import { CreateAssetCommand } from '../src/core/commands/assetCommands';
import { CommandStack } from '../src/core/commands/CommandStack';
import { AddNodeCommand, ConnectCommand } from '../src/core/commands/graphCommands';
import { AddPortsCommand } from '../src/core/commands/portCommands';
import { PlaceAssetCommand } from '../src/core/commands/sceneObjectCommands';
import { requireNodeDef } from '../src/core/commands/require';
import { AddVariableCommand } from '../src/core/commands/variableCommands';
import {
  type DeclaredPort,
  emptySharedState,
  ENTITY_HANDLE,
  type EntityHandle,
  type GraphLookup,
  type GraphNode,
  NO_LOOKUP,
  type NodeContext,
  type PointerState,
  type Value,
  type RunResult,
  portKindOf,
  PROPERTIES,
  VARIABLES,
  VARIABLES_PARAM,
} from '../src/core/graph';
import type { GraphInterpreter } from '../src/core/graph/GraphInterpreter';
import type { EaseShare } from '../src/core/model/animation';
import type { BehaviorAsset, SceneAsset, VariablesAsset } from '../src/core/model/Asset';
import { findObject } from '../src/core/model/hierarchy';
import { worldPosition } from '../src/core/properties/transform';
import { resolvedHolder } from '../src/core/model/instance';
import type { Position, PropertyBag, Vec2 } from '../src/core/model/Properties';
import { createEmptyProject, findScene, type Project } from '../src/core/model/Project';
import type { SceneObject } from '../src/core/model/SceneObject';
import { deserializeProject, serializeProject } from '../src/core/store/serialize';
import type { AudioSink } from '../src/runtime/systems/Audio';
import { BehaviorSystem, type TimeScaled } from '../src/runtime/systems/BehaviorSystem';
import type { SaveArea } from '../src/core/graph/savedValues';
import { readyPhysics } from '../src/runtime/physics/engine';
import { PhysicsSystem } from '../src/runtime/physics/PhysicsSystem';
import { CollisionSystem } from '../src/runtime/systems/CollisionSystem';
import type { CollisionSource } from '../src/runtime/systems/solids';
import { AnimationSystem } from '../src/runtime/systems/AnimationSystem';
import { Input } from '../src/runtime/systems/Input';
import { World } from '../src/runtime/World';

export interface ProjectFixture {
  project: Project;
  stack: CommandStack;
}

export interface SceneFixture extends ProjectFixture {
  sceneId: string;
  spriteId: string;
  /** The scene asset, looked up fresh (undo may replace it). */
  sceneOf(): SceneAsset;
  /** The scene with the content of placed containers resolved in – what the editor shows. */
  viewOf(): SceneAsset;
  object(id: string): SceneObject;
  /** World position of a scene object, ancestors included. */
  world(id: string): Position;
}

export function makeProject(): ProjectFixture {
  const project = createEmptyProject('p', 'P');
  return { project, stack: new CommandStack(project) };
}

/** A project with a scene "Level" and a 100×100 sprite (named "Box" unless told otherwise), plus lookups into the scene. */
export function makeSpriteScene(spriteName = 'Box'): SceneFixture {
  const fixture = makeProject();
  const scene = new CreateAssetCommand('scene', 'Level');
  const sprite = new CreateAssetCommand('sprite', spriteName);
  fixture.stack.execute(scene);
  fixture.stack.execute(sprite);
  const sceneOf = () => findScene(fixture.project, scene.asset.id)!;
  const viewOf = () => resolvedHolder(fixture.project, sceneOf()) as SceneAsset;
  const object = (id: string) => findObject(viewOf(), id)!;
  return {
    ...fixture,
    sceneId: scene.asset.id,
    spriteId: sprite.asset.id,
    sceneOf,
    viewOf,
    object,
    world: (id) => worldPosition(fixture.project, viewOf(), object(id)),
  };
}

/** Places an asset into the fixture's scene at a world position (optionally below a parent) and returns the new object's id. */
export function place(
  fixture: SceneFixture,
  assetId: string,
  position: Vec2 | Position,
  parentId = '',
): string {
  const command = new PlaceAssetCommand(fixture.sceneId, assetId, position, parentId);
  fixture.stack.execute(command);
  return command.objectId;
}

