from datetime import datetime, timezone

from sqlalchemy import ARRAY, BigInteger, DateTime, ForeignKey, Index, Integer, Text, UniqueConstraint
from sqlalchemy.orm import Mapped, mapped_column, relationship

from fabledassistant.models import Base


class RssFeed(Base):
    __tablename__ = "rss_feeds"

    id: Mapped[int] = mapped_column(primary_key=True)
    user_id: Mapped[int] = mapped_column(Integer, ForeignKey("users.id", ondelete="CASCADE"))
    url: Mapped[str] = mapped_column(Text)
    title: Mapped[str] = mapped_column(Text, default="")
    category: Mapped[str | None] = mapped_column(Text, nullable=True)
    last_fetched_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)

    items: Mapped[list["RssItem"]] = relationship(
        back_populates="feed", cascade="all, delete-orphan"
    )

    __table_args__ = (
        UniqueConstraint("user_id", "url", name="uq_rss_feeds_user_url"),
        Index("ix_rss_feeds_user_id", "user_id"),
    )

    def to_dict(self) -> dict:
        return {
            "id": self.id,
            "url": self.url,
            "title": self.title,
            "category": self.category,
            "last_fetched_at": self.last_fetched_at.isoformat() if self.last_fetched_at else None,
        }


class RssItem(Base):
    __tablename__ = "rss_items"

    id: Mapped[int] = mapped_column(primary_key=True)
    feed_id: Mapped[int] = mapped_column(Integer, ForeignKey("rss_feeds.id", ondelete="CASCADE"))
    guid: Mapped[str] = mapped_column(Text)
    title: Mapped[str] = mapped_column(Text, default="")
    url: Mapped[str] = mapped_column(Text, default="")
    published_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
    # Truncated to 2000 chars to keep DB size reasonable
    content: Mapped[str] = mapped_column(Text, default="")
    # Full trafilatura-extracted article body, populated lazily on first
    # discuss-click / enrichment pass. Nullable — most items never get this
    # cached. Expires naturally with the item (90-day retention).
    content_full: Mapped[str | None] = mapped_column(Text, nullable=True)
    # Map-reduced conversation-ready context derived from content_full. See
    # services/article_context.py — populated on first discuss click so
    # repeat clicks skip both the fetch and the LLM map step.
    context_prepared: Mapped[str | None] = mapped_column(Text, nullable=True)
    content_fetched_at: Mapped[datetime | None] = mapped_column(
        DateTime(timezone=True), nullable=True
    )
    fetched_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), default=lambda: datetime.now(timezone.utc)
    )
    topics: Mapped[list[str]] = mapped_column(
        ARRAY(Text), nullable=False, default=list, server_default="{}"
    )
    classified_at: Mapped[datetime | None] = mapped_column(
        DateTime(timezone=True), nullable=True
    )
    # Note persisting the first-click discussion summary. Set by the article
    # discussion pipeline once the seeded chat completes its first assistant
    # reply; links back into RAG so re-discussing the same article lands the
    # prior summary in context.
    discussion_note_id: Mapped[int | None] = mapped_column(
        BigInteger, ForeignKey("notes.id", ondelete="SET NULL"), nullable=True
    )

    feed: Mapped["RssFeed"] = relationship(back_populates="items")

    __table_args__ = (
        UniqueConstraint("feed_id", "guid", name="uq_rss_items_feed_guid"),
        Index("ix_rss_items_feed_id", "feed_id"),
        Index("ix_rss_items_published_at", "published_at"),
    )

    def to_dict(self) -> dict:
        return {
            "id": self.id,
            "feed_id": self.feed_id,
            "guid": self.guid,
            "title": self.title,
            "url": self.url,
            "published_at": self.published_at.isoformat() if self.published_at else None,
            "content": self.content,
            "topics": self.topics or [],
            "classified_at": self.classified_at.isoformat() if self.classified_at else None,
        }