#==================================================================================================#
#  supported macros                                                                                #
#    - TEST_CASE,                                                                                  #
#    - SCENARIO,                                                                                   #
#    - TEST_CASE_METHOD,                                                                           #
#    - CATCH_TEST_CASE,                                                                            #
#    - CATCH_SCENARIO,                                                                             #
#    - CATCH_TEST_CASE_METHOD.                                                                     #
#                                                                                                  #
#  Usage                                                                                           #
# 1. make sure this module is in the path or add this otherwise:                                   #
#    set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_SOURCE_DIR}/cmake.modules/")              #
# 2. make sure that you've enabled testing option for the project by the call:                     #
#    enable_testing()                                                                              #
# 3. add the lines to the script for testing target (sample CMakeLists.txt):                       #
#        project(testing_target)                                                                   #
#        set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_SOURCE_DIR}/cmake.modules/")          #
#        enable_testing()                                                                          #
#                                                                                                  #
#        find_path(CATCH_INCLUDE_DIR "catch.hpp")                                                  #
#        include_directories(${INCLUDE_DIRECTORIES} ${CATCH_INCLUDE_DIR})                          #
#                                                                                                  #
#        file(GLOB SOURCE_FILES "*.cpp")                                                           #
#        add_executable(${PROJECT_NAME} ${SOURCE_FILES})                                           #
#                                                                                                  #
#        include(ParseAndAddCatchTests)                                                            #
#        ParseAndAddCatchTests(${PROJECT_NAME})                                                    #
#                                                                                                  #
# The following variables affect the behavior of the script:                                       #
#                                                                                                  #
#    PARSE_CATCH_TESTS_VERBOSE (Default OFF)                                                       #
#    -- enables debug messages                                                                     #
#    PARSE_CATCH_TESTS_NO_HIDDEN_TESTS (Default OFF)                                               #
#    -- excludes tests marked with [!hide], [.] or [.foo] tags                                     #
#    PARSE_CATCH_TESTS_ADD_FIXTURE_IN_TEST_NAME (Default ON)                                       #
#    -- adds fixture class name to the test name                                                   #
#    PARSE_CATCH_TESTS_ADD_TARGET_IN_TEST_NAME (Default ON)                                        #
#    -- adds cmake target name to the test name                                                    #
#    PARSE_CATCH_TESTS_ADD_TO_CONFIGURE_DEPENDS (Default OFF)                                      #
#    -- causes CMake to rerun when file with tests changes so that new tests will be discovered    #
#                                                                                                  #
# One can also set (locally) the optional variable OptionalCatchTestLauncher to precise the way    #
# a test should be run. For instance to use test MPI, one can write                                #
#     set(OptionalCatchTestLauncher ${MPIEXEC} ${MPIEXEC_NUMPROC_FLAG} ${NUMPROC})                 #
# just before calling this ParseAndAddCatchTests function                                          #
#                                                                                                  #
# The AdditionalCatchParameters optional variable can be used to pass extra argument to the test   #
# command. For example, to include successful tests in the output, one can write                   #
#     set(AdditionalCatchParameters --success)                                                     #
#                                                                                                  #
# After the script, the ParseAndAddCatchTests_TESTS property for the target, and for each source   #
# file in the target is set, and contains the list of the tests extracted from that target, or     #
# from that file. This is useful, for example to add further labels or properties to the tests.    #
#                                                                                                  #
#==================================================================================================#

if (CMAKE_MINIMUM_REQUIRED_VERSION VERSION_LESS 2.8.8)
  message(FATAL_ERROR "ParseAndAddCatchTests requires CMake 2.8.8 or newer")
endif()

option(PARSE_CATCH_TESTS_VERBOSE "Print Catch to CTest parser debug messages" OFF)
option(PARSE_CATCH_TESTS_NO_HIDDEN_TESTS "Exclude tests with [!hide], [.] or [.foo] tags" OFF)
option(PARSE_CATCH_TESTS_ADD_FIXTURE_IN_TEST_NAME "Add fixture class name to the test name" ON)
option(PARSE_CATCH_TESTS_ADD_TARGET_IN_TEST_NAME "Add target name to the test name" ON)
option(PARSE_CATCH_TESTS_ADD_TO_CONFIGURE_DEPENDS "Add test file to CMAKE_CONFIGURE_DEPENDS property" OFF)

function(ParseAndAddCatchTests_PrintDebugMessage)
    if(PARSE_CATCH_TESTS_VERBOSE)
            message(STATUS "ParseAndAddCatchTests: ${ARGV}")
    endif()
endfunction()