/** Adds a Variables asset declaring the given number variables – what a run shares. */
export function makeVariables(
  fixture: ProjectFixture,
  name: string,
  keys: readonly string[],
): VariablesAsset {
  const command = new CreateAssetCommand('variables', name);
  fixture.stack.execute(command);
  for (const key of keys) fixture.stack.execute(new AddVariableCommand(command.asset.id, key, 'number'));
  return command.asset as VariablesAsset;
}

/** Adds a behavior asset declaring the given number variables. */
export function makeBehavior(
  fixture: ProjectFixture,
  name = 'B',
  variables: readonly string[] = [],
): BehaviorAsset {
  const command = new CreateAssetCommand('behavior', name);
  fixture.stack.execute(command);
  for (const key of variables) fixture.stack.execute(new AddVariableCommand(command.asset.id, key, 'number'));
  return command.asset as BehaviorAsset;
}

export type Edge = readonly [from: GraphNode, fromPort: string, to: GraphNode, toPort: string];

export interface GraphEditor {
  /** Adds a node with inline params (graph coordinates do not matter to tests). */
  addNode(type: string, params?: PropertyBag): GraphNode;
  /** A Variables node naming `keys`, typed by their declaration; `write` sets all of them or the listed. */
  variables(
    keys: readonly string[],
    options?: { write?: boolean | readonly string[]; params?: PropertyBag },
  ): GraphNode;
  /** A Properties node with `params` (its type) declaring `ports`. */
  properties(ports: readonly DeclaredPort[], params?: PropertyBag): GraphNode;
  connect(from: GraphNode, fromPort: string, to: GraphNode, toPort: string): void;
  wire(edges: readonly Edge[]): void;
}

/** Command-driven editing of one behavior's graph, the way the editor does it. */
export function graphEditor(fixture: ProjectFixture, behavior: BehaviorAsset): GraphEditor {
  const { stack } = fixture;
  const connect: GraphEditor['connect'] = (from, fromPort, to, toPort) => {
    stack.execute(
      new ConnectCommand(behavior.id, { node: from.id, port: fromPort }, { node: to.id, port: toPort }),
    );
  };
  return {
    addNode(type, params = {}) {
      const command = new AddNodeCommand(behavior.id, type, 0, 0, params);
      stack.execute(command);
      return command.node;
    },
    variables(keys, { write = false, params = {} } = {}) {
      const command = new AddNodeCommand(behavior.id, VARIABLES, 0, 0, params);
      stack.execute(command);
      const writes = (key: string) => write === true || (Array.isArray(write) && write.includes(key));
      const ports = keys.map((key): DeclaredPort => {
        // A node pointed at a Variables asset declares that asset's variables, not the behavior's.
        const source = fixture.project.assets.find((a) => a.id === params[VARIABLES_PARAM]);
        const declarations = source?.type === 'variables' ? source.variables : behavior.variables;
        const declared = declarations.find((v) => v.key === key);
        const kind = declared ? portKindOf(declared) : 'number';
        return writes(key) ? { key, kind, write: true } : { key, kind };
      });
      if (ports.length > 0) stack.execute(new AddPortsCommand(behavior.id, command.node.id, ports));
      return command.node;
    },
    properties(ports, params = {}) {
      const command = new AddNodeCommand(behavior.id, PROPERTIES, 0, 0, params);
      stack.execute(command);
      if (ports.length > 0) stack.execute(new AddPortsCommand(behavior.id, command.node.id, ports));
      return command.node;
    },
    connect,
    wire(edges) {
      for (const [from, fromPort, to, toPort] of edges) connect(from, fromPort, to, toPort);
    },
  };
}

export const NO_POINTER: PointerState = {
  x: 0,
  y: 0,
  inside: false,
  down: false,
  pressed: false,
  released: false,
  wheel: 0,
};

