import React, { Component, PropTypes } from 'react';
import ReactDOM from 'react-dom';

class Portal extends Component {
  static propTypes = {
    children: PropTypes.node,
    className: PropTypes.string,
    container: PropTypes.node,
  }

  static defaultProps = {
    className: '',
  }

  componentDidMount() {
    this._renderOverlay();
  }

  componentWillReceiveProps(nextProps) {
    if (this._overlayTarget && nextProps.container !== this.props.container) {
      this._portalContainerNode.removeChild(this._overlayTarget);
      this._portalContainerNode = getContainer(nextProps.container);
      this._portalContainerNode.appendChild(this._overlayTarget);
    }
  }

  componentDidUpdate() {
    this._renderOverlay();
  }

  componentWillUnmount() {
    this._unrenderOverlay();
    this._unmountOverlayTarget();
  }

  getMountNode() {
    return this._overlayTarget;
  }

  getOverlayDOMNode() {
    if (!this.isMounted()) { // eslint-disable-line
      throw new Error('getOverlayDOMNode(): A component must be mounted to have a DOM node.');
    }

    if (this._overlayInstance) {
      if (this._overlayInstance.getWrappedDOMNode) {
        return this._overlayInstance.getWrappedDOMNode();
      }
      return ReactDOM.findDOMNode(this._overlayInstance);
    }

    return null;
  }

  _getOverlay() {
    if (!this.props.children) return null;
    return <div className={this.props.className}>{this.props.children}</div>;
  }

  _renderOverlay() {
    const overlay = this._getOverlay();
    if (overlay !== null) {
      this._mountOverlayTarget();
      this._overlayInstance = ReactDOM.unstable_renderSubtreeIntoContainer(
        this, overlay, this._overlayTarget,
      );
    } else {
      this._unrenderOverlay();
      this._unmountOverlayTarget();
    }
  }

  _unrenderOverlay() {
    if (this._overlayTarget) {
      ReactDOM.unmountComponentAtNode(this._overlayTarget);
      this._overlayInstance = null;
    }
  }

  _mountOverlayTarget() {
    if (!this._overlayTarget) {
      this._overlayTarget = document.createElement('div');
      this._portalContainerNode = getContainer(this.props.container);
      this._portalContainerNode.appendChild(this._overlayTarget);
    }
  }

  _unmountOverlayTarget() {
    if (this._overlayTarget) {
      this._portalContainerNode.removeChild(this._overlayTarget);
      this._overlayTarget = null;
    }
    this._portalContainerNode = null;
  }

  render() {
    return null;
  }

}

function getContainer(container) {
  const _container = typeof container === 'function' ? container() : container;
  return ReactDOM.findDOMNode(_container) || document.body;
}

export default Portal;