5 files changed, 104 insertions, 3 deletions
diff --git a/src/global/configure.cmake b/src/global/configure.cmake
index b92de62..c8500f9 100644
--- a/src/global/configure.cmake
+++ b/src/global/configure.cmake
@@ -13,6 +13,7 @@ set(java_compiler_value "<not found>")
 set(golang_value "<not found>")
 set(maven_value "<not found>")
 set(openapi_generator_value "<not found>")
+set(doxygen_value "<not found>")
 set(build_all_tests_value "no")
 set(zlib_value "no")
 
@@ -23,6 +24,7 @@ set(golang_found FALSE)
 set(maven_found FALSE)
 set(openapi_generator_found FALSE)
 set(zlib_found FALSE)
+set(doxygen_found FALSE)
 
 # Look for zlib, which is a required dependency for the soon-to-be generated OpenAPI Common
 # library.
@@ -70,6 +72,13 @@ if(NOT QT_CONFIGURE_RUNNING)
         set(golang_found TRUE)
     endif()
 
+    # Look for doxygen, used to create documentation for the generated code
+    find_package(Doxygen)
+    if (DOXYGEN_EXECUTABLE)
+        set(doxygen_value "${DOXYGEN_EXECUTABLE}")
+        set(doxygen_found TRUE)
+    endif()
+
     # We need to find the upstream OpenAPI generator in order to build the OpenApiCommon
     # library and to be able to generate any client library
     qt_find_package(WrapOpenAPIGenerator PROVIDED_TARGETS WrapOpenAPIGenerator::WrapOpenAPIGenerator)
@@ -139,6 +148,7 @@ qt_configure_add_summary_section(NAME "Qt OpenAPI")
 qt_configure_add_summary_entry(ARGS "openapi_generator")
 qt_configure_add_summary_entry(ARGS "All test dependencies found" TYPE "message"
     MESSAGE "${build_all_tests_value}")
+qt_configure_add_summary_entry(ARGS "doxygen" TYPE "message" MESSAGE "${doxygen_value}")
 qt_configure_end_summary_section()
 
 qt_configure_add_report_entry(
@@ -194,3 +204,14 @@ if(NOT zlib_found)
         MESSAGE "${zlib_check_msg}"
     )
 endif()
+
+if(NOT doxygen_found)
+    string(CONCAT doxygen_msg
+        "The doxygen was not found. The GEN_DOXYGEN_DOCS option of the qt6_add_openapi_client "
+        "function will be ignored. It means no doxygen documentation will be generated."
+    )
+    qt_configure_add_report_entry(
+        TYPE WARNING
+        MESSAGE "${doxygen_msg}"
+    )
+endif()
diff --git a/src/openapi/Qt6OpenApiConfigureDoxygenScript.cmake b/src/openapi/Qt6OpenApiConfigureDoxygenScript.cmake
new file mode 100644
index 0000000..1241d60
--- /dev/null
+++ b/src/openapi/Qt6OpenApiConfigureDoxygenScript.cmake
@@ -0,0 +1,34 @@
+# Copyright (C) 2025 The Qt Company Ltd.
+# SPDX-License-Identifier: BSD-3-Clause
+
+cmake_minimum_required(VERSION 3.21)
+
+if(NOT DOXYGEN_IN_FILE_PATH)
+    message(FATAL_ERROR "Doxyfile input file is not set")
+endif()
+
+if(NOT DOXYGEN_OUT_FILE_PATH)
+    message(FATAL_ERROR "Doxyfile output file is not set")
+endif()
+
+if(NOT INPUT_DIR)
+    message(FATAL_ERROR "INPUT_DIR is not set")
+endif()
+
+if(NOT OUTPUT_DIR)
+    message(FATAL_ERROR "OUTPUT_DIR is not set")
+endif()
+
+if(NOT EXCLUDE_FILE)
+    message(FATAL_ERROR "EXCLUDE_FILE is not set")
+endif()
+
+set(DOXY_OUT_DIR "${OUTPUT_DIR}")
+set(DOXY_IN_DIR "${INPUT_DIR}")
+set(DOXY_EXCLUDE_FILE "${EXCLUDE_FILE}")
+
+configure_file(
+    "${DOXYGEN_IN_FILE_PATH}"
+    "${DOXYGEN_OUT_FILE_PATH}"
+    @ONLY
+)
diff --git a/src/openapi/Qt6OpenApiToolsGeneratorMacros.cmake b/src/openapi/Qt6OpenApiToolsGeneratorMacros.cmake
index 9e2d413..48a5227 100644
--- a/src/openapi/Qt6OpenApiToolsGeneratorMacros.cmake
+++ b/src/openapi/Qt6OpenApiToolsGeneratorMacros.cmake
@@ -32,6 +32,7 @@ endfunction()
 