# This removes the contents between
#  - block comments (i.e. /* ... */)
#  - full line comments (i.e. // ... )
# contents have been read into '${CppCode}'.
# !keep partial line comments
function(ParseAndAddCatchTests_RemoveComments CppCode)
  string(ASCII 2 CMakeBeginBlockComment)
  string(ASCII 3 CMakeEndBlockComment)
  string(REGEX REPLACE "/\\*" "${CMakeBeginBlockComment}" ${CppCode} "${${CppCode}}")
  string(REGEX REPLACE "\\*/" "${CMakeEndBlockComment}" ${CppCode} "${${CppCode}}")
  string(REGEX REPLACE "${CMakeBeginBlockComment}[^${CMakeEndBlockComment}]*${CMakeEndBlockComment}" "" ${CppCode} "${${CppCode}}")
  string(REGEX REPLACE "\n[ \t]*//+[^\n]+" "\n" ${CppCode} "${${CppCode}}")

  set(${CppCode} "${${CppCode}}" PARENT_SCOPE)
endfunction()

# Worker function
function(ParseAndAddCatchTests_ParseFile SourceFile TestTarget)
    # If SourceFile is an object library, do not scan it (as it is not a file). Exit without giving a warning about a missing file.
    if(SourceFile MATCHES "\\\$<TARGET_OBJECTS:.+>")
        ParseAndAddCatchTests_PrintDebugMessage("Detected OBJECT library: ${SourceFile} this will not be scanned for tests.")
        return()
    endif()
    # According to CMake docs EXISTS behavior is well-defined only for full paths.
    get_filename_component(SourceFile ${SourceFile} ABSOLUTE)
    if(NOT EXISTS ${SourceFile})
        message(WARNING "Cannot find source file: ${SourceFile}")
        return()
    endif()
    ParseAndAddCatchTests_PrintDebugMessage("parsing ${SourceFile}")
    file(STRINGS ${SourceFile} Contents NEWLINE_CONSUME)

    # Remove block and fullline comments
    ParseAndAddCatchTests_RemoveComments(Contents)

    # Find definition of test names
    string(REGEX MATCHALL "[ \t]*(CATCH_)?(TEST_CASE_METHOD|SCENARIO|TEST_CASE)[ \t]*\\([^\)]+\\)+[ \t\n]*{+[ \t]*(//[^\n]*[Tt][Ii][Mm][Ee][Oo][Uu][Tt][ \t]*[0-9]+)*" Tests "${Contents}")

    if(PARSE_CATCH_TESTS_ADD_TO_CONFIGURE_DEPENDS AND Tests)
      ParseAndAddCatchTests_PrintDebugMessage("Adding ${SourceFile} to CMAKE_CONFIGURE_DEPENDS property")
      set_property(
        DIRECTORY
        APPEND
        PROPERTY CMAKE_CONFIGURE_DEPENDS ${SourceFile}
      )
    endif()

    foreach(TestName ${Tests})
        # Strip newlines
        string(REGEX REPLACE "\\\\\n|\n" "" TestName "${TestName}")

        # Get test type and fixture if applicable
        string(REGEX MATCH "(CATCH_)?(TEST_CASE_METHOD|SCENARIO|TEST_CASE)[ \t]*\\([^,^\"]*" TestTypeAndFixture "${TestName}")
        string(REGEX MATCH "(CATCH_)?(TEST_CASE_METHOD|SCENARIO|TEST_CASE)" TestType "${TestTypeAndFixture}")
        string(REGEX REPLACE "${TestType}\\([ \t]*" "" TestFixture "${TestTypeAndFixture}")

        # Get string parts of test definition
        string(REGEX MATCHALL "\"+([^\\^\"]|\\\\\")+\"+" TestStrings "${TestName}")

        # Strip wrapping quotation marks
        string(REGEX REPLACE "^\"(.*)\"$" "\\1" TestStrings "${TestStrings}")
        string(REPLACE "\";\"" ";" TestStrings "${TestStrings}")

