from strictyaml.exceptions import YAMLSerializationError, InvalidOptionalDefault
from strictyaml.validators import Validator, MapValidator, SeqValidator
from ruamel.yaml.comments import CommentedMap, CommentedSeq
from strictyaml.representation import YAML
from strictyaml.scalar import ScalarValidator, Str
from strictyaml.yamllocation import YAMLChunk
import sys


if sys.version_info[0] == 3:
    unicode = str


class Optional(object):
    def __init__(self, key, default=None, drop_if_none=True):
        self.key = key
        self.default = default
        self.drop_if_none = drop_if_none

    def __repr__(self):
        # TODO: Add default
        return u'Optional("{0}")'.format(self.key)


class MapPattern(MapValidator):
    def __init__(
        self, key_validator, value_validator, minimum_keys=None, maximum_keys=None
    ):
        self._key_validator = key_validator
        self._value_validator = value_validator
        self._maximum_keys = maximum_keys
        self._minimum_keys = minimum_keys
        assert isinstance(
            self._key_validator, ScalarValidator
        ), "key_validator must be ScalarValidator"
        assert isinstance(
            self._value_validator, Validator
        ), "value_validator must be Validator"
        assert isinstance(
            maximum_keys, (type(None), int)
        ), "maximum_keys must be an integer"
        assert isinstance(
            minimum_keys, (type(None), int)
        ), "maximum_keys must be an integer"

    @property
    def key_validator(self):
        return self._key_validator

    def validate(self, chunk):
        items = chunk.expect_mapping()

        if self._maximum_keys is not None and len(items) > self._maximum_keys:
            chunk.expecting_but_found(
                u"while parsing a mapping",
                u"expected a maximum of {0} key{1}, found {2}.".format(
                    self._maximum_keys,
                    u"s" if self._maximum_keys > 1 else u"",
                    len(items),
                ),
            )

        if self._minimum_keys is not None and len(items) < self._minimum_keys:
            chunk.expecting_but_found(
                u"while parsing a mapping",
                u"expected a minimum of {0} key{1}, found {2}.".format(
                    self._minimum_keys,
                    u"s" if self._minimum_keys > 1 else u"",
                    len(items),
                ),
            )

        for key, value in items:
            yaml_key = self._key_validator(key)
            key.process(yaml_key)
            value.process(self._value_validator(value))
            chunk.add_key_association(key.contents, yaml_key.data)

    def to_yaml(self, data):
        self._should_be_mapping(data)
        # TODO : Maximum minimum keys
        return CommentedMap(
            [
                (self._key_validator.to_yaml(key), self._value_validator.to_yaml(value))
                for key, value in data.items()
            ]
        )

    def __repr__(self):
        return u"MapPattern({0}, {1})".format(
            repr(self._key_validator), repr(self._value_validator)
        )


class Map(MapValidator):
    def __init__(self, validator, key_validator=None):
        self._validator = validator
        self._key_validator = Str() if key_validator is None else key_validator
        assert isinstance(
            self._key_validator, ScalarValidator
        ), "key validator must be ScalarValidator"

        self._validator_dict = {
            key.key if isinstance(key, Optional) else key: value
            for key, value in validator.items()
        }

        self._required_keys = [
            key for key in validator.keys() if not isinstance(key, Optional)
        ]

        for key_val, value_val in validator.items():
            if isinstance(key_val, Optional):
                if key_val.default is not None and not key_val.drop_if_none:
                    raise InvalidOptionalDefault(
                        "If you have a default that isn't None, drop_if_none must be True."
                    )
                if key_val.default is not None and key_val.drop_if_none:
                    try:
                        value_val.to_yaml(key_val.default)
                    except YAMLSerializationError as error:
                        raise InvalidOptionalDefault(
                            "Optional default for '{}' failed validation:\n  {}".format(
                                key_val.key, error
                            )
                        )

        self._defaults = {
            key.key: key.default
            for key in validator.keys()
            if isinstance(key, Optional)
            and (key.default is not None or not key.drop_if_none)
        }

