"""Canonical knowledge asset and representation models."""

from __future__ import annotations

from dataclasses import dataclass, field, replace
from enum import Enum
from typing import Any

from .metadata import Classification, LifecycleState
from .primitives import compact_dict, content_digest, new_id, utc_now
from .provenance import SourceReference


class RepresentationKind(str, Enum):
    SOURCE = "source"
    NORMALIZED = "normalized"
    DERIVED = "derived"


@dataclass(frozen=True)
class AssetRepresentation:
    asset_id: str
    kind: RepresentationKind
    media_type: str
    digest: str
    size_bytes: int
    storage_ref: str | None = None
    producer: str | None = None
    source_ref_id: str | None = None
    metadata: dict[str, Any] = field(default_factory=dict)
    representation_id: str = field(default_factory=lambda: new_id("repr"))
    created_at: str = field(default_factory=lambda: utc_now().isoformat())

    @classmethod
    def from_content(
        cls,
        asset_id: str,
        kind: RepresentationKind | str,
        media_type: str,
        content: str | bytes,
        *,
        storage_ref: str | None = None,
        producer: str | None = None,
        source_ref_id: str | None = None,
        metadata: dict[str, Any] | None = None,
        representation_id: str | None = None,
    ) -> "AssetRepresentation":
        data = content.encode("utf-8") if isinstance(content, str) else content
        return cls(
            representation_id=representation_id or new_id("repr"),
            asset_id=asset_id,
            kind=RepresentationKind(kind),
            media_type=media_type,
            digest=content_digest(data),
            size_bytes=len(data),
            storage_ref=storage_ref,
            producer=producer,
            source_ref_id=source_ref_id,
            metadata=dict(metadata or {}),
        )

    def to_dict(self) -> dict[str, Any]:
        return compact_dict(
            {
                "representation_id": self.representation_id,
                "asset_id": self.asset_id,
                "kind": self.kind.value,
                "media_type": self.media_type,
                "digest": self.digest,
                "size_bytes": self.size_bytes,
                "storage_ref": self.storage_ref,
                "producer": self.producer,
                "source_ref_id": self.source_ref_id,
                "metadata": dict(self.metadata),
                "created_at": self.created_at,
            }
        )

    @classmethod
    def from_dict(cls, data: dict[str, Any]) -> "AssetRepresentation":
        return cls(
            representation_id=data["representation_id"],
            asset_id=data["asset_id"],
            kind=RepresentationKind(data["kind"]),
            media_type=data["media_type"],
            digest=data["digest"],
            size_bytes=int(data["size_bytes"]),
            storage_ref=data.get("storage_ref"),
            producer=data.get("producer"),
            source_ref_id=data.get("source_ref_id"),
            metadata=dict(data.get("metadata", {})),
            created_at=data["created_at"],
        )


@dataclass(frozen=True)
class KnowledgeAsset:
    id: str
    title: str
    classification: Classification
    source_refs: tuple[SourceReference, ...] = ()
    aliases: tuple[str, ...] = ()
    current_version_id: str | None = None
    lifecycle: LifecycleState = LifecycleState.ACTIVE
    metadata: dict[str, Any] = field(default_factory=dict)
    created_at: str = field(default_factory=lambda: utc_now().isoformat())
    updated_at: str = field(default_factory=lambda: utc_now().isoformat())

    @classmethod
    def create(
        cls,
        title: str,
        classification: Classification,
        *,
        asset_id: str | None = None,
        source_refs: list[SourceReference] | tuple[SourceReference, ...] | None = None,
        aliases: list[str] | tuple[str, ...] | None = None,
        metadata: dict[str, Any] | None = None,
    ) -> "KnowledgeAsset":
        return cls(
            id=asset_id or new_id("asset"),
            title=title,
            classification=classification,
            source_refs=tuple(source_refs or ()),
            aliases=tuple(aliases or ()),
            metadata=dict(metadata or {}),
            lifecycle=classification.lifecycle,
        )

    def with_source_reference(self, source_ref: SourceReference) -> "KnowledgeAsset":
        return replace(self, source_refs=self.source_refs + (source_ref,), updated_at=utc_now().isoformat())

    def with_alias(self, alias: str) -> "KnowledgeAsset":
        if alias in self.aliases:
            return self
        return replace(self, aliases=self.aliases + (alias,), updated_at=utc_now().isoformat())

    def with_current_version(self, version_id: str) -> "KnowledgeAsset":
        return replace(self, current_version_id=version_id, updated_at=utc_now().isoformat())

    def transition_lifecycle(self, lifecycle: LifecycleState | str) -> "KnowledgeAsset":
        lifecycle_state = LifecycleState(lifecycle)
        classification = replace(self.classification, lifecycle=lifecycle_state)
        return replace(
            self,
            lifecycle=lifecycle_state,
            classification=classification,
            updated_at=utc_now().isoformat(),
        )

    def to_dict(self) -> dict[str, Any]:
        return compact_dict(
            {
                "id": self.id,
                "title": self.title,
                "classification": self.classification.to_dict(),
                "source_refs": [source_ref.to_dict() for source_ref in self.source_refs],
                "aliases": list(self.aliases),
                "current_version_id": self.current_version_id,
                "lifecycle": self.lifecycle.value,
                "metadata": dict(self.metadata),
                "created_at": self.created_at,
                "updated_at": self.updated_at,
            }
        )

    @classmethod
    def from_dict(cls, data: dict[str, Any]) -> "KnowledgeAsset":
        return cls(
            id=data["id"],
            title=data["title"],
            classification=Classification.from_dict(data["classification"]),
            source_refs=tuple(SourceReference.from_dict(item) for item in data.get("source_refs", [])),
            aliases=tuple(data.get("aliases", [])),
            current_version_id=data.get("current_version_id"),
            lifecycle=LifecycleState(data.get("lifecycle", LifecycleState.ACTIVE.value)),
            metadata=dict(data.get("metadata", {})),
            created_at=data["created_at"],
            updated_at=data["updated_at"],
        )