#     Copyright 2013, Kay Hayen, mailto:kay.hayen@gmail.com
#
#     Part of "Nuitka", an optimizing Python compiler that is compatible and
#     integrates with CPython, but also works on its own.
#
#     Licensed under the Apache License, Version 2.0 (the "License");
#     you may not use this file except in compliance with the License.
#     You may obtain a copy of the License at
#
#        http://www.apache.org/licenses/LICENSE-2.0
#
#     Unless required by applicable law or agreed to in writing, software
#     distributed under the License is distributed on an "AS IS" BASIS,
#     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#     See the License for the specific language governing permissions and
#     limitations under the License.
#
""" Optimizations of builtins to builtin calls.

"""
from nuitka.nodes.ParameterSpecs import (
    ParameterSpec,
    TooManyArguments,
    matchCall
)

from nuitka.Utils import python_version

import sys, math

class BuiltinParameterSpec(ParameterSpec):
    def __init__( self, name, arg_names, default_count, list_star_arg = None,
                  dict_star_arg = None ):
        ParameterSpec.__init__(
            self,
            name           = name,
            normal_args    = arg_names,
            list_star_arg  = list_star_arg,
            dict_star_arg  = dict_star_arg,
            default_count  = default_count,
            kw_only_args   = ()
        )

        self.builtin = __builtins__[ name ]

    def __repr__(self):
        return "<BuiltinParameterSpec %s>" % self.name

    def getName(self):
        return self.name

    def isCompileTimeComputable(self, values):
        for value in values:
            if value is not None and not value.isCompileTimeConstant():
                return False
        else:
            return True

    def simulateCall(self, given_values):
        # Using star dict call for simulation and catch any exception as really
        # fatal, pylint: disable=W0142,W0703

        try:
            given_normal_args = given_values[ : len( self.normal_args ) ]

            if self.list_star_arg:
                given_list_star_args = given_values[ len( self.normal_args ) ]
            else:
                given_list_star_args = None

            if self.dict_star_arg:
                given_dict_star_args = given_values[ -1 ]
            else:
                given_dict_star_args = None

            arg_dict = {}

            for arg_name, given_value in zip(self.normal_args, given_normal_args):
                assert type( given_value ) not in ( tuple, list ), \
                  ( "do not like a tuple %s" % ( given_value, ))

                if given_value is not None:
                    arg_dict[ arg_name ] = given_value.getCompileTimeConstant()

            if given_dict_star_args:
                for given_dict_star_arg in reversed(given_dict_star_args):
                    arg_name = given_dict_star_arg.getKey()
                    arg_value = given_dict_star_arg.getValue()

                    arg_dict[ arg_name.getCompileTimeConstant() ] = arg_value.getCompileTimeConstant()

        except Exception as e:
            sys.exit( "Fatal problem: %r" % e )

        if given_list_star_args:
            return self.builtin(
                *( value.getCompileTimeConstant() for value in given_list_star_args ),
                **arg_dict
            )
        else:
            return self.builtin( **arg_dict )


class BuiltinParameterSpecNoKeywords(BuiltinParameterSpec):

    def allowsKeywords(self):
        return False

    def simulateCall(self, given_values):
        # Using star dict call for simulation and catch any exception as really fatal,
        # pylint: disable=W0142,W0703

        try:
            if self.list_star_arg:
                given_list_star_arg = given_values[ len( self.normal_args ) ]
            else:
                given_list_star_arg = None

            arg_list = []
            refuse_more = False

            for _arg_name, given_value in zip( self.normal_args, given_values ):
                assert type( given_value ) not in ( tuple, list ), ( "do not like tuple %s" % ( given_value, ))

                if given_value is not None:
                    if not refuse_more:
                        arg_list.append( given_value.getCompileTimeConstant() )
                    else:
                        assert False
                else:
                    refuse_more = True

            if given_list_star_arg is not None:
                arg_list += [ value.getCompileTimeConstant() for value in given_list_star_arg ]
        except Exception as e:
            print >> sys.stderr, "Fatal error: ",
            sys.exit( repr( e ) )

        return self.builtin( *arg_list )


class BuiltinParameterSpecExceptions(BuiltinParameterSpec):
    def __init__(self, exception_name, default_count):
        # TODO: Parameter default_count makes no sense for exceptions probably.
        BuiltinParameterSpec.__init__(
            self,
            name          = exception_name,
            arg_names     = (),
            default_count = default_count,
            list_star_arg = "args"
        )

    def allowsKeywords(self):
        return False

    def getKeywordRefusalText(self):
        return "exceptions.%s does not take keyword arguments" % self.name

    def getCallableName(self):
        return "exceptions." + self.getName()


def makeBuiltinParameterSpec(exception_name):
    if exception_name == "ImportError" and python_version >= 330:
        # TODO: Create this beast, needs keyword only arguments to be supported,
        # currently user of this function must take care to not have them.
        pass

    return BuiltinParameterSpecExceptions(
        exception_name = exception_name,
        default_count  = 0
    )

builtin_int_spec = BuiltinParameterSpec( "int", ( "x", "base" ), 2 )

