from sqlalchemy import Integer, String, Text
from sqlalchemy.dialects.sqlite import JSON
from sqlalchemy.orm import Mapped, mapped_column

from core_db import AuditMixin, Base, TenantMixin, VersionMixin
from core_shared import JSONValue


class KnowledgeChunk(TenantMixin, AuditMixin, VersionMixin, Base):
    __tablename__ = "knowledge_chunk"

    knowledge_base_id: Mapped[str] = mapped_column(String(36), index=True)
    document_id: Mapped[str] = mapped_column(String(36), index=True)
    chunk_index: Mapped[int] = mapped_column(Integer)
    content_text: Mapped[str] = mapped_column(Text)
    token_count: Mapped[int] = mapped_column(Integer, default=0)
    embedding_model: Mapped[str | None] = mapped_column(String(64), nullable=True, index=True)
    embedding_json: Mapped[list[float] | None] = mapped_column(JSON, nullable=True)
    metadata_json: Mapped[dict[str, JSONValue] | None] = mapped_column(JSON, nullable=True)