"""API and heuristic tests for trending discovery sort.

docs/planning/discovery.md (task 33706f401ad9).
"""

from datetime import datetime, timedelta, timezone
import pytest
from fastapi.testclient import TestClient
from sqlalchemy.ext.asyncio import async_sessionmaker, create_async_engine
from sqlalchemy.pool import NullPool

from app.config import settings
from app.main import app
from app.models.world_visit import WorldVisit


def _register(client: TestClient, username: str) -> tuple[int, dict[str, str]]:
    resp = client.post(
        "/api/auth/register",
        json={
            "username": username,
            "email": f"{username}@example.com",
            "password": "secret123",
            "date_of_birth": "1990-01-01",
        },
    )
    assert resp.status_code == 201, resp.text
    token = resp.json()["access_token"]
    headers = {"Authorization": f"Bearer {token}"}
    me = client.get("/api/users/me", headers=headers)
    assert me.status_code == 200, me.text
    return me.json()["id"], headers


def _session_factory():
    engine = create_async_engine(settings.DATABASE_URL, poolclass=NullPool)
    return engine, async_sessionmaker(engine, expire_on_commit=False)


@pytest.mark.asyncio
async def test_trending_sort_heuristic_and_zero_visits():
    client = TestClient(app)
    uid, headers = _register(client, "creator_trending_1")

    # Create 3 worlds
    wA = client.post(
        "/api/worlds/",
        headers=headers,
        json={"name": "Trending Hot World", "visibility": "public", "category": "Action"},
    ).json()
    wB = client.post(
        "/api/worlds/",
        headers=headers,
        json={"name": "Older Mild World", "visibility": "public", "category": "Action"},
    ).json()
    wC = client.post(
        "/api/worlds/",
        headers=headers,
        json={"name": "Zero Visit World", "visibility": "public", "category": "Action"},
    ).json()

    engine, sf = _session_factory()
    now = datetime.now(timezone.utc)
    try:
        async with sf() as session:
            # World A: 3 visits within last 2 hours (weight 3 each = score 9)
            for i in range(3):
                session.add(
                    WorldVisit(
                        world_id=wA["id"],
                        anonymous_token=f"hot_visitor_{i}",
                        visited_at=now - timedelta(hours=1, minutes=i),
                    )
                )
            # World B: 1 visit 5 days ago (weight 1 = score 1)
            session.add(
                WorldVisit(
                    world_id=wB["id"],
                    anonymous_token="old_visitor",
                    visited_at=now - timedelta(days=5),
                )
            )
            # World C: zero visits
            await session.commit()
    finally:
        await engine.dispose()

    # Query with sort=trending
    resp = client.get("/api/discovery/worlds?sort=trending&category=Action")
    assert resp.status_code == 200, resp.text
    items = resp.json()["items"]

    # Verify order: wA should be first, wB second, wC third
    ids = [item["id"] for item in items]
    assert wA["id"] in ids
    assert wB["id"] in ids
    assert wC["id"] in ids

    idxA = ids.index(wA["id"])
    idxB = ids.index(wB["id"])
    idxC = ids.index(wC["id"])

    assert idxA < idxB < idxC, f"Expected order A ({idxA}) < B ({idxB}) < C ({idxC})"