"""Tests for the transactional outbox pattern.

Covers:
- enqueue_outbox_event inserts rows with status='pending'
- process_outbox_batch publishes events to the in-process bus
- Retry logic with exponential backoff
- Max attempts → 'failed' status
- Empty batch returns 0
"""

from __future__ import annotations

import uuid

import pytest
from sqlalchemy import text
from sqlalchemy.ext.asyncio import async_sessionmaker, AsyncSession

from app.core.event_bus import get_event_bus
from app.core.outbox import enqueue_outbox_event, process_outbox_batch


@pytest.mark.asyncio
async def test_enqueue_outbox_event_inserts_pending_row(db_session):
    """enqueue_outbox_event inserts a row with status='pending'."""
    tenant_id = uuid.uuid4()

    await enqueue_outbox_event(
        db_session, tenant_id, "contact.created",
        {"contact_id": "abc-123", "tenant_id": str(tenant_id)},
    )
    await db_session.flush()

    rows = (
        await db_session.execute(
            text("SELECT event_name, status, payload FROM event_outbox WHERE tenant_id = :tid"),
            {"tid": str(tenant_id)},
        )
    ).fetchall()

    assert len(rows) == 1
    assert rows[0][0] == "contact.created"
    assert rows[0][1] == "pending"
    assert rows[0][2]["contact_id"] == "abc-123"


@pytest.mark.asyncio
async def test_process_outbox_batch_publishes_events(
    db_session, session_factory: async_sessionmaker[AsyncSession],
):
    """process_outbox_batch publishes pending events and marks them 'published'."""
    tenant_id = uuid.uuid4()
    received_events: list[tuple[str, dict]] = []

    async def _handler(payload: dict) -> None:
        received_events.append(("test.event", payload))

    bus = get_event_bus()
    bus.subscribe("test.event", _handler)
    try:
        await enqueue_outbox_event(
            db_session, tenant_id, "test.event",
            {"key": "value"},
        )
        await db_session.flush()
        await db_session.commit()

        # Use a separate session to simulate the worker
        async with session_factory() as worker_session:
            count = await process_outbox_batch(worker_session, batch_size=10, tenant_ids=[tenant_id])

        assert count == 1
        assert len(received_events) == 1
        assert received_events[0][1]["key"] == "value"

        # Verify the event is marked as published
        rows = (
            await db_session.execute(
                text("SELECT status FROM event_outbox WHERE tenant_id = :tid"),
                {"tid": str(tenant_id)},
            )
        ).fetchall()
        assert rows[0][0] == "published"
    finally:
        bus.unsubscribe("test.event", _handler)


@pytest.mark.asyncio
async def test_process_outbox_batch_empty_returns_zero(
    session_factory: async_sessionmaker[AsyncSession],
):
    """process_outbox_batch returns 0 when no pending events exist."""
    async with session_factory() as worker_session:
        count = await process_outbox_batch(worker_session, batch_size=10)
    assert count == 0


@pytest.mark.asyncio
async def test_process_outbox_batch_retry_on_failure(
    db_session, session_factory: async_sessionmaker[AsyncSession],
):
    """When a handler raises, the event is retried with exponential backoff."""
    tenant_id = uuid.uuid4()

    async def _failing_handler(payload: dict) -> None:
        raise RuntimeError("Handler failure")

    bus = get_event_bus()
    bus.subscribe("test.failing", _failing_handler)
    try:
        await enqueue_outbox_event(
            db_session, tenant_id, "test.failing",
            {"attempt": 1},
        )
        await db_session.flush()
        await db_session.commit()

        async with session_factory() as worker_session:
            count = await process_outbox_batch(worker_session, batch_size=10, tenant_ids=[tenant_id])

        assert count == 0  # nothing was successfully published

        # Verify the event is back to 'pending' with attempts=1 and a retry time
        rows = (
            await db_session.execute(
                text(
                    "SELECT status, attempts, next_retry_at "
                    "FROM event_outbox WHERE tenant_id = :tid"
                ),
                {"tid": str(tenant_id)},
            )
        ).fetchall()
        assert rows[0][0] == "pending"
        assert rows[0][1] == 1
        assert rows[0][2] is not None
    finally:
        bus.unsubscribe("test.failing", _failing_handler)


@pytest.mark.asyncio
async def test_process_outbox_batch_max_attempts_marks_failed(
    db_session, session_factory: async_sessionmaker[AsyncSession],
):
    """After max_attempts failures, the event is marked as 'failed'."""
    tenant_id = uuid.uuid4()

    async def _always_fails(payload: dict) -> None:
        raise RuntimeError("Always fails")

    bus = get_event_bus()
    bus.subscribe("test.maxfail", _always_fails)
    try:
        # Insert an event that already has attempts = max_attempts - 1
        await db_session.execute(
            text(
                "INSERT INTO event_outbox (tenant_id, event_name, payload, status, attempts, max_attempts) "
                "VALUES (:tid, 'test.maxfail', CAST(:payload AS JSONB), 'pending', 4, 5)"
            ),
            {"tid": str(tenant_id), "payload": '{"k": "v"}'},
        )
        await db_session.flush()
        await db_session.commit()

        async with session_factory() as worker_session:
            count = await process_outbox_batch(worker_session, batch_size=10, tenant_ids=[tenant_id])

        assert count == 0

        rows = (
            await db_session.execute(
                text("SELECT status, attempts FROM event_outbox WHERE tenant_id = :tid"),
                {"tid": str(tenant_id)},
            )
        ).fetchall()
        assert rows[0][0] == "failed"
    finally:
        bus.unsubscribe("test.maxfail", _always_fails)


@pytest.mark.asyncio
async def test_enqueue_multiple_events_and_batch_size(
    db_session, session_factory: async_sessionmaker[AsyncSession],
):
    """Multiple events are enqueued and batch_size limits processing."""
    tenant_id = uuid.uuid4()
    received: list[str] = []

    async def _handler(payload: dict) -> None:
        received.append(payload.get("idx", "?"))

    bus = get_event_bus()
    bus.subscribe("test.batch", _handler)
    try:
        for i in range(5):
            await enqueue_outbox_event(
                db_session, tenant_id, "test.batch",
                {"idx": str(i)},
            )
        await db_session.flush()
        await db_session.commit()

        async with session_factory() as worker_session:
            count = await process_outbox_batch(worker_session, batch_size=3, tenant_ids=[tenant_id])

        assert count == 3
        assert len(received) == 3

        # Process the remaining 2
        async with session_factory() as worker_session:
            count2 = await process_outbox_batch(worker_session, batch_size=3, tenant_ids=[tenant_id])
        assert count2 == 2
        assert len(received) == 5
    finally:
        bus.unsubscribe("test.batch", _handler)