#[=======================================================================[.rst:
GodotCPPModule.cmake
---------------------

This file contains functions and tests which may be needed by consumers.

* Generate Trimmed API
* Generate File List
* Generate Bindings

If you want to use these functions in your project extend the CMAKE_MODULE_PATH
by adding these two lines into your CMakeLists.txt after the inclusion
godot-cpp

.. highlight:: cmake

    list(APPEND CMAKE_MODULE_PATH "${godot-cpp_SOURCE_DIR}/cmake")
    include( GodotCPPModule )

]=======================================================================]
find_package(Python3 3.4 REQUIRED) # pathlib should be present

#[[ Generate Trimmed API

The build_profile.py has a __main__ and is used as a tool
Its usage is listed as:
    $ python build_profile.py BUILD_PROFILE INPUT_JSON [OUTPUT_JSON]
]]
function( build_profile_generate_trimmed_api BUILD_PROFILE INPUT_JSON OUTPUT_JSON )
    execute_process(
            COMMAND "${Python3_EXECUTABLE}"
                "${godot-cpp_SOURCE_DIR}/build_profile.py"
                "${BUILD_PROFILE}"
                "${INPUT_JSON}"
                "${OUTPUT_JSON}"
            WORKING_DIRECTORY ${godot-cpp_SOURCE_DIR}
    )
endfunction(  )


#[[ Generate File List

Use the binding_generator.py Python script to determine the list of files that
will be passed to the code generator using extension_api.json.
NOTE: This happens for every configure.]]
function( binding_generator_get_file_list OUT_VAR_NAME API_FILEPATH OUTPUT_DIR )

    # This code snippet will be squashed into a single line
    # The two strings make this a list, in CMake lists are semicolon delimited strings.
    set( PYTHON_SCRIPT
"from binding_generator import print_file_list"
"print_file_list( api_filepath='${API_FILEPATH}',
    output_dir='${OUTPUT_DIR}',
    headers=True,
    sources=True)")
    message( DEBUG "Python:\n${PYTHON_SCRIPT}" )

    # Strip newlines and whitespace to make it a one-liner.
    string( REGEX REPLACE "\n *" " " PYTHON_SCRIPT "${PYTHON_SCRIPT}" )

    execute_process( COMMAND "${Python3_EXECUTABLE}" "-c" "${PYTHON_SCRIPT}"
            WORKING_DIRECTORY "${godot-cpp_SOURCE_DIR}"
            OUTPUT_VARIABLE GENERATED_FILES_LIST
            OUTPUT_STRIP_TRAILING_WHITESPACE
    )

    # Debug output
    message( DEBUG "FileList-Begin" )
    foreach( PATH ${GENERATED_FILES_LIST} )
        message( DEBUG ${PATH} )
    endforeach()

    # Error out if the file list generator returned no files.
    list( LENGTH GENERATED_FILES_LIST LIST_LENGTH )
    if( NOT LIST_LENGTH GREATER 0 )
        message( FATAL_ERROR "File List Generation Failed")
    endif()
    message( STATUS "There are ${LIST_LENGTH} Files to generate" )

    set( ${OUT_VAR_NAME} ${GENERATED_FILES_LIST} PARENT_SCOPE )
endfunction(  )


#[[ Generate Bindings

Using the generated file list, use the binding_generator.py to generate the
godot-cpp bindings. This will run at build time only if there are files
missing. ]]
function( binding_generator_generate_bindings API_FILE USE_TEMPLATE_GET_NODE, BITS, PRECISION, OUTPUT_DIR )
    # This code snippet will be squashed into a single line
    set( PYTHON_SCRIPT
"from binding_generator import generate_bindings"
"generate_bindings(
    api_filepath='${API_FILE}',
    use_template_get_node='${USE_TEMPLATE_GET_NODE}',
    bits='${BITS}',
    precision='${PRECISION}',
    output_dir='${OUTPUT_DIR}')")

    message( DEBUG "Python:\n${PYTHON_SCRIPT}" )

    # Strip newlines and whitespace to make it a one-liner.
    string( REGEX REPLACE "\n *" " " PYTHON_SCRIPT "${PYTHON_SCRIPT}" )

    add_custom_command(OUTPUT ${GENERATED_FILES_LIST}
            COMMAND "${Python3_EXECUTABLE}" "-c" "${PYTHON_SCRIPT}"
            VERBATIM
            WORKING_DIRECTORY ${godot-cpp_SOURCE_DIR}
            MAIN_DEPENDENCY ${GODOT_GDEXTENSION_API_FILE}
            DEPENDS ${godot-cpp_SOURCE_DIR}/binding_generator.py
            COMMENT "Generating bindings"
    )
endfunction(  )

#[[ Generate doc_data.cpp
The documentation displayed in the Godot editor is compiled into the extension.
It takes a list of XML source files, and transforms them into a cpp file that
is added to the sources list.]]
function( generate_doc_source OUTPUT_PATH SOURCES )
    # Transform SOURCES CMake LIST
    # quote each path with ''
    # join with , to transform into a python list minus the surrounding []
    set( PYTHON_LIST "${SOURCES}")
    list( TRANSFORM PYTHON_LIST REPLACE "(.*\.xml)" "'\\1'" )
    list( JOIN PYTHON_LIST "," PYTHON_LIST )

    # Python one-liner to run our command
    # lists in CMake are just strings delimited by ';', so this works.
    set( PYTHON_SCRIPT "from doc_source_generator import generate_doc_source"
            "generate_doc_source( '${OUTPUT_PATH}', [${PYTHON_LIST}] )" )

    add_custom_command( OUTPUT "${OUTPUT_PATH}"
            COMMAND "${Python3_EXECUTABLE}" "-c" "${PYTHON_SCRIPT}"
            VERBATIM
            WORKING_DIRECTORY "${godot-cpp_SOURCE_DIR}"
            DEPENDS
            "${godot-cpp_SOURCE_DIR}/doc_source_generator.py"
            "${SOURCES}"
            COMMENT "Generating: ${OUTPUT_PATH}"
    )
endfunction()

#[[ target_doc_sources
A simpler interface to add xml files as doc source to a output target.
TARGET: The gdexension library target
SOURCES: a list of xml files to use for source generation and inclusion.
This function also adds a doc_gen target to test source generation.]]
function( target_doc_sources TARGET SOURCES )
    # set the generated file name
    set( DOC_SOURCE_FILE "${CMAKE_CURRENT_BINARY_DIR}/gen/doc_source.cpp" )

    # Create the file generation target, this won't be triggered unless a target
    # that depends on DOC_SOURCE_FILE is built
    generate_doc_source( "${DOC_SOURCE_FILE}" ${SOURCES} )

    # Add DOC_SOURCE_FILE as a dependency to TARGET
    target_sources( ${TARGET} PRIVATE "${DOC_SOURCE_FILE}" )

    # Create a dummy target that depends on the source so that users can
    # test the file generation task.
    if( TARGET doc_gen )
    else()
        add_custom_target( doc_gen )
    endif()
    target_sources( doc_gen PRIVATE "${DOC_SOURCE_FILE}"  )
endfunction()