# Django 4.2.11 documentation

# Source code for django.contrib.postgres.search

    from django.db.models import (
        CharField,
        Expression,
        Field,
        FloatField,
        Func,
        Lookup,
        TextField,
        Value,
    )
    from django.db.models.expressions import CombinedExpression, register_combinable_fields
    from django.db.models.functions import Cast, Coalesce

    class SearchVectorExact(Lookup):
        lookup_name = "exact"

        def process_rhs(self, qn, connection):
            if not isinstance(self.rhs, (SearchQuery, CombinedSearchQuery)):
                config = getattr(self.lhs, "config", None)
                self.rhs = SearchQuery(self.rhs, config=config)
            rhs, rhs_params = super().process_rhs(qn, connection)
            return rhs, rhs_params

        def as_sql(self, qn, connection):
            lhs, lhs_params = self.process_lhs(qn, connection)
            rhs, rhs_params = self.process_rhs(qn, connection)
            params = lhs_params + rhs_params
            return "%s @@ %s" % (lhs, rhs), params

    class SearchVectorField(Field):
        def db_type(self, connection):
            return "tsvector"

    class SearchQueryField(Field):
        def db_type(self, connection):
            return "tsquery"

    class _Float4Field(Field):
        def db_type(self, connection):
            return "float4"

    class SearchConfig(Expression):
        def __init__(self, config):
            super().__init__()
            if not hasattr(config, "resolve_expression"):
                config = Value(config)
            self.config = config

        @classmethod
        def from_parameter(cls, config):
            if config is None or isinstance(config, cls):
                return config
            return cls(config)

        def get_source_expressions(self):
            return [self.config]

        def set_source_expressions(self, exprs):
            (self.config,) = exprs

        def as_sql(self, compiler, connection):
            sql, params = compiler.compile(self.config)
            return "%s::regconfig" % sql, params

    class SearchVectorCombinable:
        ADD = "||"

        def _combine(self, other, connector, reversed):
            if not isinstance(other, SearchVectorCombinable):
                raise TypeError(
                    "SearchVector can only be combined with other SearchVector "
                    "instances, got %s." % type(other).__name__
                )
            if reversed:
                return CombinedSearchVector(other, connector, self, self.config)
            return CombinedSearchVector(self, connector, other, self.config)

    register_combinable_fields(
        SearchVectorField, SearchVectorCombinable.ADD, SearchVectorField, SearchVectorField
    )

    class SearchVector(SearchVectorCombinable, Func):
        function = "to_tsvector"
        arg_joiner = " || ' ' || "
        output_field = SearchVectorField()

        def __init__(self, *expressions, config=None, weight=None):
            super().__init__(*expressions)
            self.config = SearchConfig.from_parameter(config)
            if weight is not None and not hasattr(weight, "resolve_expression"):
                weight = Value(weight)
            self.weight = weight

        def resolve_expression(
            self, query=None, allow_joins=True, reuse=None, summarize=False, for_save=False
        ):
            resolved = super().resolve_expression(
                query, allow_joins, reuse, summarize, for_save
            )
            if self.config:
                resolved.config = self.config.resolve_expression(
                    query, allow_joins, reuse, summarize, for_save
                )
            return resolved

        def as_sql(self, compiler, connection, function=None, template=None):
            clone = self.copy()
            clone.set_source_expressions(
                [
                    Coalesce(
                        expression
                        if isinstance(expression.output_field, (CharField, TextField))
                        else Cast(expression, TextField()),
                        Value(""),
                    )
                    for expression in clone.get_source_expressions()
                ]
            )
            config_sql = None
            config_params = []
            if template is None:
                if clone.config:
                    config_sql, config_params = compiler.compile(clone.config)
                    template = "%(function)s(%(config)s, %(expressions)s)"
                else:
                    template = clone.template
            sql, params = super(SearchVector, clone).as_sql(
                compiler,
                connection,
                function=function,
                template=template,
                config=config_sql,
            )
            extra_params = []
            if clone.weight:
                weight_sql, extra_params = compiler.compile(clone.weight)
                sql = "setweight({}, {})".format(sql, weight_sql)

            return sql, config_params + params + extra_params

    class CombinedSearchVector(SearchVectorCombinable, CombinedExpression):
        def __init__(self, lhs, connector, rhs, config, output_field=None):
            self.config = config
            super().__init__(lhs, connector, rhs, output_field)

    class SearchQueryCombinable:
        BITAND = "&&"
        BITOR = "||"

        def _combine(self, other, connector, reversed):
            if not isinstance(other, SearchQueryCombinable):
                raise TypeError(
                    "SearchQuery can only be combined with other SearchQuery "
                    "instances, got %s." % type(other).__name__
                )
            if reversed:
                return CombinedSearchQuery(other, connector, self, self.config)
            return CombinedSearchQuery(self, connector, other, self.config)

