# Copyright 2006 Google, Inc. All Rights Reserved.
# Licensed to PSF under a Contributor Agreement.

"""Fixer for execfile.

This converts usages of the execfile function into calls to the built-in
exec() function.
"""

from .. import fixer_base
from ..fixer_util import (Comma, Name, Call, LParen, RParen, Dot, Node,
ArgList, String, syms)


class FixExecfile(fixer_base.BaseFix):
BM_compatible = True

PATTERN = """
power< 'execfile' trailer< '(' arglist< filename=any [',' globals=any [',' locals=any ] ] > ')' > >
|
power< 'execfile' trailer< '(' filename=any ')' > >
"""

def transform(self, node, results):
assert results
filename = results["filename"]
globals = results.get("globals")
locals = results.get("locals")

# Copy over the prefix from the right parentheses end of the execfile
# call.
execfile_paren = node.children[-1].children[-1].clone()
# Construct open().read().
open_args = ArgList([filename.clone()], rparen=execfile_paren)
open_call = Node(syms.power, [Name(u"open"), open_args])
read = [Node(syms.trailer, [Dot(), Name(u'read')]),
Node(syms.trailer, [LParen(), RParen()])]
open_expr = [open_call] + read
# Wrap the open call in a compile call. This is so the filename will be
# preserved in the execed code.
filename_arg = filename.clone()
filename_arg.prefix = u" "
exec_str = String(u"'exec'", u" ")
compile_args = open_expr + [Comma(), filename_arg, Comma(), exec_str]
compile_call = Call(Name(u"compile"), compile_args, u"")
# Finally, replace the execfile call with an exec call.
args = [compile_call]
if globals is not None:
args.extend([Comma(), globals.clone()])
if locals is not None:
args.extend([Comma(), locals.clone()])
return Call(Name(u"exec"), args, prefix=node.prefix)