# Natural Language Toolkit: Interface to Boxer
# <http://svn.ask.it.usyd.edu.au/trac/candc/wiki/boxer>
#
# Author: Dan Garrette <dhgarrette@gmail.com>
#
# Copyright (C) 2001-2019 NLTK Project
# URL: <http://nltk.org/>
# For license information, see LICENSE.TXT

"""
An interface to Boxer.

This interface relies on the latest version of the development (subversion) version of
C&C and Boxer.

Usage:
  Set the environment variable CANDC to the bin directory of your CandC installation.
  The models directory should be in the CandC root directory.
  For example:
     /path/to/candc/
        bin/
            candc
            boxer
        models/
            boxer/
"""
from __future__ import print_function, unicode_literals

import os
import re
import operator
import subprocess
from optparse import OptionParser
import tempfile
from functools import reduce

from nltk.internals import find_binary

from nltk.sem.logic import (
    ExpectedMoreTokensException,
    LogicalExpressionException,
    UnexpectedTokenException,
    Variable,
)

from nltk.sem.drt import (
    DRS,
    DrtApplicationExpression,
    DrtEqualityExpression,
    DrtNegatedExpression,
    DrtOrExpression,
    DrtParser,
    DrtProposition,
    DrtTokens,
    DrtVariableExpression,
)

from nltk.compat import python_2_unicode_compatible


class Boxer(object):
    """
    This class is an interface to Johan Bos's program Boxer, a wide-coverage
    semantic parser that produces Discourse Representation Structures (DRSs).
    """

    def __init__(
        self,
        boxer_drs_interpreter=None,
        elimeq=False,
        bin_dir=None,
        verbose=False,
        resolve=True,
    ):
        """
        :param boxer_drs_interpreter: A class that converts from the
        ``AbstractBoxerDrs`` object hierarchy to a different object.  The
        default is ``NltkDrtBoxerDrsInterpreter``, which converts to the NLTK
        DRT hierarchy.
        :param elimeq: When set to true, Boxer removes all equalities from the
        DRSs and discourse referents standing in the equality relation are
        unified, but only if this can be done in a meaning-preserving manner.
        :param resolve: When set to true, Boxer will resolve all anaphoric DRSs and perform merge-reduction.
        Resolution follows Van der Sandt's theory of binding and accommodation.
        """
        if boxer_drs_interpreter is None:
            boxer_drs_interpreter = NltkDrtBoxerDrsInterpreter()
        self._boxer_drs_interpreter = boxer_drs_interpreter

        self._resolve = resolve
        self._elimeq = elimeq

        self.set_bin_dir(bin_dir, verbose)

    def set_bin_dir(self, bin_dir, verbose=False):
        self._candc_bin = self._find_binary('candc', bin_dir, verbose)
        self._candc_models_path = os.path.normpath(
            os.path.join(self._candc_bin[:-5], '../models')
        )
        self._boxer_bin = self._find_binary('boxer', bin_dir, verbose)

    def interpret(self, input, discourse_id=None, question=False, verbose=False):
        """
        Use Boxer to give a first order representation.

        :param input: str Input sentence to parse
        :param occur_index: bool Should predicates be occurrence indexed?
        :param discourse_id: str An identifier to be inserted to each occurrence-indexed predicate.
        :return: ``drt.DrtExpression``
        """
        discourse_ids = [discourse_id] if discourse_id is not None else None
        d, = self.interpret_multi_sents([[input]], discourse_ids, question, verbose)
        if not d:
            raise Exception('Unable to interpret: "{0}"'.format(input))
        return d

    def interpret_multi(self, input, discourse_id=None, question=False, verbose=False):
        """
        Use Boxer to give a first order representation.

        :param input: list of str Input sentences to parse as a single discourse
        :param occur_index: bool Should predicates be occurrence indexed?
        :param discourse_id: str An identifier to be inserted to each occurrence-indexed predicate.
        :return: ``drt.DrtExpression``
        """
        discourse_ids = [discourse_id] if discourse_id is not None else None
        d, = self.interpret_multi_sents([input], discourse_ids, question, verbose)
        if not d:
            raise Exception('Unable to interpret: "{0}"'.format(input))
        return d

    def interpret_sents(
        self, inputs, discourse_ids=None, question=False, verbose=False
    ):
        """
        Use Boxer to give a first order representation.

        :param inputs: list of str Input sentences to parse as individual discourses
        :param occur_index: bool Should predicates be occurrence indexed?
        :param discourse_ids: list of str Identifiers to be inserted to each occurrence-indexed predicate.
        :return: list of ``drt.DrtExpression``
        """
        return self.interpret_multi_sents(
            [[input] for input in inputs], discourse_ids, question, verbose
        )

    def interpret_multi_sents(
        self, inputs, discourse_ids=None, question=False, verbose=False
    ):
        """
        Use Boxer to give a first order representation.

        :param inputs: list of list of str Input discourses to parse
        :param occur_index: bool Should predicates be occurrence indexed?
        :param discourse_ids: list of str Identifiers to be inserted to each occurrence-indexed predicate.
        :return: ``drt.DrtExpression``
        """
        if discourse_ids is not None:
            assert len(inputs) == len(discourse_ids)
            assert reduce(operator.and_, (id is not None for id in discourse_ids))
            use_disc_id = True
        else:
            discourse_ids = list(map(str, range(len(inputs))))
            use_disc_id = False

        candc_out = self._call_candc(inputs, discourse_ids, question, verbose=verbose)
        boxer_out = self._call_boxer(candc_out, verbose=verbose)

        #        if 'ERROR: input file contains no ccg/2 terms.' in boxer_out:
        #            raise UnparseableInputException('Could not parse with candc: "%s"' % input_str)

        drs_dict = self._parse_to_drs_dict(boxer_out, use_disc_id)
        return [drs_dict.get(id, None) for id in discourse_ids]

    def _call_candc(self, inputs, discourse_ids, question, verbose=False):
        """
        Call the ``candc`` binary with the given input.