        # On Combinable, these are not implemented to reduce confusion with Q. In
        # this case we are actually (ab)using them to do logical combination so
        # it's consistent with other usage in Django.
        def __or__(self, other):
            return self._combine(other, self.BITOR, False)

        def __ror__(self, other):
            return self._combine(other, self.BITOR, True)

        def __and__(self, other):
            return self._combine(other, self.BITAND, False)

        def __rand__(self, other):
            return self._combine(other, self.BITAND, True)

    class SearchQuery(SearchQueryCombinable, Func):
        output_field = SearchQueryField()
        SEARCH_TYPES = {
            "plain": "plainto_tsquery",
            "phrase": "phraseto_tsquery",
            "raw": "to_tsquery",
            "websearch": "websearch_to_tsquery",
        }

        def __init__(
            self,
            value,
            output_field=None,
            *,
            config=None,
            invert=False,
            search_type="plain",
        ):
            self.function = self.SEARCH_TYPES.get(search_type)
            if self.function is None:
                raise ValueError("Unknown search_type argument '%s'." % search_type)
            if not hasattr(value, "resolve_expression"):
                value = Value(value)
            expressions = (value,)
            self.config = SearchConfig.from_parameter(config)
            if self.config is not None:
                expressions = (self.config,) + expressions
            self.invert = invert
            super().__init__(*expressions, output_field=output_field)

        def as_sql(self, compiler, connection, function=None, template=None):
            sql, params = super().as_sql(compiler, connection, function, template)
            if self.invert:
                sql = "!!(%s)" % sql
            return sql, params

        def __invert__(self):
            clone = self.copy()
            clone.invert = not self.invert
            return clone

        def __str__(self):
            result = super().__str__()
            return ("~%s" % result) if self.invert else result

    class CombinedSearchQuery(SearchQueryCombinable, CombinedExpression):
        def __init__(self, lhs, connector, rhs, config, output_field=None):
            self.config = config
            super().__init__(lhs, connector, rhs, output_field)

        def __str__(self):
            return "(%s)" % super().__str__()

    class SearchRank(Func):
        function = "ts_rank"
        output_field = FloatField()

        def __init__(
            self,
            vector,
            query,
            weights=None,
            normalization=None,
            cover_density=False,
        ):
            from .fields.array import ArrayField

            if not hasattr(vector, "resolve_expression"):
                vector = SearchVector(vector)
            if not hasattr(query, "resolve_expression"):
                query = SearchQuery(query)
            expressions = (vector, query)
            if weights is not None:
                if not hasattr(weights, "resolve_expression"):
                    weights = Value(weights)
                weights = Cast(weights, ArrayField(_Float4Field()))
                expressions = (weights,) + expressions
            if normalization is not None:
                if not hasattr(normalization, "resolve_expression"):
                    normalization = Value(normalization)
                expressions += (normalization,)
            if cover_density:
                self.function = "ts_rank_cd"
            super().__init__(*expressions)

    class SearchHeadline(Func):
        function = "ts_headline"
        template = "%(function)s(%(expressions)s%(options)s)"
        output_field = TextField()

        def __init__(
            self,
            expression,
            query,
            *,
            config=None,
            start_sel=None,
            stop_sel=None,
            max_words=None,
            min_words=None,
            short_word=None,
            highlight_all=None,
            max_fragments=None,
            fragment_delimiter=None,
        ):
            if not hasattr(query, "resolve_expression"):
                query = SearchQuery(query)
            options = {
                "StartSel": start_sel,
                "StopSel": stop_sel,
                "MaxWords": max_words,
                "MinWords": min_words,
                "ShortWord": short_word,
                "HighlightAll": highlight_all,
                "MaxFragments": max_fragments,
                "FragmentDelimiter": fragment_delimiter,
            }
            self.options = {
                option: value for option, value in options.items() if value is not None
            }
            expressions = (expression, query)
            if config is not None:
                config = SearchConfig.from_parameter(config)
                expressions = (config,) + expressions
            super().__init__(*expressions)

        def as_sql(self, compiler, connection, function=None, template=None):
            options_sql = ""
            options_params = []
            if self.options:
                options_params.append(
                    ", ".join(
                        connection.ops.compose_sql(f"{option}=%s", [value])
                        for option, value in self.options.items()
                    )
                )
                options_sql = ", %s"
            sql, params = super().as_sql(
                compiler,
                connection,
                function=function,
                template=template,
                options=options_sql,
            )
            return sql, params + options_params

    SearchVectorField.register_lookup(SearchVectorExact)

    class TrigramBase(Func):
        output_field = FloatField()

        def __init__(self, expression, string, **extra):
            if not hasattr(string, "resolve_expression"):
                string = Value(string)
            super().__init__(expression, string, **extra)

    class TrigramWordBase(Func):
        output_field = FloatField()

        def __init__(self, string, expression, **extra):
            if not hasattr(string, "resolve_expression"):
                string = Value(string)
            super().__init__(string, expression, **extra)

    class TrigramSimilarity(TrigramBase):
        function = "SIMILARITY"

    class TrigramDistance(TrigramBase):
        function = ""
        arg_joiner = " <-> "

    class TrigramWordDistance(TrigramWordBase):
        function = ""
        arg_joiner = " <<-> "

    class TrigramStrictWordDistance(TrigramWordBase):
        function = ""
        arg_joiner = " <<<-> "

    class TrigramWordSimilarity(TrigramWordBase):
        function = "WORD_SIMILARITY"

    class TrigramStrictWordSimilarity(TrigramWordBase):
        function = "STRICT_WORD_SIMILARITY"