/**
 * Objects that travel through a `Load scene` (#165). A top-level object with "Keep on scene load"
 * moves into the next scene as it is – its children, its running behaviors, how its body moves –
 * while the scene itself is built as it is stored, whatever an earlier visit left of it.
 */
import { beforeAll, describe, expect, it } from 'vitest';
import {
  AddAnimationTrackCommand,
  SetAnimationKeyCommand,
  SetAnimationRootCommand,
} from '../../src/core/commands/animationCommands';
import { CreateAssetCommand } from '../../src/core/commands/assetCommands';
import { AddColliderCommand, AddRigidbodyCommand } from '../../src/core/commands/colliderCommands';
import { CreateContainerCommand } from '../../src/core/commands/containerCommands';
import { PlaceAssetCommand, SetOverrideCommand } from '../../src/core/commands/sceneObjectCommands';
import { findScene } from '../../src/core/model/Project';
import type { PropertyValue } from '../../src/core/model/Properties';
import { KEEP_ON_SCENE_LOAD_KEY, schemaFor } from '../../src/core/properties/PropertySchema';
import { GameRun } from '../../src/runtime/GameRun';
import { keptEntities } from '../../src/runtime/keptObjects';
import { loadPhysics, readyPhysics } from '../../src/runtime/physics/engine';
import type { AudioSink } from '../../src/runtime/systems/Audio';
import { Input } from '../../src/runtime/systems/Input';
import { graphEditor, makeBehavior, makeSpriteScene, place, type SceneFixture } from '../helpers';

beforeAll(async () => {
  await loadPhysics();
});

type Fixture = SceneFixture & { otherId: string };

/** The sprite scene plus a second, empty one. */
function twoScenes(): Fixture {
  const f = makeSpriteScene('Box');
  const second = new CreateAssetCommand('scene', 'Level 2');
  f.stack.execute(second);
  return { ...f, otherId: second.asset.id };
}

function placeIn(f: Fixture, sceneId: string, assetId: string, x: number, parentId = ''): string {
  const command = new PlaceAssetCommand(sceneId, assetId, { x, y: 0 }, parentId);
  f.stack.execute(command);
  return command.objectId;
}

function set(f: Fixture, sceneId: string, objectId: string, key: string, value: PropertyValue): void {
  f.stack.execute(new SetOverrideCommand(sceneId, objectId, key, value));
}

function keep(f: Fixture, sceneId: string, objectId: string): void {
  set(f, sceneId, objectId, KEEP_ON_SCENE_LOAD_KEY, true);
}

function start(f: Fixture, audio?: AudioSink) {
  const stoppedOwners: string[] = [];
  const sink: AudioSink = audio ?? {
    play: () => 0,
    playNote: () => 0,
    release: () => {},
    tune: () => {},
    length: () => 0,
    stop: () => {},
    tail: () => 0,
    stopVoice: () => {},
    stopOwner: (owner: string) => stoppedOwners.push(owner),
  };
  const run = GameRun.start(f.project, f.sceneId, new Input(), {
    audio: sink,
    physics: readyPhysics()!,
    clock: { scale: 1 },
    saves: { read: () => ({}), write: () => {} },
  });
  const frames = (count: number) => {
    for (let i = 0; i < count; i++) run.tick(1 / 60, 1 / 60);
  };
  const names = () => run.world.entities.map((e) => e.name);
  return { run, frames, names, stoppedOwners };
}

/** A behavior that says `start` and `destroy` in the log, placed below `ownerId`. */
function brainBelow(f: Fixture, ownerId: string): string {
  const behavior = makeBehavior(f, 'Brain', ['count']);
  const edit = graphEditor(f, behavior);
  edit.connect(edit.addNode('OnStart'), 'exec', edit.addNode('Log', { message: 'start' }), 'exec');
  edit.connect(edit.addNode('OnDestroy'), 'exec', edit.addNode('Log', { message: 'destroy' }), 'exec');
  return place(f, behavior.id, { x: 0, y: 0 }, ownerId);
}

describe('Keep on scene load', () => {
  it('is a switch every placeable object has, off unless set', () => {
    for (const type of ['sprite', 'behavior', 'container', 'camera'] as const)
      expect(schemaFor(type).find((d) => d.key === KEEP_ON_SCENE_LOAD_KEY)?.default).toBe(false);
    expect(schemaFor('scene').some((d) => d.key === KEEP_ON_SCENE_LOAD_KEY)).toBe(false);
  });