        # Validate that a test name and tags have been provided
        list(LENGTH TestStrings TestStringsLength)
        if(TestStringsLength GREATER 2 OR TestStringsLength LESS 1)
            message(FATAL_ERROR "You must provide a valid test name and tags for all tests in ${SourceFile}")
        endif()

        # Assign name and tags
        list(GET TestStrings 0 Name)
        if("${TestType}" STREQUAL "SCENARIO")
            set(Name "Scenario: ${Name}")
        endif()
        if(PARSE_CATCH_TESTS_ADD_FIXTURE_IN_TEST_NAME AND TestFixture)
            set(CTestName "${TestFixture}:${Name}")
        else()
            set(CTestName "${Name}")
        endif()
        if(PARSE_CATCH_TESTS_ADD_TARGET_IN_TEST_NAME)
            set(CTestName "${TestTarget}:${CTestName}")
        endif()
        # add target to labels to enable running all tests added from this target
        set(Labels ${TestTarget})
        if(TestStringsLength EQUAL 2)
            list(GET TestStrings 1 Tags)
            string(TOLOWER "${Tags}" Tags)
            # remove target from labels if the test is hidden
            if("${Tags}" MATCHES ".*\\[!?(hide|\\.)\\].*")
                list(REMOVE_ITEM Labels ${TestTarget})
            endif()
            string(REPLACE "]" ";" Tags "${Tags}")
            string(REPLACE "[" "" Tags "${Tags}")
        else()
          # unset tags variable from previous loop
          unset(Tags)
        endif()

        list(APPEND Labels ${Tags})

        set(HiddenTagFound OFF)
        foreach(label ${Labels})
            string(REGEX MATCH "^!hide|^\\." result ${label})
            if(result)
                set(HiddenTagFound ON)
                break()
            endif(result)
        endforeach(label)
        if(PARSE_CATCH_TESTS_NO_HIDDEN_TESTS AND ${HiddenTagFound} AND ${CMAKE_VERSION} VERSION_LESS "3.9")
            ParseAndAddCatchTests_PrintDebugMessage("Skipping test \"${CTestName}\" as it has [!hide], [.] or [.foo] label")
        else()
            ParseAndAddCatchTests_PrintDebugMessage("Adding test \"${CTestName}\"")
            if(Labels)
                ParseAndAddCatchTests_PrintDebugMessage("Setting labels to ${Labels}")
            endif()

            # Escape commas in the test spec
            string(REPLACE "," "\\," Name ${Name})

            # Add the test and set its properties
            add_test(NAME "\"${CTestName}\"" COMMAND ${OptionalCatchTestLauncher} $<TARGET_FILE:${TestTarget}> ${Name} ${AdditionalCatchParameters})
            # Old CMake versions do not document VERSION_GREATER_EQUAL, so we use VERSION_GREATER with 3.8 instead
            if(PARSE_CATCH_TESTS_NO_HIDDEN_TESTS AND ${HiddenTagFound} AND ${CMAKE_VERSION} VERSION_GREATER "3.8")
                ParseAndAddCatchTests_PrintDebugMessage("Setting DISABLED test property")
                set_tests_properties("\"${CTestName}\"" PROPERTIES DISABLED ON)
            else()
                set_tests_properties("\"${CTestName}\"" PROPERTIES FAIL_REGULAR_EXPRESSION "No tests ran"
                                                        LABELS "${Labels}")
            endif()
            set_property(
              TARGET ${TestTarget}
              APPEND
              PROPERTY ParseAndAddCatchTests_TESTS "\"${CTestName}\"")
            set_property(
              SOURCE ${SourceFile}
              APPEND
              PROPERTY ParseAndAddCatchTests_TESTS "\"${CTestName}\"")
        endif()


    endforeach()
endfunction()

# entry point
function(ParseAndAddCatchTests TestTarget)
    ParseAndAddCatchTests_PrintDebugMessage("Started parsing ${TestTarget}")
    get_target_property(SourceFiles ${TestTarget} SOURCES)
    ParseAndAddCatchTests_PrintDebugMessage("Found the following sources: ${SourceFiles}")
    foreach(SourceFile ${SourceFiles})
        ParseAndAddCatchTests_ParseFile(${SourceFile} ${TestTarget})
    endforeach()
    ParseAndAddCatchTests_PrintDebugMessage("Finished parsing ${TestTarget}")
endfunction()