#    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.

import collections
import datetime
import re

import toscaparser
from toscaparser.common.exception import ExceptionCollector
from toscaparser.common.exception import InvalidSchemaError
from toscaparser.common.exception import ValidationError
from toscaparser.elements import scalarunit
from toscaparser.utils.gettextutils import _


class Schema(collections.Mapping):

    KEYS = (
        TYPE, REQUIRED, DESCRIPTION,
        DEFAULT, CONSTRAINTS, ENTRYSCHEMA
    ) = (
        'type', 'required', 'description',
        'default', 'constraints', 'entry_schema'
    )

    PROPERTY_TYPES = (
        INTEGER, STRING, BOOLEAN, FLOAT,
        NUMBER, TIMESTAMP, LIST, MAP,
        SCALAR_UNIT_SIZE, SCALAR_UNIT_FREQUENCY, SCALAR_UNIT_TIME,
        PORTDEF, VERSION
    ) = (
        'integer', 'string', 'boolean', 'float',
        'number', 'timestamp', 'list', 'map',
        'scalar-unit.size', 'scalar-unit.frequency', 'scalar-unit.time',
        'PortDef', 'version'
    )

    SCALAR_UNIT_SIZE_DEFAULT = 'B'
    SCALAR_UNIT_SIZE_DICT = {'B': 1, 'KB': 1000, 'KIB': 1024, 'MB': 1000000,
                             'MIB': 1048576, 'GB': 1000000000,
                             'GIB': 1073741824, 'TB': 1000000000000,
                             'TIB': 1099511627776}

    def __init__(self, name, schema_dict):
        self.name = name
        if not isinstance(schema_dict, collections.Mapping):
            msg = (_('Schema definition of "%(pname)s" must be a dict.')
                   % dict(pname=name))
            ExceptionCollector.appendException(InvalidSchemaError(message=msg))

        try:
            schema_dict['type']
        except KeyError:
            msg = (_('Schema definition of "%(pname)s" must have a "type" '
                     'attribute.') % dict(pname=name))
            ExceptionCollector.appendException(InvalidSchemaError(message=msg))

        self.schema = schema_dict
        self._len = None
        self.constraints_list = []

    @property
    def type(self):
        return self.schema[self.TYPE]

    @property
    def required(self):
        return self.schema.get(self.REQUIRED, True)

    @property
    def description(self):
        return self.schema.get(self.DESCRIPTION, '')

    @property
    def default(self):
        return self.schema.get(self.DEFAULT)

    @property
    def constraints(self):
        if not self.constraints_list:
            constraint_schemata = self.schema.get(self.CONSTRAINTS)
            if constraint_schemata:
                self.constraints_list = [Constraint(self.name,
                                                    self.type,
                                                    cschema)
                                         for cschema in constraint_schemata]
        return self.constraints_list

    @property
    def entry_schema(self):
        return self.schema.get(self.ENTRYSCHEMA)

    def __getitem__(self, key):
        return self.schema[key]

    def __iter__(self):
        for k in self.KEYS:
            try:
                self.schema[k]
            except KeyError:
                pass
            else:
                yield k

    def __len__(self):
        if self._len is None:
            self._len = len(list(iter(self)))
        return self._len


class Constraint(object):
    '''Parent class for constraints for a Property or Input.'''

    CONSTRAINTS = (EQUAL, GREATER_THAN,
                   GREATER_OR_EQUAL, LESS_THAN, LESS_OR_EQUAL, IN_RANGE,
                   VALID_VALUES, LENGTH, MIN_LENGTH, MAX_LENGTH, PATTERN) = \
                  ('equal', 'greater_than', 'greater_or_equal', 'less_than',
                   'less_or_equal', 'in_range', 'valid_values', 'length',
                   'min_length', 'max_length', 'pattern')

    def __new__(cls, property_name, property_type, constraint):
        if cls is not Constraint:
            return super(Constraint, cls).__new__(cls)

        if(not isinstance(constraint, collections.Mapping) or
           len(constraint) != 1):
            ExceptionCollector.appendException(
                InvalidSchemaError(message=_('Invalid constraint schema.')))

