import Promise from "promise-polyfill";
import {ModuleStoriesOptionsObj, ResponseModuleStory} from "@/Module/gobi-module.types";
import {StoryOptions} from "@/Story/story.types";

export function forEach<T>(list:ArrayLike<T>, callback:(listItem?:T, index?:number, list?:ArrayLike<T>) => void) {
  const max = list.length;
  for (let i = 0; i < max; i++) {
    callback(list[i], i, list);
  }
}

export function addPrefixToClassName(list:ArrayLike<HTMLElement>, prefix:string) {
  const max = list.length;
  let elem:HTMLElement;
  for (let i = 0; i < max; i++) {
    elem = list[i];
    elem.className = prefix + elem.className;
  }
}

export function getModule(moduleId:string):Promise<Array<ResponseModuleStory>> {
  return new Promise(function (resolve, reject) {
    const xhr = new XMLHttpRequest();
    const url = 'https://live.gobiapp.com/projector/player/storyModules/' + moduleId;
    xhr.open('GET', url, true);
    xhr.send();
    xhr.onload = function () {
      if (this.status < 400) {
        resolve(JSON.parse(this.responseText));
      } else {
        reject(Error('Module didn\'t load successfully; error code:' + xhr.statusText));
      }
    };
    xhr.onerror = function () {
      reject(Error('There was a network error.'));
    };
  })
}

export function mergeStoriesOptions(responseStories:StoryOptions[],
    comingStories?:ModuleStoriesOptionsObj):StoryOptions[] {
  if (comingStories) {
    const mergedOptions: StoryOptions[] = [];
    for (const key in responseStories) {
      const responseStory = responseStories[key];
      const comingOptions = comingStories[key];
      mergedOptions.push(comingOptions ?
          Object.assign(responseStory, comingOptions) :
          responseStory);
    }
    return mergedOptions;
  }
  else {
    return responseStories;
  }
}

export function decorateResponseStories(responseStories:ResponseModuleStory[]):Array<StoryOptions> {
  return responseStories.map((responseStory): StoryOptions => {
    return {
      title: responseStory.title,
      avatarSrc: responseStory.thumbnail,
      description: responseStory.description,
      id: responseStory.story_id
    };
  })
}

export function addListener(object:Window | Document | HTMLElement,
                            eventName:string,
                            listener: (event?:any) => void):() => void {
  const callback = (event: Event) => listener(event);
  object.addEventListener(eventName, callback);
  return () => object.removeEventListener(eventName, callback);
}

export function returnHighestZIndex() {
  const elems = document.body.querySelectorAll('*');
  let maxZIndex = 1;
  let currentZIndex = 0;
  for (let i = elems.length; i--;) {
    currentZIndex = Number(window.getComputedStyle(elems[i]).zIndex);
    if (maxZIndex < currentZIndex) {
      maxZIndex = currentZIndex;
    }
  }
  return maxZIndex;
}

export const scrollDisabler = {
  scrollTop: 0,
  bodyOverflow: '' as string | null,
  htmlOverflow: '' as string | null,
  disable: function() {
    this.isIOS ? this.IOSDisable() : this.classicDisable();
  },
  enable: function() {
    this.isIOS ? this.IOSEnable() : this.classicEnable();
  },
  classicDisable: function() {
    this.bodyOverflow = document.body.style.overflow;
    this.htmlOverflow = document.documentElement.style.overflow;
    document.documentElement.style.overflow = 'hidden';
    document.body.style.overflow = 'hidden';
  },
  classicEnable: function() {
    document.documentElement.style.overflow = this.htmlOverflow;
    document.body.style.overflow = this.bodyOverflow;
  },
  IOSEnable: function() {
    document.documentElement.classList.remove('disabled-scroll');
    document.body.classList.remove('disabled-scroll');
    window.scrollTo(0, this.scrollTop);
  },
  IOSDisable: function() {
    this.scrollTop = window.pageYOffset;
    document.documentElement.classList.add('disabled-scroll');
    document.body.classList.add('disabled-scroll');
  },
  isIOS: /iPad|iPhone|iPod/.test(navigator.userAgent),
};

export function fetchAvatarSrc(storyId:string):Promise<string> {
    return new Promise(function (resolve, reject) {
        const xhr = new XMLHttpRequest();
        const url = 'https://live.gobiapp.com/projector/player/stories/' + storyId;
        xhr.open('GET', url, true);
        xhr.send();
        xhr.onload = function () {
          if (this.status < 400) {
            const response:any = JSON.parse(this.responseText);
            const src:string = response && response.videos && response.videos[0] && response.videos[0].poster;
            resolve(src)
          } else {
            reject(Error('Error loading avatar for story ' + storyId + ' -- ' + xhr.statusText));
          }
        }
        xhr.onerror = () => { reject(Error('Error xhr-ing avatar for storyId ' + storyId)) }
    })
};