License (the "License");
# see accompanying file COPYING-CMAKE-SCRIPTS for details.
#
# This software is distributed WITHOUT ANY WARRANTY; without even the
# implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
# See the License for more information.
#=============================================================================
# (To distribute this file outside of extra-cmake-modules, substitute the full
#  License text for the above reference.)

include(CMakeParseArguments)

macro(ecm_find_package_version_check module_name)
    if(CMAKE_VERSION VERSION_LESS 2.8.12)
        message(FATAL_ERROR "CMake 2.8.12 is required by Find${module_name}.cmake")
    endif()
    if(CMAKE_MINIMUM_REQUIRED_VERSION VERSION_LESS 2.8.12)
        message(AUTHOR_WARNING "Your project should require at least CMake 2.8.12 to use Find${module_name}.cmake")
    endif()
endmacro()

macro(ecm_find_package_parse_components module_name)
    set(ecm_fppc_options SKIP_DEPENDENCY_HANDLING)
    set(ecm_fppc_oneValueArgs RESULT_VAR)
    set(ecm_fppc_multiValueArgs KNOWN_COMPONENTS)
    cmake_parse_arguments(ECM_FPPC "${ecm_fppc_options}" "${ecm_fppc_oneValueArgs}" "${ecm_fppc_multiValueArgs}" ${ARGN})

    if(ECM_FPPC_UNPARSED_ARGUMENTS)
        message(FATAL_ERROR "Unexpected arguments to ecm_find_package_parse_components: ${ECM_FPPC_UNPARSED_ARGUMENTS}")
    endif()
    if(NOT ECM_FPPC_RESULT_VAR)
        message(FATAL_ERROR "Missing RESULT_VAR argument to ecm_find_package_parse_components")
    endif()
    if(NOT ECM_FPPC_KNOWN_COMPONENTS)
        message(FATAL_ERROR "Missing KNOWN_COMPONENTS argument to ecm_find_package_parse_components")
    endif()

    if(${module_name}_FIND_COMPONENTS)
        set(ecm_fppc_requestedComps ${${module_name}_FIND_COMPONENTS})

        if(NOT ECM_FPPC_SKIP_DEPENDENCY_HANDLING)
            # Make sure deps are included
            foreach(ecm_fppc_comp ${ecm_fppc_requestedComps})
                foreach(ecm_fppc_dep_comp ${${module_name}_${ecm_fppc_comp}_component_deps})
                    list(FIND ecm_fppc_requestedComps "${ecm_fppc_dep_comp}" ecm_fppc_index)
                    if("${ecm_fppc_index}" STREQUAL "-1")
                        if(NOT ${module_name}_FIND_QUIETLY)
                            message(STATUS "${module_name}: ${ecm_fppc_comp} requires ${${module_name}_${ecm_fppc_comp}_component_deps}")
                        endif()
                        list(APPEND ecm_fppc_requestedComps "${ecm_fppc_dep_comp}")
                    endif()
                endforeach()
            endforeach()
        else()
            message(STATUS "Skipping dependency handling for ${module_name}")
        endif()
        list(REMOVE_DUPLICATES ecm_fppc_requestedComps)

        # This makes sure components are listed in the same order as
        # KNOWN_COMPONENTS (potentially important for inter-dependencies)
        set(${ECM_FPPC_RESULT_VAR})
        foreach(ecm_fppc_comp ${ECM_FPPC_KNOWN_COMPONENTS})
            list(FIND ecm_fppc_requestedComps "${ecm_fppc_comp}" ecm_fppc_index)
            if(NOT "${ecm_fppc_index}" STREQUAL "-1")
                list(APPEND ${ECM_FPPC_RESULT_VAR} "${ecm_fppc_comp}")
                list(REMOVE_AT ecm_fppc_requestedComps ${ecm_fppc_index})
            endif()
        endforeach()
        # if there are any left, they are unknown components
        if(ecm_fppc_requestedComps)
            set(ecm_fppc_msgType STATUS)
            if(${module_name}_FIND_REQUIRED)
                set(ecm_fppc_msgType FATAL_ERROR)
            endif()
            if(NOT ${module_name}_FIND_QUIETLY)
                message(${ecm_fppc_msgType} "${module_name}: requested unknown components ${ecm_fppc_requestedComps}")
            endif()
            return()
        endif()
    else()
        set(${ECM_FPPC_RESULT_VAR} ${ECM_FPPC_KNOWN_COMPONENTS})
    endif()
endmacro()

macro(ecm_find_package_handle_library_components module_name)
    set(ecm_fpwc_options SKIP_PKG_CONFIG SKIP_DEPENDENCY_HANDLING)
    set(ecm_fpwc_oneValueArgs)
    set(ecm_fpwc_multiValueArgs COMPONENTS)
    cmake_parse_arguments(ECM_FPWC "${ecm_fpwc_options}" "${ecm_fpwc_oneValueArgs}" "${ecm_fpwc_multiValueArgs}" ${ARGN})

