# from here:
#
# https://github.com/lefticus/cppbestpractices/blob/master/02-Use_the_Tools_Avai
# lable.md
# Courtesy of Jason Turner

function(set_project_warnings project_name)
    set(MSVC_WARNINGS
            /W4     # Baseline reasonable warnings
            /w14242 # 'identifier': conversion from 'type1' to 'type1', possible loss
            # of data
            /w14254 # 'operator': conversion from 'type1:field_bits' to
            # 'type2:field_bits', possible loss of data
            /w14263 # 'function': member function does not override any base class
            # virtual member function
            /w14265 # 'classname': class has virtual functions, but destructor is not
            # virtual instances of this class may not be destructed correctly
            /w14287 # 'operator': unsigned/negative constant mismatch
            /we4289 # nonstandard extension used: 'variable': loop control variable
            # declared in the for-loop is used outside the for-loop scope
            /w14296 # 'operator': expression is always 'boolean_value'
            /w14311 # 'variable': pointer truncation from 'type1' to 'type2'
            /w14545 # expression before comma evaluates to a function which is missing
            # an argument list
            /w14546 # function call before comma missing argument list
            /w14547 # 'operator': operator before comma has no effect; expected
            # operator with side-effect
            /w14549 # 'operator': operator before comma has no effect; did you intend
            # 'operator'?
            /w14555 # expression has no effect; expected expression with side- effect
            /w14619 # pragma warning: there is no warning number 'number'
            /w14640 # Enable warning on thread un-safe static member initialization
            /w14826 # Conversion from 'type1' to 'type_2' is sign-extended. This may
            # cause unexpected runtime behavior.
            /w14905 # wide string literal cast to 'LPSTR'
            /w14906 # string literal cast to 'LPWSTR'
            /w14928 # illegal copy-initialization; more than one user-defined
            # conversion has been implicitly applied
            /permissive- # standards conformance mode for MSVC compiler.
            )

    set(CLANG_WARNINGS
            -Wall
            -Wextra  # reasonable and standard
            -Wshadow # warn the user if a variable declaration shadows one from a
            # parent context
            -Wnon-virtual-dtor # warn the user if a class with virtual functions has a
            # non-virtual destructor. This helps catch hard to
            # track down memory errors
            #-Wold-style-cast # warn for c-style casts
            -Wcast-align     # warn for potential performance problem casts
            -Wunused         # warn on anything being unused
            -Woverloaded-virtual # warn if you overload (not override) a virtual
            # function
            -Wpedantic   # warn if non-standard C++ is used
            #-Wconversion # warn on type conversions that may lose data
            #-Wsign-conversion  # warn on sign conversions
            -Wnull-dereference # warn if a null dereference is detected
            -Wdouble-promotion # warn if float is implicit promoted to double
            -Wformat=2 # warn on security issues around functions that format output
            # (ie printf)
            )

    if (${PROJECT_NAME}_WARNINGS_AS_ERRORS)
        set(CLANG_WARNINGS ${CLANG_WARNINGS} -Werror)
        set(MSVC_WARNINGS ${MSVC_WARNINGS} /WX)
    endif ()

    set(GCC_WARNINGS
            ${CLANG_WARNINGS}
            -Wmisleading-indentation # warn if indentation implies blocks where blocks
            # do not exist
            -Wduplicated-cond # warn if if / else chain has duplicated conditions
            -Wduplicated-branches # warn if if / else branches have duplicated code
            -Wlogical-op   # warn about logical operations being used where bitwise were
            # probably wanted
            -Wuseless-cast # warn if you perform a cast to the same type
            )

    if (MSVC)
        set(PROJECT_WARNINGS ${MSVC_WARNINGS})
    elseif (CMAKE_CXX_COMPILER_ID MATCHES ".*Clang")
        set(PROJECT_WARNINGS ${CLANG_WARNINGS})
    elseif (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
        set(PROJECT_WARNINGS ${GCC_WARNINGS})
    else ()
        message(AUTHOR_WARNING "No compiler warnings set for '${CMAKE_CXX_COMPILER_ID}' compiler.")
    endif ()

    if (${PROJECT_NAME}_BUILD_HEADERS_ONLY)
        target_compile_options(${project_name} INTERFACE ${PROJECT_WARNINGS})
    else ()
        target_compile_options(${project_name} PUBLIC ${PROJECT_WARNINGS})
    endif ()

    if (NOT TARGET ${project_name})
        message(AUTHOR_WARNING "${project_name} is not a target, thus no compiler warning were added.")
    endif ()
endfunction()