from __future__ import annotations

import uuid
from typing import Any

from sqlalchemy import JSON, Enum, Float, ForeignKey, String
from sqlalchemy.orm import Mapped, mapped_column

from app.db.base import Base, TimestampMixin, UUIDPrimaryKeyMixin
from app.models.enums import ChangeStatus, ChangeType, SeverityLevel


class DetectedChange(Base, UUIDPrimaryKeyMixin, TimestampMixin):
    __tablename__ = "detected_changes"

    company_id: Mapped[uuid.UUID] = mapped_column(
        ForeignKey("companies.id", ondelete="CASCADE"), index=True
    )
    source_id: Mapped[uuid.UUID] = mapped_column(
        ForeignKey("sources.id", ondelete="CASCADE"), index=True
    )
    monitoring_run_id: Mapped[uuid.UUID] = mapped_column(
        ForeignKey("monitoring_runs.id", ondelete="CASCADE"), index=True
    )
    previous_snapshot_id: Mapped[uuid.UUID | None] = mapped_column(
        ForeignKey("snapshots.id", ondelete="SET NULL"), nullable=True
    )
    current_snapshot_id: Mapped[uuid.UUID] = mapped_column(
        ForeignKey("snapshots.id", ondelete="CASCADE")
    )
    change_type: Mapped[ChangeType] = mapped_column(Enum(ChangeType, native_enum=False, length=30))
    raw_diff: Mapped[dict[str, Any]] = mapped_column(JSON, default=dict)
    significance_score: Mapped[float] = mapped_column(Float)
    confidence_score: Mapped[float] = mapped_column(Float)
    severity: Mapped[SeverityLevel] = mapped_column(
        Enum(SeverityLevel, native_enum=False, length=20)
    )
    status: Mapped[ChangeStatus] = mapped_column(
        Enum(ChangeStatus, native_enum=False, length=20), default=ChangeStatus.NEW
    )
    # Short human-readable label, e.g. "3 new job postings detected" -
    # populated deterministically here; Phase 7's LLM may later add a
    # richer "why it matters" narrative on top without replacing this.
    summary: Mapped[str] = mapped_column(String(500))