# Django 4.2.11 documentation

# Source code for django.db.models.functions.datetime

    from datetime import datetime

    from django.conf import settings
    from django.db.models.expressions import Func
    from django.db.models.fields import (
        DateField,
        DateTimeField,
        DurationField,
        Field,
        IntegerField,
        TimeField,
    )
    from django.db.models.lookups import (
        Transform,
        YearExact,
        YearGt,
        YearGte,
        YearLt,
        YearLte,
    )
    from django.utils import timezone

    class TimezoneMixin:
        tzinfo = None

        def get_tzname(self):
            # Timezone conversions must happen to the input datetime *before*
            # applying a function. 2015-12-31 23:00:00 -02:00 is stored in the
            # database as 2016-01-01 01:00:00 +00:00. Any results should be
            # based on the input datetime not the stored datetime.
            tzname = None
            if settings.USE_TZ:
                if self.tzinfo is None:
                    tzname = timezone.get_current_timezone_name()
                else:
                    tzname = timezone._get_timezone_name(self.tzinfo)
            return tzname

    class Extract(TimezoneMixin, Transform):
        lookup_name = None
        output_field = IntegerField()

        def __init__(self, expression, lookup_name=None, tzinfo=None, **extra):
            if self.lookup_name is None:
                self.lookup_name = lookup_name
            if self.lookup_name is None:
                raise ValueError("lookup_name must be provided")
            self.tzinfo = tzinfo
            super().__init__(expression, **extra)

        def as_sql(self, compiler, connection):
            sql, params = compiler.compile(self.lhs)
            lhs_output_field = self.lhs.output_field
            if isinstance(lhs_output_field, DateTimeField):
                tzname = self.get_tzname()
                sql, params = connection.ops.datetime_extract_sql(
                    self.lookup_name, sql, tuple(params), tzname
                )
            elif self.tzinfo is not None:
                raise ValueError("tzinfo can only be used with DateTimeField.")
            elif isinstance(lhs_output_field, DateField):
                sql, params = connection.ops.date_extract_sql(
                    self.lookup_name, sql, tuple(params)
                )
            elif isinstance(lhs_output_field, TimeField):
                sql, params = connection.ops.time_extract_sql(
                    self.lookup_name, sql, tuple(params)
                )
            elif isinstance(lhs_output_field, DurationField):
                if not connection.features.has_native_duration_field:
                    raise ValueError(
                        "Extract requires native DurationField database support."
                    )
                sql, params = connection.ops.time_extract_sql(
                    self.lookup_name, sql, tuple(params)
                )
            else:
                # resolve_expression has already validated the output_field so this
                # assert should never be hit.
                assert False, "Tried to Extract from an invalid type."
            return sql, params

        def resolve_expression(
            self, query=None, allow_joins=True, reuse=None, summarize=False, for_save=False
        ):
            copy = super().resolve_expression(
                query, allow_joins, reuse, summarize, for_save
            )
            field = getattr(copy.lhs, "output_field", None)
            if field is None:
                return copy
            if not isinstance(field, (DateField, DateTimeField, TimeField, DurationField)):
                raise ValueError(
                    "Extract input expression must be DateField, DateTimeField, "
                    "TimeField, or DurationField."
                )
            # Passing dates to functions expecting datetimes is most likely a mistake.
            if type(field) is DateField and copy.lookup_name in (
                "hour",
                "minute",
                "second",
            ):
                raise ValueError(
                    "Cannot extract time component '%s' from DateField '%s'."
                    % (copy.lookup_name, field.name)
                )
            if isinstance(field, DurationField) and copy.lookup_name in (
                "year",
                "iso_year",
                "month",
                "week",
                "week_day",
                "iso_week_day",
                "quarter",
            ):
                raise ValueError(
                    "Cannot extract component '%s' from DurationField '%s'."
                    % (copy.lookup_name, field.name)
                )
            return copy

    class ExtractYear(Extract):
        lookup_name = "year"

    class ExtractIsoYear(Extract):
        """Return the ISO-8601 week-numbering year."""

        lookup_name = "iso_year"

    class ExtractMonth(Extract):
        lookup_name = "month"

    class ExtractDay(Extract):
        lookup_name = "day"

    class ExtractWeek(Extract):
        """
        Return 1-52 or 53, based on ISO-8601, i.e., Monday is the first of the
        week.
        """

        lookup_name = "week"

    class ExtractWeekDay(Extract):
        """
        Return Sunday=1 through Saturday=7.

