content: // @inheritedComponent Modal
  
  import React from 'react';
  import PropTypes from 'prop-types';
  import ReactDOM from 'react-dom';
  import warning from 'warning';
  import debounce from 'debounce'; // < 1kb payload overhead when lodash/debounce is > 3kb.
  import EventListener from 'react-event-listener';
  import { componentPropType } from '@material-ui/utils';
  import ownerDocument from '../utils/ownerDocument';
  import ownerWindow from '../utils/ownerWindow';
  import { createChainedFunction } from '../utils/helpers';
  import withStyles from '../styles/withStyles';
  import Modal from '../Modal';
  import Grow from '../Grow';
  import Paper from '../Paper';
  
  function getOffsetTop(rect, vertical) {
    let offset = 0;
  
    if (typeof vertical === 'number') {
      offset = vertical;
    } else if (vertical === 'center') {
      offset = rect.height / 2;
    } else if (vertical === 'bottom') {
      offset = rect.height;
    }
  
    return offset;
  }
  
  function getOffsetLeft(rect, horizontal) {
    let offset = 0;
  
    if (typeof horizontal === 'number') {
      offset = horizontal;
    } else if (horizontal === 'center') {
      offset = rect.width / 2;
    } else if (horizontal === 'right') {
      offset = rect.width;
    }
  
    return offset;
  }
  
  function getTransformOriginValue(transformOrigin) {
    return [transformOrigin.horizontal, transformOrigin.vertical]
      .map(n => {
        return typeof n === 'number' ? `${n}px` : n;
      })
      .join(' ');
  }
  
  // Sum the scrollTop between two elements.
  function getScrollParent(parent, child) {
    let element = child;
    let scrollTop = 0;
  
    while (element && element !== parent) {
      element = element.parentNode;
      scrollTop += element.scrollTop;
    }
    return scrollTop;
  }
  
  function getAnchorEl(anchorEl) {
    return typeof anchorEl === 'function' ? anchorEl() : anchorEl;
  }
  
  export const styles = {
    /* Styles applied to the `Paper` component. */
    paper: {
      position: 'absolute',
      overflowY: 'auto',
      overflowX: 'hidden',
      // So we see the popover when it's empty.
      // It's most likely on issue on userland.
      minWidth: 16,
      minHeight: 16,
      maxWidth: 'calc(100% - 32px)',
      maxHeight: 'calc(100% - 32px)',
      // We disable the focus ring for mouse, touch and keyboard users.
      outline: 'none',
    },
  };
  
  class Popover extends React.Component {
    handleGetOffsetTop = getOffsetTop;
  
    handleGetOffsetLeft = getOffsetLeft;
  
    constructor() {
      super();
  
      if (typeof window !== 'undefined') {
        this.handleResize = debounce(() => {
          // Because we debounce the event, the open property might no longer be true
          // when the callback resolves.
          if (!this.props.open) {
            return;
          }
  
          this.setPositioningStyles(this.paperRef);
        }, 166); // Corresponds to 10 frames at 60 Hz.
      }
    }
  
    componentDidMount() {
      if (this.props.action) {
        this.props.action({
          updatePosition: this.handleResize,
        });
      }
    }
  
    componentWillUnmount = () => {
      this.handleResize.clear();
    };
  
    setPositioningStyles = element => {
      const positioning = this.getPositioningStyle(element);
      if (positioning.top !== null) {
        element.style.top = positioning.top;
      }
      if (positioning.left !== null) {
        element.style.left = positioning.left;
      }
      element.style.transformOrigin = positioning.transformOrigin;
    };
  
    getPositioningStyle = element => {
      const { anchorEl, anchorReference, marginThreshold } = this.props;
  
      // Check if the parent has requested anchoring on an inner content node
      const contentAnchorOffset = this.getContentAnchorOffset(element);
      const elemRect = {
        width: element.offsetWidth,
        height: element.offsetHeight,
      };
  
      // Get the transform origin point on the element itself
      const transformOrigin = this.getTransformOrigin(elemRect, contentAnchorOffset);
  
      if (anchorReference === 'none') {
        return {
          top: null,
          left: null,
          transformOrigin: getTransformOriginValue(transformOrigin),
        };
      }
  
