#.rst:
# ECMCheckOutboundLicense
# -----------------------
#
# Assert that source file licenses are compatible with a desired outbound license
# of a compiled binary artifact (e.g., library, plugin or application).
#
# This module provides the ``ecm_check_outbound_license`` function that
# generates unit tests for checking the compatibility of license statements.
# The license statements in all tested files are required to be added by using
# the SPDX marker ``SPDX-License-Identifier``.
#
# During the CMake configuration of the project, a temporary license bill of
# materials (BOM) in SPDX format is generated by calling the REUSE tool
# (see <https://reuse.software>). That BOM is parsed and license computations
# based on an internal compatibility matrix are performed.
#
# Preconditions for using this module:
#     * All tested input source files must contain the SPDX-License-Identifier tag.
#     * Python3 must be available.
#     * The REUSE tool must be available, which generates the bill-of-materials
#       by running ``reuse spdx`` on the tested directory.
#
# When this module is included, a ``SKIP_LICENSE_TESTS`` option is added (default
# OFF). Turning this option on skips the generation of license tests, which might
# be convenient if licenses shall not be tested in all build configurations.
#
# ::
#
#   ecm_check_outbound_license(LICENSES <outbound-licenses>
#                              FILES <source-files>
#                              [TEST_NAME <name>]
#                              [WILL_FAIL])
#
# This method adds a custom unit test to ensure the specified outbound license to be
# compatible with the specified license headers. Note that a convenient way is to use
# the CMake GLOB command of the FILE function.
#
# ``LICENSES``  : List of one or multiple outbound license regarding which the compatibility
#                  of the source code files shall be tested. Currently, the following values
#                 are supported (values are SPDX registry identifiers):
#                    * MIT
#                    * BSD-2-Clause
#                    * BSD-3-Clause
#                    * LGPL-2.0-only
#                    * LGPL-2.1-only
#                    * LGPL-3.0-only
#                    * GPL-2.0-only
#                    * GPL-3.0-only
#
# ``FILES:``    : List of source files that contain valid SPDX-License-Identifier markers.
#                 The paths can be relative to the CMake file that generates the test case
#                 or be absolute paths.
#
# ``TEST_NAME`` : Optional parameter that defines the name of the generated test case.
#                 If no name is defined, the relative path to the test directory with appended
#                 license name is used. Every test has ``licensecheck_`` as prefix.
#
# ``WILL_FAIL`` : Optional parameter that inverts the test result. This parameter is usually only
#                 used for tests of the module.
#
# Since 5.75.0

#=============================================================================
# SPDX-FileCopyrightText: 2020 Andreas Cord-Landwehr <cordlandwehr@kde.org>
# SPDX-License-Identifier: BSD-3-Clause

include(FeatureSummary)

option(SKIP_LICENSE_TESTS "Skip outbound license tests" OFF)

find_package(Python3)
set_package_properties(Python3 PROPERTIES
    PURPOSE "Required to run tests of module ECMCheckOutboundLicense"
    TYPE OPTIONAL
)

find_package(ReuseTool)
set_package_properties(ReuseTool PROPERTIES
    PURPOSE "Required to run tests of module ECMCheckOutboundLicense"
    TYPE OPTIONAL
)

if (NOT SKIP_LICENSE_TESTS AND NOT REUSETOOL_FOUND)
    add_feature_info(SPDX_LICENSE_TESTING FALSE "Automatic license testing based on SPDX definitions (requires reuse tool)")
    message(WARNING "Reuse tool not found, skipping test generation")
else()
    add_feature_info(SPDX_LICENSE_TESTING TRUE "Automatic license testing based on SPDX definitions (requires reuse tool)")
endif()

set(SPDX_BOM_OUTPUT "${CMAKE_BINARY_DIR}/spdx.txt")

# test fixture for generating SPDX bill of materials
if(SKIP_LICENSE_TESTS OR NOT REUSETOOL_FOUND)
    message(STATUS "Skipping execution of outbound license tests.")
else()
    add_test(
        NAME generate_spdx_bom
        COMMAND reuse spdx -o ${SPDX_BOM_OUTPUT}
        WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
    )
    set_tests_properties(generate_spdx_bom PROPERTIES FIXTURES_SETUP SPDX_BOM)
endif()

function(ecm_check_outbound_license)
    if(SKIP_LICENSE_TESTS OR NOT REUSETOOL_FOUND)
        return()
    endif()

    set(_options WILL_FAIL)
    set(_oneValueArgs TEST_NAME)
    set(_multiValueArgs LICENSES FILES)
    cmake_parse_arguments(ARG "${_options}" "${_oneValueArgs}" "${_multiValueArgs}" ${ARGN} )

    if(NOT ARG_LICENSES)
        message(FATAL_ERROR "No LICENSES argument given to ecm_check_outbound_license")
    endif()

    if(NOT ARG_FILES)
        message(WARNING "No FILES argument given to ecm_check_outbound_license")
        return()
    endif()

    if(NOT ARG_TEST_NAME)
        # compute test name based on licensecheck_<relative-path>_<licence> if not name given
        string(REPLACE "${CMAKE_SOURCE_DIR}/" "" TEMP_TEST_NAME "${CMAKE_CURRENT_SOURCE_DIR}_${ARG_LICENSE}")
        string(MAKE_C_IDENTIFIER ${TEMP_TEST_NAME} ARG_TEST_NAME)
    endif()

    # generate file with list of relative file paths
    string(REPLACE "${CMAKE_BINARY_DIR}/" "" RELATIVE_PREFIX_PATH ${CMAKE_CURRENT_BINARY_DIR})
    set(OUTPUT_FILE ${CMAKE_BINARY_DIR}/licensecheck_${ARG_TEST_NAME}.txt)
    file(REMOVE ${OUTPUT_FILE})
    foreach(_file ${ARG_FILES})
        # check script expects files to start with "./", which must be relative to CMAKE_SOURCE_DIR
        if (IS_ABSOLUTE ${_file})
            string(REPLACE ${CMAKE_SOURCE_DIR} "." TEMPORARY_PATH ${_file})
            file(APPEND ${OUTPUT_FILE} "${TEMPORARY_PATH}\n")
        else()
            file(APPEND ${OUTPUT_FILE} "./${RELATIVE_PREFIX_PATH}/${_file}\n")
        endif()
    endforeach()

    file(COPY ${ECM_MODULE_DIR}/check-outbound-license.py DESTINATION ${CMAKE_BINARY_DIR})

    foreach(_license ${ARG_LICENSES})
        string(MAKE_C_IDENTIFIER ${_license} LICENSE_ID)
        add_test(
            NAME licensecheck_${ARG_TEST_NAME}_${LICENSE_ID}
            COMMAND python3 ${CMAKE_BINARY_DIR}/check-outbound-license.py -l ${_license} -s ${SPDX_BOM_OUTPUT} -i ${OUTPUT_FILE}
        )
        set_tests_properties(licensecheck_${ARG_TEST_NAME}_${LICENSE_ID} PROPERTIES FIXTURES_REQUIRED SPDX_BOM)
        set_tests_properties(licensecheck_${ARG_TEST_NAME}_${LICENSE_ID} PROPERTIES WILL_FAIL ${ARG_WILL_FAIL})
    endforeach()
endfunction()