        for type in constraint.keys():
            ConstraintClass = get_constraint_class(type)
            if not ConstraintClass:
                msg = _('Invalid property "%s".') % type
                ExceptionCollector.appendException(
                    InvalidSchemaError(message=msg))

        return ConstraintClass(property_name, property_type, constraint)

    def __init__(self, property_name, property_type, constraint):
        self.property_name = property_name
        self.property_type = property_type
        self.constraint_value = constraint[self.constraint_key]
        self.constraint_value_msg = self.constraint_value
        if self.property_type in scalarunit.ScalarUnit.SCALAR_UNIT_TYPES:
            self.constraint_value = self._get_scalarunit_constraint_value()
        # check if constraint is valid for property type
        if property_type not in self.valid_prop_types:
            msg = _('Property "%(ctype)s" is not valid for data type '
                    '"%(dtype)s".') % dict(
                        ctype=self.constraint_key,
                        dtype=property_type)
            ExceptionCollector.appendException(InvalidSchemaError(message=msg))

    def _get_scalarunit_constraint_value(self):
        if self.property_type in scalarunit.ScalarUnit.SCALAR_UNIT_TYPES:
            ScalarUnit_Class = (scalarunit.
                                get_scalarunit_class(self.property_type))
        if isinstance(self.constraint_value, list):
            return [ScalarUnit_Class(v).get_num_from_scalar_unit()
                    for v in self.constraint_value]
        else:
            return (ScalarUnit_Class(self.constraint_value).
                    get_num_from_scalar_unit())

    def _err_msg(self, value):
        return _('Property "%s" could not be validated.') % self.property_name

    def validate(self, value):
        self.value_msg = value
        if self.property_type in scalarunit.ScalarUnit.SCALAR_UNIT_TYPES:
            value = scalarunit.get_scalarunit_value(self.property_type, value)
        if not self._is_valid(value):
            err_msg = self._err_msg(value)
            ExceptionCollector.appendException(
                ValidationError(message=err_msg))


class Equal(Constraint):
    """Constraint class for "equal"

    Constrains a property or parameter to a value equal to ('=')
    the value declared.
    """

    constraint_key = Constraint.EQUAL

    valid_prop_types = Schema.PROPERTY_TYPES

    def _is_valid(self, value):
        if value == self.constraint_value:
            return True

        return False

    def _err_msg(self, value):
        return (_('The value "%(pvalue)s" of property "%(pname)s" is not '
                  'equal to "%(cvalue)s".') %
                dict(pname=self.property_name,
                     pvalue=self.value_msg,
                     cvalue=self.constraint_value_msg))


class GreaterThan(Constraint):
    """Constraint class for "greater_than"

    Constrains a property or parameter to a value greater than ('>')
    the value declared.
    """

    constraint_key = Constraint.GREATER_THAN

    valid_types = (int, float, datetime.date,
                   datetime.time, datetime.datetime)

    valid_prop_types = (Schema.INTEGER, Schema.FLOAT, Schema.TIMESTAMP,
                        Schema.SCALAR_UNIT_SIZE, Schema.SCALAR_UNIT_FREQUENCY,
                        Schema.SCALAR_UNIT_TIME)

    def __init__(self, property_name, property_type, constraint):
        super(GreaterThan, self).__init__(property_name, property_type,
                                          constraint)
        if not isinstance(constraint[self.GREATER_THAN], self.valid_types):
            ExceptionCollector.appendException(
                InvalidSchemaError(message=_('The property "greater_than" '
                                             'expects comparable values.')))

    def _is_valid(self, value):
        if value > self.constraint_value:
            return True

        return False

    def _err_msg(self, value):
        return (_('The value "%(pvalue)s" of property "%(pname)s" must be '
                  'greater than "%(cvalue)s".') %
                dict(pname=self.property_name,
                     pvalue=self.value_msg,
                     cvalue=self.constraint_value_msg))


class GreaterOrEqual(Constraint):
    """Constraint class for "greater_or_equal"

    Constrains a property or parameter to a value greater than or equal
    to ('>=') the value declared.
    """

    constraint_key = Constraint.GREATER_OR_EQUAL

    valid_types = (int, float, datetime.date,
                   datetime.time, datetime.datetime)

    valid_prop_types = (Schema.INTEGER, Schema.FLOAT, Schema.TIMESTAMP,
                        Schema.SCALAR_UNIT_SIZE, Schema.SCALAR_UNIT_FREQUENCY,
                        Schema.SCALAR_UNIT_TIME)

    def __init__(self, property_name, property_type, constraint):
        super(GreaterOrEqual, self).__init__(property_name, property_type,
                                             constraint)
        if not isinstance(self.constraint_value, self.valid_types):
            ExceptionCollector.appendException(
                InvalidSchemaError(message=_('The property '
                                             '"greater_or_equal" expects '
                                             'comparable values.')))

    def _is_valid(self, value):
        if toscaparser.functions.is_function(value) or \
           value >= self.constraint_value:
            return True
        return False

    def _err_msg(self, value):
        return (_('The value "%(pvalue)s" of property "%(pname)s" must be '
                  'greater than or equal to "%(cvalue)s".') %
                dict(pname=self.property_name,
                     pvalue=self.value_msg,
                     cvalue=self.constraint_value_msg))


class LessThan(Constraint):
    """Constraint class for "less_than"

