/**
 * The third scope (#164). `global` belongs to the run and survives `Load scene`; `scene` belongs to
 * the scene and is built again from the declarations with every swap. What a level counts is gone
 * with the level, while the score beside it is not.
 */
import { describe, expect, it } from 'vitest';
import {
  CreateAssetCommand,
  SetAssetPropertyCommand,
  SetMachineScopeCommand,
  SetVariablesPersistentCommand,
  SetVariablesScopeCommand,
} from '../../src/core/commands/assetCommands';
import { AddNodeCommand } from '../../src/core/commands/graphCommands';
import { PlaceAssetCommand } from '../../src/core/commands/sceneObjectCommands';
import { isPersistent, STATE, STATE_NAME_PARAM } from '../../src/core/graph';
import type { StateMachineAsset, VariablesAsset } from '../../src/core/model/Asset';
import { addGameSystems } from '../../src/runtime/systems/BehaviorSystem';
import { Input } from '../../src/runtime/systems/Input';
import { World } from '../../src/runtime/World';
import {
  graphEditor,
  makeBehavior,
  makeSpriteScene,
  makeVariables,
  roundTrip,
  type SceneFixture,
} from '../helpers';

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

/** A machine with one state, `start` set to it, in the given scope. */
function makeMachine(f: SceneFixture, name: string, scope: 'local' | 'global' | 'scene') {
  const created = new CreateAssetCommand('statemachine', name);
  f.stack.execute(created);
  const state = new AddNodeCommand(created.asset.id, STATE, 0, 0, { [STATE_NAME_PARAM]: 'Idle' });
  f.stack.execute(state);
  (created.asset as StateMachineAsset).start = state.node.id;
  if (scope !== 'local') f.stack.execute(new SetMachineScopeCommand(created.asset.id, scope));
  return { id: created.asset.id, stateId: state.node.id };
}

/** Runs the first scene, moves the shared values on, then swaps to the second scene of the same run. */
function swap(
  f: SceneFixture & { otherId: string },
  move: (system: ReturnType<typeof addGameSystems>) => void,
) {
  const input = new Input();
  const first = World.instantiate(f.project, f.sceneId);
  const before = addGameSystems(first, f.project, input);
  move(before);
  const second = World.instantiate(f.project, f.otherId);
  return addGameSystems(second, f.project, input, { carried: before.shared });
}

/**
 * A behavior placed in the second scene that writes `run`/`level` when the machine of that name
 * enters its state. What it wrote is the only evidence an entry was announced at all.
 */
function watching(
  f: SceneFixture & { otherId: string },
  forRun: { id: string; stateId: string },
  forLevel: { id: string; stateId: string },
) {
  const behavior = makeBehavior(f, 'Watcher', ['run', 'level']);
  const editor = graphEditor(f, behavior);
  for (const [machine, key] of [
    [forRun, 'run'],
    [forLevel, 'level'],
  ] as const) {
    const entered = editor.addNode('OnStateEntered', { machine: machine.id });
    const one = editor.addNode('Add', { a: 1, b: 0 });
    const write = editor.variables([key], { write: true });
    editor.wire([
      [entered, machine.stateId, write, 'exec'],
      [one, 'result', write, key],
    ]);
  }
  f.stack.execute(new PlaceAssetCommand(f.otherId, behavior.id, { x: 0, y: 0 }));
  return behavior;
}

describe('a Variables asset scoped to the scene', () => {
  it('starts over on a scene swap while a global one carries on', () => {
    const f = twoScenes();
    const run = makeVariables(f, 'Run', ['score']);
    const level = makeVariables(f, 'Level', ['enemies']);
    f.stack.execute(new SetVariablesScopeCommand(level.id, 'scene'));
    f.stack.execute(new SetAssetPropertyCommand(level.id, 'enemies', 5));

    const after = swap(f, (before) => {
      before.liveVariables(run.id)!.score = 7;
      before.liveVariables(level.id)!.enemies = 1;
    });
    expect(after.liveVariables(run.id)?.score).toBe(7);
    expect(after.liveVariables(level.id)?.enemies).toBe(5);
  });