    @property
    def key_validator(self):
        return self._key_validator

    def __repr__(self):
        # TODO : repr key_validator
        return u"Map({{{0}}})".format(
            ", ".join(
                [
                    "{0}: {1}".format(repr(key), repr(value))
                    for key, value in self._validator.items()
                ]
            )
        )

    def validate(self, chunk):
        found_keys = set()
        items = chunk.expect_mapping()

        for key, value in items:
            yaml_key = self._key_validator(key)

            if yaml_key.scalar not in self._validator_dict.keys():
                key.expecting_but_found(
                    u"while parsing a mapping",
                    u"unexpected key not in schema '{0}'".format(
                        unicode(yaml_key.scalar)
                    ),
                )

            value.process(self._validator_dict[yaml_key.scalar](value))
            key.process(yaml_key)
            chunk.add_key_association(key.contents, yaml_key.data)
            found_keys.add(yaml_key.scalar)

        for default_key, default_data in self._defaults.items():
            if default_key not in [key.contents for key, _ in items]:
                key_chunk = YAMLChunk(default_key)
                yaml_key = self._key_validator(key_chunk)
                strictindex = yaml_key.data
                value_validator = self._validator_dict[default_key]
                new_value = value_validator(
                    YAMLChunk(value_validator.to_yaml(default_data))
                )
                forked_chunk = chunk.fork(strictindex, new_value)
                forked_chunk.val(strictindex).process(new_value)
                updated_value = value_validator(forked_chunk.val(strictindex))
                updated_value._chunk.make_child_of(chunk.val(strictindex))
                # marked_up = new_value.as_marked_up()
                # chunk.contents[chunk.ruamelindex(strictindex)] = marked_up
                chunk.add_key_association(default_key, strictindex)
                sp = chunk.strictparsed()
                if isinstance(sp, YAML):
                    # Do not trigger __setitem__ validation at this point, as
                    # we just ran the validator, and
                    # representation.py:revalidate() doesn't overwrite the
                    # _validator property until after all values are checked,
                    # which leads to an exception being raised if it is
                    # re-checked.
                    sp._value[yaml_key] = updated_value
                else:
                    sp[yaml_key] = updated_value

        if not set(self._required_keys).issubset(found_keys):
            chunk.while_parsing_found(
                u"a mapping",
                u"required key(s) '{0}' not found".format(
                    "', '".join(
                        sorted(list(set(self._required_keys).difference(found_keys)))
                    )
                ),
            )

    def to_yaml(self, data):
        self._should_be_mapping(data)
        # TODO : if keys not in list or required keys missing, raise exception.
        return CommentedMap(
            [
                (key, self._validator_dict[key].to_yaml(value))
                for key, value in data.items()
                if key not in self._defaults.keys()
                or key in self._defaults.keys()
                and value != self._defaults[key]
            ]
        )


class Seq(SeqValidator):
    def __init__(self, validator):
        self._validator = validator

    def __repr__(self):
        return "Seq({0})".format(repr(self._validator))

    def validate(self, chunk):
        for item in chunk.expect_sequence():
            item.process(self._validator(item))

    def to_yaml(self, data):
        self._should_be_list(data)
        return CommentedSeq([self._validator.to_yaml(item) for item in data])


class FixedSeq(SeqValidator):
    def __init__(self, validators):
        self._validators = validators
        for item in validators:
            assert isinstance(
                item, Validator
            ), "all FixedSeq validators must be Validators"

    def __repr__(self):
        return "FixedSeq({0})".format(repr(self._validators))

    def validate(self, chunk):
        sequence = chunk.expect_sequence(
            "when expecting a sequence of {0} elements".format(len(self._validators))
        )

        if len(self._validators) != len(sequence):
            chunk.expecting_but_found(
                "when expecting a sequence of {0} elements".format(
                    len(self._validators)
                ),
                "found a sequence of {0} elements".format(len(chunk.contents)),
            )

        for item, validator in zip(sequence, self._validators):
            item.process(validator(item))

    def to_yaml(self, data):
        self._should_be_list(data)
        # TODO : Different length string
        return CommentedSeq(
            [validator.to_yaml(item) for item, validator in zip(data, self._validators)]
        )


class UniqueSeq(SeqValidator):
    def __init__(self, validator):
        self._validator = validator
        assert isinstance(
            self._validator, ScalarValidator
        ), "UniqueSeq validator must be ScalarValidator"

    def __repr__(self):
        return "UniqueSeq({0})".format(repr(self._validator))

    def validate(self, chunk):
        existing_items = set()

        for item in chunk.expect_sequence("when expecting a unique sequence"):
            if item.contents in existing_items:
                chunk.while_parsing_found("a sequence", "duplicate found")
            else:
                existing_items.add(item.contents)
                item.process(self._validator(item))

    def to_yaml(self, data):
        self._should_be_list(data)

        if len(set(data)) < len(data):
            raise YAMLSerializationError(
                (
                    "Expecting all unique items, "
                    "but duplicates were found in '{}'.".format(data)
                )
            )

        return CommentedSeq([self._validator.to_yaml(item) for item in data])