from datetime import datetime, timezone
from typing import Any, Optional

from sqlalchemy import DateTime, ForeignKey, Index, JSON, String, Text, UniqueConstraint
from sqlalchemy.orm import Mapped, mapped_column

from app.db import Base


class ContractLifecycleTask(Base):
    __tablename__ = "contract_lifecycle_tasks"
    __table_args__ = (
        UniqueConstraint("tenant_id", "task_key", name="uq_contract_lifecycle_tasks_tenant_task_key"),
        Index("ix_contract_lifecycle_tasks_tenant_contract", "tenant_id", "contract_id"),
        Index("ix_contract_lifecycle_tasks_tenant_status", "tenant_id", "status"),
        Index("ix_contract_lifecycle_tasks_tenant_due_at", "tenant_id", "due_at"),
    )

    id: Mapped[str] = mapped_column(String(64), primary_key=True)
    tenant_id: Mapped[str] = mapped_column(String(64), nullable=False, index=True)
    contract_id: Mapped[str] = mapped_column(String(64), ForeignKey("generated_contracts.id"), nullable=False, index=True)
    task_key: Mapped[str] = mapped_column(String(160), nullable=False)
    task_type: Mapped[str] = mapped_column(String(64), nullable=False, index=True)
    title: Mapped[str] = mapped_column(String(200), nullable=False)
    description: Mapped[Optional[str]] = mapped_column(Text, nullable=True)
    priority: Mapped[str] = mapped_column(String(32), nullable=False, default="medium", index=True)
    status: Mapped[str] = mapped_column(String(32), nullable=False, default="open", index=True)
    due_at: Mapped[Optional[datetime]] = mapped_column(DateTime(timezone=True), nullable=True, index=True)
    completed_by: Mapped[Optional[str]] = mapped_column(String(64), nullable=True)
    completed_at: Mapped[Optional[datetime]] = mapped_column(DateTime(timezone=True), nullable=True)
    evidence_file_id: Mapped[Optional[str]] = mapped_column(String(64), ForeignKey("files.id"), nullable=True, index=True)
    evidence_note: Mapped[Optional[str]] = mapped_column(Text, nullable=True)
    metadata_json: Mapped[Optional[dict[str, Any]]] = mapped_column(JSON, nullable=True)
    created_by: Mapped[Optional[str]] = mapped_column(String(64), nullable=True)
    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=lambda: datetime.now(timezone.utc), index=True)
    updated_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        default=lambda: datetime.now(timezone.utc),
        onupdate=lambda: datetime.now(timezone.utc),
    )