        :param inputs: list of list of str Input discourses to parse
        :param discourse_ids: list of str Identifiers to be inserted to each occurrence-indexed predicate.
        :param filename: str A filename for the output file
        :return: stdout
        """
        args = [
            '--models',
            os.path.join(self._candc_models_path, ['boxer', 'questions'][question]),
            '--candc-printer',
            'boxer',
        ]
        return self._call(
            '\n'.join(
                sum(
                    (
                        ["<META>'{0}'".format(id)] + d
                        for d, id in zip(inputs, discourse_ids)
                    ),
                    [],
                )
            ),
            self._candc_bin,
            args,
            verbose,
        )

    def _call_boxer(self, candc_out, verbose=False):
        """
        Call the ``boxer`` binary with the given input.

        :param candc_out: str output from C&C parser
        :return: stdout
        """
        f = None
        try:
            fd, temp_filename = tempfile.mkstemp(
                prefix='boxer-', suffix='.in', text=True
            )
            f = os.fdopen(fd, 'w')
            f.write(candc_out)
        finally:
            if f:
                f.close()

        args = [
            '--box',
            'false',
            '--semantics',
            'drs',
            #'--flat', 'false', # removed from boxer
            '--resolve',
            ['false', 'true'][self._resolve],
            '--elimeq',
            ['false', 'true'][self._elimeq],
            '--format',
            'prolog',
            '--instantiate',
            'true',
            '--input',
            temp_filename,
        ]
        stdout = self._call(None, self._boxer_bin, args, verbose)
        os.remove(temp_filename)
        return stdout

    def _find_binary(self, name, bin_dir, verbose=False):
        return find_binary(
            name,
            path_to_bin=bin_dir,
            env_vars=['CANDC'],
            url='http://svn.ask.it.usyd.edu.au/trac/candc/',
            binary_names=[name, name + '.exe'],
            verbose=verbose,
        )

    def _call(self, input_str, binary, args=[], verbose=False):
        """
        Call the binary with the given input.

        :param input_str: A string whose contents are used as stdin.
        :param binary: The location of the binary to call
        :param args: A list of command-line arguments.
        :return: stdout
        """
        if verbose:
            print('Calling:', binary)
            print('Args:', args)
            print('Input:', input_str)
            print('Command:', binary + ' ' + ' '.join(args))

        # Call via a subprocess
        if input_str is None:
            cmd = [binary] + args
            p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
        else:
            cmd = 'echo "{0}" | {1} {2}'.format(input_str, binary, ' '.join(args))
            p = subprocess.Popen(
                cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=True
            )
        stdout, stderr = p.communicate()

        if verbose:
            print('Return code:', p.returncode)
            if stdout:
                print('stdout:\n', stdout, '\n')
            if stderr:
                print('stderr:\n', stderr, '\n')
        if p.returncode != 0:
            raise Exception(
                'ERROR CALLING: {0} {1}\nReturncode: {2}\n{3}'.format(
                    binary, ' '.join(args), p.returncode, stderr
                )
            )

        return stdout

    def _parse_to_drs_dict(self, boxer_out, use_disc_id):
        lines = boxer_out.split('\n')
        drs_dict = {}
        i = 0
        while i < len(lines):
            line = lines[i]
            if line.startswith('id('):
                comma_idx = line.index(',')
                discourse_id = line[3:comma_idx]
                if discourse_id[0] == "'" and discourse_id[-1] == "'":
                    discourse_id = discourse_id[1:-1]
                drs_id = line[comma_idx + 1 : line.index(')')]
                i += 1
                line = lines[i]
                assert line.startswith('sem({0},'.format(drs_id))
                if line[-4:] == "').'":
                    line = line[:-4] + ")."
                assert line.endswith(').'), "can't parse line: {0}".format(line)

                search_start = len('sem({0},['.format(drs_id))
                brace_count = 1
                drs_start = -1
                for j, c in enumerate(line[search_start:]):
                    if c == '[':
                        brace_count += 1
                    if c == ']':
                        brace_count -= 1
                        if brace_count == 0:
                            drs_start = search_start + j + 1
                            if line[drs_start : drs_start + 3] == "','":
                                drs_start = drs_start + 3
                            else:
                                drs_start = drs_start + 1
                            break
                assert drs_start > -1

                drs_input = line[drs_start:-2].strip()
                parsed = self._parse_drs(drs_input, discourse_id, use_disc_id)
                drs_dict[discourse_id] = self._boxer_drs_interpreter.interpret(parsed)
            i += 1
        return drs_dict

    def _parse_drs(self, drs_string, discourse_id, use_disc_id):
        return BoxerOutputDrsParser([None, discourse_id][use_disc_id]).parse(drs_string)


class BoxerOutputDrsParser(DrtParser):
    def __init__(self, discourse_id=None):
        """
        This class is used to parse the Prolog DRS output from Boxer into a
        hierarchy of python objects.
        """
        DrtParser.__init__(self)
        self.discourse_id = discourse_id
        self.sentence_id_offset = None
        self.quote_chars = [("'", "'", "\\", False)]

    def parse(self, data, signature=None):
        return DrtParser.parse(self, data, signature)

    def get_all_symbols(self):
        return ['(', ')', ',', '[', ']', ':']

    def handle(self, tok, context):
        return self.handle_drs(tok)

    def attempt_adjuncts(self, expression, context):
        return expression

    def parse_condition(self, indices):
        """
        Parse a DRS condition

        :return: list of ``DrtExpression``
        """
        tok = self.token()
        accum = self.handle_condition(tok, indices)
        if accum is None:
            raise UnexpectedTokenException(tok)
        return accum

    def handle_drs(self, tok):
        if tok == 'drs':
            return self.parse_drs()
        elif tok in ['merge', 'smerge']:
            return self._handle_binary_expression(self._make_merge_expression)(None, [])
        elif tok in ['alfa']:
            return self._handle_alfa(self._make_merge_expression)(None, [])

    def handle_condition(self, tok, indices):
        """
        Handle a DRS condition

