"""Source and Citation — the first-class provenance spine.

A Source is a reusable record of an origin; a Citation links one Source to one
specific fact (a Person, Name, Event, or Relationship — and OwnershipEvent once
property lands). A CHECK enforces exactly one target so a citation always points
at a single fact.
"""

import uuid

from sqlalchemy import CheckConstraint, ForeignKey, String, Text
from sqlalchemy import Enum as SAEnum
from sqlalchemy.orm import Mapped, mapped_column

from app.models.base import Base
from app.models.enums import CitationConfidence
from app.models.mixins import SoftDelete, TenantScoped, Timestamps, UUIDPrimaryKey


class Source(Base, UUIDPrimaryKey, TenantScoped, Timestamps, SoftDelete):
    __tablename__ = "sources"

    title: Mapped[str] = mapped_column(String(512))
    author: Mapped[str | None] = mapped_column(String(255))
    source_type: Mapped[str | None] = mapped_column(String(64))  # book, census, deed, ...
    repository: Mapped[str | None] = mapped_column(String(255))
    url: Mapped[str | None] = mapped_column(String(1024))
    citation_text: Mapped[str | None] = mapped_column(Text)
    publication_info: Mapped[str | None] = mapped_column(Text)
    quality_note: Mapped[str | None] = mapped_column(String(255))


class Citation(Base, UUIDPrimaryKey, TenantScoped, Timestamps, SoftDelete):
    __tablename__ = "citations"
    __table_args__ = (
        CheckConstraint(
            "(person_id IS NOT NULL)::int + (event_id IS NOT NULL)::int "
            "+ (name_id IS NOT NULL)::int + (relationship_id IS NOT NULL)::int = 1",
            name="exactly_one_target",
        ),
    )

    source_id: Mapped[uuid.UUID] = mapped_column(
        ForeignKey("sources.id", ondelete="CASCADE"), index=True
    )

    # Exactly one of these is set (see CHECK above).
    person_id: Mapped[uuid.UUID | None] = mapped_column(
        ForeignKey("persons.id", ondelete="CASCADE"), index=True
    )
    event_id: Mapped[uuid.UUID | None] = mapped_column(
        ForeignKey("events.id", ondelete="CASCADE"), index=True
    )
    name_id: Mapped[uuid.UUID | None] = mapped_column(
        ForeignKey("names.id", ondelete="CASCADE"), index=True
    )
    relationship_id: Mapped[uuid.UUID | None] = mapped_column(
        ForeignKey("relationships.id", ondelete="CASCADE"), index=True
    )

    # Locality within the source.
    page: Mapped[str | None] = mapped_column(String(255))
    detail: Mapped[str | None] = mapped_column(Text)  # entry, line, free notes
    confidence: Mapped[CitationConfidence | None] = mapped_column(
        SAEnum(CitationConfidence, name="citation_confidence")
    )