"""Durable delivery queue for alert notifications."""

import enum
from datetime import datetime

from sqlalchemy import BigInteger, Column, DateTime, Enum, Index, Integer, String, Text

from .device import Base


PRIMARY_KEY_TYPE = BigInteger().with_variant(Integer, "sqlite")


class NotificationStatus(str, enum.Enum):
    """Lifecycle states for a notification delivery attempt."""

    pending = "pending"
    sending = "sending"
    sent = "sent"
    failed = "failed"


class NotificationOutbox(Base):
    """A notification retained until a dispatcher records its final outcome."""

    __tablename__ = "notification_outbox"

    id = Column(PRIMARY_KEY_TYPE, primary_key=True, autoincrement=True)
    alert_event_id = Column(BigInteger, nullable=False, index=True, comment="关联告警事件 ID")
    message_content = Column(Text, nullable=False, comment="待发送的脱敏消息摘要")
    delivery_scope = Column(String(256), nullable=True, comment="受控投递范围摘要")
    status = Column(
        Enum(NotificationStatus),
        nullable=False,
        default=NotificationStatus.pending,
        server_default=NotificationStatus.pending.value,
        comment="投递状态",
    )
    attempt_count = Column(Integer, nullable=False, default=0, comment="投递尝试次数")
    next_attempt_at = Column(DateTime, nullable=True, comment="下次允许投递时间")
    locked_at = Column(DateTime, nullable=True, comment="投递器领取时间")
    sent_at = Column(DateTime, nullable=True, comment="成功投递时间")
    last_error = Column(String(512), nullable=True, comment="最近一次投递错误摘要")
    created_at = Column(DateTime, default=datetime.now, nullable=False, comment="创建时间")
    updated_at = Column(
        DateTime,
        default=datetime.now,
        onupdate=datetime.now,
        nullable=False,
        comment="更新时间",
    )

    __table_args__ = (
        Index("idx_notification_outbox_status_next_attempt", "status", "next_attempt_at"),
    )