"""Database models and session management."""

from __future__ import annotations

import os
from datetime import datetime
from enum import Enum
from typing import Generator

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


class Base(DeclarativeBase):
    pass


class ReviewStatus(str, Enum):
    PENDING = "pending"
    APPROVED = "approved"
    REJECTED = "rejected"


class InvoiceReview(Base):
    __tablename__ = "invoice_reviews"

    id: Mapped[str] = mapped_column(String(36), primary_key=True)
    vendor_name: Mapped[str | None] = mapped_column(String(255), nullable=True)
    invoice_number: Mapped[str | None] = mapped_column(String(100), nullable=True)
    total_amount: Mapped[float | None] = mapped_column(nullable=True)
    currency: Mapped[str] = mapped_column(String(10), default="IRR")
    confidence: Mapped[float] = mapped_column(default=0.0)
    status: Mapped[str] = mapped_column(String(20), default=ReviewStatus.PENDING.value)
    invoice_data: Mapped[dict] = mapped_column(JSON)
    validation_data: Mapped[dict | None] = mapped_column(JSON, nullable=True)
    reviewer: Mapped[str | None] = mapped_column(String(100), nullable=True)
    review_notes: Mapped[str | None] = mapped_column(Text, nullable=True)
    created_at: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow)
    reviewed_at: Mapped[datetime | None] = mapped_column(DateTime, nullable=True)


def get_database_url() -> str:
    return os.getenv(
        "DATABASE_URL",
        "postgresql://docflow:docflow_secret@postgres:5432/docflow",
    )


engine = create_engine(get_database_url(), pool_pre_ping=True)
SessionLocal = sessionmaker(bind=engine, autoflush=False, autocommit=False)


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


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