import { StateEffect, StateField } from '@codemirror/state';

import { Decoration, EditorView } from '@codemirror/view';

export const setFlash = StateEffect.define();

export const flashField = StateField.define({

  create() {

    return Decoration.none;

  },

  update(flash, tr) {

    try {

      for (let e of tr.effects) {

        if (e.is(setFlash)) {

          if (e.value && tr.newDoc.length > 0) {

            const mark = Decoration.mark({

              attributes: { style: `background-color: rgba(255,255,255, .4); filter: invert(10%)` },

            });

            flash = Decoration.set([mark.range(0, tr.newDoc.length)]);

          } else {

            flash = Decoration.set([]);

          }

        }

      }

      return flash;

    } catch (err) {

      console.warn('flash error', err);

      return flash;

    }

  },

  provide: (f) => EditorView.decorations.from(f),

});

export const flash = (view, ms = 200) => {

  view.dispatch({ effects: setFlash.of(true) });

  setTimeout(() => {

    view.dispatch({ effects: setFlash.of(false) });

  }, ms);

};

export const isFlashEnabled = (on) => (on ? flashField : []);