1 files changed, 133 insertions, 0 deletions
diff --git a/app/javascript/flavours/glitch/components/modal_root.js b/app/javascript/flavours/glitch/components/modal_root.js
new file mode 100644
index 000000000..13a8e8702
--- /dev/null
+++ b/app/javascript/flavours/glitch/components/modal_root.js
@@ -0,0 +1,133 @@
+import React from 'react';
+import PropTypes from 'prop-types';
+import 'wicg-inert';
+import { createBrowserHistory } from 'history';
+
+export default class ModalRoot extends React.PureComponent {
+  static contextTypes = {
+    router: PropTypes.object,
+  };
+
+  static propTypes = {
+    children: PropTypes.node,
+    onClose: PropTypes.func.isRequired,
+    noEsc: PropTypes.bool,
+  };
+
+  activeElement = this.props.children ? document.activeElement : null;
+
+  handleKeyUp = (e) => {
+    if ((e.key === 'Escape' || e.key === 'Esc' || e.keyCode === 27)
+         && !!this.props.children && !this.props.noEsc) {
+      this.props.onClose();
+    }
+  }
+
+  handleKeyDown = (e) => {
+    if (e.key === 'Tab') {
+      const focusable = Array.from(this.node.querySelectorAll('button:not([disabled]), [href], input:not([disabled]), select:not([disabled]), textarea:not([disabled]), [tabindex]:not([tabindex="-1"])')).filter((x) => window.getComputedStyle(x).display !== 'none');
+      const index = focusable.indexOf(e.target);
+
+      let element;
+
+      if (e.shiftKey) {
+        element = focusable[index - 1] || focusable[focusable.length - 1];
+      } else {
+        element = focusable[index + 1] || focusable[0];
+      }
+
+      if (element) {
+        element.focus();
+        e.stopPropagation();
+        e.preventDefault();
+      }
+    }
+  }
+
+  componentDidMount () {
+    window.addEventListener('keyup', this.handleKeyUp, false);
+    window.addEventListener('keydown', this.handleKeyDown, false);
+    this.history = this.context.router ? this.context.router.history : createBrowserHistory();
+  }
+
+  componentWillReceiveProps (nextProps) {
+    if (!!nextProps.children && !this.props.children) {
+      this.activeElement = document.activeElement;
+
+      this.getSiblings().forEach(sibling => sibling.setAttribute('inert', true));
+    }
+  }
+
+  componentDidUpdate (prevProps) {
+    if (!this.props.children && !!prevProps.children) {
+      this.getSiblings().forEach(sibling => sibling.removeAttribute('inert'));
+
+      // Because of the wicg-inert polyfill, the activeElement may not be
+      // immediately selectable, we have to wait for observers to run, as
+      // described in https://github.com/WICG/inert#performance-and-gotchas
+      Promise.resolve().then(() => {
+        this.activeElement.focus({ preventScroll: true });
+        this.activeElement = null;
+      }).catch((error) => {
+        console.error(error);
+      });
+
+      this.handleModalClose();
+    }
+    if (this.props.children && !prevProps.children) {
+      this.handleModalOpen();
+    }
+  }
+
+  componentWillUnmount () {
+    window.removeEventListener('keyup', this.handleKeyUp);
+    window.removeEventListener('keydown', this.handleKeyDown);
+  }
+
+  handleModalClose () {
+    this.unlistenHistory();
+
+    const state = this.history.location.state;
+    if (state && state.mastodonModalOpen) {
+      this.history.goBack();
+    }
+  }
+
+  handleModalOpen () {
+    const history = this.history;
+    const state   = {...history.location.state, mastodonModalOpen: true};
+    history.push(history.location.pathname, state);
+    this.unlistenHistory = history.listen(() => {
+      this.props.onClose();
+    });
+  }
+
+  getSiblings = () => {
+    return Array(...this.node.parentElement.childNodes).filter(node => node !== this.node);
+  }
+
+  setRef = ref => {
+    this.node = ref;
+  }
+
+  render () {
+    const { children, onClose } = this.props;
+    const visible = !!children;
+
+    if (!visible) {
+      return (
+        <div className='modal-root' ref={this.setRef} style={{ opacity: 0 }} />
+      );
+    }
+
+    return (
+      <div className='modal-root' ref={this.setRef}>
+        <div style={{ pointerEvents: visible ? 'auto' : 'none' }}>
+          <div role='presentation' className='modal-root__overlay' onClick={onClose} />
+          <div role='dialog' className='modal-root__container'>{children}</div>
+        </div>
+      </div>
+    );
+  }
+
+}