      // Get the offset of of the anchoring element
      const anchorOffset = this.getAnchorOffset(contentAnchorOffset);
  
      // Calculate element positioning
      let top = anchorOffset.top - transformOrigin.vertical;
      let left = anchorOffset.left - transformOrigin.horizontal;
      const bottom = top + elemRect.height;
      const right = left + elemRect.width;
  
      // Use the parent window of the anchorEl if provided
      const containerWindow = ownerWindow(getAnchorEl(anchorEl));
  
      // Window thresholds taking required margin into account
      const heightThreshold = containerWindow.innerHeight - marginThreshold;
      const widthThreshold = containerWindow.innerWidth - marginThreshold;
  
      // Check if the vertical axis needs shifting
      if (top < marginThreshold) {
        const diff = top - marginThreshold;
        top -= diff;
        transformOrigin.vertical += diff;
      } else if (bottom > heightThreshold) {
        const diff = bottom - heightThreshold;
        top -= diff;
        transformOrigin.vertical += diff;
      }
  
      warning(
        elemRect.height < heightThreshold || !elemRect.height || !heightThreshold,
        [
          'Material-UI: the popover component is too tall.',
          `Some part of it can not be seen on the screen (${elemRect.height - heightThreshold}px).`,
          'Please consider adding a `max-height` to improve the user-experience.',
        ].join('\n'),
      );
  
      // Check if the horizontal axis needs shifting
      if (left < marginThreshold) {
        const diff = left - marginThreshold;
        left -= diff;
        transformOrigin.horizontal += diff;
      } else if (right > widthThreshold) {
        const diff = right - widthThreshold;
        left -= diff;
        transformOrigin.horizontal += diff;
      }
  
      return {
        top: `${top}px`,
        left: `${left}px`,
        transformOrigin: getTransformOriginValue(transformOrigin),
      };
    };
  
    // Returns the top/left offset of the position
    // to attach to on the anchor element (or body if none is provided)
    getAnchorOffset(contentAnchorOffset) {
      const { anchorEl, anchorOrigin, anchorReference, anchorPosition } = this.props;
  
      if (anchorReference === 'anchorPosition') {
        warning(
          anchorPosition,
          'Material-UI: you need to provide a `anchorPosition` property when using ' +
            '<Popover anchorReference="anchorPosition" />.',
        );
        return anchorPosition;
      }
  
      // If an anchor element wasn't provided, just use the parent body element of this Popover
      const anchorElement = getAnchorEl(anchorEl) || ownerDocument(this.paperRef).body;
      const anchorRect = anchorElement.getBoundingClientRect();
      const anchorVertical = contentAnchorOffset === 0 ? anchorOrigin.vertical : 'center';
  
      return {
        top: anchorRect.top + this.handleGetOffsetTop(anchorRect, anchorVertical),
        left: anchorRect.left + this.handleGetOffsetLeft(anchorRect, anchorOrigin.horizontal),
      };
    }
  
    // Returns the vertical offset of inner content to anchor the transform on if provided
    getContentAnchorOffset(element) {
      const { getContentAnchorEl, anchorReference } = this.props;
      let contentAnchorOffset = 0;
  
      if (getContentAnchorEl && anchorReference === 'anchorEl') {
        const contentAnchorEl = getContentAnchorEl(element);
  
        if (contentAnchorEl && element.contains(contentAnchorEl)) {
          const scrollTop = getScrollParent(element, contentAnchorEl);
          contentAnchorOffset =
            contentAnchorEl.offsetTop + contentAnchorEl.clientHeight / 2 - scrollTop || 0;
        }
  