    Constrains a property or parameter to a value less than ('<')
    the value declared.
    """

    constraint_key = Constraint.LESS_THAN

    valid_types = (int, float, datetime.date,
                   datetime.time, datetime.datetime)

    valid_prop_types = (Schema.INTEGER, Schema.FLOAT, Schema.TIMESTAMP,
                        Schema.SCALAR_UNIT_SIZE, Schema.SCALAR_UNIT_FREQUENCY,
                        Schema.SCALAR_UNIT_TIME)

    def __init__(self, property_name, property_type, constraint):
        super(LessThan, self).__init__(property_name, property_type,
                                       constraint)
        if not isinstance(self.constraint_value, self.valid_types):
            ExceptionCollector.appendException(
                InvalidSchemaError(message=_('The property "less_than" '
                                             'expects comparable values.')))

    def _is_valid(self, value):
        if value < self.constraint_value:
            return True

        return False

    def _err_msg(self, value):
        return (_('The value "%(pvalue)s" of property "%(pname)s" must be '
                  'less than "%(cvalue)s".') %
                dict(pname=self.property_name,
                     pvalue=self.value_msg,
                     cvalue=self.constraint_value_msg))


class LessOrEqual(Constraint):
    """Constraint class for "less_or_equal"

    Constrains a property or parameter to a value less than or equal
    to ('<=') the value declared.
    """

    constraint_key = Constraint.LESS_OR_EQUAL

    valid_types = (int, float, datetime.date,
                   datetime.time, datetime.datetime)

    valid_prop_types = (Schema.INTEGER, Schema.FLOAT, Schema.TIMESTAMP,
                        Schema.SCALAR_UNIT_SIZE, Schema.SCALAR_UNIT_FREQUENCY,
                        Schema.SCALAR_UNIT_TIME)

    def __init__(self, property_name, property_type, constraint):
        super(LessOrEqual, self).__init__(property_name, property_type,
                                          constraint)
        if not isinstance(self.constraint_value, self.valid_types):
            ExceptionCollector.appendException(
                InvalidSchemaError(message=_('The property "less_or_equal" '
                                             'expects comparable values.')))

    def _is_valid(self, value):
        if value <= self.constraint_value:
            return True

        return False

    def _err_msg(self, value):
        return (_('The value "%(pvalue)s" of property "%(pname)s" must be '
                  'less than or equal to "%(cvalue)s".') %
                dict(pname=self.property_name,
                     pvalue=self.value_msg,
                     cvalue=self.constraint_value_msg))


class InRange(Constraint):
    """Constraint class for "in_range"

    Constrains a property or parameter to a value in range of (inclusive)
    the two values declared.
    """

    constraint_key = Constraint.IN_RANGE

    valid_types = (int, float, datetime.date,
                   datetime.time, datetime.datetime)

    valid_prop_types = (Schema.INTEGER, Schema.FLOAT, Schema.TIMESTAMP,
                        Schema.SCALAR_UNIT_SIZE, Schema.SCALAR_UNIT_FREQUENCY,
                        Schema.SCALAR_UNIT_TIME)

    def __init__(self, property_name, property_type, constraint):
        super(InRange, self).__init__(property_name, property_type, constraint)
        if(not isinstance(self.constraint_value, collections.Sequence) or
           (len(constraint[self.IN_RANGE]) != 2)):
            ExceptionCollector.appendException(
                InvalidSchemaError(message=_('The property "in_range" '
                                             'expects a list.')))

        for value in self.constraint_value:
            if not isinstance(value, self.valid_types):
                ExceptionCollector.appendException(
                    InvalidSchemaError(_('The property "in_range" expects '
                                         'comparable values.')))

        self.min = self.constraint_value[0]
        self.max = self.constraint_value[1]

    def _is_valid(self, value):
        if value < self.min:
            return False
        if value > self.max:
            return False

        return True

    def _err_msg(self, value):
        return (_('The value "%(pvalue)s" of property "%(pname)s" is out of '
                  'range "(min:%(vmin)s, max:%(vmax)s)".') %
                dict(pname=self.property_name,
                     pvalue=self.value_msg,
                     vmin=self.constraint_value_msg[0],
                     vmax=self.constraint_value_msg[1]))


class ValidValues(Constraint):
    """Constraint class for "valid_values"

    Constrains a property or parameter to a value that is in the list of
    declared values.
    """
    constraint_key = Constraint.VALID_VALUES

    valid_prop_types = Schema.PROPERTY_TYPES

    def __init__(self, property_name, property_type, constraint):
        super(ValidValues, self).__init__(property_name, property_type,
                                          constraint)
        if not isinstance(self.constraint_value, collections.Sequence):
            ExceptionCollector.appendException(
                InvalidSchemaError(message=_('The property "valid_values" '
                                             'expects a list.')))