        :param indices: list of int
        :return: list of ``DrtExpression``
        """
        if tok == 'not':
            return [self._handle_not()]

        if tok == 'or':
            conds = [self._handle_binary_expression(self._make_or_expression)]
        elif tok == 'imp':
            conds = [self._handle_binary_expression(self._make_imp_expression)]
        elif tok == 'eq':
            conds = [self._handle_eq()]
        elif tok == 'prop':
            conds = [self._handle_prop()]

        elif tok == 'pred':
            conds = [self._handle_pred()]
        elif tok == 'named':
            conds = [self._handle_named()]
        elif tok == 'rel':
            conds = [self._handle_rel()]
        elif tok == 'timex':
            conds = self._handle_timex()
        elif tok == 'card':
            conds = [self._handle_card()]

        elif tok == 'whq':
            conds = [self._handle_whq()]
        elif tok == 'duplex':
            conds = [self._handle_duplex()]

        else:
            conds = []

        return sum(
            [
                [cond(sent_index, word_indices) for cond in conds]
                for sent_index, word_indices in self._sent_and_word_indices(indices)
            ],
            [],
        )

    def _handle_not(self):
        self.assertToken(self.token(), '(')
        drs = self.process_next_expression(None)
        self.assertToken(self.token(), ')')
        return BoxerNot(drs)

    def _handle_pred(self):
        # pred(_G3943, dog, n, 0)
        self.assertToken(self.token(), '(')
        variable = self.parse_variable()
        self.assertToken(self.token(), ',')
        name = self.token()
        self.assertToken(self.token(), ',')
        pos = self.token()
        self.assertToken(self.token(), ',')
        sense = int(self.token())
        self.assertToken(self.token(), ')')

        def _handle_pred_f(sent_index, word_indices):
            return BoxerPred(
                self.discourse_id, sent_index, word_indices, variable, name, pos, sense
            )

        return _handle_pred_f

    def _handle_duplex(self):
        # duplex(whq, drs(...), var, drs(...))
        self.assertToken(self.token(), '(')
        # self.assertToken(self.token(), '[')
        ans_types = []
        # while self.token(0) != ']':
        #     cat = self.token()
        #     self.assertToken(self.token(), ':')
        #     if cat == 'des':
        #         ans_types.append(self.token())
        #     elif cat == 'num':
        #         ans_types.append('number')
        #         typ = self.token()
        #         if typ == 'cou':
        #             ans_types.append('count')
        #         else:
        #             ans_types.append(typ)
        #     else:
        #         ans_types.append(self.token())
        # self.token() #swallow the ']'

        self.assertToken(self.token(), 'whq')
        self.assertToken(self.token(), ',')
        d1 = self.process_next_expression(None)
        self.assertToken(self.token(), ',')
        ref = self.parse_variable()
        self.assertToken(self.token(), ',')
        d2 = self.process_next_expression(None)
        self.assertToken(self.token(), ')')
        return lambda sent_index, word_indices: BoxerWhq(
            self.discourse_id, sent_index, word_indices, ans_types, d1, ref, d2
        )

    def _handle_named(self):
        # named(x0, john, per, 0)
        self.assertToken(self.token(), '(')
        variable = self.parse_variable()
        self.assertToken(self.token(), ',')
        name = self.token()
        self.assertToken(self.token(), ',')
        type = self.token()
        self.assertToken(self.token(), ',')
        sense = self.token()  # as per boxer rev 2554
        self.assertToken(self.token(), ')')
        return lambda sent_index, word_indices: BoxerNamed(
            self.discourse_id, sent_index, word_indices, variable, name, type, sense
        )

    def _handle_rel(self):
        # rel(_G3993, _G3943, agent, 0)
        self.assertToken(self.token(), '(')
        var1 = self.parse_variable()
        self.assertToken(self.token(), ',')
        var2 = self.parse_variable()
        self.assertToken(self.token(), ',')
        rel = self.token()
        self.assertToken(self.token(), ',')
        sense = int(self.token())
        self.assertToken(self.token(), ')')
        return lambda sent_index, word_indices: BoxerRel(
            self.discourse_id, sent_index, word_indices, var1, var2, rel, sense
        )

    def _handle_timex(self):
        # timex(_G18322, date([]: (+), []:'XXXX', [1004]:'04', []:'XX'))
        self.assertToken(self.token(), '(')
        arg = self.parse_variable()
        self.assertToken(self.token(), ',')
        new_conds = self._handle_time_expression(arg)
        self.assertToken(self.token(), ')')
        return new_conds

    def _handle_time_expression(self, arg):
        # date([]: (+), []:'XXXX', [1004]:'04', []:'XX')
        tok = self.token()
        self.assertToken(self.token(), '(')
        if tok == 'date':
            conds = self._handle_date(arg)
        elif tok == 'time':
            conds = self._handle_time(arg)
        else:
            return None
        self.assertToken(self.token(), ')')
        return [
            lambda sent_index, word_indices: BoxerPred(
                self.discourse_id, sent_index, word_indices, arg, tok, 'n', 0
            )
        ] + [lambda sent_index, word_indices: cond for cond in conds]

    def _handle_date(self, arg):
        # []: (+), []:'XXXX', [1004]:'04', []:'XX'
        conds = []
        (sent_index, word_indices), = self._sent_and_word_indices(
            self._parse_index_list()
        )
        self.assertToken(self.token(), '(')
        pol = self.token()
        self.assertToken(self.token(), ')')
        conds.append(
            BoxerPred(
                self.discourse_id,
                sent_index,
                word_indices,
                arg,
                'date_pol_{0}'.format(pol),
                'a',
                0,
            )
        )
        self.assertToken(self.token(), ',')

        (sent_index, word_indices), = self._sent_and_word_indices(
            self._parse_index_list()
        )
        year = self.token()
        if year != 'XXXX':
            year = year.replace(':', '_')
            conds.append(
                BoxerPred(
                    self.discourse_id,
                    sent_index,
                    word_indices,
                    arg,
                    'date_year_{0}'.format(year),
                    'a',
                    0,
                )
            )
        self.assertToken(self.token(), ',')

        (sent_index, word_indices), = self._sent_and_word_indices(
            self._parse_index_list()
        )
        month = self.token()
        if month != 'XX':
            conds.append(
                BoxerPred(
                    self.discourse_id,
                    sent_index,
                    word_indices,
                    arg,
                    'date_month_{0}'.format(month),
                    'a',
                    0,
                )
            )
        self.assertToken(self.token(), ',')

