import json
import subprocess
from pathlib import Path


POLLER = Path(__file__).parents[1] / "frontend" / "context-poller.js"


def run_node(script: str) -> dict:
    result = subprocess.run(
        ["node", "-e", script], check=True, capture_output=True, text=True
    )
    return json.loads(result.stdout)


def test_context_poller_is_single_flight_and_pauses_until_visible():
    script = f"""
const createContextPoller = require({json.dumps(str(POLLER))});
let calls = 0;
let hidden = false;
let resolveRequest;
const timers = [];
const poller = createContextPoller({{
  fetchContext: () => {{
    calls += 1;
    if (calls > 1) return Promise.resolve({{ repos: [] }});
    return new Promise((resolve) => {{ resolveRequest = resolve; }});
  }},
  onSnapshot: () => {{}},
  onError: () => {{}},
  isHidden: () => hidden,
  setTimer: (callback) => {{ timers.push(callback); return timers.length; }},
  clearTimer: () => {{}},
  intervalMs: 8000,
}});

(async () => {{
  const first = poller.start();
  const joined = poller.refresh();
  const callsWhilePending = calls;
  resolveRequest({{ repos: [] }});
  await Promise.all([first, joined]);

  hidden = true;
  poller.setVisible(false);
  const scheduled = timers.shift();
  if (scheduled) scheduled();
  await Promise.resolve();
  const callsWhileHidden = calls;

  hidden = false;
  await poller.setVisible(true);
  process.stdout.write(JSON.stringify({{
    callsWhilePending,
    callsWhileHidden,
    callsAfterResume: calls,
  }}));
}})();
"""

    assert run_node(script) == {
        "callsWhilePending": 1,
        "callsWhileHidden": 1,
        "callsAfterResume": 2,
    }


def test_context_poller_sends_revisions_and_merges_changed_sections():
    script = f"""
const createContextPoller = require({json.dumps(str(POLLER))});
const requested = [];
const rendered = [];
const responses = [
  {{ context: {{ user: {{ login: 'timmy' }} }}, events: [{{ id: 1 }}], notifications: [],
     sections: {{ context: 'fresh', events: 'fresh', notifications: 'fresh' }},
     revisions: {{ context: 1, events: 1, notifications: 1 }}, freshness: {{ age_seconds: 0 }} }},
  {{ sections: {{ context: 'fresh', events: 'fresh', notifications: 'fresh' }},
     revisions: {{ context: 1, events: 2, notifications: 1 }}, events: [{{ id: 2 }}],
     freshness: {{ age_seconds: 1 }} }},
  {{ sections: {{ context: 'fresh', events: 'fresh', notifications: 'fresh' }},
     revisions: {{ context: 1, events: 2, notifications: 1 }}, freshness: {{ age_seconds: 2 }} }},
];
const poller = createContextPoller({{
  fetchContext: revisions => {{ requested.push({{ ...revisions }}); return Promise.resolve(responses.shift()); }},
  onSnapshot: (snapshot, changed) => rendered.push({{
    context: snapshot.context.user.login,
    event: snapshot.events[0].id,
    age: snapshot.freshness.age_seconds,
    changed,
  }}),
  onError: error => {{ throw error; }},
  setTimer: () => 1,
  clearTimer: () => {{}},
}});
(async () => {{
  await poller.refresh();
  await poller.refresh();
  await poller.refresh();
  process.stdout.write(JSON.stringify({{ requested, rendered }}));
}})();
"""

    assert run_node(script) == {
        "requested": [
            {},
            {"context": 1, "events": 1, "notifications": 1},
            {"context": 1, "events": 2, "notifications": 1},
        ],
        "rendered": [
            {"context": "timmy", "event": 1, "age": 0,
             "changed": ["context", "events", "notifications"]},
            {"context": "timmy", "event": 2, "age": 1,
             "changed": ["events"]},
            {"context": "timmy", "event": 2, "age": 2, "changed": []},
        ],
    }