        To replicate this in Python: (mydatetime.isoweekday() % 7) + 1
        """

        lookup_name = "week_day"

    class ExtractIsoWeekDay(Extract):
        """Return Monday=1 through Sunday=7, based on ISO-8601."""

        lookup_name = "iso_week_day"

    class ExtractQuarter(Extract):
        lookup_name = "quarter"

    class ExtractHour(Extract):
        lookup_name = "hour"

    class ExtractMinute(Extract):
        lookup_name = "minute"

    class ExtractSecond(Extract):
        lookup_name = "second"

    DateField.register_lookup(ExtractYear)
    DateField.register_lookup(ExtractMonth)
    DateField.register_lookup(ExtractDay)
    DateField.register_lookup(ExtractWeekDay)
    DateField.register_lookup(ExtractIsoWeekDay)
    DateField.register_lookup(ExtractWeek)
    DateField.register_lookup(ExtractIsoYear)
    DateField.register_lookup(ExtractQuarter)

    TimeField.register_lookup(ExtractHour)
    TimeField.register_lookup(ExtractMinute)
    TimeField.register_lookup(ExtractSecond)

    DateTimeField.register_lookup(ExtractHour)
    DateTimeField.register_lookup(ExtractMinute)
    DateTimeField.register_lookup(ExtractSecond)

    ExtractYear.register_lookup(YearExact)
    ExtractYear.register_lookup(YearGt)
    ExtractYear.register_lookup(YearGte)
    ExtractYear.register_lookup(YearLt)
    ExtractYear.register_lookup(YearLte)

    ExtractIsoYear.register_lookup(YearExact)
    ExtractIsoYear.register_lookup(YearGt)
    ExtractIsoYear.register_lookup(YearGte)
    ExtractIsoYear.register_lookup(YearLt)
    ExtractIsoYear.register_lookup(YearLte)

    class Now(Func):
        template = "CURRENT_TIMESTAMP"
        output_field = DateTimeField()

        def as_postgresql(self, compiler, connection, **extra_context):
            # PostgreSQL's CURRENT_TIMESTAMP means "the time at the start of the
            # transaction". Use STATEMENT_TIMESTAMP to be cross-compatible with
            # other databases.
            return self.as_sql(
                compiler, connection, template="STATEMENT_TIMESTAMP()", **extra_context
            )

        def as_mysql(self, compiler, connection, **extra_context):
            return self.as_sql(
                compiler, connection, template="CURRENT_TIMESTAMP(6)", **extra_context
            )

        def as_sqlite(self, compiler, connection, **extra_context):
            return self.as_sql(
                compiler,
                connection,
                template="STRFTIME('%%%%Y-%%%%m-%%%%d %%%%H:%%%%M:%%%%f', 'NOW')",
                **extra_context,
            )

    class TruncBase(TimezoneMixin, Transform):
        kind = None
        tzinfo = None

        # RemovedInDjango50Warning: when the deprecation ends, remove is_dst
        # argument.
        def __init__(
            self,
            expression,
            output_field=None,
            tzinfo=None,
            is_dst=timezone.NOT_PASSED,
            **extra,
        ):
            self.tzinfo = tzinfo
            self.is_dst = is_dst
            super().__init__(expression, output_field=output_field, **extra)

        def as_sql(self, compiler, connection):
            sql, params = compiler.compile(self.lhs)
            tzname = None
            if isinstance(self.lhs.output_field, DateTimeField):
                tzname = self.get_tzname()
            elif self.tzinfo is not None:
                raise ValueError("tzinfo can only be used with DateTimeField.")
            if isinstance(self.output_field, DateTimeField):
                sql, params = connection.ops.datetime_trunc_sql(
                    self.kind, sql, tuple(params), tzname
                )
            elif isinstance(self.output_field, DateField):
                sql, params = connection.ops.date_trunc_sql(
                    self.kind, sql, tuple(params), tzname
                )
            elif isinstance(self.output_field, TimeField):
                sql, params = connection.ops.time_trunc_sql(
                    self.kind, sql, tuple(params), tzname
                )
            else:
                raise ValueError(
                    "Trunc only valid on DateField, TimeField, or DateTimeField."
                )
            return sql, params

