import dataclasses

from pytorch_ie import AnnotationLayer, annotation_field
from pytorch_ie.annotations import BinaryRelation
from pytorch_ie.documents import (
    TextDocumentWithLabeledMultiSpansBinaryRelationsAndLabeledPartitions,
)


@dataclasses.dataclass(eq=True, frozen=True)
class RelatedRelation(BinaryRelation):
    link_relation: BinaryRelation = dataclasses.field(default=None, compare=False)
    relation: BinaryRelation = dataclasses.field(default=None, compare=False)

    def __post_init__(self):
        super().__post_init__()
        # check if the reference_span is correct
        self.reference_span

    @property
    def reference_span(self):
        if self.link_relation is None:
            raise ValueError(
                "No semantically_same_relation available, cannot return reference_span"
            )
        if self.link_relation.head == self.head:
            return self.link_relation.tail
        elif self.link_relation.tail == self.head:
            return self.link_relation.head
        elif self.link_relation.head == self.tail:
            return self.link_relation.tail
        elif self.link_relation.tail == self.tail:
            return self.link_relation.head
        else:
            raise ValueError(
                "The semantically_same_relation is neither linked to head nor tail of the current relation"
            )


@dataclasses.dataclass
class TextDocumentWithLabeledMultiSpansBinaryRelationsLabeledPartitionsAndRelatedRelations(
    TextDocumentWithLabeledMultiSpansBinaryRelationsAndLabeledPartitions,
):
    related_relations: AnnotationLayer[RelatedRelation] = annotation_field(
        targets=["labeled_multi_spans", "binary_relations"]
    )