# Django 5.2 documentation

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

    from django.db import NotSupportedError
    from django.db.models.expressions import Func, Value
    from django.db.models.fields import TextField
    from django.db.models.fields.json import JSONField
    from django.db.models.functions import Cast

    class JSONArray(Func):
        function = "JSON_ARRAY"
        output_field = JSONField()

        def as_sql(self, compiler, connection, **extra_context):
            if not connection.features.supports_json_field:
                raise NotSupportedError(
                    "JSONFields are not supported on this database backend."
                )
            return super().as_sql(compiler, connection, **extra_context)

        def as_native(self, compiler, connection, *, returning, **extra_context):
            # PostgreSQL 16+ and Oracle remove SQL NULL values from the array by
            # default. Adds the NULL ON NULL clause to keep NULL values in the
            # array, mapping them to JSON null values, which matches the behavior
            # of SQLite.
            null_on_null = "NULL ON NULL" if len(self.get_source_expressions()) > 0 else ""

            return self.as_sql(
                compiler,
                connection,
                template=(
                    f"%(function)s(%(expressions)s {null_on_null} RETURNING {returning})"
                ),
                **extra_context,
            )

        def as_postgresql(self, compiler, connection, **extra_context):
            # Casting source expressions is only required using JSONB_BUILD_ARRAY
            # or when using JSON_ARRAY on PostgreSQL 16+ with server-side bindings.
            # This is done in all cases for consistency.
            casted_obj = self.copy()
            casted_obj.set_source_expressions(
                [
                    (
                        # Conditional Cast to avoid unnecessary wrapping.
                        expression
                        if isinstance(expression, Cast)
                        else Cast(expression, expression.output_field)
                    )
                    for expression in casted_obj.get_source_expressions()
                ]
            )

            if connection.features.is_postgresql_16:
                return casted_obj.as_native(
                    compiler, connection, returning="JSONB", **extra_context
                )

            return casted_obj.as_sql(
                compiler,
                connection,
                function="JSONB_BUILD_ARRAY",
                **extra_context,
            )

        def as_oracle(self, compiler, connection, **extra_context):
            return self.as_native(compiler, connection, returning="CLOB", **extra_context)

    class JSONObject(Func):
        function = "JSON_OBJECT"
        output_field = JSONField()

        def __init__(self, **fields):
            expressions = []
            for key, value in fields.items():
                expressions.extend((Value(key), value))
            super().__init__(*expressions)

        def as_sql(self, compiler, connection, **extra_context):
            if not connection.features.has_json_object_function:
                raise NotSupportedError(
                    "JSONObject() is not supported on this database backend."
                )
            return super().as_sql(compiler, connection, **extra_context)

        def join(self, args):
            pairs = zip(args[::2], args[1::2], strict=True)
            # Wrap 'key' in parentheses in case of postgres cast :: syntax.
            return ", ".join([f"({key}) VALUE {value}" for key, value in pairs])

        def as_native(self, compiler, connection, *, returning, **extra_context):
            return self.as_sql(
                compiler,
                connection,
                arg_joiner=self,
                template=f"%(function)s(%(expressions)s RETURNING {returning})",
                **extra_context,
            )

        def as_postgresql(self, compiler, connection, **extra_context):
            # Casting keys to text is only required when using JSONB_BUILD_OBJECT
            # or when using JSON_OBJECT on PostgreSQL 16+ with server-side bindings.
            # This is done in all cases for consistency.
            copy = self.copy()
            copy.set_source_expressions(
                [
                    Cast(expression, TextField()) if index % 2 == 0 else expression
                    for index, expression in enumerate(copy.get_source_expressions())
                ]
            )

            if connection.features.is_postgresql_16:
                return copy.as_native(
                    compiler, connection, returning="JSONB", **extra_context
                )

            return super(JSONObject, copy).as_sql(
                compiler,
                connection,
                function="JSONB_BUILD_OBJECT",
                **extra_context,
            )

        def as_oracle(self, compiler, connection, **extra_context):
            return self.as_native(compiler, connection, returning="CLOB", **extra_context)