        (sent_index, word_indices), = self._sent_and_word_indices(
            self._parse_index_list()
        )
        day = self.token()
        if day != 'XX':
            conds.append(
                BoxerPred(
                    self.discourse_id,
                    sent_index,
                    word_indices,
                    arg,
                    'date_day_{0}'.format(day),
                    'a',
                    0,
                )
            )

        return conds

    def _handle_time(self, arg):
        # time([1018]:'18', []:'XX', []:'XX')
        conds = []
        self._parse_index_list()
        hour = self.token()
        if hour != 'XX':
            conds.append(self._make_atom('r_hour_2', arg, hour))
        self.assertToken(self.token(), ',')

        self._parse_index_list()
        min = self.token()
        if min != 'XX':
            conds.append(self._make_atom('r_min_2', arg, min))
        self.assertToken(self.token(), ',')

        self._parse_index_list()
        sec = self.token()
        if sec != 'XX':
            conds.append(self._make_atom('r_sec_2', arg, sec))

        return conds

    def _handle_card(self):
        # card(_G18535, 28, ge)
        self.assertToken(self.token(), '(')
        variable = self.parse_variable()
        self.assertToken(self.token(), ',')
        value = self.token()
        self.assertToken(self.token(), ',')
        type = self.token()
        self.assertToken(self.token(), ')')
        return lambda sent_index, word_indices: BoxerCard(
            self.discourse_id, sent_index, word_indices, variable, value, type
        )

    def _handle_prop(self):
        # prop(_G15949, drs(...))
        self.assertToken(self.token(), '(')
        variable = self.parse_variable()
        self.assertToken(self.token(), ',')
        drs = self.process_next_expression(None)
        self.assertToken(self.token(), ')')
        return lambda sent_index, word_indices: BoxerProp(
            self.discourse_id, sent_index, word_indices, variable, drs
        )

    def _parse_index_list(self):
        # [1001,1002]:
        indices = []
        self.assertToken(self.token(), '[')
        while self.token(0) != ']':
            indices.append(self.parse_index())
            if self.token(0) == ',':
                self.token()  # swallow ','
        self.token()  # swallow ']'
        self.assertToken(self.token(), ':')
        return indices

    def parse_drs(self):
        # drs([[1001]:_G3943],
        #    [[1002]:pred(_G3943, dog, n, 0)]
        #   )
        self.assertToken(self.token(), '(')
        self.assertToken(self.token(), '[')
        refs = set()
        while self.token(0) != ']':
            indices = self._parse_index_list()
            refs.add(self.parse_variable())
            if self.token(0) == ',':
                self.token()  # swallow ','
        self.token()  # swallow ']'
        self.assertToken(self.token(), ',')
        self.assertToken(self.token(), '[')
        conds = []
        while self.token(0) != ']':
            indices = self._parse_index_list()
            conds.extend(self.parse_condition(indices))
            if self.token(0) == ',':
                self.token()  # swallow ','
        self.token()  # swallow ']'
        self.assertToken(self.token(), ')')
        return BoxerDrs(list(refs), conds)

    def _handle_binary_expression(self, make_callback):
        self.assertToken(self.token(), '(')
        drs1 = self.process_next_expression(None)
        self.assertToken(self.token(), ',')
        drs2 = self.process_next_expression(None)
        self.assertToken(self.token(), ')')
        return lambda sent_index, word_indices: make_callback(
            sent_index, word_indices, drs1, drs2
        )

    def _handle_alfa(self, make_callback):
        self.assertToken(self.token(), '(')
        type = self.token()
        self.assertToken(self.token(), ',')
        drs1 = self.process_next_expression(None)
        self.assertToken(self.token(), ',')
        drs2 = self.process_next_expression(None)
        self.assertToken(self.token(), ')')
        return lambda sent_index, word_indices: make_callback(
            sent_index, word_indices, drs1, drs2
        )

    def _handle_eq(self):
        self.assertToken(self.token(), '(')
        var1 = self.parse_variable()
        self.assertToken(self.token(), ',')
        var2 = self.parse_variable()
        self.assertToken(self.token(), ')')
        return lambda sent_index, word_indices: BoxerEq(
            self.discourse_id, sent_index, word_indices, var1, var2
        )

    def _handle_whq(self):
        self.assertToken(self.token(), '(')
        self.assertToken(self.token(), '[')
        ans_types = []
        while self.token(0) != ']':
            cat = self.token()
            self.assertToken(self.token(), ':')
            if cat == 'des':
                ans_types.append(self.token())
            elif cat == 'num':
                ans_types.append('number')
                typ = self.token()
                if typ == 'cou':
                    ans_types.append('count')
                else:
                    ans_types.append(typ)
            else:
                ans_types.append(self.token())
        self.token()  # swallow the ']'

        self.assertToken(self.token(), ',')
        d1 = self.process_next_expression(None)
        self.assertToken(self.token(), ',')
        ref = self.parse_variable()
        self.assertToken(self.token(), ',')
        d2 = self.process_next_expression(None)
        self.assertToken(self.token(), ')')
        return lambda sent_index, word_indices: BoxerWhq(
            self.discourse_id, sent_index, word_indices, ans_types, d1, ref, d2
        )

    def _make_merge_expression(self, sent_index, word_indices, drs1, drs2):
        return BoxerDrs(drs1.refs + drs2.refs, drs1.conds + drs2.conds)

    def _make_or_expression(self, sent_index, word_indices, drs1, drs2):
        return BoxerOr(self.discourse_id, sent_index, word_indices, drs1, drs2)

    def _make_imp_expression(self, sent_index, word_indices, drs1, drs2):
        return BoxerDrs(drs1.refs, drs1.conds, drs2)

    def parse_variable(self):
        var = self.token()
        assert re.match('^[exps]\d+$', var), var
        return var

    def parse_index(self):
        return int(self.token())

    def _sent_and_word_indices(self, indices):
        """
        :return: list of (sent_index, word_indices) tuples
        """
        sent_indices = set((i / 1000) - 1 for i in indices if i >= 0)
        if sent_indices:
            pairs = []
            for sent_index in sent_indices:
                word_indices = [
                    (i % 1000) - 1 for i in indices if sent_index == (i / 1000) - 1
                ]
                pairs.append((sent_index, word_indices))
            return pairs
        else:
            word_indices = [(i % 1000) - 1 for i in indices]
            return [(None, word_indices)]


