import cx from 'classnames';
import React, { Component, PropTypes } from 'react';
import styles from './Image.css';

class Image extends Component {

  static propTypes = {
    alt: PropTypes.string,
    src: PropTypes.string,

    /**
     * Ratio of the image height to width
     *
     * http://aspiringwebdev.com/stop-your-web-pages-from-jumping-around-while-images-load/
     *
     * The page jumps occur because the browser does not know the width and height of the images in advance.
     * On a responsive site, the image could be a different height and width depending on the screen size.
     * We may, however, know the ratio of the image’s height to its width. That will not change for a given image, no matter the screen size
     * It’s easy to find an images height to width ratio:
     * Image height / Image width * 100
     * For the images in our example, image height: 217 and width: 325 we found the ratio:
     * 217px / 325px * 100 = 66.769230769
     *
     * Caveats:
     *   To accomodate different aspect ratios, create multiple image containers and use them where appropriate.
     *   Use this technique only where the aspect ratio is certain; images that don’t fit the aspect ratio will look distorted.
     *   A common challenge in responsive design – not just with this technique – is maintaining the right image quality for each screen.
     *
     *   Check out the Smashing Magazine article below for ideas on this.
     *   Thanks to Smashing Magazine for this technique. Check out a case study of a news site that implemented it successfully, and a similar technique for embedded content.
     *   http://www.smashingmagazine.com/2013/09/16/responsive-images-performance-problem-case-study/
     *   http://www.smashingmagazine.com/2014/02/27/making-embedded-content-work-in-responsive-design/
     * @type {[type]}
     */
    imageRatio: PropTypes.number
  };

  static defaultProps = {
    alt: '',
    src: '../images/placeholder.png', //This asset needs to added as per UX
    imageRatio: 100
  }

  render() {
    const { src, alt } = this.props;

    // Wrap this css to stop the page jump around when images are loading
    const imageWrapperClass = cx({
      [styles['image-box-main']]: (this.props.imageRatio > 0)
    });

    //We have to add this styling to div once we figure out the imageRatio issue fix.
    const imageStyle = {
    };

    if (this.props.imageRatio > 0) {
      imageStyle.paddingBottom = `${this.props.imageRatio}%`;
    }

    return (
      <div className={imageWrapperClass}>
        <img src={src} alt={alt} />
      </div>
    );
  }
}

export default Image;