  it('takes the object into the next scene as the same entity, where the run left it', () => {
    const f = twoScenes();
    const hero = place(f, f.spriteId, { x: 10, y: 0 });
    const hat = place(f, f.spriteId, { x: 1, y: 2 }, hero);
    const other = place(f, f.spriteId, { x: 50, y: 0 });
    keep(f, f.sceneId, hero);
    const { run } = start(f);
    const before = run.world.findByObjectId(hero)!;
    const child = run.world.findByObjectId(hat)!;
    before.x = 77;
    before.props.rotation = 45;

    run.loadScene(f.otherId);

    expect(run.world.sceneId).toBe(f.otherId);
    expect(run.world.findByObjectId(hero)).toBe(before);
    expect(run.world.findByObjectId(hat)).toBe(child);
    expect(child.parent).toBe(before);
    expect(run.world.findByObjectId(other)).toBeUndefined();
    expect([before.x, before.props.rotation]).toEqual([77, 45]);
    // The new scene holds the objects now, and the next write-back says where the run has them –
    // and that the scene is another one, which is what brings the panels up to date.
    expect(run.world.syncToModel().structure).toBe(true);
    const stored = findScene(f.project, f.otherId)!.objects;
    expect(stored.map((o) => o.id)).toEqual([hero, hat]);
    expect(stored[0]!.position.x).toBe(77);
    expect(stored[0]!.overrides.rotation).toBe(45);
  });

  it('keeps only top-level objects: a switch further down keeps nothing', () => {
    const f = twoScenes();
    const parent = place(f, f.spriteId, { x: 0, y: 0 });
    const child = place(f, f.spriteId, { x: 0, y: 0 }, parent);
    set(f, f.sceneId, child, KEEP_ON_SCENE_LOAD_KEY, true);
    const { run } = start(f);
    expect(keptEntities(run.world.entities)).toEqual([]);
    run.loadScene(f.otherId);
    expect(run.world.entities).toEqual([]);
  });

  it('parents what it brings as the run has it, written back or not', () => {
    const f = twoScenes();
    const hero = place(f, f.spriteId, { x: 0, y: 0 });
    const arm = place(f, f.spriteId, { x: 5, y: 0 }, hero);
    const hand = place(f, f.spriteId, { x: 5, y: 0 }, arm);
    keep(f, f.sceneId, hero);
    const { run } = start(f);
    const top = run.world.findByObjectId(hero)!;
    // A released game never writes the run back, so the scene still says the hand hangs on the arm.
    run.world.removeKeepingChildren(run.world.findByObjectId(arm)!);

    run.loadScene(f.otherId);

    expect(run.world.entities.map((e) => e.objectId)).toEqual([hero, hand]);
    expect(run.world.findByObjectId(hand)!.parent).toBe(top);
  });

  it('carries a running behavior on: no second On start, no On destroy, its values and sounds stay', () => {
    const f = twoScenes();
    const hero = place(f, f.spriteId, { x: 0, y: 0 });
    const brain = brainBelow(f, hero);
    const lost = brainBelow(f, place(f, f.spriteId, { x: 0, y: 0 }));
    keep(f, f.sceneId, hero);
    const { run, frames, stoppedOwners } = start(f);
    frames(1);
    const first = run.world;
    const entity = first.findByObjectId(brain)!;
    entity.props.count = 5;
    expect(first.log).toEqual(['start', 'start']);

    run.loadScene(f.otherId);
    frames(2);

    // The behavior left behind said goodbye in its own world, the kept one said nothing anywhere.
    expect(first.log).toEqual(['start', 'start', 'destroy']);
    expect(run.world.log).toEqual([]);
    expect(run.behaviors.runningIds()).toEqual([brain]);
    expect(run.world.findByObjectId(brain)!.props.count).toBe(5);
    expect(stoppedOwners).toEqual([first.findByObjectId(lost)?.id ?? `e-${lost}`]);
  });

  it('times the trace of a carried behavior by the world it runs in now', () => {
    const f = twoScenes();
    const hero = place(f, f.spriteId, { x: 0, y: 0 });
    const behavior = makeBehavior(f, 'Ticker');
    const edit = graphEditor(f, behavior);
    const update = edit.addNode('OnUpdate');
    edit.connect(update, 'exec', edit.addNode('Log', { message: 'tick' }), 'exec');
    place(f, behavior.id, { x: 0, y: 0 }, hero);
    keep(f, f.sceneId, hero);
    const { run, frames } = start(f);
    frames(30);
    run.loadScene(f.otherId);
    frames(1);
    const seen = run.behaviors.traceFor(behavior.id).nodes.get(update.id)!;
    expect(seen).toBeLessThanOrEqual(run.world.time);
    expect(run.world.log).toEqual(['tick']);
  });