class BoxerDrsParser(DrtParser):
    """
    Reparse the str form of subclasses of ``AbstractBoxerDrs``
    """

    def __init__(self, discourse_id=None):
        DrtParser.__init__(self)
        self.discourse_id = discourse_id

    def get_all_symbols(self):
        return [
            DrtTokens.OPEN,
            DrtTokens.CLOSE,
            DrtTokens.COMMA,
            DrtTokens.OPEN_BRACKET,
            DrtTokens.CLOSE_BRACKET,
        ]

    def attempt_adjuncts(self, expression, context):
        return expression

    def handle(self, tok, context):
        try:
            #             if tok == 'drs':
            #                 self.assertNextToken(DrtTokens.OPEN)
            #                 label = int(self.token())
            #                 self.assertNextToken(DrtTokens.COMMA)
            #                 refs = list(map(int, self.handle_refs()))
            #                 self.assertNextToken(DrtTokens.COMMA)
            #                 conds = self.handle_conds(None)
            #                 self.assertNextToken(DrtTokens.CLOSE)
            #                 return BoxerDrs(label, refs, conds)
            if tok == 'pred':
                self.assertNextToken(DrtTokens.OPEN)
                disc_id = (
                    self.discourse_id if self.discourse_id is not None else self.token()
                )
                self.assertNextToken(DrtTokens.COMMA)
                sent_id = self.nullableIntToken()
                self.assertNextToken(DrtTokens.COMMA)
                word_ids = list(map(int, self.handle_refs()))
                self.assertNextToken(DrtTokens.COMMA)
                variable = int(self.token())
                self.assertNextToken(DrtTokens.COMMA)
                name = self.token()
                self.assertNextToken(DrtTokens.COMMA)
                pos = self.token()
                self.assertNextToken(DrtTokens.COMMA)
                sense = int(self.token())
                self.assertNextToken(DrtTokens.CLOSE)
                return BoxerPred(disc_id, sent_id, word_ids, variable, name, pos, sense)
            elif tok == 'named':
                self.assertNextToken(DrtTokens.OPEN)
                disc_id = (
                    self.discourse_id if self.discourse_id is not None else self.token()
                )
                self.assertNextToken(DrtTokens.COMMA)
                sent_id = int(self.token())
                self.assertNextToken(DrtTokens.COMMA)
                word_ids = map(int, self.handle_refs())
                self.assertNextToken(DrtTokens.COMMA)
                variable = int(self.token())
                self.assertNextToken(DrtTokens.COMMA)
                name = self.token()
                self.assertNextToken(DrtTokens.COMMA)
                type = self.token()
                self.assertNextToken(DrtTokens.COMMA)
                sense = int(self.token())
                self.assertNextToken(DrtTokens.CLOSE)
                return BoxerNamed(
                    disc_id, sent_id, word_ids, variable, name, type, sense
                )
            elif tok == 'rel':
                self.assertNextToken(DrtTokens.OPEN)
                disc_id = (
                    self.discourse_id if self.discourse_id is not None else self.token()
                )
                self.assertNextToken(DrtTokens.COMMA)
                sent_id = self.nullableIntToken()
                self.assertNextToken(DrtTokens.COMMA)
                word_ids = list(map(int, self.handle_refs()))
                self.assertNextToken(DrtTokens.COMMA)
                var1 = int(self.token())
                self.assertNextToken(DrtTokens.COMMA)
                var2 = int(self.token())
                self.assertNextToken(DrtTokens.COMMA)
                rel = self.token()
                self.assertNextToken(DrtTokens.COMMA)
                sense = int(self.token())
                self.assertNextToken(DrtTokens.CLOSE)
                return BoxerRel(disc_id, sent_id, word_ids, var1, var2, rel, sense)
            elif tok == 'prop':
                self.assertNextToken(DrtTokens.OPEN)
                disc_id = (
                    self.discourse_id if self.discourse_id is not None else self.token()
                )
                self.assertNextToken(DrtTokens.COMMA)
                sent_id = int(self.token())
                self.assertNextToken(DrtTokens.COMMA)
                word_ids = list(map(int, self.handle_refs()))
                self.assertNextToken(DrtTokens.COMMA)
                variable = int(self.token())
                self.assertNextToken(DrtTokens.COMMA)
                drs = self.process_next_expression(None)
                self.assertNextToken(DrtTokens.CLOSE)
                return BoxerProp(disc_id, sent_id, word_ids, variable, drs)
            elif tok == 'not':
                self.assertNextToken(DrtTokens.OPEN)
                drs = self.process_next_expression(None)
                self.assertNextToken(DrtTokens.CLOSE)
                return BoxerNot(drs)
            elif tok == 'imp':
                self.assertNextToken(DrtTokens.OPEN)
                drs1 = self.process_next_expression(None)
                self.assertNextToken(DrtTokens.COMMA)
                drs2 = self.process_next_expression(None)
                self.assertNextToken(DrtTokens.CLOSE)
                return BoxerDrs(drs1.refs, drs1.conds, drs2)
            elif tok == 'or':
                self.assertNextToken(DrtTokens.OPEN)
                disc_id = (
                    self.discourse_id if self.discourse_id is not None else self.token()
                )
                self.assertNextToken(DrtTokens.COMMA)
                sent_id = self.nullableIntToken()
                self.assertNextToken(DrtTokens.COMMA)
                word_ids = map(int, self.handle_refs())
                self.assertNextToken(DrtTokens.COMMA)
                drs1 = self.process_next_expression(None)
                self.assertNextToken(DrtTokens.COMMA)
                drs2 = self.process_next_expression(None)
                self.assertNextToken(DrtTokens.CLOSE)
                return BoxerOr(disc_id, sent_id, word_ids, drs1, drs2)
            elif tok == 'eq':
                self.assertNextToken(DrtTokens.OPEN)
                disc_id = (
                    self.discourse_id if self.discourse_id is not None else self.token()
                )
                self.assertNextToken(DrtTokens.COMMA)
                sent_id = self.nullableIntToken()
                self.assertNextToken(DrtTokens.COMMA)
                word_ids = list(map(int, self.handle_refs()))
                self.assertNextToken(DrtTokens.COMMA)
                var1 = int(self.token())
                self.assertNextToken(DrtTokens.COMMA)
                var2 = int(self.token())
                self.assertNextToken(DrtTokens.CLOSE)
                return BoxerEq(disc_id, sent_id, word_ids, var1, var2)
            elif tok == 'card':
                self.assertNextToken(DrtTokens.OPEN)
                disc_id = (
                    self.discourse_id if self.discourse_id is not None else self.token()
                )
                self.assertNextToken(DrtTokens.COMMA)
                sent_id = self.nullableIntToken()
                self.assertNextToken(DrtTokens.COMMA)
                word_ids = map(int, self.handle_refs())
                self.assertNextToken(DrtTokens.COMMA)
                var = int(self.token())
                self.assertNextToken(DrtTokens.COMMA)
                value = self.token()
                self.assertNextToken(DrtTokens.COMMA)
                type = self.token()
                self.assertNextToken(DrtTokens.CLOSE)
                return BoxerCard(disc_id, sent_id, word_ids, var, value, type)
            elif tok == 'whq':
                self.assertNextToken(DrtTokens.OPEN)
                disc_id = (
                    self.discourse_id if self.discourse_id is not None else self.token()
                )
                self.assertNextToken(DrtTokens.COMMA)
                sent_id = self.nullableIntToken()
                self.assertNextToken(DrtTokens.COMMA)
                word_ids = list(map(int, self.handle_refs()))
                self.assertNextToken(DrtTokens.COMMA)
                ans_types = self.handle_refs()
                self.assertNextToken(DrtTokens.COMMA)
                drs1 = self.process_next_expression(None)
                self.assertNextToken(DrtTokens.COMMA)
                var = int(self.token())
                self.assertNextToken(DrtTokens.COMMA)
                drs2 = self.process_next_expression(None)
                self.assertNextToken(DrtTokens.CLOSE)
                return BoxerWhq(disc_id, sent_id, word_ids, ans_types, drs1, var, drs2)
        except Exception as e:
            raise LogicalExpressionException(self._currentIndex, str(e))
        assert False, repr(tok)