 function(qt6_add_openapi_client target)
     set(options
+        GENERATE_DOCUMENTATION
         __QT_INTERNAL_GENERATE_COMMON_LIBRARY_TARGET
     )
     set(oneValueArgs
@@ -39,6 +40,7 @@ function(qt6_add_openapi_client target)
         CPP_NAMESPACE
         CLIENT_PREFIX
         OUTPUT_DIRECTORY
+        DOCUMENTATION_OUTPUT_DIRECTORY
         OUTPUT_PUBLIC_HEADERS_DIR
         OUTPUT_PRIVATE_HEADERS_DIR
     )
@@ -87,6 +89,9 @@ function(qt6_add_openapi_client target)
     endif()
 
     file(MAKE_DIRECTORY "${arg_OUTPUT_DIRECTORY}")
+    if(NOT arg_DOCUMENTATION_OUTPUT_DIRECTORY)
+        set(arg_DOCUMENTATION_OUTPUT_DIRECTORY "${arg_OUTPUT_DIRECTORY}")
+    endif()
     set(openapi_cli_entrypoint_class "org.openapitools.codegen.OpenAPIGenerator")
     set(generator_name ${QT_OPENAPI_GENERATOR_NAME})
     get_filename_component(openapi_generator_cli_dir
@@ -175,6 +180,7 @@ function(qt6_add_openapi_client target)
         list(APPEND client_sources
             "${client_dir_path}${target_lower_case}combinedmodelsandapis.cpp")
         list(APPEND client_sources "${client_dir_path}${target_lower_case}exports.h")
+        list(APPEND client_sources "${client_dir_path}doc/Doxyfile.in")
         list(APPEND generating_sources ${client_sources})
     endif()
 
@@ -287,6 +293,43 @@ function(qt6_add_openapi_client target)
         target_sources(${target} PRIVATE ${client_sources})
     endif()
 
