syncer/packages/shared/test/shooter.test.mjs

import assert from "node:assert/strict";
import test from "node:test";
import {
  BOT_COUNT,
  BOT_ID_BASE,
  Weapon,
  createShooterGame,
  shooterGame,
} from "../dist/index.js";

function runHeadlessMatch(ticks) {
  const server = shooterGame.createServer();
  const totals = {
    shots: 0,
    damageEvents: 0,
    eliminations: 0,
    respawns: 0,
  };

  for (let tick = 0; tick < ticks; tick += 1) {
    const result = server.step();
    for (const event of result.events) {
      if (event.type === "shot") totals.shots += 1;
      if (event.type === "damage") totals.damageEvents += 1;
      if (event.type === "elimination") totals.eliminations += 1;
      if (event.type === "respawn") totals.respawns += 1;
    }
  }

  return {
    ...totals,
    tick: server.tick,
    scores: [...server.currentState.players.values()]
      .map((player) => ({
        id: player.id,
        kills: player.kills,
        deaths: player.deaths,
        alive: player.alive,
        x: Number(player.x.toFixed(5)),
        z: Number(player.z.toFixed(5)),
      }))
      .sort((a, b) => a.id - b.id),
  };
}

test("the complete shooter match simulates headlessly on the backend", () => {
  const match = runHeadlessMatch(7_200);
  assert.equal(match.tick, 7_200);
  assert.equal(match.scores.length, BOT_COUNT);
  assert.ok(match.shots > 700, `expected active combat, saw ${match.shots} shots`);
  assert.ok(match.damageEvents > 50, `expected hits, saw ${match.damageEvents}`);
  assert.ok(match.eliminations >= 10, `expected kills, saw ${match.eliminations}`);
  assert.ok(match.respawns >= 8, `expected respawns, saw ${match.respawns}`);
  assert.equal(
    match.scores.reduce((sum, score) => sum + score.kills, 0),
    match.eliminations,
  );
  assert.ok(match.scores.every((score) => Number.isFinite(score.x + score.z)));
});

test("backend simulation is deterministic", () => {
  assert.deepEqual(runHeadlessMatch(2_400), runHeadlessMatch(2_400));
});

test("held automatic fire follows server ticks while semi-auto remains edge-triggered", () => {
  const game = createShooterGame({ botCount: 0 });

  const runHeldFire = (weapon, ticks) => {
    const server = game.createServer();
    server.addPlayer(1);
    server.currentState.players.get(1).weapon = weapon;
    const packet = {
      sequence: 1,
      targetTick: 1,
      observedTick: 0,
      input: {
        strafe: 0,
        forward: 0,
        yaw: 0,
        pitch: 0,
        fire: true,
        sprint: false,
        reload: false,
        weapon,
      },
    };
    assert.deepEqual(server.submitInput(1, packet), { accepted: true });
    let shots = 0;
    for (let tick = 0; tick < ticks; tick += 1) {
      if (tick > 0 && tick % 10 === 0) {
        assert.deepEqual(server.submitInput(1, packet), { accepted: true });
      }
      shots += server.step().events.filter((event) => event.type === "shot").length;
    }
    return shots;
  };

  assert.equal(runHeldFire(Weapon.PulseRifle, 60), 10);
  assert.equal(runHeldFire(Weapon.Scattergun, 100), 1);
});

test("human hitscan damages the historical target without rewinding live positions", () => {
  const server = shooterGame.createServer();
  server.addPlayer(1);
  const shooter = server.currentState.players.get(1);
  const target = server.currentState.players.get(BOT_ID_BASE);

  for (const bot of server.currentState.players.values()) {
    if (bot.id === BOT_ID_BASE || bot.id === 1) continue;
    bot.alive = false;
    bot.respawnTicks = 10_000;
  }
  shooter.x = -4;
  shooter.z = -15;
  shooter.yaw = Math.PI / 2;
  shooter.pitch = 0;
  shooter.spawnProtectionTicks = 0;
  target.x = 0;
  target.z = -15;
  target.velocityX = 0;
  target.velocityZ = 0;
  target.inputForward = 0;
  target.inputStrafe = 0;
  target.spawnProtectionTicks = 0;
  target.bot = null;

  server.step();
  target.z = -12.5;
  const healthBefore = target.health;
  server.submitInput(1, {
    sequence: 1,
    targetTick: 2,
    observedTick: 1,
    input: {
      strafe: 0,
      forward: 0,
      yaw: Math.PI / 2,
      pitch: 0,
      fire: true,
      sprint: false,
      reload: false,
      weapon: Weapon.PulseRifle,
    },
  });
  const result = server.step();

  assert.equal(target.z, -12.5, "the live target must not move backward");
  assert.ok(target.health < healthBefore, "the rewound hitbox should take damage");
  assert.ok(
    result.events.some(
      (event) => event.type === "damage" && event.targetId === BOT_ID_BASE,
    ),
  );
  const shot = result.events.find(
    (event) => event.type === "shot" && event.sourceId === 1,
  );
  assert.ok(shot);
  assert.ok(Math.abs(shot.endZ + 15) < 0.01);
});

test("shooter recordings seek through checkpoints with privacy intact", () => {
  const server = shooterGame.createServer({ replaySeed: 99 });
  server.addPlayer(1);
  for (let tick = 0; tick < 420; tick += 1) server.step();