/** A top-level entity handle named after itself, with empty props. */
export function fakeEntity(name: string, x = 0, assetId = `asset-${name}`): EntityHandle {
  return { [ENTITY_HANDLE]: true, id: name, assetId, name, x, y: 0, z: 0, props: {}, parent: null };
}

/** An entity handle "h" carrying the given props, optionally below a parent. */
export function fakeHandle(props: PropertyBag, parent: EntityHandle | null = null): EntityHandle {
  return { [ENTITY_HANDLE]: true, id: 'h', assetId: 'a', name: 'h', x: 0, y: 0, z: 0, props, parent };
}

/** `changes` records the state moves the context was told about, in the order they were reported. */
export type FakeContext = NodeContext & {
  logs: string[];
  stopped: boolean;
  changes: { machineId: string; from: string; to: string }[];
  /** What the context was asked to play and to silence, in order – nothing here makes a noise. */
  played: {
    assetId: string;
    volume: number;
    loop: boolean | undefined;
    detached: boolean;
    fx: string;
    fxParams: Readonly<Record<string, number>>;
  }[];
  silenced: string[];
  tuned: { voice: number; fxParams: Readonly<Record<string, number>>; time: number; ease: EaseShare }[];
  /** The scenes the context was asked to load, in order. */
  loaded: string[];
  /** The time scale and the pause the context holds, as the game nodes left them. */
  scale: number;
  paused: boolean;
};

/** A NodeContext double: self/owner handles, `speed = 100`, dt 0.5, moves applied directly, `log` and `stop` recorded. */
export function fakeContext(overrides: Partial<NodeContext> = {}): FakeContext {
  const logs: string[] = [];
  const ctx: FakeContext = {
    self: fakeEntity('self'),
    owner: fakeEntity('owner'),
    variables: { speed: 100 },
    states: {},
    shared: emptySharedState(),
    changes: [],
    stateChanged: (machineId, from, to) => ctx.changes.push({ machineId, from, to }),
    time: 0,
    dt: 0.5,
    logs,
    stopped: false,
    findByName: () => null,
    isAlive: () => true,
    findReferenced: () => null,
    childByName: () => null,
    objects: () => [],
    isKeyDown: () => false,
    wasKeyPressed: () => false,
    wasKeyReleased: () => false,
    pointer: { ...NO_POINTER },
    pointerThrough: () => ({ x: 0, y: 0, inside: false }),
    hitTest: () => false,
    isTouching: () => false,
    raycast: () => null,
    raycastAll: () => [],
    collisionLayerOf: () => null,
    renderLayerOf: () => null,
    ignoreOneWay: () => {},
    isTilemap: () => false,
    tileAt: () => null,
    setTile: () => false,
    moveAndSlide: (target, dx, dy) => {
      target.x += dx;
      target.y += dy;
      return { blockedX: false, blockedY: false, hit: false, normal: { x: 0, y: 0 } };
    },
    log: (message) => logs.push(message),
    played: [],
    silenced: [],
    loaded: [],
    // The number of a voice is how many have been played: unique, and never 0.
    playSound: (assetId, volume, loop, detached, fx, fxParams) =>
      ctx.played.push({ assetId, volume, loop, detached, fx, fxParams }),
    // Every sound lasts a quarter of a second, as if it had been loaded.
    soundLength: () => 0.25,
    stopSound: (assetId) => ctx.silenced.push(assetId),
    tuned: [],
    tuneSound: (voice, fxParams, time, ease) => ctx.tuned.push({ voice, fxParams, time, ease }),
    loadScene: (sceneId) => ctx.loaded.push(sceneId),
    spawn: () => null,
    addJoint: () => null,
    destroy: () => [],
    stop: () => {
      ctx.stopped = true;
    },
    restart: () => {},
    scale: 1,
    paused: false,
    timeScale: () => ctx.scale,
    setTimeScale: (scale) => {
      ctx.scale = scale;
    },
    isPaused: () => ctx.paused,
    setPaused: (paused) => {
      ctx.paused = paused;
    },
    ...overrides,
  };
  return ctx;
}

