# Copyright 2006 Google, Inc. All Rights Reserved.

# Licensed to PSF under a Contributor Agreement.

"""Fixer for print.

Change:

    'print'          into 'print()'

    'print ...'      into 'print(...)'

    'print ... ,'    into 'print(..., end=" ")'

    'print >>x, ...' into 'print(..., file=x)'

No changes are applied if print_function is imported from __future__

"""

# Local imports

from .. import patcomp

from .. import pytree

from ..pgen2 import token

from .. import fixer_base

from ..fixer_util import Name, Call, Comma, String, is_tuple

parend_expr = patcomp.compile_pattern(

              """atom< '(' [atom|STRING|NAME] ')' >"""

              )

class FixPrint(fixer_base.ConditionalFix):

    PATTERN = """

              simple_stmt< any* bare='print' any* > | print_stmt

              """

    skip_on = '__future__.print_function'

    def transform(self, node, results):

        assert results

        if self.should_skip(node):

            return

        bare_print = results.get("bare")

        if bare_print:

            # Special-case print all by itself

            bare_print.replace(Call(Name("print"), [],

                               prefix=bare_print.get_prefix()))

            return

        assert node.children[0] == Name("print")

        args = node.children[1:]

        if len(args) == 1 and parend_expr.match(args[0]):

            # We don't want to keep sticking parens around an

            # already-parenthesised expression.

            return

        sep = end = file = None

        if args and args[-1] == Comma():

            args = args[:-1]

            end = " "

        if args and args[0] == pytree.Leaf(token.RIGHTSHIFT, ">>"):

            assert len(args) >= 2

            file = args[1].clone()

            args = args[3:] # Strip a possible comma after the file expression

        # Now synthesize a print(args, sep=..., end=..., file=...) node.

        l_args = [arg.clone() for arg in args]

        if l_args:

            l_args[0].set_prefix("")

        if sep is not None or end is not None or file is not None:

            if sep is not None:

                self.add_kwarg(l_args, "sep", String(repr(sep)))

            if end is not None:

                self.add_kwarg(l_args, "end", String(repr(end)))

            if file is not None:

                self.add_kwarg(l_args, "file", file)

        n_stmt = Call(Name("print"), l_args)

        n_stmt.set_prefix(node.get_prefix())

        return n_stmt

    def add_kwarg(self, l_nodes, s_kwd, n_expr):

        # XXX All this prefix-setting may lose comments (though rarely)

        n_expr.set_prefix("")

        n_argument = pytree.Node(self.syms.argument,

                                 (Name(s_kwd),

                                  pytree.Leaf(token.EQUAL, "="),

                                  n_expr))

        if l_nodes:

            l_nodes.append(Comma())

            n_argument.set_prefix(" ")

        l_nodes.append(n_argument)