from __future__ import annotations

from datetime import datetime, timezone
from typing import Any

from sqlalchemy import Boolean, DateTime, Float, Integer, String
from sqlalchemy.dialects.postgresql import JSONB
from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column
from sqlalchemy.types import JSON


JsonColumn = JSON().with_variant(JSONB, "postgresql")


def utcnow() -> datetime:
    return datetime.now(timezone.utc)


class Base(DeclarativeBase):
    pass


class PredictionLog(Base):
    __tablename__ = "prediction_logs"

    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
    timestamp: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False)
    event: Mapped[str] = mapped_column(String(40), nullable=False, default="prediction")
    input_data: Mapped[dict[str, Any]] = mapped_column(JsonColumn, nullable=False)
    prediction: Mapped[int | None] = mapped_column(Integer, nullable=True)
    probability_of_default: Mapped[float | None] = mapped_column(Float, nullable=True)
    risk_category: Mapped[str | None] = mapped_column(String(20), nullable=True)
    inference_time_ms: Mapped[float | None] = mapped_column(Float, nullable=True)
    error: Mapped[str | None] = mapped_column(String, nullable=True)
    model_version: Mapped[str | None] = mapped_column(String(120), nullable=True)
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        nullable=False,
        default=utcnow,
    )


class DriftEvent(Base):
    __tablename__ = "drift_events"

    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
    timestamp: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False)
    drift_detected: Mapped[bool | None] = mapped_column(Boolean, nullable=True)
    feature: Mapped[str | None] = mapped_column(String(100), nullable=True)
    drift_score: Mapped[float | None] = mapped_column(Float, nullable=True)
    p_value: Mapped[float | None] = mapped_column(Float, nullable=True)
    ks_statistic: Mapped[float | None] = mapped_column(Float, nullable=True)
    method: Mapped[str | None] = mapped_column(String(50), nullable=True)
    batch_size: Mapped[int | None] = mapped_column(Integer, nullable=True)
    details: Mapped[dict[str, Any] | None] = mapped_column(JsonColumn, nullable=True)
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        nullable=False,
        default=utcnow,
    )