  const recording = server.exportRecording();
  assert.equal(recording.durationTicks, 420);
  assert.deepEqual(
    recording.checkpoints.map(({ tick }) => tick),
    [0, 120, 240, 360],
  );

  const replay = shooterGame.createReplay(recording);
  replay.seek(135);
  const finalFrame = replay.seek(420);
  assert.deepEqual(finalFrame.state, server.currentState);

  const playerView = replay.viewAs(1).state;
  assert.ok(playerView.players.has(1));
  assert.equal("nextEventId" in playerView, false);
  assert.ok(
    [...playerView.players.values()].every((player) => !("bot" in player)),
  );
});

test("a human elimination creates a bounded attacker-perspective killcam", () => {
  const server = shooterGame.createServer();
  server.addPlayer(1);
  let ticket = null;
  for (let tick = 0; tick < 600 && !ticket; tick += 1) {
    server.step();
    ticket = server.drainReplayTickets(1)[0] ?? null;
  }

  assert.ok(ticket, "expected the standing human to receive a bot killcam");
  assert.equal(ticket.requesterId, 1);
  assert.ok(ticket.perspectiveId >= BOT_ID_BASE);
  assert.equal(ticket.toTick, ticket.issuedAtTick);
  assert.ok(ticket.frames.length > 60);
  assert.ok(ticket.frames.length < 300);
  assert.ok(
    ticket.frames.every(({ state }) =>
      [...state.players.values()].every(
        (player) => !("bot" in player) && !("kills" in player),
      ),
    ),
  );
});

test("snapshots and perception events cross the binary protocol", () => {
  const server = shooterGame.createServer();
  server.addPlayer(1);
  const snapshot = server.createSnapshot(1, 123.5);
  const snapshotFrame = shooterGame.protocol.encodeServer({
    kind: "snapshot",
    snapshot,
  });
  const decodedSnapshot = shooterGame.protocol.decodeServer(snapshotFrame);
  assert.equal(decodedSnapshot.kind, "snapshot");
  assert.equal(decodedSnapshot.snapshot.state.players.get(1).ammo.length, 3);

  const event = {
    id: 99,
    type: "shot",
    weapon: Weapon.RailRifle,
    sourceId: 1,
    originX: 1,
    originY: 1.58,
    originZ: 2,
    endX: 11,
    endY: 1.4,
    endZ: -4,
    impact: "wall",
  };
  const eventFrame = shooterGame.protocol.encodeServer({
    kind: "event",
    tick: 50,
    event,
  });
  const decodedEvent = shooterGame.protocol.decodeServer(eventFrame);
  assert.equal(decodedEvent.kind, "event");
  assert.equal(decodedEvent.tick, 50);
  assert.deepEqual(
    {
      ...decodedEvent.event,
      originY: Number(decodedEvent.event.originY.toFixed(2)),
      endY: Number(decodedEvent.event.endY.toFixed(2)),
    },
    event,
  );
});

test("occluded combatants stay private while their gunfire becomes anonymous audio", () => {
  const server = shooterGame.createServer();
  server.addPlayer(1);
  const authority = server.currentState;
  const viewer = authority.players.get(1);
  const hiddenBot = authority.players.get(BOT_ID_BASE);
  viewer.x = 0;
  viewer.z = -6;
  viewer.yaw = 0;
  hiddenBot.x = 0;
  hiddenBot.z = 6;

  const snapshot = server.createSnapshot(1, 0);
  assert.equal(snapshot.state.players.has(BOT_ID_BASE), false);

  const perceptions = server.createPerceptions(1, [
    {
      id: 777,
      type: "shot",
      sourceId: BOT_ID_BASE,
      weapon: Weapon.PulseRifle,
      originX: hiddenBot.x,
      originY: 1.58,
      originZ: hiddenBot.z,
      endX: hiddenBot.x,
      endY: 1.58,
      endZ: hiddenBot.z - 10,
      impact: "wall",
    },
  ]);
  assert.equal(perceptions.length, 1);
  assert.equal(perceptions[0].type, "sound");
  assert.equal("sourceId" in perceptions[0], false);
  assert.equal("originX" in perceptions[0], false);
});

test("visible opponents expose exact health but redact armor and inventory", () => {
  const server = shooterGame.createServer();
  server.addPlayer(1);
  const viewer = server.currentState.players.get(1);
  const opponent = server.currentState.players.get(BOT_ID_BASE);
  viewer.x = -4;
  viewer.z = -15;
  viewer.yaw = Math.PI / 2;
  opponent.x = 0;
  opponent.z = -15;
  opponent.health = 37;
  opponent.armor = 19;
  opponent.ammo[Weapon.PulseRifle].magazine = 3;

  const replicated = server.createSnapshot(1, 0).state.players.get(BOT_ID_BASE);
  assert.ok(replicated, "opponent should be visible in the clear corridor");
  assert.equal(replicated.health, 37);
  assert.equal(replicated.armor, 0);
  assert.ok(
    replicated.ammo.every(
      (ammo) => ammo.magazine === 0 && ammo.reserve === 0,
    ),
  );
  assert.equal(replicated.x, opponent.x);
  assert.equal(replicated.weapon, opponent.weapon);

  viewer.yaw = -Math.PI / 2;
  assert.equal(
    server.createSnapshot(1, 0).state.players.has(BOT_ID_BASE),
    false,
  );
});