/**
 * 处理逻辑与helper.wxs内image方法严格一致
 * 保证wx.previewImage时链接于wxs生成的链接相同
 */
let regExpWidth = RegExp('{width}', 'g');
let regExpHeight = RegExp('{height}', 'g');
let regExpMode = RegExp('{mode}', 'g');
let regExpQg = RegExp('/q/d+', 'g');
let regExpQ = RegExp('/q/d+');
let regExpQuality = RegExp('/quality/d+');
let regExpQualityg = RegExp('/quality/d+', 'g');
let regExpImageView = RegExp('imageView');
let regExpImageMogr = RegExp('imageMogr');

let defaultQuality = 75;

function image(imgUrl, w, h, mode, q) {
  let urls,
    query,
    url;

  let params = {
    w: w,
    h: h,
    mode: mode || 2,
    q: q || defaultQuality
  };

  if (imgUrl && (typeof imgUrl === 'string')) {
    urls = imgUrl.split('?');
    query = urls[1] || '';
    url = urls[0];

    if (url.indexOf('http:') === 0) {
      url = url.replace('http:', 'https:');
    }

    if (!query || query === 'imageslim') {
      url += params.q === defaultQuality ? '?imageslim' : '?imageView2/0/interlace/1/q/' + params.q;
      imgUrl = url;
    } else {
      imgUrl = imgUrl.replace(regExpWidth, params.w)
        .replace(regExpHeight, params.h)
        .replace(regExpMode, (params.mode));

      if (regExpImageView.test(query)) { // imageView2 || imageView
        if (!regExpQ.test(query)) {
          imgUrl += '/q/' + params.q;
        } else {
          imgUrl = imgUrl.replace(regExpQg, '/q/' + params.q);
        }
      } else if (regExpImageMogr.test(query)) {
        if (!regExpQuality.test(query)) {
          imgUrl += '/quality/' + params.q;
        } else {
          imgUrl = imgUrl.replace(regExpQualityg, '/quality/' + params.q);
        }
      }
    }
    return imgUrl;
  } else {
    return '';
  }
}

module.exports = {
  image: image
};