"""typesystem.py -- Typesystem-specific operations for RTyper."""

from pypy.tool.pairtype import extendabletype

from pypy.rpython.ootypesystem import ootype
from pypy.rpython.lltypesystem import lltype
from pypy.rpython.error import TyperError

class TypeSystem(object):
    __metaclass__ = extendabletype

    offers_exceptiondata = True

    def __getattr__(self, name):
        """Lazy import to avoid circular dependencies."""
        def load(modname):
            try:
                return __import__("pypy.rpython.%s.%s" % (self.name, modname),
                                  None, None, ['__doc__'])
            except ImportError:
                return None
        if name in ('rclass', 'rpbc', 'rbuiltin', 'rtuple', 'rlist',
                    'rslice', 'rdict', 'rrange', 'rstr', 'rgeneric',
                    'll_str', 'rbuilder', 'rvirtualizable2',
                    'exceptiondata'):
            mod = load(name)
            if mod is not None:
                setattr(self, name, mod)
                return mod

        raise AttributeError(name)

    def derefType(self, T):
        raise NotImplementedError()

    def deref(self, obj):
        """Dereference `obj' to concrete object."""
        raise NotImplementedError()

    def check_null(self, repr, hop):
        """Emit operations to check that `hop's argument is not a null object.
"""
        raise NotImplementedError()

    def null_callable(self, T):
        """null callable object of type T"""
        raise NotImplementedError()

    def getcallabletype(self, ARGS, RESTYPE):
        cls = self.callable_trait[0]
        return cls(ARGS, RESTYPE)
        
    def getcallable(self, graph, getconcretetype=None):
        """Return callable given a Python function."""
        if getconcretetype is None:
            getconcretetype = self.getconcretetype
        llinputs = [getconcretetype(v) for v in graph.getargs()]
        lloutput = getconcretetype(graph.getreturnvar())

        typ, constr = self.callable_trait
        
        FT = typ(llinputs, lloutput)
        name = graph.name
        if hasattr(graph, 'func') and callable(graph.func):
            # the Python function object can have _llfnobjattrs_, specifying
            # attributes that are forced upon the functionptr().  The idea
            # for not passing these extra attributes as arguments to
            # getcallable() itself is that multiple calls to getcallable()
            # for the same graph should return equal functionptr() objects.
            if hasattr(graph.func, '_llfnobjattrs_'):
                fnobjattrs = graph.func._llfnobjattrs_.copy()
                # can specify a '_name', but use graph.name by default
                name = fnobjattrs.pop('_name', name)
            else:
                fnobjattrs = {}
            # _callable is normally graph.func, but can be overridden:
            # see fakeimpl in extfunc.py
            _callable = fnobjattrs.pop('_callable', graph.func)
            return constr(FT, name, graph = graph, _callable = _callable,
                          **fnobjattrs)
        else:
            return constr(FT, name, graph = graph)

    def getexternalcallable(self, ll_args, ll_result, name, **kwds):
        typ, constr = self.callable_trait

        FT = typ(ll_args, ll_result)
        return constr(FT, name, **kwds)

    def getconcretetype(self, v):
        """Helper called by getcallable() to get the conrete type of a variable
in a graph."""
        raise NotImplementedError()

    def perform_normalizations(self, rtyper):
        """Prepare the annotator's internal data structures for rtyping
        with the specified type system.
        """
        # default implementation
        from pypy.rpython.normalizecalls import perform_normalizations
        perform_normalizations(rtyper)

class LowLevelTypeSystem(TypeSystem):
    name = "lltypesystem"
    callable_trait = (lltype.FuncType, lltype.functionptr)

    def derefType(self, T):
        assert isinstance(T, lltype.Ptr)
        return T.TO

    def deref(self, obj):
        assert isinstance(lltype.typeOf(obj), lltype.Ptr)
        return obj._obj

    def check_null(self, repr, hop):
        # None is a nullptr, which is false; everything else is true.
        vlist = hop.inputargs(repr)
        return hop.genop('ptr_nonzero', vlist, resulttype=lltype.Bool)

    def getconcretetype(self, v):
        return getattr(v, 'concretetype', lltype.Ptr(lltype.PyObject))

    def null_callable(self, T):
        return lltype.nullptr(T.TO)

    def generic_is(self, robj1, robj2, hop):
        roriginal1 = robj1
        roriginal2 = robj2
        if robj1.lowleveltype is lltype.Void:
            robj1 = robj2
        elif robj2.lowleveltype is lltype.Void:
            robj2 = robj1
        if (not isinstance(robj1.lowleveltype, lltype.Ptr) or
            not isinstance(robj2.lowleveltype, lltype.Ptr)):
            raise TyperError('is of instances of the non-pointers: %r, %r' % (
                roriginal1, roriginal2))
        if robj1.lowleveltype != robj2.lowleveltype:
            raise TyperError('is of instances of different pointer types: %r, %r' % (
                roriginal1, roriginal2))
            
        v_list = hop.inputargs(robj1, robj2)
        return hop.genop('ptr_eq', v_list, resulttype=lltype.Bool)

class ObjectOrientedTypeSystem(TypeSystem):
    name = "ootypesystem"
    callable_trait = (ootype.StaticMethod, ootype.static_meth)

    def derefType(self, T):
        assert isinstance(T, ootype.OOType)
        return T

    def deref(self, obj):
        assert isinstance(ootype.typeOf(obj), ootype.OOType)
        return obj

    def check_null(self, repr, hop):
        vlist = hop.inputargs(repr)
        return hop.genop('oononnull', vlist, resulttype=ootype.Bool)

    def getconcretetype(self, v):
        return v.concretetype

    def null_callable(self, T):
        return ootype.null(T)

    def generic_is(self, robj1, robj2, hop):
        roriginal1 = robj1
        roriginal2 = robj2
        if robj1.lowleveltype is lltype.Void:
            robj1 = robj2
        elif robj2.lowleveltype is lltype.Void:
            robj2 = robj1
        if (not isinstance(robj1.lowleveltype, (ootype.Instance, ootype.BuiltinADTType)) or
            not isinstance(robj2.lowleveltype, (ootype.Instance, ootype.BuiltinADTType))) and \
            (robj1.lowleveltype is not ootype.Class or
             robj2.lowleveltype is not ootype.Class):
            raise TyperError('is of instances of the non-instances: %r, %r' % (
                roriginal1, roriginal2))
            
        v_list = hop.inputargs(robj1, robj2)
        return hop.genop('oois', v_list, resulttype=lltype.Bool)

# All typesystems are singletons
LowLevelTypeSystem.instance = LowLevelTypeSystem()
ObjectOrientedTypeSystem.instance = ObjectOrientedTypeSystem()

getfunctionptr = LowLevelTypeSystem.instance.getcallable

# Multiple dispatch on type system and high-level annotation

from pypy.tool.pairtype import pairtype
from pypy.annotation.model import SomeObject

class __extend__(pairtype(TypeSystem, SomeObject)):
    def rtyper_makerepr((ts, s_obj), rtyper):
        return s_obj.rtyper_makerepr(rtyper)

    def rtyper_makekey((ts, s_obj), rtyper):
        if hasattr(s_obj, "rtyper_makekey_ex"):
            return s_obj.rtyper_makekey_ex(rtyper)
        return s_obj.rtyper_makekey()