# SPDX-FileCopyrightText: 2022-present deepset GmbH <info@deepset.ai>
#
# SPDX-License-Identifier: Apache-2.0

from dataclasses import asdict, dataclass, field
from typing import Any, Optional, Protocol, runtime_checkable

from haystack.core.serialization import default_from_dict, default_to_dict
from haystack.dataclasses import ChatMessage, Document
from haystack.utils.dataclasses import _warn_on_inplace_mutation


@runtime_checkable
@dataclass
class Answer(Protocol):
    data: Any
    query: str
    meta: dict[str, Any]

    def to_dict(self) -> dict[str, Any]:  # noqa: D102
        ...

    @classmethod
    def from_dict(cls, data: dict[str, Any]) -> "Answer":  # noqa: D102
        ...


@_warn_on_inplace_mutation
@dataclass
class ExtractedAnswer:
    """
    Holds an answer extracted by an extractive Reader (query, score, text, and optional document/context).
    """

    query: str
    score: float
    data: str | None = None
    document: Document | None = None
    context: str | None = None
    document_offset: Optional["Span"] = None
    context_offset: Optional["Span"] = None
    meta: dict[str, Any] = field(default_factory=dict)

    @_warn_on_inplace_mutation
    @dataclass
    class Span:
        start: int
        end: int

    def to_dict(self) -> dict[str, Any]:
        """
        Serialize the object to a dictionary.

        :returns:
            Serialized dictionary representation of the object.
        """
        document = self.document.to_dict(flatten=False) if self.document is not None else None
        document_offset = asdict(self.document_offset) if self.document_offset is not None else None
        context_offset = asdict(self.context_offset) if self.context_offset is not None else None
        return default_to_dict(
            self,
            data=self.data,
            query=self.query,
            document=document,
            context=self.context,
            score=self.score,
            document_offset=document_offset,
            context_offset=context_offset,
            meta=self.meta,
        )

    @classmethod
    def from_dict(cls, data: dict[str, Any]) -> "ExtractedAnswer":
        """
        Deserialize the object from a dictionary.

        :param data:
            Dictionary representation of the object.
        :returns:
            Deserialized object.
        """
        # Shallow-copy the init parameters so `from_dict` stays side-effect free: the nested
        # replacements below otherwise mutate the caller's dict in place, corrupting it for reuse
        # (a second deserialization of the same dict would then receive already-parsed objects).
        init_params = data.get("init_parameters", {})
        new_params = dict(init_params)
        if (doc := init_params.get("document")) is not None:
            new_params["document"] = Document.from_dict(doc)

        if (offset := init_params.get("document_offset")) is not None:
            new_params["document_offset"] = ExtractedAnswer.Span(**offset)

        if (offset := init_params.get("context_offset")) is not None:
            new_params["context_offset"] = ExtractedAnswer.Span(**offset)
        return default_from_dict(cls, {**data, "init_parameters": new_params})


@_warn_on_inplace_mutation
@dataclass
class GeneratedAnswer:
    """
    Holds a generated answer from a Generator (answer text, query, referenced documents, and metadata).
    """

    data: str
    query: str
    documents: list[Document]
    meta: dict[str, Any] = field(default_factory=dict)

    def to_dict(self) -> dict[str, Any]:
        """
        Serialize the object to a dictionary.

        :returns:
            Serialized dictionary representation of the object.
        """
        documents = [doc.to_dict(flatten=False) for doc in self.documents]

        # Serialize ChatMessage objects to dicts
        meta = self.meta
        all_messages = meta.get("all_messages")

        # all_messages is either a list of ChatMessage objects or a list of strings
        if all_messages and isinstance(all_messages[0], ChatMessage):
            meta = {**meta, "all_messages": [msg.to_dict() for msg in all_messages]}

        return default_to_dict(self, data=self.data, query=self.query, documents=documents, meta=meta)

    @classmethod
    def from_dict(cls, data: dict[str, Any]) -> "GeneratedAnswer":
        """
        Deserialize the object from a dictionary.

        :param data:
            Dictionary representation of the object.

        :returns:
            Deserialized object.
        """
        # Shallow-copy the init parameters so `from_dict` stays side-effect free: the nested
        # replacements below otherwise mutate the caller's dict in place, corrupting it for reuse
        # (a second deserialization of the same dict would then receive already-parsed objects).
        init_params = data.get("init_parameters", {})
        new_params = dict(init_params)

        if (documents := init_params.get("documents")) is not None:
            new_params["documents"] = [Document.from_dict(d) for d in documents]

        # Shallow-copy `meta` before touching `all_messages` so the caller's nested dict is
        # left untouched as well.
        meta = dict(init_params.get("meta", {}))
        if (all_messages := meta.get("all_messages")) and isinstance(all_messages[0], dict):
            meta["all_messages"] = [ChatMessage.from_dict(m) for m in all_messages]
        new_params["meta"] = meta

        return default_from_dict(cls, {**data, "init_parameters": new_params})