from typing import Dict, Optional, Union

from django.conf import settings
from django.db.utils import IntegrityError

from ..forms import LocalizedIntegerFieldForm
from ..value import LocalizedIntegerValue, LocalizedValue
from .field import LocalizedField


class LocalizedIntegerField(LocalizedField):
    """Stores integers as a localized value."""

    attr_class = LocalizedIntegerValue

    @classmethod
    def from_db_value(cls, value, *_) -> Optional[LocalizedIntegerValue]:
        db_value = super().from_db_value(value)
        if db_value is None:
            return db_value

        # if we were used in an expression somehow then it might be
        # that we're returning an individual value or an array, so
        # we should not convert that into an :see:LocalizedIntegerValue
        if not isinstance(db_value, LocalizedValue):
            return db_value

        return cls._convert_localized_value(db_value)

    def to_python(
        self, value: Union[Dict[str, int], int, None]
    ) -> LocalizedIntegerValue:
        """Converts the value from a database value into a Python value."""

        db_value = super().to_python(value)
        return self._convert_localized_value(db_value)

    def get_prep_value(self, value: LocalizedIntegerValue) -> dict:
        """Gets the value in a format to store into the database."""

        # apply default values
        default_values = LocalizedIntegerValue(self.default)
        if isinstance(value, LocalizedIntegerValue):
            for lang_code, _ in settings.LANGUAGES:
                local_value = value.get(lang_code)
                if local_value is None:
                    value.set(lang_code, default_values.get(lang_code, None))

        prepped_value = super().get_prep_value(value)
        if prepped_value is None:
            return None

        # make sure all values are proper integers
        for lang_code, _ in settings.LANGUAGES:
            local_value = prepped_value[lang_code]
            try:
                if local_value is not None:
                    int(local_value)
            except (TypeError, ValueError):
                raise IntegrityError(
                    'non-integer value in column "%s.%s" violates '
                    "integer constraint" % (self.name, lang_code)
                )

            # convert to a string before saving because the underlying
            # type is hstore, which only accept strings
            prepped_value[lang_code] = (
                str(local_value) if local_value is not None else None
            )

        return prepped_value

    def formfield(self, **kwargs):
        """Gets the form field associated with this field."""
        defaults = {"form_class": LocalizedIntegerFieldForm}

        defaults.update(kwargs)
        return super().formfield(**defaults)

    @staticmethod
    def _convert_localized_value(
        value: LocalizedValue
    ) -> LocalizedIntegerValue:
        """Converts from :see:LocalizedValue to :see:LocalizedIntegerValue."""

        integer_values = {}
        for lang_code, _ in settings.LANGUAGES:
            local_value = value.get(lang_code, None)
            if local_value is None or local_value.strip() == "":
                local_value = None

            try:
                integer_values[lang_code] = int(local_value)
            except (ValueError, TypeError):
                integer_values[lang_code] = None

        return LocalizedIntegerValue(integer_values)