    if(ECM_FPWC_UNPARSED_ARGUMENTS)
        message(FATAL_ERROR "Unexpected arguments to ecm_find_package_handle_components: ${ECM_FPWC_UNPARSED_ARGUMENTS}")
    endif()
    if(NOT ECM_FPWC_COMPONENTS)
        message(FATAL_ERROR "Missing COMPONENTS argument to ecm_find_package_handle_components")
    endif()

    include(FindPackageHandleStandardArgs)
    find_package(PkgConfig)
    foreach(ecm_fpwc_comp ${ECM_FPWC_COMPONENTS})
        set(ecm_fpwc_dep_vars)
        set(ecm_fpwc_dep_targets)
        if(NOT SKIP_DEPENDENCY_HANDLING)
            foreach(ecm_fpwc_dep ${${module_name}_${ecm_fpwc_comp}_component_deps})
                list(APPEND ecm_fpwc_dep_vars "${module_name}_${ecm_fpwc_dep}_FOUND")
                list(APPEND ecm_fpwc_dep_targets "${module_name}::${ecm_fpwc_dep}")
            endforeach()
        endif()

        if(NOT ECM_FPWC_SKIP_PKG_CONFIG AND ${module_name}_${ecm_fpwc_comp}_pkg_config)
            pkg_check_modules(PKG_${module_name}_${ecm_fpwc_comp} QUIET
                              ${${module_name}_${ecm_fpwc_comp}_pkg_config})
        endif()

        find_path(${module_name}_${ecm_fpwc_comp}_INCLUDE_DIR
            NAMES ${${module_name}_${ecm_fpwc_comp}_header}
            HINTS ${PKG_${module_name}_${ecm_fpwc_comp}_INCLUDE_DIRS}
        )
        find_library(${module_name}_${ecm_fpwc_comp}_LIBRARY
            NAMES ${${module_name}_${ecm_fpwc_comp}_lib}
            HINTS ${PKG_${module_name}_${ecm_fpwc_comp}_LIBRARY_DIRS}
        )

        set(${module_name}_${ecm_fpwc_comp}_VERSION "${PKG_${module_name}_${ecm_fpwc_comp}_VERSION}")
        if(NOT ${module_name}_VERSION)
            set(${module_name}_VERSION ${${module_name}_${ecm_fpwc_comp}_VERSION})
        endif()

        find_package_handle_standard_args(${module_name}_${ecm_fpwc_comp}
            FOUND_VAR
                ${module_name}_${ecm_fpwc_comp}_FOUND
            REQUIRED_VARS
                ${module_name}_${ecm_fpwc_comp}_LIBRARY
                ${module_name}_${ecm_fpwc_comp}_INCLUDE_DIR
                ${ecm_fpwc_dep_vars}
            VERSION_VAR
                ${module_name}_${ecm_fpwc_comp}_VERSION
            )

        mark_as_advanced(
            ${module_name}_${ecm_fpwc_comp}_LIBRARY
            ${module_name}_${ecm_fpwc_comp}_INCLUDE_DIR
        )

        if(${module_name}_${ecm_fpwc_comp}_FOUND)
            list(APPEND ${module_name}_LIBRARIES
                        "${${module_name}_${ecm_fpwc_comp}_LIBRARY}")
            list(APPEND ${module_name}_INCLUDE_DIRS
                        "${${module_name}_${ecm_fpwc_comp}_INCLUDE_DIR}")
            set(${module_name}_DEFINITIONS
                    ${${module_name}_DEFINITIONS}
                    ${PKG_${module_name}_${ecm_fpwc_comp}_DEFINITIONS})
            if(NOT TARGET ${module_name}::${ecm_fpwc_comp})
                add_library(${module_name}::${ecm_fpwc_comp} UNKNOWN IMPORTED)
                set_target_properties(${module_name}::${ecm_fpwc_comp} PROPERTIES
                    IMPORTED_LOCATION "${${module_name}_${ecm_fpwc_comp}_LIBRARY}"
                    INTERFACE_COMPILE_OPTIONS "${PKG_${module_name}_${ecm_fpwc_comp}_DEFINITIONS}"
                    INTERFACE_INCLUDE_DIRECTORIES "${${module_name}_${ecm_fpwc_comp}_INCLUDE_DIR}"
                    INTERFACE_LINK_LIBRARIES "${ecm_fpwc_dep_targets}"
                )
            endif()
            list(APPEND ${module_name}_TARGETS
                        "${module_name}::${ecm_fpwc_comp}")
        endif()
    endforeach()
    if(${module_name}_LIBRARIES)
        list(REMOVE_DUPLICATES ${module_name}_LIBRARIES)
    endif()
    if(${module_name}_INCLUDE_DIRS)
        list(REMOVE_DUPLICATES ${module_name}_INCLUDE_DIRS)
    endif()
    if(${module_name}_DEFINITIONS)
        list(REMOVE_DUPLICATES ${module_name}_DEFINITIONS)
    endif()
    if(${module_name}_TARGETS)
        list(REMOVE_DUPLICATES ${module_name}_TARGETS)
    endif()
endmacro()

