ENH: add Doxygen documentation

CMakeLists.txt

@@ -10,4 +10,28 @@ include_directories(src)
 
 add_subdirectory(src)
 
-target_link_libraries(${CMAKE_PROJECT_NAME}_run ${CMAKE_PROJECT_NAME}_lib)
+target_link_libraries(${CMAKE_PROJECT_NAME}_run ${CMAKE_PROJECT_NAME}_lib)
+
+# Doxygen Build
+option(BUILD_DOC "Build Documentation" ON)
+
+find_package(Doxygen)
+if(DOXYGEN_FOUND)
+    set(BUILD_DOC_DIR ${CMAKE_SOURCE_DIR}/build/docs)
+    if(NOT EXISTS ${BUILD_DOC_DIR})
+        file(MAKE_DIRECTORY ${BUILD_DOC_DIR})
+    endif()
+
+    set(DOXYGEN_IN ${CMAKE_CURRENT_SOURCE_DIR}/docs/Doxyfile)
+    set(DOXYGEN_OUT ${CMAKE_CURRENT_BINARY_DIR}/Doxyfile)
+    configure_file(${DOXYGEN_IN} ${DOXYGEN_OUT} @ONLY)
+
+    message("Doxygen buld started")
+    add_custom_target(Doxygen ALL
+            COMMAND ${DOXYGEN_EXECUTABLE} ${DOXYGEN_OUT}
+            WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
+            COMMENT "Generating API documentation with Doxygen"
+            VERBATIM)
+else(DOXYGEN_FOUND)
+    message("Doxygen needs to be installed to generate the documentation.")
+endif(DOXYGEN_FOUND)