    def nullableIntToken(self):
        t = self.token()
        return int(t) if t != 'None' else None

    def get_next_token_variable(self, description):
        try:
            return self.token()
        except ExpectedMoreTokensException as e:
            raise ExpectedMoreTokensException(e.index, 'Variable expected.')


class AbstractBoxerDrs(object):
    def variables(self):
        """
        :return: (set<variables>, set<events>, set<propositions>)
        """
        variables, events, propositions = self._variables()
        return (variables - (events | propositions), events, propositions - events)

    def variable_types(self):
        vartypes = {}
        for t, vars in zip(('z', 'e', 'p'), self.variables()):
            for v in vars:
                vartypes[v] = t
        return vartypes

    def _variables(self):
        """
        :return: (set<variables>, set<events>, set<propositions>)
        """
        return (set(), set(), set())

    def atoms(self):
        return set()

    def clean(self):
        return self

    def _clean_name(self, name):
        return name.replace('-', '_').replace("'", "_")

    def renumber_sentences(self, f):
        return self

    def __hash__(self):
        return hash("{0}".format(self))


@python_2_unicode_compatible
class BoxerDrs(AbstractBoxerDrs):
    def __init__(self, refs, conds, consequent=None):
        AbstractBoxerDrs.__init__(self)
        self.refs = refs
        self.conds = conds
        self.consequent = consequent

    def _variables(self):
        variables = (set(), set(), set())
        for cond in self.conds:
            for s, v in zip(variables, cond._variables()):
                s.update(v)
        if self.consequent is not None:
            for s, v in zip(variables, self.consequent._variables()):
                s.update(v)
        return variables

    def atoms(self):
        atoms = reduce(operator.or_, (cond.atoms() for cond in self.conds), set())
        if self.consequent is not None:
            atoms.update(self.consequent.atoms())
        return atoms

    def clean(self):
        consequent = self.consequent.clean() if self.consequent else None
        return BoxerDrs(self.refs, [c.clean() for c in self.conds], consequent)

    def renumber_sentences(self, f):
        consequent = self.consequent.renumber_sentences(f) if self.consequent else None
        return BoxerDrs(
            self.refs, [c.renumber_sentences(f) for c in self.conds], consequent
        )

    def __repr__(self):
        s = 'drs([%s], [%s])' % (
            ', '.join("%s" % r for r in self.refs),
            ', '.join("%s" % c for c in self.conds),
        )
        if self.consequent is not None:
            s = 'imp(%s, %s)' % (s, self.consequent)
        return s

    def __eq__(self, other):
        return (
            self.__class__ == other.__class__
            and self.refs == other.refs
            and len(self.conds) == len(other.conds)
            and reduce(
                operator.and_, (c1 == c2 for c1, c2 in zip(self.conds, other.conds))
            )
            and self.consequent == other.consequent
        )

    def __ne__(self, other):
        return not self == other

    __hash__ = AbstractBoxerDrs.__hash__


@python_2_unicode_compatible
class BoxerNot(AbstractBoxerDrs):
    def __init__(self, drs):
        AbstractBoxerDrs.__init__(self)
        self.drs = drs

    def _variables(self):
        return self.drs._variables()

    def atoms(self):
        return self.drs.atoms()

    def clean(self):
        return BoxerNot(self.drs.clean())

    def renumber_sentences(self, f):
        return BoxerNot(self.drs.renumber_sentences(f))

    def __repr__(self):
        return 'not(%s)' % (self.drs)

    def __eq__(self, other):
        return self.__class__ == other.__class__ and self.drs == other.drs

    def __ne__(self, other):
        return not self == other

    __hash__ = AbstractBoxerDrs.__hash__


@python_2_unicode_compatible
class BoxerIndexed(AbstractBoxerDrs):
    def __init__(self, discourse_id, sent_index, word_indices):
        AbstractBoxerDrs.__init__(self)
        self.discourse_id = discourse_id
        self.sent_index = sent_index
        self.word_indices = word_indices

