function(qt_internal_write_depends_file target)
    set(module Qt${target})
    set(outfile "${QT_BUILD_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()

macro(qt_collect_third_party_deps)
    # 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()
endmacro()

function(qt_internal_create_module_depends_file target)
    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 "")

    get_target_property(extra_depends "${target}" QT_EXTRA_PACKAGE_DEPENDENCIES)
    if(NOT extra_depends STREQUAL "${extra_depends}-NOTFOUND")
        list(APPEND target_deps ${extra_depends})
    endif()

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

    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()

    qt_collect_third_party_deps()

    # 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)
        set(path_suffix "${INSTALL_CMAKE_NAMESPACE}${target}")
        qt_path_join(config_build_dir ${QT_CONFIG_BUILD_DIR} ${path_suffix})
        qt_path_join(config_install_dir ${QT_CONFIG_INSTALL_DIR} ${path_suffix})

        # Configure and install ModuleDependencies file.
        configure_file(
            "${QT_CMAKE_DIR}/QtModuleDependencies.cmake.in"
            "${config_build_dir}/${INSTALL_CMAKE_NAMESPACE}${target}Dependencies.cmake"
            @ONLY
        )

        qt_install(FILES
            "${config_build_dir}/${INSTALL_CMAKE_NAMESPACE}${target}Dependencies.cmake"
            DESTINATION "${config_install_dir}"
            COMPONENT Devel
        )

    endif()
    if(tool_deps)
        set(path_suffix "${INSTALL_CMAKE_NAMESPACE}${target}Tools")
        qt_path_join(config_build_dir ${QT_CONFIG_BUILD_DIR} ${path_suffix})
        qt_path_join(config_install_dir ${QT_CONFIG_INSTALL_DIR} ${path_suffix})

        # Configure and install ModuleToolDependencies file.
        configure_file(
            "${QT_CMAKE_DIR}/QtModuleToolsDependencies.cmake.in"
            "${config_build_dir}/${INSTALL_CMAKE_NAMESPACE}${target}ToolsDependencies.cmake"
            @ONLY
        )

        qt_install(FILES
            "${config_build_dir}/${INSTALL_CMAKE_NAMESPACE}${target}ToolsDependencies.cmake"
            DESTINATION "${config_install_dir}"
            COMPONENT Devel
        )

    endif()
endfunction()

function(qt_internal_create_plugin_depends_file target)
    get_target_property(qt_module "${target}" QT_MODULE)
    get_target_property(depends "${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 "")

    qt_collect_third_party_deps()

    # 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(third_party_deps OR target_deps)
        # Setup build and install paths
        if(qt_module)
            set(path_suffix "${INSTALL_CMAKE_NAMESPACE}${qt_module}")
        else()
            set(path_suffix "${INSTALL_CMAKE_NAMESPACE}${target}")
        endif()

        qt_path_join(config_build_dir ${QT_CONFIG_BUILD_DIR} ${path_suffix})
        qt_path_join(config_install_dir ${QT_CONFIG_INSTALL_DIR} ${path_suffix})

        # Configure and install ModuleDependencies file.
        configure_file(
            "${QT_CMAKE_DIR}/QtPluginDependencies.cmake.in"
            "${config_build_dir}/${target}Dependencies.cmake"
            @ONLY
        )

        qt_install(FILES
            "${config_build_dir}/${target}Dependencies.cmake"
            DESTINATION "${config_install_dir}"
            COMPONENT Devel
        )
    endif()
endfunction()

# Create Depends.cmake & Depends.h files for all modules and plug-ins.
function(qt_internal_create_depends_files)
    message("Generating depends files for ${QT_KNOWN_MODULES}...")
    foreach (target ${QT_KNOWN_MODULES})
        qt_internal_create_module_depends_file(${target})
    endforeach()

    message("Generating depends files for ${QT_KNOWN_PLUGINS}...")
    foreach (target ${QT_KNOWN_PLUGINS})
        qt_internal_create_plugin_depends_file(${target})
    endforeach()
endfunction()

# This function creates the Qt<Module>Plugins.cmake used to list all
# the plug-in target files.
function(qt_internal_create_plugins_files)
    message("Generating Plugins files for ${QT_KNOWN_MODULES}...")
    foreach (QT_MODULE ${QT_KNOWN_MODULES})
        qt_path_join(config_build_dir ${QT_CONFIG_BUILD_DIR} ${INSTALL_CMAKE_NAMESPACE}${QT_MODULE})
        qt_path_join(config_install_dir ${QT_CONFIG_INSTALL_DIR} ${INSTALL_CMAKE_NAMESPACE}${QT_MODULE})
        set(QT_MODULE_PLUGIN_INCLUDES "")

        get_target_property(qt_plugins "${QT_MODULE}" QT_PLUGINS)
        if(qt_plugins)
            foreach (pluginTarget ${qt_plugins})
                set(QT_MODULE_PLUGIN_INCLUDES "${QT_MODULE_PLUGIN_INCLUDES}include(\"\${CMAKE_CURRENT_LIST_DIR}/${pluginTarget}Config.cmake\")\n")
            endforeach()
            configure_file(
                "${QT_CMAKE_DIR}/QtPlugins.cmake.in"
                "${config_build_dir}/${INSTALL_CMAKE_NAMESPACE}${QT_MODULE}Plugins.cmake"
                @ONLY
            )
            qt_install(FILES
                "${config_build_dir}/${INSTALL_CMAKE_NAMESPACE}${QT_MODULE}Plugins.cmake"
                DESTINATION "${config_install_dir}"
                COMPONENT Devel
            )
        endif()
    endforeach()
endfunction()

function(qt_generate_build_internals_extra_cmake_code)
    if(PROJECT_NAME STREQUAL "QtBase")

        set(QT_SOURCE_TREE "${QtBase_SOURCE_DIR}")
        qt_path_join(extra_file_path
                     ${QT_CONFIG_BUILD_DIR}
                     ${INSTALL_CMAKE_NAMESPACE}BuildInternals/QtBuildInternalsExtra.cmake)
        configure_file(
            "${CMAKE_CURRENT_LIST_DIR}/QtBuildInternalsExtra.cmake.in"
            "${extra_file_path}"
            @ONLY
        )
    endif()
endfunction()

# For every Qt module check if there any android dependencies that require
# processing.
function(qt_modules_process_android_dependencies)
    foreach (target ${QT_KNOWN_MODULES})
        qt_android_dependencies(${target})
    endforeach()
endfunction()

qt_internal_create_depends_files()
qt_generate_build_internals_extra_cmake_code()
qt_internal_create_plugins_files()

if (ANDROID)
    qt_modules_process_android_dependencies()
endif()