import { DirectUploadController } from './direct_upload_controller';
import { findElements, dispatchEvent, toArray } from './helpers';

const inputSelector =
  'input[type=file][data-direct-upload-url]:not([disabled])';

export class DirectUploadsController {
  constructor(form) {
    this.form = form;
    this.inputs = findElements(form, inputSelector).filter(
      input => input.files.length
    );
  }

  start(callback) {
    const controllers = this.createDirectUploadControllers();

    const startNextController = () => {
      const controller = controllers.shift();
      if (controller) {
        controller.start(error => {
          if (error) {
            callback(error);
            this.dispatch('end');
          } else {
            startNextController();
          }
        });
      } else {
        callback();
        this.dispatch('end');
      }
    };

    this.dispatch('start');
    startNextController();
  }

  createDirectUploadControllers() {
    const controllers = [];
    this.inputs.forEach(input => {
      toArray(input.files).forEach(file => {
        const controller = new DirectUploadController(input, file);
        controllers.push(controller);
      });
    });
    return controllers;
  }

  dispatch(name, detail = {}) {
    return dispatchEvent(this.form, `direct-uploads:${name}`, { detail });
  }
}