# -*- coding: utf-8 -*-

import sys

from copy import copy

from ..parser import parse_content
from ..eraser import remove_object_by_id
from ..plugin import Plugin

class AmericanInstituteOfPhysics(Plugin):
    """
    American Institute of Physics
    ~~~~~~~~~~~~~~~

    These watermarks are pretty basic, but sometimes they don't have indexes
    attached for whatever reason.
    """

    @classmethod
    def scrub(cls, content, verbose=0):
        evil_ids = []

        # parse the pdf into a pdfminer document
        pdf = parse_content(content)

        # get a list of all object ids
        xrefs = pdf._parser.read_xref()
        xref = xrefs[0]
        objids = xref.get_objids()

        # check each object in the pdf
        for objid in objids:
            # get an object by id
            obj = pdf.getobj(objid)

            if hasattr(obj, "attrs"):
                # watermarks tend to be in FlateDecode elements
                if obj.attrs.has_key("Filter") and str(obj.attrs["Filter"]) == "/FlateDecode":
                    length = obj.attrs["Length"]

                    # the watermark is never very long
                    if length < 1000:
                        #rawdata = copy(obj.rawdata)
                        data = copy(obj.get_data())

                        phrase="Redistribution subject to AIP license or copyright"
                        if phrase in data:
                            if verbose >= 2:
                                sys.stderr.write("%s: Found object %s with %r: %r; omitting..." % (cls.__name__, objid, phrase, data))
                            elif verbose >= 1:
                                sys.stderr.write("%s: Found object %s with %r; omitting..." % (cls.__name__, objid, phrase,))

                            evil_ids.append(objid)

        for objid in evil_ids:
            content = remove_object_by_id(content, objid)

        return content

