from collections.abc import Generator
from datetime import datetime

from sqlalchemy import JSON, DateTime, Float, String, create_engine
from sqlalchemy.orm import DeclarativeBase, Mapped, Session, mapped_column, sessionmaker

from app.config import get_settings


class Base(DeclarativeBase):
    pass


def json_type():
    return JSON()


class TimestampMixin:
    created_at: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow)
    updated_at: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)


class Task(Base, TimestampMixin):
    __tablename__ = "tasks"

    id: Mapped[int] = mapped_column(primary_key=True)
    title: Mapped[str] = mapped_column(String(240))
    assignee: Mapped[str | None] = mapped_column(String(120), nullable=True)
    due_date: Mapped[datetime | None] = mapped_column(DateTime, nullable=True)
    status: Mapped[str] = mapped_column(String(40), default="pending")


class Note(Base, TimestampMixin):
    __tablename__ = "notes"

    id: Mapped[int] = mapped_column(primary_key=True)
    content: Mapped[str] = mapped_column(String(2000))
    category: Mapped[str] = mapped_column(String(40), default="general")


class Reservation(Base, TimestampMixin):
    __tablename__ = "reservations"

    id: Mapped[int] = mapped_column(primary_key=True)
    vendor: Mapped[str] = mapped_column(String(180))
    reservation_date: Mapped[datetime] = mapped_column(DateTime)
    status: Mapped[str] = mapped_column(String(40), default="pending")


class PendingAction(Base, TimestampMixin):
    __tablename__ = "pending_actions"

    id: Mapped[int] = mapped_column(primary_key=True)
    meeting_id: Mapped[str] = mapped_column(String(120), index=True)
    tool: Mapped[str] = mapped_column(String(120))
    intent: Mapped[str] = mapped_column(String(120))
    reasoning: Mapped[str] = mapped_column(String(1000))
    confidence: Mapped[float] = mapped_column(Float)
    payload: Mapped[dict] = mapped_column(json_type())
    extracted_entities: Mapped[dict] = mapped_column(json_type(), default=dict)
    validation: Mapped[dict] = mapped_column(json_type())
    policy: Mapped[dict] = mapped_column(json_type())
    status: Mapped[str] = mapped_column(String(40), default="pending_review")
    execution_result: Mapped[dict | None] = mapped_column(json_type(), nullable=True)


engine = create_engine(get_settings().database_url, pool_pre_ping=True)
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)


def init_db() -> None:
    Base.metadata.create_all(bind=engine)


def get_session() -> Generator[Session, None, None]:
    session = SessionLocal()
    try:
        yield session
    finally:
        session.close()