"""SSE activity stream: resumable event ids, reconnect without duplicate/lost
events, and parity with the polling fallback."""

import pytest
from fastapi.testclient import TestClient

from photo_pipeline.api.app import create_app
from photo_pipeline.config import Config
from photo_pipeline.db import run_migrations
from photo_pipeline.services.jobs import ItemState, JobService, JobState


@pytest.fixture
def client(tmp_path):
    (tmp_path / "data").mkdir()
    config = Config.from_env({"PHOTO_PIPELINE_DATA_DIR": str(tmp_path / "data")})
    run_migrations(config.database_url)
    app = create_app(config)
    with TestClient(app) as test_client:
        test_client.app = app
        yield test_client


def _finished_job(client):
    job = client.post("/api/v1/jobs", json={"job_type": "scan", "items": ["a", "b"]}).json()
    service = JobService(client.app.state.session_factory)
    service.claim(["scan"], "w1")
    for item in ("a", "b"):
        service.set_item(job["id"], item, ItemState.RUNNING)
        service.set_item(job["id"], item, ItemState.SUCCEEDED)
    service.transition(job["id"], JobState.SUCCEEDED, worker_id="w1")
    return job["id"]


def _read_ids(client, job_id, headers=None):
    ids, saw_done = [], False
    with client.stream(
        "GET", f"/api/v1/jobs/{job_id}/events/stream", headers=headers or {}
    ) as stream:
        assert stream.headers["content-type"].startswith("text/event-stream")
        for line in stream.iter_lines():
            if line.startswith("id:"):
                ids.append(int(line.split(":", 1)[1]))
            elif line.startswith("event: done"):
                saw_done = True
    return ids, saw_done


def test_sse_streams_all_events_then_closes(client):
    job_id = _finished_job(client)
    ids, saw_done = _read_ids(client, job_id)
    assert ids == sorted(ids) and len(ids) >= 3
    assert saw_done  # terminal job closes the stream


def test_sse_reconnect_has_no_duplicate_or_lost_events(client):
    job_id = _finished_job(client)
    full, _ = _read_ids(client, job_id)
    resume_from = full[1]
    resumed, saw_done = _read_ids(client, job_id, headers={"Last-Event-ID": str(resume_from)})
    assert resumed == [i for i in full if i > resume_from]  # no dup, none lost
    assert saw_done


def test_sse_matches_polling(client):
    job_id = _finished_job(client)
    sse_ids, _ = _read_ids(client, job_id)
    polled = client.get(f"/api/v1/jobs/{job_id}/events").json()["events"]
    assert sse_ids == [e["seq"] for e in polled]