    def atoms(self):
        return set([self])

    def __eq__(self, other):
        return (
            self.__class__ == other.__class__
            and self.discourse_id == other.discourse_id
            and self.sent_index == other.sent_index
            and self.word_indices == other.word_indices
            and reduce(operator.and_, (s == o for s, o in zip(self, other)))
        )

    def __ne__(self, other):
        return not self == other

    __hash__ = AbstractBoxerDrs.__hash__

    def __repr__(self):
        s = '%s(%s, %s, [%s]' % (
            self._pred(),
            self.discourse_id,
            self.sent_index,
            ', '.join("%s" % wi for wi in self.word_indices),
        )
        for v in self:
            s += ', %s' % v
        return s + ')'


class BoxerPred(BoxerIndexed):
    def __init__(self, discourse_id, sent_index, word_indices, var, name, pos, sense):
        BoxerIndexed.__init__(self, discourse_id, sent_index, word_indices)
        self.var = var
        self.name = name
        self.pos = pos
        self.sense = sense

    def _variables(self):
        return (set([self.var]), set(), set())

    def change_var(self, var):
        return BoxerPred(
            self.discourse_id,
            self.sent_index,
            self.word_indices,
            var,
            self.name,
            self.pos,
            self.sense,
        )

    def clean(self):
        return BoxerPred(
            self.discourse_id,
            self.sent_index,
            self.word_indices,
            self.var,
            self._clean_name(self.name),
            self.pos,
            self.sense,
        )

    def renumber_sentences(self, f):
        new_sent_index = f(self.sent_index)
        return BoxerPred(
            self.discourse_id,
            new_sent_index,
            self.word_indices,
            self.var,
            self.name,
            self.pos,
            self.sense,
        )

    def __iter__(self):
        return iter((self.var, self.name, self.pos, self.sense))

    def _pred(self):
        return 'pred'


class BoxerNamed(BoxerIndexed):
    def __init__(self, discourse_id, sent_index, word_indices, var, name, type, sense):
        BoxerIndexed.__init__(self, discourse_id, sent_index, word_indices)
        self.var = var
        self.name = name
        self.type = type
        self.sense = sense

    def _variables(self):
        return (set([self.var]), set(), set())

    def change_var(self, var):
        return BoxerNamed(
            self.discourse_id,
            self.sent_index,
            self.word_indices,
            var,
            self.name,
            self.type,
            self.sense,
        )

    def clean(self):
        return BoxerNamed(
            self.discourse_id,
            self.sent_index,
            self.word_indices,
            self.var,
            self._clean_name(self.name),
            self.type,
            self.sense,
        )

    def renumber_sentences(self, f):
        return BoxerNamed(
            self.discourse_id,
            f(self.sent_index),
            self.word_indices,
            self.var,
            self.name,
            self.type,
            self.sense,
        )

    def __iter__(self):
        return iter((self.var, self.name, self.type, self.sense))

    def _pred(self):
        return 'named'


class BoxerRel(BoxerIndexed):
    def __init__(self, discourse_id, sent_index, word_indices, var1, var2, rel, sense):
        BoxerIndexed.__init__(self, discourse_id, sent_index, word_indices)
        self.var1 = var1
        self.var2 = var2
        self.rel = rel
        self.sense = sense

    def _variables(self):
        return (set([self.var1, self.var2]), set(), set())

    def clean(self):
        return BoxerRel(
            self.discourse_id,
            self.sent_index,
            self.word_indices,
            self.var1,
            self.var2,
            self._clean_name(self.rel),
            self.sense,
        )

    def renumber_sentences(self, f):
        return BoxerRel(
            self.discourse_id,
            f(self.sent_index),
            self.word_indices,
            self.var1,
            self.var2,
            self.rel,
            self.sense,
        )

    def __iter__(self):
        return iter((self.var1, self.var2, self.rel, self.sense))

    def _pred(self):
        return 'rel'


class BoxerProp(BoxerIndexed):
    def __init__(self, discourse_id, sent_index, word_indices, var, drs):
        BoxerIndexed.__init__(self, discourse_id, sent_index, word_indices)
        self.var = var
        self.drs = drs

    def _variables(self):
        return tuple(
            map(operator.or_, (set(), set(), set([self.var])), self.drs._variables())
        )

    def referenced_labels(self):
        return set([self.drs])

    def atoms(self):
        return self.drs.atoms()

    def clean(self):
        return BoxerProp(
            self.discourse_id,
            self.sent_index,
            self.word_indices,
            self.var,
            self.drs.clean(),
        )

    def renumber_sentences(self, f):
        return BoxerProp(
            self.discourse_id,
            f(self.sent_index),
            self.word_indices,
            self.var,
            self.drs.renumber_sentences(f),
        )

    def __iter__(self):
        return iter((self.var, self.drs))

    def _pred(self):
        return 'prop'


class BoxerEq(BoxerIndexed):
    def __init__(self, discourse_id, sent_index, word_indices, var1, var2):
        BoxerIndexed.__init__(self, discourse_id, sent_index, word_indices)
        self.var1 = var1
        self.var2 = var2

    def _variables(self):
        return (set([self.var1, self.var2]), set(), set())

    def atoms(self):
        return set()

    def renumber_sentences(self, f):
        return BoxerEq(
            self.discourse_id,
            f(self.sent_index),
            self.word_indices,
            self.var1,
            self.var2,
        )

    def __iter__(self):
        return iter((self.var1, self.var2))

    def _pred(self):
        return 'eq'


class BoxerCard(BoxerIndexed):
    def __init__(self, discourse_id, sent_index, word_indices, var, value, type):
        BoxerIndexed.__init__(self, discourse_id, sent_index, word_indices)
        self.var = var
        self.value = value
        self.type = type

    def _variables(self):
        return (set([self.var]), set(), set())

    def renumber_sentences(self, f):
        return BoxerCard(
            self.discourse_id,
            f(self.sent_index),
            self.word_indices,
            self.var,
            self.value,
            self.type,
        )

    def __iter__(self):
        return iter((self.var, self.value, self.type))

    def _pred(self):
        return 'card'