    def _is_valid(self, value):
        if isinstance(value, list):
            return all(v in self.constraint_value for v in value)
        return value in self.constraint_value

    def _err_msg(self, value):
        allowed = '[%s]' % ', '.join(str(a) for a in self.constraint_value)
        return (_('The value "%(pvalue)s" of property "%(pname)s" is not '
                  'valid. Expected a value from "%(cvalue)s".') %
                dict(pname=self.property_name,
                     pvalue=value,
                     cvalue=allowed))


class Length(Constraint):
    """Constraint class for "length"

    Constrains the property or parameter to a value of a given length.
    """

    constraint_key = Constraint.LENGTH

    valid_types = (int, )

    valid_prop_types = (Schema.STRING, )

    def __init__(self, property_name, property_type, constraint):
        super(Length, self).__init__(property_name, property_type, constraint)
        if not isinstance(self.constraint_value, self.valid_types):
            ExceptionCollector.appendException(
                InvalidSchemaError(message=_('The property "length" expects '
                                             'an integer.')))

    def _is_valid(self, value):
        if isinstance(value, str) and len(value) == self.constraint_value:
            return True

        return False

    def _err_msg(self, value):
        return (_('Length of value "%(pvalue)s" of property "%(pname)s" '
                  'must be equal to "%(cvalue)s".') %
                dict(pname=self.property_name,
                     pvalue=value,
                     cvalue=self.constraint_value))


class MinLength(Constraint):
    """Constraint class for "min_length"

    Constrains the property or parameter to a value to a minimum length.
    """

    constraint_key = Constraint.MIN_LENGTH

    valid_types = (int, )

    valid_prop_types = (Schema.STRING, )

    def __init__(self, property_name, property_type, constraint):
        super(MinLength, self).__init__(property_name, property_type,
                                        constraint)
        if not isinstance(self.constraint_value, self.valid_types):
            ExceptionCollector.appendException(
                InvalidSchemaError(message=_('The property "min_length" '
                                             'expects an integer.')))

    def _is_valid(self, value):
        if isinstance(value, str) and len(value) >= self.constraint_value:
            return True

        return False

    def _err_msg(self, value):
        return (_('Length of value "%(pvalue)s" of property "%(pname)s" '
                  'must be at least "%(cvalue)s".') %
                dict(pname=self.property_name,
                     pvalue=value,
                     cvalue=self.constraint_value))


class MaxLength(Constraint):
    """Constraint class for "max_length"

    Constrains the property or parameter to a value to a maximum length.
    """

    constraint_key = Constraint.MAX_LENGTH

    valid_types = (int, )

    valid_prop_types = (Schema.STRING, )

    def __init__(self, property_name, property_type, constraint):
        super(MaxLength, self).__init__(property_name, property_type,
                                        constraint)
        if not isinstance(self.constraint_value, self.valid_types):
            ExceptionCollector.appendException(
                InvalidSchemaError(message=_('The property "max_length" '
                                             'expects an integer.')))

    def _is_valid(self, value):
        if isinstance(value, str) and len(value) <= self.constraint_value:
            return True

        return False

    def _err_msg(self, value):
        return (_('Length of value "%(pvalue)s" of property "%(pname)s" '
                  'must be no greater than "%(cvalue)s".') %
                dict(pname=self.property_name,
                     pvalue=value,
                     cvalue=self.constraint_value))


class Pattern(Constraint):
    """Constraint class for "pattern"

    Constrains the property or parameter to a value that is allowed by
    the provided regular expression.
    """

    constraint_key = Constraint.PATTERN

    valid_types = (str, )

    valid_prop_types = (Schema.STRING, )

    def __init__(self, property_name, property_type, constraint):
        super(Pattern, self).__init__(property_name, property_type, constraint)
        if not isinstance(self.constraint_value, self.valid_types):
            ExceptionCollector.appendException(
                InvalidSchemaError(message=_('The property "pattern" '
                                             'expects a string.')))
        self.match = re.compile(self.constraint_value).match

    def _is_valid(self, value):
        match = self.match(value)
        return match is not None and match.end() == len(value)

    def _err_msg(self, value):
        return (_('The value "%(pvalue)s" of property "%(pname)s" does not '
                  'match pattern "%(cvalue)s".') %
                dict(pname=self.property_name,
                     pvalue=value,
                     cvalue=self.constraint_value))


constraint_mapping = {
    Constraint.EQUAL: Equal,
    Constraint.GREATER_THAN: GreaterThan,
    Constraint.GREATER_OR_EQUAL: GreaterOrEqual,
    Constraint.LESS_THAN: LessThan,
    Constraint.LESS_OR_EQUAL: LessOrEqual,
    Constraint.IN_RANGE: InRange,
    Constraint.VALID_VALUES: ValidValues,
    Constraint.LENGTH: Length,
    Constraint.MIN_LENGTH: MinLength,
    Constraint.MAX_LENGTH: MaxLength,
    Constraint.PATTERN: Pattern
    }


def get_constraint_class(type):
    return constraint_mapping.get(type)