"""Integration tests for the offline-first sync endpoints.

Drives POST /sync/push (idempotent append of like/play events) and GET
/sync/changes (delta pull with a server-clock cursor). Requires a reachable
Postgres; skips otherwise.
"""

import asyncio
import os
import uuid
from collections.abc import AsyncIterator
from pathlib import Path

import pytest
from app.core.config import get_settings
from app.infrastructure.db import Base, dispose_engine, get_engine, session_scope
from app.infrastructure.db.repositories import (
    SqlAlchemyArtistRepository,
    SqlAlchemyRefreshTokenRepository,
    SqlAlchemyTrackRepository,
    SqlAlchemyUserRepository,
)
from asgi_lifespan import LifespanManager
from httpx import ASGITransport, AsyncClient

pytestmark = pytest.mark.asyncio

_db_reachable_cache: bool | None = None


async def _db_reachable() -> bool:
    global _db_reachable_cache
    if _db_reachable_cache is not None:
        return _db_reachable_cache
    from sqlalchemy import text

    try:
        async with asyncio.timeout(3):
            async with get_engine().connect() as conn:
                await conn.execute(text("SELECT 1"))
        _db_reachable_cache = True
    except Exception:
        _db_reachable_cache = False
    return _db_reachable_cache


async def _seed_track(source_id: str = "sync-1") -> uuid.UUID:
    async with session_scope() as session:
        artist = await SqlAlchemyArtistRepository(session).get_or_create("Sync Artist")
        tid = uuid.uuid4()
        await SqlAlchemyTrackRepository(session).add(
            id=tid,
            title="Sync Track",
            artist_id=artist.id,
            storage_uri=f"tracks/zz/{source_id}.mp3",
            file_format="mp3",
            file_size=10,
            source="upload",
            source_id=source_id,
            metadata_status="enriched",
            added_by=None,
        )
        return tid


@pytest.fixture
async def api(tmp_path: Path) -> AsyncIterator[AsyncClient]:
    if not await _db_reachable():
        pytest.skip("Postgres not reachable — integration test skipped.")

    os.environ["MEDIA_PATH"] = str(tmp_path)
    get_settings.cache_clear()

    try:
        async with get_engine().begin() as conn:
            await conn.run_sync(Base.metadata.drop_all)
            await conn.run_sync(Base.metadata.create_all)

        from app.application.user_service import UserService
        from app.core.security import Argon2PasswordHasher

        async with session_scope() as session:
            await UserService(
                users=SqlAlchemyUserRepository(session),
                refresh_tokens=SqlAlchemyRefreshTokenRepository(session),
                hasher=Argon2PasswordHasher(),
            ).create_user(username="syncer", password="testpass1", is_superuser=False)

        from app.main import create_app

        app = create_app()
        async with LifespanManager(app):
            transport = ASGITransport(app=app)
            async with AsyncClient(transport=transport, base_url="http://test") as client:
                yield client

        async with get_engine().begin() as conn:
            await conn.run_sync(Base.metadata.drop_all)
        await dispose_engine()
    finally:
        os.environ.pop("MEDIA_PATH", None)
        get_settings.cache_clear()


async def _auth(api: AsyncClient) -> dict[str, str]:
    resp = await api.post(
        "/api/v1/auth/login", json={"username": "syncer", "password": "testpass1"}
    )
    assert resp.status_code == 200, resp.text
    return {"Authorization": f"Bearer {resp.json()['access_token']}"}


async def test_push_is_idempotent_and_pull_returns_events(api: AsyncClient) -> None:
    headers = await _auth(api)
    track_id = await _seed_track()
    like_id, play_id = str(uuid.uuid4()), str(uuid.uuid4())

    push_body = {
        "likes": [
            {
                "id": like_id,
                "track_id": str(track_id),
                "value": "like",
                "created_at": "2020-01-01T00:00:00+00:00",
            }
        ],
        "plays": [
            {
                "id": play_id,
                "track_id": str(track_id),
                "played_at": "2020-01-01T00:05:00+00:00",
                "play_duration_seconds": 180,
                "completed": True,
            }
        ],
    }

    first = await api.post("/api/v1/sync/push", json=push_body, headers=headers)
    assert first.status_code == 200, first.text
    assert first.json()["accepted_likes"] == 1
    assert first.json()["accepted_plays"] == 1