class BoxerOr(BoxerIndexed):
    def __init__(self, discourse_id, sent_index, word_indices, drs1, drs2):
        BoxerIndexed.__init__(self, discourse_id, sent_index, word_indices)
        self.drs1 = drs1
        self.drs2 = drs2

    def _variables(self):
        return tuple(map(operator.or_, self.drs1._variables(), self.drs2._variables()))

    def atoms(self):
        return self.drs1.atoms() | self.drs2.atoms()

    def clean(self):
        return BoxerOr(
            self.discourse_id,
            self.sent_index,
            self.word_indices,
            self.drs1.clean(),
            self.drs2.clean(),
        )

    def renumber_sentences(self, f):
        return BoxerOr(
            self.discourse_id,
            f(self.sent_index),
            self.word_indices,
            self.drs1,
            self.drs2,
        )

    def __iter__(self):
        return iter((self.drs1, self.drs2))

    def _pred(self):
        return 'or'


class BoxerWhq(BoxerIndexed):
    def __init__(
        self, discourse_id, sent_index, word_indices, ans_types, drs1, variable, drs2
    ):
        BoxerIndexed.__init__(self, discourse_id, sent_index, word_indices)
        self.ans_types = ans_types
        self.drs1 = drs1
        self.variable = variable
        self.drs2 = drs2

    def _variables(self):
        return tuple(
            map(
                operator.or_,
                (set([self.variable]), set(), set()),
                self.drs1._variables(),
                self.drs2._variables(),
            )
        )

    def atoms(self):
        return self.drs1.atoms() | self.drs2.atoms()

    def clean(self):
        return BoxerWhq(
            self.discourse_id,
            self.sent_index,
            self.word_indices,
            self.ans_types,
            self.drs1.clean(),
            self.variable,
            self.drs2.clean(),
        )

    def renumber_sentences(self, f):
        return BoxerWhq(
            self.discourse_id,
            f(self.sent_index),
            self.word_indices,
            self.ans_types,
            self.drs1,
            self.variable,
            self.drs2,
        )

    def __iter__(self):
        return iter(
            ('[' + ','.join(self.ans_types) + ']', self.drs1, self.variable, self.drs2)
        )

    def _pred(self):
        return 'whq'


class PassthroughBoxerDrsInterpreter(object):
    def interpret(self, ex):
        return ex


class NltkDrtBoxerDrsInterpreter(object):
    def __init__(self, occur_index=False):
        self._occur_index = occur_index

    def interpret(self, ex):
        """
        :param ex: ``AbstractBoxerDrs``
        :return: ``DrtExpression``
        """
        if isinstance(ex, BoxerDrs):
            drs = DRS(
                [Variable(r) for r in ex.refs], list(map(self.interpret, ex.conds))
            )
            if ex.consequent is not None:
                drs.consequent = self.interpret(ex.consequent)
            return drs
        elif isinstance(ex, BoxerNot):
            return DrtNegatedExpression(self.interpret(ex.drs))
        elif isinstance(ex, BoxerPred):
            pred = self._add_occur_indexing('%s_%s' % (ex.pos, ex.name), ex)
            return self._make_atom(pred, ex.var)
        elif isinstance(ex, BoxerNamed):
            pred = self._add_occur_indexing('ne_%s_%s' % (ex.type, ex.name), ex)
            return self._make_atom(pred, ex.var)
        elif isinstance(ex, BoxerRel):
            pred = self._add_occur_indexing('%s' % (ex.rel), ex)
            return self._make_atom(pred, ex.var1, ex.var2)
        elif isinstance(ex, BoxerProp):
            return DrtProposition(Variable(ex.var), self.interpret(ex.drs))
        elif isinstance(ex, BoxerEq):
            return DrtEqualityExpression(
                DrtVariableExpression(Variable(ex.var1)),
                DrtVariableExpression(Variable(ex.var2)),
            )
        elif isinstance(ex, BoxerCard):
            pred = self._add_occur_indexing('card_%s_%s' % (ex.type, ex.value), ex)
            return self._make_atom(pred, ex.var)
        elif isinstance(ex, BoxerOr):
            return DrtOrExpression(self.interpret(ex.drs1), self.interpret(ex.drs2))
        elif isinstance(ex, BoxerWhq):
            drs1 = self.interpret(ex.drs1)
            drs2 = self.interpret(ex.drs2)
            return DRS(drs1.refs + drs2.refs, drs1.conds + drs2.conds)
        assert False, '%s: %s' % (ex.__class__.__name__, ex)

    def _make_atom(self, pred, *args):
        accum = DrtVariableExpression(Variable(pred))
        for arg in args:
            accum = DrtApplicationExpression(
                accum, DrtVariableExpression(Variable(arg))
            )
        return accum

    def _add_occur_indexing(self, base, ex):
        if self._occur_index and ex.sent_index is not None:
            if ex.discourse_id:
                base += '_%s' % ex.discourse_id
            base += '_s%s' % ex.sent_index
            base += '_w%s' % sorted(ex.word_indices)[0]
        return base


class UnparseableInputException(Exception):
    pass


if __name__ == '__main__':
    opts = OptionParser("usage: %prog TEXT [options]")
    opts.add_option(
        "--verbose",
        "-v",
        help="display verbose logs",
        action="store_true",
        default=False,
        dest="verbose",
    )
    opts.add_option(
        "--fol", "-f", help="output FOL", action="store_true", default=False, dest="fol"
    )
    opts.add_option(
        "--question",
        "-q",
        help="input is a question",
        action="store_true",
        default=False,
        dest="question",
    )
    opts.add_option(
        "--occur",
        "-o",
        help="occurrence index",
        action="store_true",
        default=False,
        dest="occur_index",
    )
    (options, args) = opts.parse_args()

    if len(args) != 1:
        opts.error("incorrect number of arguments")

    interpreter = NltkDrtBoxerDrsInterpreter(occur_index=options.occur_index)
    drs = Boxer(interpreter).interpret_multi(
        args[0].split(r'\n'), question=options.question, verbose=options.verbose
    )
    if drs is None:
        print(None)
    else:
        drs = drs.simplify().eliminate_equality()
        if options.fol:
            print(drs.fol().normalize())
        else:
            drs.pretty_print()