  it('is built from the declarations at the start of a run, like every other one', () => {
    const f = twoScenes();
    const level = makeVariables(f, 'Level', ['enemies']);
    f.stack.execute(new SetVariablesScopeCommand(level.id, 'scene'));
    f.stack.execute(new SetAssetPropertyCommand(level.id, 'enemies', 3));

    const world = World.instantiate(f.project, f.sceneId);
    const system = addGameSystems(world, f.project, new Input());
    expect(system.liveVariables(level.id)?.enemies).toBe(3);
  });

  it('is never persistent, and switching to it takes the switch off', () => {
    const f = twoScenes();
    const level = makeVariables(f, 'Level', ['enemies']);
    f.stack.execute(new SetVariablesPersistentCommand(level.id, true));
    expect(isPersistent(level)).toBe(true);

    f.stack.execute(new SetVariablesScopeCommand(level.id, 'scene'));
    expect(level.persistent).toBeUndefined();
    expect(isPersistent(level)).toBe(false);

    f.stack.undo();
    expect(level.scope).toBeUndefined();
    expect(isPersistent(level)).toBe(true);
  });

  /** A flag left over from an older file must not outvote the scope it contradicts. */
  it('reads as not persistent even when the document says both', () => {
    const f = twoScenes();
    const level = makeVariables(f, 'Level', ['enemies']);
    level.persistent = true;
    level.scope = 'scene';
    expect(isPersistent(level)).toBe(false);
    expect(
      (roundTrip(f.project).assets.find((a) => a.id === level.id) as VariablesAsset).persistent,
    ).toBeUndefined();
  });

  it('survives a round trip, and an unknown word reads as global', () => {
    const f = twoScenes();
    const level = makeVariables(f, 'Level', ['enemies']);
    f.stack.execute(new SetVariablesScopeCommand(level.id, 'scene'));
    const loaded = () => roundTrip(f.project).assets.find((a) => a.id === level.id) as VariablesAsset;
    expect(loaded().scope).toBe('scene');

    level.scope = 'nonsense' as never;
    expect(loaded().scope).toBeUndefined();
  });
});

describe('a state machine scoped to the scene', () => {
  it('starts over on a scene swap while a global one keeps its state', () => {
    const f = twoScenes();
    const forRun = makeMachine(f, 'Run', 'global');
    const forLevel = makeMachine(f, 'Level', 'scene');

    const after = swap(f, (before) => {
      before.shared.states[forRun.id] = 'moved';
      before.shared.states[forLevel.id] = 'moved';
    });
    expect(after.shared.states[forRun.id]).toBe('moved');
    expect(after.shared.states[forLevel.id]).toBe(forLevel.stateId);
  });

  it('is shared between instances, the way a global one is', () => {
    const f = twoScenes();
    const machine = makeMachine(f, 'Level', 'scene');
    const world = World.instantiate(f.project, f.sceneId);
    const system = addGameSystems(world, f.project, new Input());
    expect(system.shared.states[machine.id]).toBe(machine.stateId);
  });

  it('survives a round trip', () => {
    const f = twoScenes();
    const machine = makeMachine(f, 'Level', 'scene');
    const loaded = roundTrip(f.project).assets.find((a) => a.id === machine.id) as StateMachineAsset;
    expect(loaded.scope).toBe('scene');
  });

  /**
   * The entry of a shared machine is announced once, before any instance exists. After a swap a
   * `global` machine stands where it stood, so announcing it again would be a move that never
   * happened – a `scene` machine really was entered again, and has to say so.
   */
  it('announces its entry again in the next scene, where a global one stays quiet', () => {
    const f = twoScenes();
    const forRun = makeMachine(f, 'Run', 'global');
    const forLevel = makeMachine(f, 'Level', 'scene');
    const watcher = watching(f, forRun, forLevel);

    const input = new Input();
    const first = World.instantiate(f.project, f.sceneId);
    const before = addGameSystems(first, f.project, input);
    first.tick(1 / 60);

    const second = World.instantiate(f.project, f.otherId);
    addGameSystems(second, f.project, input, { carried: before.shared });
    second.tick(1 / 60);

    const heard = second.entities.find((e) => e.assetId === watcher.id)!;
    expect(heard.props.level).toBe(1);
    expect(heard.props.run).toBe(0);
  });
});