import { edge, node } from '../lib/builders.mjs';
import { LANES, scaffoldBehavior } from './lib/scaffold.mjs';

/**
 * Pausing freezes world and clock and drops input instead of replaying it on resume. Brings its own
 * self-drifting box, since the fixture's Mover only moves on arrow keys and a pause would look like idling.
 */

const DRIFT_PER_SECOND = 100;
const KEY_LOG = 'arrow down';

/**
 * Two independent things in one graph: `On update → Move` drifts the owner right without any
 * input, and `On key down → Log` leaves a mark for every *edge* the world saw – which is what a
 * pause has to swallow.
 */
const pauseGraph = {
  nodes: [
    node('p-update', 'OnUpdate', 0, 0),
    node('p-owner', 'Owner', 0, 120),
    node('p-move', 'Move', 340, 0, { dx: 1, scale: DRIFT_PER_SECOND }),
    node('p-key', 'OnKeyDown', 0, 260, { key: 'ArrowRight' }),
    node('p-log', 'Log', 340, 260, { message: KEY_LOG }),
  ],
  edges: [
    edge('p-e1', 'p-update', 'exec', 'p-move', 'exec'),
    edge('p-e2', 'p-update', 'dt', 'p-move', 'dt'),
    edge('p-e3', 'p-owner', 'object', 'p-move', 'object'),
    edge('p-e4', 'p-key', 'exec', 'p-log', 'exec'),
  ],
};

export async function pause(t) {
  const { check, sleep, json, has, shot, clickText, press, entity, world, stop } = t;
  const playInfo = () => json('__gm.playInfo()');
  const boxX = async () => (await entity('p-box')).x;
  const keyHits = async () => (await world()).log.filter((line) => line.includes(KEY_LOG)).length;

  // 19a. A box with a drifting behavior below it, written into the model directly: what is under
  //      test is the pause, not another way of building a graph.
  const rig = await scaffoldBehavior(t, {
    assetId: 'pauser',
    name: 'Pauser',
    graph: pauseGraph,
    boxId: 'p-box',
    boxName: 'Pause box',
    logicId: 'p-logic',
    y: LANES.pause,
  });

  await t.play();
  const running = await playInfo();
  const beforeDrift = await boxX();
  await sleep(500);
  const drifted = await boxX();
  // The precondition of everything below: without movement, "it stood still" is trivially true.
  check(
    'the box drifts on its own while playing, with nothing held down',
    running.playing === true && running.paused === false && drifted > beforeDrift + 20,
    `x ${beforeDrift} → ${drifted}, ${JSON.stringify(running)}`,
  );

  // 19b. The toolbar button holds it. Both the clock and the box have to stop – a world that keeps
  //      ticking while the picture happens to look the same would pass a position check alone.
  await clickText('❚❚  Pause');
  await sleep(200);
  const held = await playInfo();
  const heldX = await boxX();
  await sleep(1000);
  const stillHeld = await playInfo();
  check(
    'pausing stops the world where it is: the box and the clock both stand still',
    held.paused === true &&
      stillHeld.playing === true &&
      Math.abs((await boxX()) - heldX) < 0.001 &&
      Math.abs(stillHeld.time - held.time) < 0.05,
    `x ${heldX} → ${await boxX()}, clock ${held.time.toFixed(2)} → ${stillHeld.time.toFixed(2)} over 1 s`,
  );
  // `locate` throws on a missing label, so the button that must be *gone* is asked for through
  // the hook, which answers with null.
  check(
    'the button offers to resume while it is held, and no longer to pause',
    (await has('▶  Resume')) === true && (await has('❚❚  Pause')) === false,
    `resume=${await has('▶  Resume')} pause=${await has('❚❚  Pause')}`,
  );
  await shot('36-paused');

  // 19c. Keys pressed while it is held are dropped, not queued: resuming must not fire an edge for
  //      each of them. The count before proves the graph reacts at all.
  const hitsBefore = await keyHits();
  await press('ArrowRight');
  await sleep(1000);
  const hitsWhilePaused = await keyHits();
  await press('ArrowRight');
  await press('ArrowRight');
  await sleep(200);

  // 19d. Ctrl+Enter resumes, the same shortcut that started play.
  await press('Enter', { ctrl: true });
  await sleep(400);
  const resumed = await playInfo();
  const resumedX = await boxX();
  check(
    'resuming lets it move on from where it stopped, without catching up the held time',
    resumed.paused === false &&
      resumedX > heldX &&
      // A second of pause plus the pressing above: catching up would show as a jump far beyond
      // what the resumed run itself had time for.
      resumedX < heldX + DRIFT_PER_SECOND * 1.2,
    `x ${heldX} → ${resumedX}, clock ${stillHeld.time.toFixed(2)} → ${resumed.time.toFixed(2)}`,
  );
  const hitsAfter = await keyHits();
  check(
    'a key pressed while paused is swallowed instead of firing on resume',
    hitsWhilePaused === hitsBefore && hitsAfter === hitsBefore,
    `${hitsBefore} hits before, ${hitsWhilePaused} while held, ${hitsAfter} after resuming`,
  );
  // Without this the check above would also pass on a graph that never logs anything at all.
  await press('ArrowRight');
  await sleep(300);
  check(
    'the same key does fire once the game is running again',
    (await keyHits()) === hitsBefore + 1,
    `${hitsBefore} → ${await keyHits()}`,
  );

  // 19e. A hold must never outlive its play: Esc stops from a paused game, and the next run starts
  //      moving. A pause left standing would leave the editor unable to run anything.
  await press('Enter', { ctrl: true });
  await sleep(200);
  check('Ctrl+Enter holds it again', (await playInfo()).paused === true);
  await stop();
  const afterStop = await playInfo();
  await t.play();
  await sleep(500);
  const restartedX = await boxX();
  await sleep(400);
  check(
    'stopping clears the hold, so the next play runs',
    afterStop.playing === false &&
      afterStop.paused === false &&
      (await playInfo()).paused === false &&
      (await boxX()) > restartedX,
    `after stop ${JSON.stringify(afterStop)}, x ${restartedX} → ${await boxX()}`,
  );
  await stop();
  await sleep(200);

  // 19f. Play discarded its copy, so the box is back at the position the model holds.
  const left = await rig.remove();
  check(
    'the step leaves nothing of its own behind',
    left.objects === 0 && left.assets === 0,
    JSON.stringify(left),
  );
}