  it('lets a dynamic body move on as it moved', () => {
    const f = twoScenes();
    const ball = place(f, f.spriteId, { x: 0, y: 0 });
    f.stack.execute(new AddColliderCommand(f.sceneId, ball));
    f.stack.execute(new AddRigidbodyCommand(f.sceneId, ball));
    keep(f, f.sceneId, ball);
    const { run, frames } = start(f);
    const entity = run.world.findByObjectId(ball)!;
    frames(30);
    const y = entity.y;
    frames(1);
    const falling = entity.y - y;
    expect(falling).toBeGreaterThan(1);

    run.loadScene(f.otherId);
    // The picture is drawn between the last two steps, so the first frame of a new engine stands still.
    frames(1);
    const arrived = entity.y;
    frames(1);
    // From rest it would fall a fraction of a unit by now, not as far as it did before the swap.
    expect(entity.y - arrived).toBeGreaterThan(falling * 0.9);
  });

  it('lets an animation play on from where it is', () => {
    const f = twoScenes();
    const hero = place(f, f.spriteId, { x: 0, y: 0 });
    const walk = new CreateAssetCommand('animation', 'Walk', { fps: 10, playback: 'once' });
    f.stack.execute(walk);
    f.stack.execute(new SetAnimationRootCommand(walk.asset.id, f.spriteId));
    const row = new AddAnimationTrackCommand(walk.asset.id, '', 'x');
    f.stack.execute(row);
    f.stack.execute(new SetAnimationKeyCommand(walk.asset.id, row.trackId, 0, 0));
    f.stack.execute(new SetAnimationKeyCommand(walk.asset.id, row.trackId, 10, 100));
    const behavior = makeBehavior(f, 'Walker');
    const edit = graphEditor(f, behavior);
    const play = edit.addNode('PlayAnimation', { animation: walk.asset.id });
    edit.wire([
      [edit.addNode('OnStart'), 'exec', play, 'exec'],
      [edit.addNode('Owner'), 'object', play, 'object'],
    ]);
    place(f, behavior.id, { x: 0, y: 0 }, hero);
    keep(f, f.sceneId, hero);
    const { run, frames } = start(f);
    const entity = run.world.findByObjectId(hero)!;
    frames(19);
    const half = entity.x;
    expect(half).toBeGreaterThan(20);
    expect(half).toBeLessThan(40);

    run.loadScene(f.otherId);
    frames(18);

    // 0.3 s more of the same second: it went on from where it was instead of starting over or stopping.
    expect(entity.x).toBeCloseTo(half + 30, 5);
    expect(entity.animations).toHaveLength(1);
  });

  it('finds collisions anew: two kept objects that were touching get their Enter again', () => {
    const f = twoScenes();
    const ids = [0, 1].map(() => {
      const id = place(f, f.spriteId, { x: 0, y: 0 });
      f.stack.execute(new AddColliderCommand(f.sceneId, id));
      keep(f, f.sceneId, id);
      return id;
    });
    const behavior = makeBehavior(f, 'Feeler');
    const edit = graphEditor(f, behavior);
    edit.connect(edit.addNode('OnCollisionEnter'), 'exec', edit.addNode('Log', { message: 'enter' }), 'exec');
    place(f, behavior.id, { x: 0, y: 0 }, ids[0]);
    const { run, frames } = start(f);
    frames(3);
    expect(run.world.log).toEqual(['enter']);

    run.loadScene(f.otherId);
    frames(3);

    expect(run.world.log).toEqual(['enter']);
  });

  it('wins over what the next scene holds of the same thing, and answers for it', () => {
    const f = twoScenes();
    const hero = place(f, f.spriteId, { x: 10, y: 0 });
    keep(f, f.sceneId, hero);
    const twin = placeIn(f, f.otherId, f.spriteId, 500);
    const twinHat = placeIn(f, f.otherId, f.spriteId, 0, twin);
    keep(f, f.otherId, twin);
    const plain = placeIn(f, f.otherId, f.spriteId, 900);
    const { run } = start(f);
    const entity = run.world.findByObjectId(hero)!;

    run.loadScene(f.otherId);