/** Runs a node on its registered definition: the shape it has while sitting in no graph. */
export function runDef(
  type: string,
  ctx: NodeContext,
  inputs: Record<string, Value>,
  params: PropertyBag = {},
  entry = 'exec',
  lookup: GraphLookup = NO_LOOKUP,
): RunResult {
  const def = requireNodeDef(type);
  return def.run!(ctx, inputs, params, def, entry, lookup);
}

/**
 * Runs every event node of `type` in the graph, in the order the graph holds them, and answers how
 * many ran. A game orders its events across all behaviors instead (#264); a test of one graph does not.
 */
export function fire(
  interpreter: GraphInterpreter,
  type: string,
  ctx: NodeContext,
  outputs: Record<string, Value> = {},
  filter?: (node: GraphNode) => boolean,
): number {
  const nodes = interpreter.eventNodes(type).filter((node) => !filter || filter(node));
  for (const node of nodes) interpreter.pulse(node, ctx, outputs);
  return nodes.length;
}

/** Runs one node definition in isolation and returns its data outputs. */
export function runNode(
  type: string,
  inputs: Record<string, Value>,
  params: PropertyBag = {},
  ctx: NodeContext = fakeContext(),
): Record<string, Value> {
  return runDef(type, ctx, inputs, params).outputs ?? {};
}

export interface WorldOptions {
  collisions?: boolean;
  /**
   * With `collisions`: the played game's physics engine rather than the editor run's detection
   * (#146). The engine has to be loaded first – `await loadPhysics()` in a `beforeAll`.
   */
  physics?: boolean;
  animations?: boolean;
  behaviors?: boolean;
  /** Where `Play sound` ends up; without one the run plays to nobody (see `SILENT_AUDIO`). */
  audio?: AudioSink;
  /** The clock `Set time scale` turns; without one the run is treated like the editor run. */
  clock?: TimeScaled;
  /** Where persistent Variables assets keep their values; without one nothing outlives the run. */
  saves?: SaveArea;
}

export interface StartedWorld {
  world: World;
  collisions: CollisionSource | null;
  behaviors: BehaviorSystem | null;
  /** Feed keys with `input.press('a')`; `frame()` clears the edges the way the editor does. */
  input: Input;
  /** One tick plus the end-of-frame bookkeeping the editor's play loop performs. */
  frame(dt?: number): void;
}

/** Instantiates the fixture's scene, optionally with collisions, animations and a BehaviorSystem fed by both. */
export function startWorld(
  fixture: SceneFixture,
  options: WorldOptions & { collisions: true },
): StartedWorld & { collisions: CollisionSource };
export function startWorld(fixture: SceneFixture, options?: WorldOptions): StartedWorld;
export function startWorld(fixture: SceneFixture, options: WorldOptions = {}): StartedWorld {
  const world = World.instantiate(fixture.project, fixture.sceneId);
  const collisions = options.collisions
    ? options.physics
      ? new PhysicsSystem(readyPhysics() ?? fail('load the physics engine before starting a world with it'))
      : new CollisionSystem()
    : null;
  const input = new Input();
  const animations = options.animations ? new AnimationSystem() : null;
  if (collisions) world.addSystem(collisions);
  if (animations) world.addSystem(animations);
  const behaviors = options.behaviors
    ? new BehaviorSystem(fixture.project, input, {
        collisions,
        animations,
        audio: options.audio,
        clock: options.clock,
        saves: options.saves,
      })
    : null;
  if (behaviors) world.addSystem(behaviors);
  return {
    world,
    collisions,
    behaviors,
    input,
    frame(dt = 1 / 60) {
      world.tick(dt);
      input.endFrame();
    },
  };
}

/**
 * Both ways a run detects collisions: the editor run's own and the played game's engine (#146).
 * Everything without a rigidbody must come out the same on either.
 */
export const COLLISION_SYSTEMS = [
  { system: 'CollisionSystem', physics: false },
  { system: 'PhysicsSystem', physics: true },
] as const;

function fail(message: string): never {
  throw new Error(message);
}

/** The project as it comes back after being saved and loaded again. */
export function roundTrip(project: Project): Project {
  return deserializeProject(serializeProject(project));
}