        // != the default value
        warning(
          this.props.anchorOrigin.vertical === 'top',
          [
            'Material-UI: you can not change the default `anchorOrigin.vertical` value ',
            'when also providing the `getContentAnchorEl` property to the popover component.',
            'Only use one of the two properties.',
            'Set `getContentAnchorEl` to `null | undefined`' +
              ' or leave `anchorOrigin.vertical` unchanged.',
          ].join('\n'),
        );
      }
  
      return contentAnchorOffset;
    }
  
    // Return the base transform origin using the element
    // and taking the content anchor offset into account if in use
    getTransformOrigin(elemRect, contentAnchorOffset = 0) {
      const { transformOrigin } = this.props;
      return {
        vertical: this.handleGetOffsetTop(elemRect, transformOrigin.vertical) + contentAnchorOffset,
        horizontal: this.handleGetOffsetLeft(elemRect, transformOrigin.horizontal),
      };
    }
  
    handleEntering = element => {
      if (this.props.onEntering) {
        this.props.onEntering(element);
      }
  
      this.setPositioningStyles(element);
    };
  
    render() {
      const {
        action,
        anchorEl,
        anchorOrigin,
        anchorPosition,
        anchorReference,
        children,
        classes,
        container: containerProp,
        elevation,
        getContentAnchorEl,
        marginThreshold,
        ModalClasses,
        onEnter,
        onEntered,
        onEntering,
        onExit,
        onExited,
        onExiting,
        open,
        PaperProps,
        role,
        transformOrigin,
        TransitionComponent,
        transitionDuration: transitionDurationProp,
        TransitionProps = {},
        ...other
      } = this.props;
  
      let transitionDuration = transitionDurationProp;
  
      if (transitionDurationProp === 'auto' && !TransitionComponent.muiSupportAuto) {
        transitionDuration = undefined;
      }
  
      // If the container prop is provided, use that
      // If the anchorEl prop is provided, use its parent body element as the container
      // If neither are provided let the Modal take care of choosing the container
      const container =
        containerProp || (anchorEl ? ownerDocument(getAnchorEl(anchorEl)).body : undefined);
  
      return (
        <Modal
          classes={ModalClasses}
          container={container}
          open={open}
          BackdropProps={{ invisible: true }}
          {...other}
        >
          <TransitionComponent
            appear
            in={open}
            onEnter={onEnter}
            onEntered={onEntered}
            onExit={onExit}
            onExited={onExited}
            onExiting={onExiting}
            role={role}
            timeout={transitionDuration}
            {...TransitionProps}
            onEntering={createChainedFunction(this.handleEntering, TransitionProps.onEntering)}
          >
            <Paper
              className={classes.paper}
              data-mui-test="Popover"
              elevation={elevation}
              ref={ref => {
                this.paperRef = ReactDOM.findDOMNode(ref);
              }}
              {...PaperProps}
            >
              <EventListener target="window" onResize={this.handleResize} />
              {children}
            </Paper>
          </TransitionComponent>
        </Modal>
      );
    }
  }
  
