import uuid
from datetime import datetime

from sqlalchemy import CheckConstraint, DateTime, Index, Integer, String, Text
from sqlalchemy.dialects.postgresql import JSONB, UUID
from sqlalchemy.orm import Mapped, mapped_column

from app.core.db import Base
from app.models.mixins import TimestampMixin

DELIVERY_STATUSES = ("pending", "delivering", "succeeded", "failed")

# The one delivery failure the demo seed deliberately plants (BK-H-0020, see
# seed/workflow_runs.csv). It exists to show retry and audit working, so it must never
# be read as an integration-health problem: it is a scripted prop, not evidence that
# n8n is unhealthy. A dedicated error code -- rather than the generic
# "connectionError" a real timeout produces -- is what lets every reader tell the two
# apart without guessing from the message text.
#
# It is deliberately a `last_error_code` value and not a new column: the code is
# already persisted, already surfaced to the UI, and already localizable, so no schema
# change or migration is needed. A genuine later failure of this same event overwrites
# the code with the real one, which is exactly right -- from that moment it *is* a real
# failure.
DEMO_SCENARIO_ERROR_CODE = "demoScenarioTimeout"


def is_demo_scenario_failure(event: "OutboxEvent") -> bool:
    """True for the prepared demo failure, false for every real one."""
    return event.delivery_status == "failed" and event.last_error_code == DEMO_SCENARIO_ERROR_CODE


class OutboxEvent(TimestampMixin, Base):
    __tablename__ = "outbox_events"
    __table_args__ = (
        CheckConstraint(
            "delivery_status IN ('pending','delivering','succeeded','failed')",
            name="ck_outbox_delivery_status",
        ),
        CheckConstraint("attempts >= 0", name="ck_outbox_attempts"),
        Index("ix_outbox_delivery_next_attempt", "delivery_status", "next_attempt_at"),
    )

    event_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True), primary_key=True, default=uuid.uuid4
    )
    event_type: Mapped[str] = mapped_column(String(60), nullable=False)
    aggregate_type: Mapped[str] = mapped_column(String(30), nullable=False)
    aggregate_id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), nullable=False)
    payload_json: Mapped[dict] = mapped_column(JSONB, nullable=False, default=dict)
    occurred_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False)
    delivery_status: Mapped[str] = mapped_column(String(20), nullable=False, default="pending")
    attempts: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
    next_attempt_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))
    last_error: Mapped[str | None] = mapped_column(Text)
    # Stable, localizable classification of last_error -- the frontend renders a
    # localized summary from this code as the primary text and shows last_error itself
    # only under "Technical details" (section 10 of docs/fleet-ops-correction/
    # current-gap-audit.md). Kept alongside the raw message for backward compatibility.
    last_error_code: Mapped[str | None] = mapped_column(String(60))
    external_run_id: Mapped[str | None] = mapped_column(String(120))