# These builtins are only available for Python2
if python_version < 300:
    builtin_long_spec = BuiltinParameterSpec(
        "long",
        ("x", "base"),
        2
    )
    builtin_execfile_spec = BuiltinParameterSpecNoKeywords(
        "execfile",
        ("filename", "globals", "locals"),
        2
    )
    builtin_unicode_spec = BuiltinParameterSpec(
        "unicode",
        ("string", "encoding", "errors"),
        3
    )
    builtin_xrange_spec = BuiltinParameterSpec(
        "xrange",
        ("start", "stop", "step"),
        2
    )


builtin_bool_spec = BuiltinParameterSpec( "bool", ( "x", ), 1 )
builtin_float_spec = BuiltinParameterSpec( "float", ( "x", ), 1 )

# This builtin have variable parameters for Python2/3
if python_version < 300:
    builtin_str_spec = BuiltinParameterSpec( "str", ( "object", ), 1 )
else:
    builtin_str_spec = BuiltinParameterSpec( "str", ( "object", "encoding", "errors" ), 3 )

builtin_len_spec = BuiltinParameterSpecNoKeywords( "len", ( "object", ), 0 )
builtin_dict_spec = BuiltinParameterSpec( "dict", (), 0, "list_args", "dict_args" )
builtin_len_spec = BuiltinParameterSpecNoKeywords( "len", ( "object", ), 0 )
builtin_tuple_spec = BuiltinParameterSpec( "tuple", ( "sequence", ), 1 )
builtin_list_spec = BuiltinParameterSpec( "list", ( "sequence", ), 1 )
builtin_set_spec = BuiltinParameterSpecNoKeywords( "set", ( "iterable", ), 1 )

builtin_import_spec = BuiltinParameterSpec( "__import__", ( "name", "globals", "locals", "fromlist", "level" ), 4 )
builtin_open_spec = BuiltinParameterSpec( "open", ( "name", "mode", "buffering" ), 2 )
builtin_chr_spec = BuiltinParameterSpecNoKeywords( "chr", ( "i", ), 0 )
builtin_ord_spec = BuiltinParameterSpecNoKeywords( "ord", ( "c", ), 0 )
builtin_bin_spec = BuiltinParameterSpecNoKeywords( "bin", ( "number", ), 0 )
builtin_oct_spec = BuiltinParameterSpecNoKeywords( "oct", ( "number", ), 0 )
builtin_hex_spec = BuiltinParameterSpecNoKeywords( "hex", ( "number", ), 0 )
builtin_repr_spec = BuiltinParameterSpecNoKeywords( "repr", ( "object", ), 0 )

builtin_dir_spec = BuiltinParameterSpecNoKeywords( "dir", ( "object", ), 1 )
builtin_vars_spec = BuiltinParameterSpecNoKeywords( "vars", ( "object", ), 1 )

builtin_locals_spec = BuiltinParameterSpecNoKeywords( "locals", (), 0 )
builtin_globals_spec = BuiltinParameterSpecNoKeywords( "globals", (), 0 )
builtin_eval_spec = BuiltinParameterSpecNoKeywords( "eval", ( "source", "globals", "locals" ), 2 )
if python_version >= 300:
    builtin_exec_spec = BuiltinParameterSpecNoKeywords( "exec", ( "source", "globals", "locals" ), 2 )

# Note: Iter in fact names its first argument if the default applies "collection", but it
# won't matter much, fixed up in a wrapper.
builtin_iter_spec = BuiltinParameterSpecNoKeywords( "iter", ( "callable", "sentinel" ), 1 )
builtin_next_spec = BuiltinParameterSpecNoKeywords( "next", ( "iterator", "default" ), 1 )