    # Replaying the exact same events must store nothing (idempotent by id).
    replay = await api.post("/api/v1/sync/push", json=push_body, headers=headers)
    assert replay.json()["accepted_likes"] == 0
    assert replay.json()["accepted_plays"] == 0

    # Full pull returns the events + the catalogue track, with a cursor.
    changes = await api.get("/api/v1/sync/changes", headers=headers)
    assert changes.status_code == 200, changes.text
    body = changes.json()
    assert [lk["id"] for lk in body["likes"]] == [like_id]
    assert body["likes"][0]["created_at"].startswith("2020-01-01")  # event time preserved
    assert [p["id"] for p in body["plays"]] == [play_id]
    assert str(track_id) in [t["id"] for t in body["tracks"]]
    assert body["cursor"]


async def test_cursor_advances_and_empty_delta(api: AsyncClient) -> None:
    headers = await _auth(api)
    track_id = await _seed_track()
    await api.post(
        "/api/v1/sync/push",
        json={
            "likes": [
                {
                    "id": str(uuid.uuid4()),
                    "track_id": str(track_id),
                    "value": "like",
                    "created_at": "2024-01-01T00:00:00+00:00",
                }
            ]
        },
        headers=headers,
    )
    cursor = (await api.get("/api/v1/sync/changes", headers=headers)).json()["cursor"]

    # Nothing changed since the cursor → empty delta (but a fresh cursor).
    delta = await api.get("/api/v1/sync/changes", params={"since": cursor}, headers=headers)
    assert delta.status_code == 200, delta.text
    assert delta.json()["likes"] == []
    assert delta.json()["plays"] == []


async def test_offline_event_with_old_time_still_syncs(api: AsyncClient) -> None:
    # The delta is keyed by server-ingestion time, not the client event time, so
    # an event pushed now with an old created_at still surfaces for a cursor that
    # sits *after* that old event time.
    headers = await _auth(api)
    track_id = await _seed_track()
    baseline = (await api.get("/api/v1/sync/changes", headers=headers)).json()["cursor"]

    await api.post(
        "/api/v1/sync/push",
        json={
            "likes": [
                {
                    "id": str(uuid.uuid4()),
                    "track_id": str(track_id),
                    "value": "like",
                    "created_at": "2019-06-01T00:00:00+00:00",  # long before `baseline`
                }
            ]
        },
        headers=headers,
    )

    delta = await api.get("/api/v1/sync/changes", params={"since": baseline}, headers=headers)
    assert len(delta.json()["likes"]) == 1  # surfaced despite the old event time


async def test_push_skips_unknown_track(api: AsyncClient) -> None:
    headers = await _auth(api)
    resp = await api.post(
        "/api/v1/sync/push",
        json={
            "likes": [
                {
                    "id": str(uuid.uuid4()),
                    "track_id": str(uuid.uuid4()),  # not in the catalogue
                    "value": "like",
                    "created_at": "2024-01-01T00:00:00+00:00",
                }
            ]
        },
        headers=headers,
    )
    assert resp.status_code == 200, resp.text
    assert resp.json()["accepted_likes"] == 0


async def test_pull_includes_changed_playlists_with_track_ids(api: AsyncClient) -> None:
    headers = await _auth(api)
    track_id = await _seed_track()

    created = await api.post("/api/v1/playlists", json={"name": "Sync Mix"}, headers=headers)
    playlist_id = created.json()["id"]
    await api.post(
        f"/api/v1/playlists/{playlist_id}/tracks",
        json={"track_id": str(track_id)},
        headers=headers,
    )

    body = (await api.get("/api/v1/sync/changes", headers=headers)).json()
    playlists = {p["id"]: p for p in body["playlists"]}
    assert playlist_id in playlists
    assert playlists[playlist_id]["track_ids"] == [str(track_id)]


async def test_sync_requires_auth(api: AsyncClient) -> None:
    assert (await api.get("/api/v1/sync/changes")).status_code == 401
    assert (await api.post("/api/v1/sync/push", json={})).status_code == 401