penpot/plugins/libs/plugins-runtime/src/lib/modal/plugin-modal.ts

const closeSvg = `
<svg width="16"  height="16"xmlns="http://www.w3.org/2000/svg" fill="none"><g class="fills"><rect rx="0" ry="0" width="16" height="16" class="frame-background"/></g><g class="frame-children"><path d="M11.997 3.997 8 8l-3.997 4.003m-.006-8L8 8l4.003 3.997" class="fills"/><g class="strokes"><path d="M11.997 3.997 8 8l-3.997 4.003m-.006-8L8 8l4.003 3.997" style="fill: none; stroke-width: 1; stroke: rgb(143, 157, 163); stroke-opacity: 1; stroke-linecap: round;" class="stroke-shape"/></g></g></svg>`;

import type { Theme } from '@penpot/plugin-types';
import { dragHandler } from '../drag-handler.js';
import modalCss from './plugin.modal.css?inline';
import { resizeModal } from '../create-modal.js';

const MIN_Z_INDEX = 300;
const Z_INDEX_VAR = '--z-index-set';

export class PluginModalElement extends HTMLElement {
  constructor() {
    super();
    this.attachShadow({ mode: 'open' });
  }

  wrapper = document.createElement('div');
  #inner = document.createElement('div');
  #dragEvents: ReturnType<typeof dragHandler> | null = null;
  #iframe: HTMLIFrameElement | null = null;

  setTheme(theme: Theme) {
    if (this.wrapper) {
      this.wrapper.setAttribute('data-theme', theme);
    }
  }

  resize(width: number, height: number) {
    if (this.wrapper) {
      resizeModal(this, width, height);
    }
  }

  disconnectedCallback() {
    this.#dragEvents?.();
  }

  calculateZIndex() {
    const modals = document.querySelectorAll<HTMLElement>('plugin-modal');

    const zIndexModals = Array.from(modals)
      .filter((modal) => modal !== this)
      .map((modal) => {
        return Number(modal.style.zIndex);
      });

    // Read the application z-index scale via the inherited CSS custom property
    // `--z-index-set` (defined on :root). Custom properties pierce shadow DOM
    // boundaries, so the value is available even though the modal uses a Shadow
    // root. Falls back to MIN_Z_INDEX when the variable is unset or unparseable
    // (e.g. when the runtime is used outside the Penpot app shell).
    const declared = getComputedStyle(this)
      .getPropertyValue(Z_INDEX_VAR)
      .trim();
    const parsed = Number(declared);
    const baseZIndex =
      Number.isFinite(parsed) && parsed > 0 ? parsed : MIN_Z_INDEX;

    const maxZIndex = Math.max(...zIndexModals, baseZIndex);

    this.style.zIndex = (maxZIndex + 1).toString();
  }

  connectedCallback() {
    const title = this.getAttribute('title');
    const iframeSrc = this.getAttribute('iframe-src');
    const allowDownloads = this.getAttribute('allow-downloads') || false;
    const allowClipboardRead =
      this.getAttribute('allow-clipboard-read') || false;
    const allowClipboardWrite =
      this.getAttribute('allow-clipboard-write') || false;

    if (!title || !iframeSrc) {
      throw new Error('title and iframe-src attributes are required');
    }

    if (!this.shadowRoot) {
      throw new Error('Error creating shadow root');
    }

    this.#inner.classList.add('inner');

    this.wrapper.classList.add('wrapper');
    this.wrapper.style.maxInlineSize = '90vw';
    this.wrapper.style.maxBlockSize = '90vh';

    const header = document.createElement('div');
    header.classList.add('header');

    const h1 = document.createElement('h1');
    h1.textContent = title;

    header.appendChild(h1);

    const closeButton = document.createElement('button');
    closeButton.setAttribute('type', 'button');
    closeButton.innerHTML = `<div class="close">${closeSvg}</div>`;
    closeButton.addEventListener('click', () => {
      if (!this.shadowRoot) {
        return;
      }

      this.shadowRoot.dispatchEvent(
        new CustomEvent('close', {
          composed: true,
          bubbles: true,
        }),
      );
    });

    header.appendChild(closeButton);

    this.#iframe = document.createElement('iframe');
    this.#iframe.src = iframeSrc;

    const allowList: string[] = [];
    if (allowClipboardRead) allowList.push('clipboard-read');
    if (allowClipboardWrite) allowList.push('clipboard-write');
    this.#iframe.allow = allowList.join('; ');

    this.#iframe.sandbox.add(
      'allow-scripts',
      'allow-forms',
      'allow-modals',
      'allow-popups',
      'allow-popups-to-escape-sandbox',
      'allow-storage-access-by-user-activation',
      'allow-same-origin',
    );

    if (allowDownloads) {
      this.#iframe.sandbox.add('allow-downloads');
    }

    this.#iframe.addEventListener('load', () => {
      this.shadowRoot?.dispatchEvent(
        new CustomEvent('load', {
          composed: true,
          bubbles: true,
        }),
      );
    });

    // move modal to the top
    this.#dragEvents = dragHandler(
      header,
      this.wrapper,
      () => {
        this.calculateZIndex();
      },
      {
        start: () => {
          this.wrapper.classList.add('is-dragging');
        },
        end: () => {
          this.wrapper.classList.remove('is-dragging');
        },
      },
    );

    this.addEventListener('message', (e: Event) => {
      if (!this.#iframe?.contentWindow) {
        return;
      }

      try {
        this.#iframe.contentWindow.postMessage((e as CustomEvent).detail, '*');
      } catch (err) {
        console.error(
          'plugin modal: failed to send message to iframe via postMessage.',
          err,
        );
      }
    });

    this.shadowRoot.appendChild(this.wrapper);

    this.wrapper.appendChild(this.#inner);
    this.#inner.appendChild(header);
    this.#inner.appendChild(this.#iframe);

    const style = document.createElement('style');
    style.textContent = modalCss;

    this.shadowRoot.appendChild(style);

    this.calculateZIndex();
  }

  getIframeContentWindow(): Window | null {
    return this.#iframe?.contentWindow ?? null;
  }

  size() {
    const width = Number(this.wrapper.style.width.replace('px', '') || '300');
    const height = Number(this.wrapper.style.height.replace('px', '') || '400');

    return { width, height };
  }
}

customElements.define('plugin-modal', PluginModalElement);