/**
 * The game's own pause and time scale (#167): Pause game holds the world from the next frame and
 * leaves only the behaviors that run while paused ticking; Set time scale turns the clock a played
 * game hands the behaviors, and nothing else.
 */
import { beforeAll, describe, expect, it } from 'vitest';
import { AddColliderCommand } from '../../src/core/commands/colliderCommands';
import { SetAssetPropertyCommand } from '../../src/core/commands/assetCommands';
import type { BehaviorAsset } from '../../src/core/model/Asset';
import { GameClock } from '../../src/core/time';
import { loadPhysics } from '../../src/runtime/physics/engine';
import {
  COLLISION_SYSTEMS,
  graphEditor,
  makeBehavior,
  makeSpriteScene,
  place,
  startWorld,
  type SceneFixture,
} from '../helpers';

/** Wires `<event>(params) → Log(message)`. */
function logOn(f: SceneFixture, behavior: BehaviorAsset, event: string, message: string, params = {}): void {
  const edit = graphEditor(f, behavior);
  edit.connect(edit.addNode(event, params), 'exec', edit.addNode('Log', { message }), 'exec');
}

/**
 * A box with two behaviors: "Game" logs every frame, "Menu" runs while paused, logs every frame and
 * toggles the pause on P – the one-key toggle a pause menu is built from.
 */
function pauseMenu() {
  const f = makeSpriteScene('Box');
  const box = place(f, f.spriteId, { x: 0, y: 0 });
  const game = makeBehavior(f, 'Game');
  logOn(f, game, 'OnUpdate', 'game');
  const menu = makeBehavior(f, 'Menu');
  f.stack.execute(new SetAssetPropertyCommand(menu.id, 'runWhilePaused', true));
  logOn(f, menu, 'OnUpdate', 'menu');
  const edit = graphEditor(f, menu);
  const key = edit.addNode('OnKeyDown', { key: 'p' });
  const paused = edit.addNode('IsGamePaused');
  const branch = edit.addNode('Branch');
  const resume = edit.addNode('ResumeGame');
  const pause = edit.addNode('PauseGame');
  edit.wire([
    [key, 'exec', branch, 'exec'],
    [paused, 'paused', branch, 'condition'],
    [branch, 'then', resume, 'exec'],
    [branch, 'else', pause, 'exec'],
  ]);
  place(f, game.id, { x: 0, y: 0 }, box);
  place(f, menu.id, { x: 0, y: 0 }, box);
  return startWorld(f, { behaviors: true });
}

describe('Pause game', () => {
  it('holds the world from the next frame, and only a behavior that runs while paused is ticked', () => {
    const { world, input, frame } = pauseMenu();
    frame(0.1);
    expect(world.log).toEqual(['game', 'menu']);

    input.press('p');
    frame(0.1);
    // The frame that asked still runs whole: the pause starts with the next one.
    expect(world.log.slice(2)).toEqual(['game', 'menu']);
    expect(world.paused).toBe(true);
    const heldAt = world.time;

    world.log.length = 0;
    frame(0.1);
    frame(0.1);
    expect(world.log).toEqual(['menu', 'menu']);
    expect(world.time).toBe(heldAt);

    input.release('p');
    input.press('p');
    frame(0.1);
    expect(world.paused).toBe(false);
    world.log.length = 0;
    frame(0.1);
    expect(world.log).toEqual(['game', 'menu']);
    expect(world.time).toBeCloseTo(heldAt + 0.1);
  });

  it('switches nothing off: a paused behavior runs on from where it stood, without an On disable', () => {
    const f = makeSpriteScene('Box');
    const box = place(f, f.spriteId, { x: 0, y: 0 });
    const game = makeBehavior(f, 'Game');
    logOn(f, game, 'OnDisable', 'disabled');
    logOn(f, game, 'OnEnable', 'enabled');
    logOn(f, game, 'OnTimer', 'timer', { interval: 0.25 });
    place(f, game.id, { x: 0, y: 0 }, box);
    const { world, frame } = startWorld(f, { behaviors: true });
    frame(0.1);
    frame(0.1);
    world.paused = true;
    for (let i = 0; i < 10; i++) frame(0.1);
    world.paused = false;
    frame(0.1);
    // 0.3 s of unpaused time: the timer fired once, and the paused second did not count.
    expect(world.log).toEqual(['enabled', 'timer']);
  });
});

describe.each(COLLISION_SYSTEMS)('$system', ({ physics }) => {
  beforeAll(async () => {
    await loadPhysics();
  });

  it('tells a behavior running while paused no collision again: nothing collides in a held world', () => {
    const f = makeSpriteScene('Crate');
    const a = place(f, f.spriteId, { x: 0, y: 0 });
    const b = place(f, f.spriteId, { x: 50, y: 0 });
    f.stack.execute(new AddColliderCommand(f.sceneId, a));
    f.stack.execute(new AddColliderCommand(f.sceneId, b));
    const hit = makeBehavior(f, 'Hit');
    f.stack.execute(new SetAssetPropertyCommand(hit.id, 'runWhilePaused', true));
    logOn(f, hit, 'OnCollisionEnter', 'enter');
    logOn(f, hit, 'OnCollisionStay', 'stay');
    place(f, hit.id, { x: 0, y: 0 }, a);
    const { world, frame } = startWorld(f, { physics, collisions: true, behaviors: true });

    frame(0.1);
    frame(0.1);
    expect(world.log).toEqual(['enter', 'stay']);
    world.paused = true;
    frame(0.1);
    frame(0.1);
    expect(world.log).toEqual(['enter', 'stay']);
    world.paused = false;
    frame(0.1);
    expect(world.log).toEqual(['enter', 'stay', 'stay']);
  });
});

describe('Set time scale', () => {
  /** `On start → Set time scale(scale)`, and `On update → Log(Time scale)`. */
  function scaler(scale: number) {
    const f = makeSpriteScene('Box');
    const box = place(f, f.spriteId, { x: 0, y: 0 });
    const behavior = makeBehavior(f, 'Scaler');
    const edit = graphEditor(f, behavior);
    const start = edit.addNode('OnStart');
    const set = edit.addNode('SetTimeScale', { scale });
    const update = edit.addNode('OnUpdate');
    const read = edit.addNode('TimeScale');
    const log = edit.addNode('Log');
    edit.wire([
      [start, 'exec', set, 'exec'],
      [update, 'exec', log, 'exec'],
      [read, 'scale', log, 'message'],
    ]);
    place(f, behavior.id, { x: 0, y: 0 }, box);
    return f;
  }

  it('turns the clock a played game hands over, and Time scale reads it back', () => {
    const clock = new GameClock();
    const { world, frame } = startWorld(scaler(0.5), { behaviors: true, clock });
    frame();
    expect(clock.scale).toBe(0.5);
    expect(world.log).toEqual(['0.5']);
  });

  it('is ignored without a clock – the editor run, which shares its clock with the previews', () => {
    const { world, frame } = startWorld(scaler(0.5), { behaviors: true });
    frame();
    expect(world.log).toEqual(['Set time scale is ignored in the editor run (0.5)', '1']);
  });

  it('ends with the run: resetting the clock puts it back to real time', () => {
    const clock = new GameClock();
    clock.scale = 0.25;
    clock.advance(0.05);
    clock.reset();
    expect({ now: clock.now, scale: clock.scale }).toEqual({ now: 0, scale: 1 });
  });
});