    // The scene's own kept object of that asset is not built, one that is not kept is.
    expect(run.world.entities.map((e) => e.objectId)).toEqual([plain, hero]);
    expect(entity.x).toBe(10);
    // Whatever in the scene named its own one finds the one that came instead.
    expect(run.world.findByObjectId(twin)).toBe(entity);
    expect(run.world.findByObjectId(twinHat)).toBeUndefined();
    run.world.remove(entity);
    expect(run.world.findByObjectId(twin)).toBeUndefined();
  });

  it('comes back to the scene it left as the one object, not as two', () => {
    const f = twoScenes();
    const hero = place(f, f.spriteId, { x: 10, y: 0 });
    const other = place(f, f.spriteId, { x: 50, y: 0 });
    keep(f, f.sceneId, hero);
    const { run } = start(f);
    const entity = run.world.findByObjectId(hero)!;
    entity.x = 77;

    run.loadScene(f.otherId);
    run.loadScene(f.sceneId);

    expect(run.world.entities.map((e) => e.objectId)).toEqual([other, hero]);
    expect(run.world.findByObjectId(hero)).toBe(entity);
    expect(entity.x).toBe(77);
    // The scene holds it once as well: its own object of that id made way for the one coming back.
    expect(findScene(f.project, f.sceneId)!.objects.map((o) => o.id)).toEqual([other, hero]);
    // Loading the scene it is in keeps it just the same.
    run.loadScene(f.sceneId);
    expect(run.world.entities.map((e) => e.objectId)).toEqual([other, hero]);
    expect(run.world.findByObjectId(hero)).toBe(entity);
  });

  it('keeps an object the run itself switched to kept, and it too comes back as the one object', () => {
    const f = twoScenes();
    const hero = place(f, f.spriteId, { x: 10, y: 0 });
    const { run } = start(f);
    const entity = run.world.findByObjectId(hero)!;
    // What a `Properties` node set to "Set" does; the scene's own object never hears of it.
    entity.props[KEEP_ON_SCENE_LOAD_KEY] = true;

    run.loadScene(f.otherId);
    run.loadScene(f.sceneId);

    expect(run.world.entities).toEqual([entity]);
    expect(findScene(f.project, f.sceneId)!.objects.map((o) => o.id)).toEqual([hero]);
  });

  it('takes a placed container along with its content', () => {
    const f = twoScenes();
    const a = place(f, f.spriteId, { x: 0, y: 0 });
    const b = place(f, f.spriteId, { x: 20, y: 0 });
    const create = new CreateContainerCommand(f.sceneId, [a, b]);
    f.stack.execute(create);
    const placed = findScene(f.project, f.sceneId)!.objects[0]!;
    keep(f, f.sceneId, placed.id);
    const { run } = start(f);
    const before = [...run.world.entities];
    expect(before).toHaveLength(3);

    run.loadScene(f.otherId);

    expect(run.world.entities).toEqual(before);
    expect(run.world.entities.slice(1).every((e) => e.parent === before[0])).toBe(true);
  });
});

describe('Load scene builds the scene as it is stored', () => {
  it('whatever the run did in it on an earlier visit', () => {
    const f = twoScenes();
    const moved = place(f, f.spriteId, { x: 10, y: 0 });
    const destroyed = place(f, f.spriteId, { x: 20, y: 0 });
    const { run } = start(f);
    run.world.findByObjectId(moved)!.x = 99;
    run.world.remove(run.world.findByObjectId(destroyed)!);
    run.world.spawn(f.spriteId, { x: 0, y: 0, z: 0 }, null);
    run.world.syncToModel();
    expect(findScene(f.project, f.sceneId)!.objects).toHaveLength(2);

    run.loadScene(f.sceneId);
    expect(run.world.entities.map((e) => [e.objectId, e.x])).toEqual([
      [moved, 10],
      [destroyed, 20],
    ]);

    run.world.findByObjectId(moved)!.x = 55;
    run.world.syncToModel();
    run.loadScene(f.otherId);
    run.loadScene(f.sceneId);
    expect(run.world.findByObjectId(moved)!.x).toBe(10);
  });

  it('and the end of a run gives every scene back what it held before', () => {
    const f = twoScenes();
    const a = place(f, f.spriteId, { x: 0, y: 0 });
    const hero = place(f, f.spriteId, { x: 20, y: 0 });
    f.stack.execute(new CreateContainerCommand(f.sceneId, [a]));
    keep(f, f.sceneId, hero);
    placeIn(f, f.otherId, f.spriteId, 5);
    const before = structuredClone([f.sceneId, f.otherId].map((id) => findScene(f.project, id)!.objects));
    const { run } = start(f);
    run.world.spawn(f.spriteId, { x: 0, y: 0, z: 0 }, null);
    run.loadScene(f.otherId);
    run.world.syncToModel();
    expect(findScene(f.project, f.otherId)!.objects).toHaveLength(2);

    run.end();

    expect([f.sceneId, f.otherId].map((id) => findScene(f.project, id)!.objects)).toEqual(before);
    expect(findScene(f.project, f.sceneId)!.groups).toBeUndefined();
  });
});