# Note: type with 1 and type with 3 arguments are too different.
builtin_type1_spec = BuiltinParameterSpecNoKeywords( "type", ( "object", ), 0 )
builtin_type3_spec = BuiltinParameterSpecNoKeywords( "type", ( "name", "bases", "dict" ), 0 )

builtin_super_spec = BuiltinParameterSpecNoKeywords( "super", ( "type", "object" ), 1 if python_version < 300 else 2 )

builtin_hasattr_spec = BuiltinParameterSpecNoKeywords( "hasattr", ( "object", "name" ), 0 )
builtin_getattr_spec = BuiltinParameterSpecNoKeywords( "getattr", ( "object", "name", "default" ), 1 )
builtin_setattr_spec = BuiltinParameterSpecNoKeywords( "setattr", ( "object", "name", "value" ), 0 )

builtin_isinstance_spec = BuiltinParameterSpecNoKeywords( "isinstance", ( "instance", "cls" ), 0 )


class BuiltinRangeSpec(BuiltinParameterSpecNoKeywords):
    def __init__(self, *args):
        BuiltinParameterSpecNoKeywords.__init__( self, *args )

    def isCompileTimeComputable(self, values):
        result = BuiltinParameterSpecNoKeywords.isCompileTimeComputable(
            self,
            values = values
        )

        if result:
            arg_count = len(values)

            if arg_count == 1:
                low = values[0]

                # If it's not a number constant, we can compute the exception
                # that will be raised.
                if not low.isNumberConstant():
                    return True

                return low.getConstant() < 256
            elif arg_count == 2:
                low, high = values

                # If it's not a number constant, we can compute the exception
                # that will be raised.
                if not low.isNumberConstant() or not high.isNumberConstant():
                    return True

                return high.getConstant() - low.getConstant() < 256
            elif arg_count == 3:
                low, high, step = values

                if not low.isNumberConstant() or \
                   not high.isNumberConstant() or \
                   not step.isNumberConstant():
                    return True

                low = low.getConstant()
                high = high.getConstant()
                step = step.getConstant()

                # It's going to give a ZeroDivisionError in this case.
                if step == 0:
                    return True

                if low < high:
                    if step < 0:
                        return True
                    else:
                        return math.ceil( float( high - low ) / step ) < 256
                else:
                    if step > 0:
                        return True
                    else:
                        return math.ceil( float( high - low ) / step ) < 256
            else:
                assert False
        else:
            return False


builtin_range_spec = BuiltinRangeSpec("range", ( "start", "stop", "step" ), 2)


def extractBuiltinArgs( node, builtin_spec, builtin_class,
                        empty_special_class = None ):
    try:
        kw = node.getCallKw()


        # TODO: Could check for too many / too few, even if they are unknown, we
        # might raise that error, but that need not be optimized immediately.
        if not kw.isMappingWithConstantStringKeys():
            return None

        pairs = kw.getMappingStringKeyPairs()

        if pairs and not builtin_spec.allowsKeywords():
            raise TooManyArguments(
                TypeError( builtin_spec.getKeywordRefusalText() )
            )

        args = node.getCallArgs()

        if not args.canPredictIterationValues():
            return None

        positional = args.getIterationValues()

        if not positional and not pairs and empty_special_class is not None:
            return empty_special_class(source_ref = node.getSourceReference())

        args_dict = matchCall(
            func_name     = builtin_spec.getName(),
            args          = builtin_spec.getArgumentNames(),
            star_list_arg = builtin_spec.getStarListArgumentName(),
            star_dict_arg = builtin_spec.getStarDictArgumentName(),
            num_defaults  = builtin_spec.getDefaultCount(),
            positional    = positional,
            pairs         = pairs
        )
    except TooManyArguments as e:
        from nuitka.nodes.NodeMakingHelpers import (
            makeRaiseExceptionReplacementExpressionFromInstance,
            wrapExpressionWithSideEffects
        )

        return wrapExpressionWithSideEffects(
            new_node     = makeRaiseExceptionReplacementExpressionFromInstance(
                expression     = node,
                exception      = e.getRealException()
            ),
            old_node     = node,
            side_effects = node.extractPreCallSideEffects()
        )

    args_list = []

    for argument_name in builtin_spec.getArgumentNames():
        args_list.append( args_dict[ argument_name ] )

    if builtin_spec.getStarListArgumentName() is not None:
        args_list.append( args_dict[ builtin_spec.getStarListArgumentName() ] )

    if builtin_spec.getStarDictArgumentName() is not None:
        args_list.append( args_dict[ builtin_spec.getStarDictArgumentName() ] )

    # Using list reference for passing the arguments without names,
    # pylint: disable=W0142
    return builtin_class(
        *args_list,
        source_ref = node.getSourceReference()
    )
