"""Fixer that changes bytes % whatever to a function that actually formats

it."""

from lib2to3 import fixer_base

from lib2to3.fixer_util import is_tuple, Call, Comma, Name, touch_import

# XXX: Implementing a blacklist in 2to3 turned out to be more troublesome than

# blacklisting some modules inside the fixers. So, this is what I came with.

blacklist = ['mercurial/demandimport.py',

             'mercurial/py3kcompat.py',

             'mercurial/i18n.py',

            ]

def isnumberremainder(formatstr, data):

    try:

        if data.value.isdigit():

            return True

    except AttributeError:

        return False

class FixBytesmod(fixer_base.BaseFix):

    # XXX: There's one case (I suppose) I can't handle: when a remainder

    # operation like foo % bar is performed, I can't really know what the

    # contents of foo and bar are. I believe the best approach is to "correct"

    # the to-be-converted code and let bytesformatter handle that case in

    # runtime.

    PATTERN = '''

              term< formatstr=STRING '%' data=STRING > |

              term< formatstr=STRING '%' data=atom > |

              term< formatstr=NAME '%' data=any > |

              term< formatstr=any '%' data=any >

              '''

    def transform(self, node, results):

        if self.filename in blacklist:

            return

        elif self.filename == 'mercurial/util.py':

            touch_import('.', 'py3kcompat', node=node)

        formatstr = results['formatstr'].clone()

        data = results['data'].clone()

        formatstr.prefix = '' # remove spaces from start

        if isnumberremainder(formatstr, data):

            return

        # We have two possibilities:

        # 1- An identifier or name is passed, it is going to be a leaf, thus, we

        #    just need to copy its value as an argument to the formatter;

        # 2- A tuple is explicitly passed. In this case, we're gonna explode it

        # to pass to the formatter

        # TODO: Check for normal strings. They don't need to be translated

        if is_tuple(data):

            args = [formatstr, Comma().clone()] + \

                   [c.clone() for c in data.children[:]]

        else:

            args = [formatstr, Comma().clone(), data]

        call = Call(Name('bytesformatter', prefix = ' '), args)

        return call