"""Garbage collection integration tests (ARTIFACT-STORE-WP-0006)."""

from __future__ import annotations

from collections.abc import AsyncIterator
from datetime import UTC, datetime, timedelta
from pathlib import Path
from uuid import UUID

import pytest
import pytest_asyncio
from sqlalchemy import insert, select
from sqlalchemy.ext.asyncio import AsyncEngine, create_async_engine

from artifactstore.dataplane import InProcessDataPlane
from artifactstore.db.schema import (
    metadata,
    retention_classes,
    storage_locations,
)
from artifactstore.db.seed import RETENTION_CLASS_SEEDS
from artifactstore.events import RegistryViewWriter, replay
from artifactstore.registry import FileNotFoundError, Registry
from artifactstore.retention import RetentionPolicy
from artifactstore.storage import LocalBackend


@pytest_asyncio.fixture
async def engine(tmp_path: Path) -> AsyncIterator[AsyncEngine]:
    db_path = tmp_path / "gc.db"
    eng = create_async_engine(f"sqlite+aiosqlite:///{db_path}")
    async with eng.begin() as conn:
        await conn.run_sync(metadata.create_all)
        for seed in RETENTION_CLASS_SEEDS:
            await conn.execute(insert(retention_classes).values(**seed))
    yield eng
    await eng.dispose()


@pytest.fixture
def view_writer() -> RegistryViewWriter:
    return RegistryViewWriter()


@pytest.fixture
def registry(
    engine: AsyncEngine,
    tmp_path: Path,
    view_writer: RegistryViewWriter,
) -> Registry:
    backend = LocalBackend(tmp_path / "storage", backend_id="local")
    dataplane = InProcessDataPlane(backend, tmp_dir=tmp_path / "dp-tmp")
    return Registry(
        engine,
        dataplane,
        view_writer,
        RetentionPolicy({"transient": 0}),
    )


async def _stream(data: bytes) -> AsyncIterator[bytes]:
    yield data


async def _consume(it: AsyncIterator[bytes]) -> bytes:
    out = bytearray()
    async for chunk in it:
        out.extend(chunk)
    return bytes(out)


async def _package_with_file(
    registry: Registry,
    *,
    name: str,
    retention_class: str,
    data: bytes,
) -> tuple[UUID, UUID]:
    package_id = await registry.create_package(
        name=name,
        producer="tests",
        subject=name,
        retention_class=retention_class,
        actor="ops",
    )
    file_id = await registry.ingest_file(
        package_id,
        relative_path="payload.bin",
        media_type="application/octet-stream",
        stream=_stream(data),
        actor="ops",
    )
    await registry.finalize_package(package_id, actor="ops")
    return package_id, file_id


async def _location_statuses(engine: AsyncEngine) -> dict[UUID, str]:
    async with engine.connect() as conn:
        rows = (
            await conn.execute(
                select(
                    storage_locations.c.artifact_file_id,
                    storage_locations.c.status,
                )
            )
        ).all()
    return {row.artifact_file_id: row.status for row in rows}


async def test_gc_deletes_unique_expired_object_and_replays(
    registry: Registry,
    engine: AsyncEngine,
    view_writer: RegistryViewWriter,
) -> None:
    package_id, file_id = await _package_with_file(
        registry,
        name="unique",
        retention_class="transient",
        data=b"unique bytes",
    )
    marked = await registry.sweep_deletion_eligibility(
        now=datetime.now(UTC) + timedelta(seconds=1)
    )
    assert marked == [package_id]

    results = await registry.collect_garbage()
    assert len(results) == 1
    assert results[0].file_id == file_id
    assert results[0].object_delete_attempted is True
    assert results[0].object_deleted is True
    assert results[0].ref_count_before == 1
    assert results[0].ref_count_after == 0

    with pytest.raises(FileNotFoundError):
        await registry.get_file(file_id)
    assert await registry.collect_garbage() == []

    pre = await _location_statuses(engine)
    await replay(engine, view_writer, reset=True)
    post = await _location_statuses(engine)
    assert pre == post == {file_id: "deleted"}

    package = await registry.get_package(package_id)
    assert package.status == "garbage_collected"


async def test_gc_releases_shared_reference_without_deleting_retained_bytes(
    registry: Registry,
    engine: AsyncEngine,
) -> None:
    data = b"shared bytes"
    expired_package, expired_file = await _package_with_file(
        registry,
        name="expired",
        retention_class="transient",
        data=data,
    )
    retained_package, retained_file = await _package_with_file(
        registry,
        name="retained",
        retention_class="raw-evidence",
        data=data,
    )
    marked = await registry.sweep_deletion_eligibility(
        now=datetime.now(UTC) + timedelta(seconds=1)
    )
    assert marked == [expired_package]

    results = await registry.collect_garbage()
    assert len(results) == 1
    assert results[0].package_id == expired_package
    assert results[0].object_delete_attempted is False
    assert results[0].object_deleted is False
    assert results[0].ref_count_before == 2
    assert results[0].ref_count_after == 1

    statuses = await _location_statuses(engine)
    assert statuses[expired_file] == "deleted"
    assert statuses[retained_file] == "recorded"
    assert (await registry.get_package(expired_package)).status == "garbage_collected"
    assert (await registry.get_package(retained_package)).status == "finalized"

    with pytest.raises(FileNotFoundError):
        await registry.get_file(expired_file)
    retained_stream = await registry.get_file(retained_file)
    assert await _consume(retained_stream) == data


async def test_gc_respects_active_hold(registry: Registry, engine: AsyncEngine) -> None:
    package_id, file_id = await _package_with_file(
        registry,
        name="held",
        retention_class="transient",
        data=b"held bytes",
    )
    await registry.apply_retention_hold(package_id, reason="legal hold", actor="ops")

    marked = await registry.sweep_deletion_eligibility(
        now=datetime.now(UTC) + timedelta(seconds=1)
    )
    assert marked == []
    assert await registry.collect_garbage() == []
    assert await _location_statuses(engine) == {file_id: "recorded"}

    stream = await registry.get_file(file_id)
    assert await _consume(stream) == b"held bytes"