+    # Generate Doxygen documentation for the Client.
+    if(arg_GENERATE_DOCUMENTATION)
+        # If Doxygen is not installed, then just skipping.
+        if(TARGET Doxygen::doxygen)
+            file(MAKE_DIRECTORY "${arg_DOCUMENTATION_OUTPUT_DIRECTORY}")
+            set(configure_doxygen_script
+            "${__qt_openapi_macros_module_base_dir}/Qt6OpenApiConfigureDoxygenScript.cmake")
+            set(MAIN_GEN_DOC_FILE
+                "${arg_DOCUMENTATION_OUTPUT_DIRECTORY}/doc/html/index.html")
+            set(DOXYGEN_FILE "${client_dir_path}doc/Doxyfile")
+            add_custom_command(
+                OUTPUT "${MAIN_GEN_DOC_FILE}"
+                COMMAND "${CMAKE_COMMAND}"
+                    "-DDOXYGEN_IN_FILE_PATH=${DOXYGEN_FILE}.in"
+                    "-DDOXYGEN_OUT_FILE_PATH=${DOXYGEN_FILE}"
+                    "-DEXCLUDE_FILE=${client_dir_path}${target_lower_case}combinedmodelsandapis.cpp"
+                    "-DINPUT_DIR=${client_dir_path}"
+                    "-DOUTPUT_DIR=${arg_DOCUMENTATION_OUTPUT_DIRECTORY}/doc"
+                    -P "${configure_doxygen_script}"
+                COMMAND $<TARGET_FILE:Doxygen::doxygen> "${DOXYGEN_FILE}"
+                ${extra_dependencies}
+                ${generating_sources}
+                COMMENT "Generating doxygen documentation for target '${target}'"
+                VERBATIM
+                COMMAND_EXPAND_LISTS
+            )
+            add_custom_target(${target}_openapi_docs ALL
+                DEPENDS "${MAIN_GEN_DOC_FILE}"
+            )
+        else()
+            message(WARNING "Could not find doxygen to generate documentation. "
+                    "Either install it or make sure it's added to PATH and then call "
+                    "find_package(Doxygen) in your project."
+                    "Skipping documentation generation.")
+        endif()
+    endif()
+
     if(arg_OUTPUT_PUBLIC_HEADERS_DIR OR arg_OUTPUT_PRIVATE_HEADERS_DIR)
         set(client_public_headers_dir "${arg_OUTPUT_DIRECTORY}/${client_dir}_public_headers")
         set(client_private_headers_dir "${arg_OUTPUT_DIRECTORY}/${client_dir}_private_headers")
diff --git a/src/tools/qtopenapi-generator/src/main/resources/cpp-qt6-client/doc/Doxyfile.in.mustache b/src/tools/qtopenapi-generator/src/main/resources/cpp-qt6-client/doc/Doxyfile.in.mustache
index 0c8f553..443a07d 100644
--- a/src/tools/qtopenapi-generator/src/main/resources/cpp-qt6-client/doc/Doxyfile.in.mustache
+++ b/src/tools/qtopenapi-generator/src/main/resources/cpp-qt6-client/doc/Doxyfile.in.mustache
@@ -68,7 +68,7 @@ PROJECT_LOGO           =
 # entered, it will be relative to the location where doxygen was started. If
 # left blank the current directory will be used.
 
-OUTPUT_DIRECTORY       = "./doc"
+OUTPUT_DIRECTORY       = @DOXY_OUT_DIR@
 
 # If the CREATE_SUBDIRS tag is set to YES then doxygen will create up to 4096
 # sub-directories (in 2 levels) under the output directory of each output format
@@ -943,7 +943,7 @@ WARN_LOGFILE           =
 # spaces. See also FILE_PATTERNS and EXTENSION_MAPPING
 # Note: If this tag is empty the current directory is searched.
 
-INPUT                  = ""
+INPUT                  = @DOXY_IN_DIR@
 
 # This tag can be used to specify the character encoding of the source files
 # that doxygen parses. Internally doxygen uses the UTF-8 encoding. Doxygen uses
@@ -1047,7 +1047,7 @@ RECURSIVE              = NO
 # Note that relative paths are relative to the directory from which doxygen is
 # run.
 
-EXCLUDE                = {{prefix}}CombinedModelsAndAPIs.cpp
+EXCLUDE                =  @DOXY_EXCLUDE_FILE@
 
 # The EXCLUDE_SYMLINKS tag can be used to select whether or not files or
 # directories that are symbolic links (a Unix file system feature) are excluded
diff --git a/tests/auto/compression/client/tst_compression/CMakeLists.txt b/tests/auto/compression/client/tst_compression/CMakeLists.txt
index f195a95..fb828c3 100644
--- a/tests/auto/compression/client/tst_compression/CMakeLists.txt
+++ b/tests/auto/compression/client/tst_compression/CMakeLists.txt
@@ -22,6 +22,8 @@ else()
     endif()
 endif()
 
+find_package(Doxygen)
+
 qt_internal_add_test(cpp-qt-compression
     SOURCES
         tst_compression.cpp
@@ -35,6 +37,7 @@ qt_add_library(CompressionClient)
 qt6_add_openapi_client(CompressionClient
     SPEC_FILE
         ${CMAKE_CURRENT_SOURCE_DIR}/compression.yaml
+    GENERATE_DOCUMENTATION
 )
 
 # target_compile_definitions(cpp-qt-compression