from typing import IO, Any, MutableMapping, Optional, Union

from rdflib.graph import Graph
from rdflib.namespace import RDF, Namespace
from rdflib.query import Result, ResultParser
from rdflib.term import Node, Variable

RS = Namespace("http://www.w3.org/2001/sw/DataAccess/tests/result-set#")


class RDFResultParser(ResultParser):
    def parse(self, source: Union[IO, Graph], **kwargs: Any) -> Result:
        return RDFResult(source, **kwargs)


class RDFResult(Result):
    def __init__(self, source: Union[IO, Graph], **kwargs: Any):
        if not isinstance(source, Graph):
            graph = Graph()
            graph.parse(source, **kwargs)
        else:
            graph = source

        rs = graph.value(predicate=RDF.type, object=RS.ResultSet)
        # there better be only one :)

        if rs is None:
            type_ = "CONSTRUCT"

            # use a new graph
            g = Graph()
            g += graph

        else:
            askAnswer = graph.value(rs, RS.boolean)

            if askAnswer is not None:
                type_ = "ASK"
            else:
                type_ = "SELECT"

        Result.__init__(self, type_)

        if type_ == "SELECT":
            # type error: Argument 1 to "Variable" has incompatible type "Node"; expected "str"
            self.vars = [Variable(v) for v in graph.objects(rs, RS.resultVariable)]  # type: ignore[arg-type]

            self.bindings = []

            for s in graph.objects(rs, RS.solution):
                sol: MutableMapping[Variable, Optional[Node]] = {}
                for b in graph.objects(s, RS.binding):
                    # type error: Argument 1 to "Variable" has incompatible type "Optional[Node]"; expected "str"
                    sol[Variable(graph.value(b, RS.variable))] = graph.value(  # type: ignore[arg-type]
                        b, RS.value
                    )
                # error: Argument 1 to "append" of "list" has incompatible type "MutableMapping[Variable, Optional[Node]]"; expected "Mapping[Variable, Identifier]"
                self.bindings.append(sol)  # type: ignore[arg-type]
        elif type_ == "ASK":
            # type error: Item "Node" of "Optional[Node]" has no attribute "value"
            # type error: Item "None" of "Optional[Node]" has no attribute "value"
            self.askAnswer = askAnswer.value  # type: ignore[union-attr]
            # type error: Item "Node" of "Optional[Node]" has no attribute "value"
            # type error: Item "None" of "Optional[Node]" has no attribute "value"
            if askAnswer.value is None:  # type: ignore[union-attr]
                raise Exception("Malformed boolean in ask answer!")
        elif type_ == "CONSTRUCT":
            self.graph = g
