function(qt_internal_write_depends_file target)
    set(module Qt${target})
    set(outfile "${PROJECT_BINARY_DIR}/include/${module}/${module}Depends")
    message("Generate ${outfile}...")
    set(contents "/* This file was generated by cmake with the info from ${module} target. */\n")
    string(APPEND contents "#ifdef __cplusplus /* create empty PCH in C mode */\n")
    foreach (m ${ARGN})
        string(APPEND contents "#  include <Qt${m}/Qt${m}>\n")
    endforeach()
    string(APPEND contents "#endif\n")

    file(GENERATE OUTPUT "${outfile}" CONTENT "${contents}")
endfunction()

function(qt_internal_create_depends_files)
    message("Generating depends files for ${QT_KNOWN_MODULES}...")
    foreach (target ${QT_KNOWN_MODULES})
        get_target_property(depends "${target}" LINK_LIBRARIES)
        get_target_property(public_depends "${target}" INTERFACE_LINK_LIBRARIES)
        get_target_property(target_deps "${target}" _qt_target_deps)
        set(target_deps_seen "")

        set(qtdeps "")
        set(third_party_deps "")
        set(third_party_deps_seen "")
        set(tool_deps "")
        set(tool_deps_seen "")

        foreach (dep ${depends})
            # Normalize module by stripping leading "Qt::" and trailing "Private"
            if (dep MATCHES "Qt::(.*)")
                set(dep "${CMAKE_MATCH_1}")
            endif()
            if (dep MATCHES "(.*)Private")
                set(dep "${CMAKE_MATCH_1}")
            endif()

            list(FIND QT_KNOWN_MODULES "${dep}" _pos)
            if (_pos GREATER -1)
                list(APPEND qtdeps "${dep}")

                # Make the ModuleTool package depend on dep's ModuleTool package.
                list(FIND tool_deps_seen ${dep} dep_seen)
                if(dep_seen EQUAL -1 AND ${dep} IN_LIST QT_KNOWN_MODULES_WITH_TOOLS)
                    list(APPEND tool_deps_seen ${dep})
                    list(APPEND tool_deps
                                "${INSTALL_CMAKE_NAMESPACE}${dep}Tools\;${PROJECT_VERSION}")
                endif()
            endif()
        endforeach()

        # If we are doing a non-static Qt build, we only want to propagate public dependencies.
        # If we are doing a static Qt build, we need to propagate all dependencies.
        set(depends_var "public_depends")
        if(NOT QT_BUILD_SHARED_LIBS)
            set(depends_var "depends")
        endif()

        foreach(dep ${${depends_var}})
            # Gather third party packages that should be found when using the Qt module.
            # Also handle nolink target dependencies.
            string(REGEX REPLACE "_nolink$" "" base_dep "${dep}")
            if(NOT base_dep STREQUAL dep)
                # Resets target name like Vulkan_nolink to Vulkan, because we need to call
                # find_package(Vulkan).
                set(dep ${base_dep})
            endif()

            if(TARGET ${dep})
                list(FIND third_party_deps_seen ${dep} dep_seen)

                get_target_property(package_name ${dep} INTERFACE_QT_PACKAGE_NAME)
                if(dep_seen EQUAL -1 AND package_name)
                    list(APPEND third_party_deps_seen ${dep})
                    get_target_property(package_version ${dep} INTERFACE_QT_PACKAGE_VERSION)
                    if(NOT package_version)
                        set(package_version "")
                    endif()

                    get_target_property(package_components ${dep} INTERFACE_QT_PACKAGE_COMPONENTS)
                    if(NOT package_components)
                        set(package_components "")
                    endif()

                    list(APPEND third_party_deps
                                "${package_name}\;${package_version}\;${package_components}")
                endif()
            endif()
        endforeach()

        # Add dependency to the main ModuleTool package to ModuleDependencies file.
        if(${target} IN_LIST QT_KNOWN_MODULES_WITH_TOOLS)
            set(main_module_tool_deps
                "${INSTALL_CMAKE_NAMESPACE}${target}Tools\;${PROJECT_VERSION}")
        endif()

        # Dirty hack because https://gitlab.kitware.com/cmake/cmake/issues/19200
        foreach(dep ${target_deps})
            if(dep)
                list(FIND target_deps_seen "${dep}" dep_seen)
                if(dep_seen EQUAL -1)
                    list(LENGTH dep len)
                    if(NOT (len EQUAL 2))
                        message(FATAL_ERROR "List '${dep}' should look like QtFoo;version")
                    endif()
                    list(GET dep 0 dep_name)
                    list(GET dep 1 dep_ver)

                    list(APPEND target_deps_seen "${dep_name}\;${dep_ver}")
                endif()
            endif()
        endforeach()
        set(target_deps "${target_deps_seen}")

        if (DEFINED qtdeps)
            list(REMOVE_DUPLICATES qtdeps)
        endif()

        get_target_property(hasModuleHeaders "${target}" MODULE_HAS_HEADERS)
        if (${hasModuleHeaders})
            qt_internal_write_depends_file("${target}" ${qtdeps})
        endif()


        if(third_party_deps OR main_module_tool_deps OR target_deps)
            # Configure and install ModuleDependencies file.
            configure_file(
                "${QT_CMAKE_DIR}/QtModuleDependencies.cmake.in"
                "${CMAKE_CURRENT_BINARY_DIR}/${INSTALL_CMAKE_NAMESPACE}${target}Dependencies.cmake"
                @ONLY
            )

            set(config_install_dir "${INSTALL_LIBDIR}/cmake/${INSTALL_CMAKE_NAMESPACE}${target}")

            install(FILES
                "${CMAKE_CURRENT_BINARY_DIR}/${INSTALL_CMAKE_NAMESPACE}${target}Dependencies.cmake"
                DESTINATION "${config_install_dir}"
                COMPONENT Devel
            )
        endif()
        if(tool_deps)
            # Configure and install ModuleToolDependencies file.
            configure_file(
                "${QT_CMAKE_DIR}/QtModuleToolsDependencies.cmake.in"
                "${CMAKE_CURRENT_BINARY_DIR}/${INSTALL_CMAKE_NAMESPACE}${target}ToolsDependencies.cmake"
                @ONLY
            )

            set(config_install_dir
                "${INSTALL_LIBDIR}/cmake/${INSTALL_CMAKE_NAMESPACE}${target}Tools")

            install(FILES
                "${CMAKE_CURRENT_BINARY_DIR}/${INSTALL_CMAKE_NAMESPACE}${target}ToolsDependencies.cmake"
                DESTINATION "${config_install_dir}"
                COMPONENT Devel
            )
        endif()
    endforeach()


endfunction()

qt_internal_create_depends_files()