import MdxModel from './model';
import MdxModelInstance from './modelinstance';
import Attachment from './attachment';

// Heap allocations needed for this module.
const visibilityHeap = new Float32Array(1);

/**
 * An attachment instance.
 */
export default class AttachmentInstance {
  instance: MdxModelInstance;
  attachment: Attachment;
  internalInstance: MdxModelInstance;

  constructor(instance: MdxModelInstance, attachment: Attachment) {
    let internalModel = <MdxModel>attachment.internalModel;
    let internalInstance = <MdxModelInstance>internalModel.addInstance();

    internalInstance.setSequenceLoopMode(2);
    internalInstance.dontInheritScaling = false;
    internalInstance.hide();
    internalInstance.setParent(instance.nodes[attachment.objectId]);

    this.instance = instance;
    this.attachment = attachment;
    this.internalInstance = internalInstance;
  }

  update() {
    let instance = this.instance;
    let internalInstance = this.internalInstance;

    if (instance.scene && instance.sequence !== -1) {
      this.attachment.getVisibility(visibilityHeap, instance.sequence, instance.frame, instance.counter);

      if (visibilityHeap[0] > 0.1) {
        // The parent instance might not actually be in a scene.
        // This happens if loading a local model, where loading is instant and adding to a scene always comes afterwards.
        // Therefore, do it here dynamically.
        instance.scene.addInstance(internalInstance);

        if (internalInstance.hidden()) {
          internalInstance.show();

          // Every time the attachment becomes visible again, restart its first sequence.
          internalInstance.setSequence(0);
        }
      } else {
        internalInstance.hide();
      }
    }
  }
}