  Popover.propTypes = {
    /**
     * This is callback property. It's called by the component on mount.
     * This is useful when you want to trigger an action programmatically.
     * It currently only supports updatePosition() action.
     *
     * @param {object} actions This object contains all possible actions
     * that can be triggered programmatically.
     */
    action: PropTypes.func,
    /**
     * This is the DOM element, or a function that returns the DOM element,
     * that may be used to set the position of the popover.
     */
    anchorEl: PropTypes.oneOfType([PropTypes.object, PropTypes.func]),
    /**
     * This is the point on the anchor where the popover's
     * `anchorEl` will attach to. This is not used when the
     * anchorReference is 'anchorPosition'.
     *
     * Options:
     * vertical: [top, center, bottom];
     * horizontal: [left, center, right].
     */
    anchorOrigin: PropTypes.shape({
      horizontal: PropTypes.oneOfType([
        PropTypes.number,
        PropTypes.oneOf(['left', 'center', 'right']),
      ]).isRequired,
      vertical: PropTypes.oneOfType([PropTypes.number, PropTypes.oneOf(['top', 'center', 'bottom'])])
        .isRequired,
    }),
    /**
     * This is the position that may be used
     * to set the position of the popover.
     * The coordinates are relative to
     * the application's client area.
     */
    anchorPosition: PropTypes.shape({
      left: PropTypes.number.isRequired,
      top: PropTypes.number.isRequired,
    }),
    /*
     * This determines which anchor prop to refer to to set
     * the position of the popover.
     */
    anchorReference: PropTypes.oneOf(['anchorEl', 'anchorPosition', 'none']),
    /**
     * The content of the component.
     */
    children: PropTypes.node,
    /**
     * Override or extend the styles applied to the component.
     * See [CSS API](#css-api) below for more details.
     */
    classes: PropTypes.object.isRequired,
    /**
     * A node, component instance, or function that returns either.
     * The `container` will passed to the Modal component.
     * By default, it uses the body of the anchorEl's top-level document object,
     * so it's simply `document.body` most of the time.
     */
    container: PropTypes.oneOfType([PropTypes.object, PropTypes.func]),
    /**
     * The elevation of the popover.
     */
    elevation: PropTypes.number,
    /**
     * This function is called in order to retrieve the content anchor element.
     * It's the opposite of the `anchorEl` property.
     * The content anchor element should be an element inside the popover.
     * It's used to correctly scroll and set the position of the popover.
     * The positioning strategy tries to make the content anchor element just above the
     * anchor element.
     */
    getContentAnchorEl: PropTypes.func,
    /**
     * Specifies how close to the edge of the window the popover can appear.
     */
    marginThreshold: PropTypes.number,
    /**
     * `classes` property applied to the [`Modal`](/api/modal/) element.
     */
    ModalClasses: PropTypes.object,
    /**
     * Callback fired when the component requests to be closed.
     *
     * @param {object} event The event source of the callback.
     * @param {string} reason Can be:`"escapeKeyDown"`, `"backdropClick"`
     */
    onClose: PropTypes.func,
    /**
     * Callback fired before the component is entering.
     */
    onEnter: PropTypes.func,
    /**
     * Callback fired when the component has entered.
     */
    onEntered: PropTypes.func,
    /**
     * Callback fired when the component is entering.
     */
    onEntering: PropTypes.func,
    /**
     * Callback fired before the component is exiting.
     */
    onExit: PropTypes.func,
    /**
     * Callback fired when the component has exited.
     */
    onExited: PropTypes.func,
    /**
     * Callback fired when the component is exiting.
     */
    onExiting: PropTypes.func,
    /**
     * If `true`, the popover is visible.
     */
    open: PropTypes.bool.isRequired,
    /**
     * Properties applied to the [`Paper`](/api/paper/) element.
     */
    PaperProps: PropTypes.object,
    /**
     * @ignore
     */
    role: PropTypes.string,
    /**
     * This is the point on the popover which
     * will attach to the anchor's origin.
     *
     * Options:
     * vertical: [top, center, bottom, x(px)];
     * horizontal: [left, center, right, x(px)].
     */
    transformOrigin: PropTypes.shape({
      horizontal: PropTypes.oneOfType([
        PropTypes.number,
        PropTypes.oneOf(['left', 'center', 'right']),
      ]).isRequired,
      vertical: PropTypes.oneOfType([PropTypes.number, PropTypes.oneOf(['top', 'center', 'bottom'])])
        .isRequired,
    }),
    /**
     * The component used for the transition.
     */
    TransitionComponent: componentPropType,
    /**
     * Set to 'auto' to automatically calculate transition time based on height.
     */
    transitionDuration: PropTypes.oneOfType([
      PropTypes.number,
      PropTypes.shape({ enter: PropTypes.number, exit: PropTypes.number }),
      PropTypes.oneOf(['auto']),
    ]),
    /**
     * Properties applied to the `Transition` element.
     */
    TransitionProps: PropTypes.object,
  };
  
  Popover.defaultProps = {
    anchorReference: 'anchorEl',
    anchorOrigin: {
      vertical: 'top',
      horizontal: 'left',
    },
    elevation: 8,
    marginThreshold: 16,
    transformOrigin: {
      vertical: 'top',
      horizontal: 'left',
    },
    TransitionComponent: Grow,
    transitionDuration: 'auto',
  };
  
  export default withStyles(styles, { name: 'MuiPopover' })(Popover);
  