/**
 * @file
 * An abstract Backbone View that controls an in-place editor.
 */

(function($, Backbone, Drupal) {
  Drupal.quickedit.EditorView = Backbone.View.extend(
    /** @lends Drupal.quickedit.EditorView# */ {
      /**
       * A base implementation that outlines the structure for in-place editors.
       *
       * Specific in-place editor implementations should subclass (extend) this
       * View and override whichever method they deem necessary to override.
       *
       * Typically you would want to override this method to set the
       * originalValue attribute in the FieldModel to such a value that your
       * in-place editor can revert to the original value when necessary.
       *
       * @example
       * <caption>If you override this method, you should call this
       * method (the parent class' initialize()) first.</caption>
       * Drupal.quickedit.EditorView.prototype.initialize.call(this, options);
       *
       * @constructs
       *
       * @augments Backbone.View
       *
       * @param {object} options
       *   An object with the following keys:
       * @param {Drupal.quickedit.EditorModel} options.model
       *   The in-place editor state model.
       * @param {Drupal.quickedit.FieldModel} options.fieldModel
       *   The field model.
       *
       * @see Drupal.quickedit.EditorModel
       * @see Drupal.quickedit.editors.plain_text
       */
      initialize(options) {
        this.fieldModel = options.fieldModel;
        this.listenTo(this.fieldModel, 'change:state', this.stateChange);
      },

      /**
       * @inheritdoc
       */
      remove() {
        // The el property is the field, which should not be removed. Remove the
        // pointer to it, then call Backbone.View.prototype.remove().
        this.setElement();
        Backbone.View.prototype.remove.call(this);
      },

      /**
       * Returns the edited element.
       *
       * For some single cardinality fields, it may be necessary or useful to
       * not in-place edit (and hence decorate) the DOM element with the
       * data-quickedit-field-id attribute (which is the field's wrapper), but a
       * specific element within the field's wrapper.
       * e.g. using a WYSIWYG editor on a body field should happen on the DOM
       * element containing the text itself, not on the field wrapper.
       *
       * @return {jQuery}
       *   A jQuery-wrapped DOM element.
       *
       * @see Drupal.quickedit.editors.plain_text
       */
      getEditedElement() {
        return this.$el;
      },

      /**
       *
       * @return {object}
       * Returns 3 Quick Edit UI settings that depend on the in-place editor:
       *  - Boolean padding: indicates whether padding should be applied to the
       *    edited element, to guarantee legibility of text.
       *  - Boolean unifiedToolbar: provides the in-place editor with the ability
       *    to insert its own toolbar UI into Quick Edit's tightly integrated
       *    toolbar.
       *  - Boolean fullWidthToolbar: indicates whether Quick Edit's tightly
       *    integrated toolbar should consume the full width of the element,
       *    rather than being just long enough to accommodate a label.
       */
      getQuickEditUISettings() {
        return {
          padding: false,
          unifiedToolbar: false,
          fullWidthToolbar: false,
          popup: false,
        };
      },

      /**
       * Determines the actions to take given a change of state.
       *
       * @param {Drupal.quickedit.FieldModel} fieldModel
       *   The quickedit `FieldModel` that holds the state.
       * @param {string} state
       *   The state of the associated field. One of
       *   {@link Drupal.quickedit.FieldModel.states}.
       */
      stateChange(fieldModel, state) {
        const from = fieldModel.previous('state');
        const to = state;
        switch (to) {
          case 'inactive':
            // An in-place editor view will not yet exist in this state, hence
            // this will never be reached. Listed for sake of completeness.
            break;

          case 'candidate':
            // Nothing to do for the typical in-place editor: it should not be
            // visible yet. Except when we come from the 'invalid' state, then we
            // clean up.
            if (from === 'invalid') {
              this.removeValidationErrors();
            }
            break;

          case 'highlighted':
            // Nothing to do for the typical in-place editor: it should not be
            // visible yet.
            break;

          case 'activating': {
            // The user is in the process of activating in-place editing: if
            // something needs to be loaded (CSS/JavaScript/server data/…), then
            // do so at this stage, and once the in-place editor is ready,
            // set the 'active' state. A "loading" indicator will be shown in the
            // UI for as long as the field remains in this state.
            const loadDependencies = function(callback) {
              // Do the loading here.
              callback();
            };
            loadDependencies(() => {
              fieldModel.set('state', 'active');
            });
            break;
          }

          case 'active':
            // The user can now actually use the in-place editor.
            break;

          case 'changed':
            // Nothing to do for the typical in-place editor. The UI will show an
            // indicator that the field has changed.
            break;

          case 'saving':
            // When the user has triggered a save to this field, this state will
            // be entered. If the previous saving attempt resulted in validation
            // errors, the previous state will be 'invalid'. Clean up those
            // validation errors while the user is saving.
            if (from === 'invalid') {
              this.removeValidationErrors();
            }
            this.save();
            break;

          case 'saved':
            // Nothing to do for the typical in-place editor. Immediately after
            // being saved, a field will go to the 'candidate' state, where it
            // should no longer be visible (after all, the field will then again
            // just be a *candidate* to be in-place edited).
            break;

          case 'invalid':
            // The modified field value was attempted to be saved, but there were
            // validation errors.
            this.showValidationErrors();
            break;
        }
      },

