import uuid
from datetime import datetime

from pgvector.sqlalchemy import Vector
from sqlalchemy import (
    CheckConstraint,
    DateTime,
    Float,
    ForeignKey,
    Index,
    PrimaryKeyConstraint,
    String,
    Text,
)
from sqlalchemy.dialects.postgresql import UUID
from sqlalchemy.orm import Mapped, mapped_column, relationship
from sqlalchemy.sql import func

from app.config import get_settings
from app.db import Base

_dim = get_settings().embedding_dim


class LostDog(Base):
    """A registered missing-dog cluster: name + last-seen + 1..N reference photos.

    Carries a small state machine on top of the cluster:

    - ``status`` flips from ``looking`` (default) to ``found`` (owner action)
      or ``archived`` (system, after 6 months of no owner activity). Archived
      dogs drop out of /search results.
    - ``last_owner_visit_at`` is bumped on every owner read/write; drives
      both the "what's new since last visit" UI and the inactivity job.
    - ``inactivity_email_sent_at`` records the 5-month "are you still
      looking?" nudge so we don't re-send.
    - ``archived_at`` is stamped by the inactivity job when the dog flips
      to ``archived`` after another 30 days of silence post-nudge.
    """

    __tablename__ = "lost_dogs"
    __table_args__ = (
        CheckConstraint(
            "status IN ('looking', 'found', 'archived')",
            name="lost_dogs_status_check",
        ),
        Index("lost_dogs_status_visit_idx", "status", "last_owner_visit_at"),
    )

    id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True), primary_key=True, default=uuid.uuid4
    )
    name: Mapped[str | None] = mapped_column(String(80), nullable=True)
    last_seen_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), nullable=False
    )
    last_seen_lat: Mapped[float] = mapped_column(Float, nullable=False)
    last_seen_lng: Mapped[float] = mapped_column(Float, nullable=False)
    contact_name: Mapped[str | None] = mapped_column(String(80), nullable=True)
    contact_email: Mapped[str | None] = mapped_column(String(200), nullable=True)
    contact_phone: Mapped[str | None] = mapped_column(String(40), nullable=True)
    status: Mapped[str] = mapped_column(
        String(16), nullable=False, server_default="looking", default="looking"
    )
    last_owner_visit_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now(), nullable=False
    )
    inactivity_email_sent_at: Mapped[datetime | None] = mapped_column(
        DateTime(timezone=True), nullable=True
    )
    archived_at: Mapped[datetime | None] = mapped_column(
        DateTime(timezone=True), nullable=True
    )
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now(), nullable=False
    )

    photos: Mapped[list["Sighting"]] = relationship(
        back_populates="lost_dog",
        cascade="all, delete-orphan",
    )


class Sighting(Base):
    __tablename__ = "sightings"

    id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True), primary_key=True, default=uuid.uuid4
    )
    image_url: Mapped[str] = mapped_column(Text, nullable=False)
    cropped_url: Mapped[str] = mapped_column(Text, nullable=False)
    embedding: Mapped[list[float]] = mapped_column(Vector(_dim), nullable=False)
    latitude: Mapped[float] = mapped_column(Float, nullable=False)
    longitude: Mapped[float] = mapped_column(Float, nullable=False)
    sighted_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False)
    notes: Mapped[str | None] = mapped_column(Text, nullable=True)
    source: Mapped[str] = mapped_column(String(16), nullable=False, default="user")
    identity: Mapped[str | None] = mapped_column(String(64), nullable=True)
    lost_dog_id: Mapped[uuid.UUID | None] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("lost_dogs.id", ondelete="CASCADE"),
        nullable=True,
    )
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now(), nullable=False
    )

    lost_dog: Mapped[LostDog | None] = relationship(back_populates="photos")


class SightingRejection(Base):
    """Owner said 'not my dog' on a possible spotting.

    Composite PK on (lost_dog_id, sighting_id) makes inserts idempotent and
    keeps the LEFT JOIN anti-join filter on possible-sightings cheap.
    """

    __tablename__ = "sighting_rejections"
    __table_args__ = (
        PrimaryKeyConstraint("lost_dog_id", "sighting_id"),
        Index("sighting_rejections_sighting_idx", "sighting_id"),
    )

    lost_dog_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("lost_dogs.id", ondelete="CASCADE"),
        nullable=False,
    )
    sighting_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("sightings.id", ondelete="CASCADE"),
        nullable=False,
    )
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now(), nullable=False
    )