        def resolve_expression(
            self, query=None, allow_joins=True, reuse=None, summarize=False, for_save=False
        ):
            copy = super().resolve_expression(
                query, allow_joins, reuse, summarize, for_save
            )
            field = copy.lhs.output_field
            # DateTimeField is a subclass of DateField so this works for both.
            if not isinstance(field, (DateField, TimeField)):
                raise TypeError(
                    "%r isn't a DateField, TimeField, or DateTimeField." % field.name
                )
            # If self.output_field was None, then accessing the field will trigger
            # the resolver to assign it to self.lhs.output_field.
            if not isinstance(copy.output_field, (DateField, DateTimeField, TimeField)):
                raise ValueError(
                    "output_field must be either DateField, TimeField, or DateTimeField"
                )
            # Passing dates or times to functions expecting datetimes is most
            # likely a mistake.
            class_output_field = (
                self.__class__.output_field
                if isinstance(self.__class__.output_field, Field)
                else None
            )
            output_field = class_output_field or copy.output_field
            has_explicit_output_field = (
                class_output_field or field.__class__ is not copy.output_field.__class__
            )
            if type(field) is DateField and (
                isinstance(output_field, DateTimeField)
                or copy.kind in ("hour", "minute", "second", "time")
            ):
                raise ValueError(
                    "Cannot truncate DateField '%s' to %s."
                    % (
                        field.name,
                        output_field.__class__.__name__
                        if has_explicit_output_field
                        else "DateTimeField",
                    )
                )
            elif isinstance(field, TimeField) and (
                isinstance(output_field, DateTimeField)
                or copy.kind in ("year", "quarter", "month", "week", "day", "date")
            ):
                raise ValueError(
                    "Cannot truncate TimeField '%s' to %s."
                    % (
                        field.name,
                        output_field.__class__.__name__
                        if has_explicit_output_field
                        else "DateTimeField",
                    )
                )
            return copy

        def convert_value(self, value, expression, connection):
            if isinstance(self.output_field, DateTimeField):
                if not settings.USE_TZ:
                    pass
                elif value is not None:
                    value = value.replace(tzinfo=None)
                    value = timezone.make_aware(value, self.tzinfo, is_dst=self.is_dst)
                elif not connection.features.has_zoneinfo_database:
                    raise ValueError(
                        "Database returned an invalid datetime value. Are time "
                        "zone definitions for your database installed?"
                    )
            elif isinstance(value, datetime):
                if value is None:
                    pass
                elif isinstance(self.output_field, DateField):
                    value = value.date()
                elif isinstance(self.output_field, TimeField):
                    value = value.time()
            return value

    class Trunc(TruncBase):
        # RemovedInDjango50Warning: when the deprecation ends, remove is_dst
        # argument.
        def __init__(
            self,
            expression,
            kind,
            output_field=None,
            tzinfo=None,
            is_dst=timezone.NOT_PASSED,
            **extra,
        ):
            self.kind = kind
            super().__init__(
                expression, output_field=output_field, tzinfo=tzinfo, is_dst=is_dst, **extra
            )

    class TruncYear(TruncBase):
        kind = "year"

    class TruncQuarter(TruncBase):
        kind = "quarter"

    class TruncMonth(TruncBase):
        kind = "month"

    class TruncWeek(TruncBase):
        """Truncate to midnight on the Monday of the week."""

        kind = "week"

    class TruncDay(TruncBase):
        kind = "day"

    class TruncDate(TruncBase):
        kind = "date"
        lookup_name = "date"
        output_field = DateField()

        def as_sql(self, compiler, connection):
            # Cast to date rather than truncate to date.
            sql, params = compiler.compile(self.lhs)
            tzname = self.get_tzname()
            return connection.ops.datetime_cast_date_sql(sql, tuple(params), tzname)

    class TruncTime(TruncBase):
        kind = "time"
        lookup_name = "time"
        output_field = TimeField()

        def as_sql(self, compiler, connection):
            # Cast to time rather than truncate to time.
            sql, params = compiler.compile(self.lhs)
            tzname = self.get_tzname()
            return connection.ops.datetime_cast_time_sql(sql, tuple(params), tzname)

    class TruncHour(TruncBase):
        kind = "hour"

    class TruncMinute(TruncBase):
        kind = "minute"

    class TruncSecond(TruncBase):
        kind = "second"

    DateTimeField.register_lookup(TruncDate)
    DateTimeField.register_lookup(TruncTime)