      /**
       * Reverts the modified value to the original, before editing started.
       */
      revert() {
        // A no-op by default; each editor should implement reverting itself.
        // Note that if the in-place editor does not cause the FieldModel's
        // element to be modified, then nothing needs to happen.
      },

      /**
       * Saves the modified value in the in-place editor for this field.
       */
      save() {
        const fieldModel = this.fieldModel;
        const editorModel = this.model;
        const backstageId = `quickedit_backstage-${this.fieldModel.id.replace(
          /[/[\]_\s]/g,
          '-',
        )}`;

        function fillAndSubmitForm(value) {
          const $form = $(`#${backstageId}`).find('form');
          // Fill in the value in any <input> that isn't hidden or a submit
          // button.
          $form
            .find(':input[type!="hidden"][type!="submit"]:not(select)')
            // Don't mess with the node summary.
            .not('[name$="\\[summary\\]"]')
            .val(value);
          // Submit the form.
          $form.find('.quickedit-form-submit').trigger('click.quickedit');
        }

        const formOptions = {
          fieldID: this.fieldModel.get('fieldID'),
          $el: this.$el,
          nocssjs: true,
          other_view_modes: fieldModel.findOtherViewModes(),
          // Reset an existing entry for this entity in the PrivateTempStore (if
          // any) when saving the field. Logically speaking, this should happen in
          // a separate request because this is an entity-level operation, not a
          // field-level operation. But that would require an additional request,
          // that might not even be necessary: it is only when a user saves a
          // first changed field for an entity that this needs to happen:
          // precisely now!
          reset: !this.fieldModel.get('entity').get('inTempStore'),
        };

        const self = this;
        Drupal.quickedit.util.form.load(formOptions, (form, ajax) => {
          // Create a backstage area for storing forms that are hidden from view
          // (hence "backstage" — since the editing doesn't happen in the form, it
          // happens "directly" in the content, the form is only used for saving).
          const $backstage = $(
            Drupal.theme('quickeditBackstage', { id: backstageId }),
          ).appendTo('body');
          // Hidden forms are stuffed into the backstage container for this field.
          const $form = $(form).appendTo($backstage);
          // Disable the browser's HTML5 validation; we only care about server-
          // side validation. (Not disabling this will actually cause problems
          // because browsers don't like to set HTML5 validation errors on hidden
          // forms.)
          $form.prop('novalidate', true);
          const $submit = $form.find('.quickedit-form-submit');
          self.formSaveAjax = Drupal.quickedit.util.form.ajaxifySaving(
            formOptions,
            $submit,
          );

          function removeHiddenForm() {
            Drupal.quickedit.util.form.unajaxifySaving(self.formSaveAjax);
            delete self.formSaveAjax;
            $backstage.remove();
          }

          // Successfully saved.
          self.formSaveAjax.commands.quickeditFieldFormSaved = function(
            ajax,
            response,
            status,
          ) {
            removeHiddenForm();
            // First, transition the state to 'saved'.
            fieldModel.set('state', 'saved');
            // Second, set the 'htmlForOtherViewModes' attribute, so that when
            // this field is rerendered, the change can be propagated to other
            // instances of this field, which may be displayed in different view
            // modes.
            fieldModel.set('htmlForOtherViewModes', response.other_view_modes);
            // Finally, set the 'html' attribute on the field model. This will
            // cause the field to be rerendered.
            fieldModel.set('html', response.data);
          };

          // Unsuccessfully saved; validation errors.
          self.formSaveAjax.commands.quickeditFieldFormValidationErrors = function(
            ajax,
            response,
            status,
          ) {
            removeHiddenForm();
            editorModel.set('validationErrors', response.data);
            fieldModel.set('state', 'invalid');
          };

          // The quickeditFieldForm AJAX command is only called upon loading the
          // form for the first time, and when there are validation errors in the
          // form; Form API then marks which form items have errors. This is
          // useful for the form-based in-place editor, but pointless for any
          // other: the form itself won't be visible at all anyway! So, we just
          // ignore it.
          self.formSaveAjax.commands.quickeditFieldForm = function() {};

          fillAndSubmitForm(editorModel.get('currentValue'));
        });
      },

      /**
       * Shows validation error messages.
       *
       * Should be called when the state is changed to 'invalid'.
       */
      showValidationErrors() {
        const $errors = $(
          '<div class="quickedit-validation-errors"></div>',
        ).append(this.model.get('validationErrors'));
        this.getEditedElement()
          .addClass('quickedit-validation-error')
          .after($errors);
      },

      /**
       * Cleans up validation error messages.
       *
       * Should be called when the state is changed to 'candidate' or 'saving'. In
       * the case of the latter: the user has modified the value in the in-place
       * editor again to attempt to save again. In the case of the latter: the
       * invalid value was discarded.
       */
      removeValidationErrors() {
        this.getEditedElement()
          .removeClass('quickedit-validation-error')
          .next('.quickedit-validation-errors')
          .remove();
      },
    },
  );
})(jQuery, Backbone, Drupal);
