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# Copyright 2010 United States Government as represented by the
# Administrator of the National Aeronautics and Space Administration.
# Copyright 2012 Hewlett-Packard Development Company, L.P.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.

"""Matcher classes to be used inside of the testtools assertThat framework."""

import pprint


class DictKeysMismatch(object):
    def __init__(self, d1only, d2only):
        self.d1only = d1only
        self.d2only = d2only

    def describe(self):
        return ('Keys in d1 and not d2: %(d1only)s.'
                ' Keys in d2 and not d1: %(d2only)s' % {'d1only': self.d1only,
                                                        'd2only': self.d2only})

    def get_details(self):
        return {}


class DictMismatch(object):
    def __init__(self, key, d1_value, d2_value):
        self.key = key
        self.d1_value = d1_value
        self.d2_value = d2_value

    def describe(self):
        return ("Dictionaries do not match at %(key)s."
                " d1: %(d1_value)s d2: %(d2_value)s"
                % {'key': self.key, 'd1_value': self.d1_value,
                   'd2_value': self.d2_value})

    def get_details(self):
        return {}


class DictMatches(object):

    def __init__(self, d1, approx_equal=False, tolerance=0.001):
        self.d1 = d1
        self.approx_equal = approx_equal
        self.tolerance = tolerance

    def __str__(self):
        return 'DictMatches(%s)' % (pprint.pformat(self.d1))

    # Useful assertions
    def match(self, d2):
        """Assert two dicts are equivalent.

        This is a 'deep' match in the sense that it handles nested
        dictionaries appropriately.

        NOTE:

            If you don't care (or don't know) a given value, you can specify
            the string DONTCARE as the value. This will cause that dict-item
            to be skipped.

        """

        d1keys = set(self.d1.keys())
        d2keys = set(d2.keys())
        if d1keys != d2keys:
            d1only = d1keys - d2keys
            d2only = d2keys - d1keys
            return DictKeysMismatch(d1only, d2only)

        for key in d1keys:
            d1value = self.d1[key]
            d2value = d2[key]
            try:
                error = abs(float(d1value) - float(d2value))
                within_tolerance = error <= self.tolerance
            except (ValueError, TypeError):
                # If both values aren't convertible to float, just ignore
                # ValueError if arg is a str, TypeError if it's something else
                # (like None)
                within_tolerance = False

            if hasattr(d1value, 'keys') and hasattr(d2value, 'keys'):
                matcher = DictMatches(d1value)
                did_match = matcher.match(d2value)
                if did_match is not None:
                    return did_match
            elif 'DONTCARE' in (d1value, d2value):
                continue
            elif self.approx_equal and within_tolerance:
                continue
            elif d1value != d2value:
                return DictMismatch(key, d1value, d2value)
