import {
  isObject,
  getObjectName,
  getType,
  getValuePreview,
  getPreview,
  cssClass,
  createElement
} from './helpers';

import './style.less';

const DATE_STRING_REGEX = /(^\d{1,4}[\.|\\/|-]\d{1,2}[\.|\\/|-]\d{1,4})(\s*(?:0?[1-9]:[0-5]|1(?=[012])\d:[0-5])\d\s*[ap]m)?$/;
const PARTIAL_DATE_REGEX = /\d{2}:\d{2}:\d{2} GMT-\d{4}/;
const JSON_DATE_REGEX = /\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}.\d{3}Z/;

// When toggleing, don't animated removal or addition of more than a few items
const MAX_ANIMATED_TOGGLE_ITEMS = 10;

const requestAnimationFrame = window.requestAnimationFrame || function(cb: ()=>void) { cb(); return 0; };

export interface JSONFormatterConfiguration {
  hoverPreviewEnabled?: boolean;
  hoverPreviewArrayCount?: number;
  hoverPreviewFieldCount?: number;
  animateOpen?: boolean;
  animateClose?: boolean;
  theme?: string;
};

const _defaultConfig: JSONFormatterConfiguration = {
  hoverPreviewEnabled: false,
  hoverPreviewArrayCount: 100,
  hoverPreviewFieldCount: 5,
  animateOpen: true,
  animateClose: true,
  theme: null
};


/**
 * @class JSONFormatter
 *
 * JSONFormatter allows you to render JSON objects in HTML with a
 * **collapsible** navigation.
*/
export default class JSONFormatter {

  // Hold the open state after the toggler is used
  private _isOpen : boolean = null;

  // A reference to the element that we render to
  private element: Element;

  /**
   * @param {object} json The JSON object you want to render. It has to be an
   * object or array. Do NOT pass raw JSON string.
   *
   * @param {number} [open=1] his number indicates up to how many levels the
   * rendered tree should expand. Set it to `0` to make the whole tree collapsed
   * or set it to `Infinity` to expand the tree deeply
   *
   * @param {object} [config=defaultConfig] -
   *  defaultConfig = {
   *   hoverPreviewEnabled: false,
   *   hoverPreviewArrayCount: 100,
   *   hoverPreviewFieldCount: 5
   * }
   *
   * Available configurations:
   *  #####Hover Preview
   * * `hoverPreviewEnabled`:  enable preview on hover
   * * `hoverPreviewArrayCount`: number of array items to show in preview Any
   *    array larger than this number will be shown as `Array[XXX]` where `XXX`
   *    is length of the array.
   * * `hoverPreviewFieldCount`: number of object properties to show for object
   *   preview. Any object with more properties that thin number will be
   *   truncated.
   *
   * @param {string} [key=undefined] The key that this object in it's parent
   * context
  */
  constructor(public json: any, private open = 1, private config: JSONFormatterConfiguration = _defaultConfig, private key?: string) {

    // Setting default values for config object
    if (this.config.hoverPreviewEnabled === undefined) {
      this.config.hoverPreviewEnabled = _defaultConfig.hoverPreviewEnabled;
    }
    if (this.config.hoverPreviewArrayCount === undefined) {
      this.config.hoverPreviewArrayCount = _defaultConfig.hoverPreviewArrayCount;
    }
    if (this.config.hoverPreviewFieldCount === undefined) {
      this.config.hoverPreviewFieldCount = _defaultConfig.hoverPreviewFieldCount;
    }
  }

  /*
   * is formatter open?
  */
  private get isOpen(): boolean {
    if (this._isOpen !== null) {
      return this._isOpen
    } else {
      return this.open > 0;
    }
  }

  /*
   * set open state (from toggler)
  */
  private set isOpen(value: boolean) {
    this._isOpen = value;
  }

  /*
   * is this a date string?
  */
  private get isDate(): boolean {
    return (this.type === 'string') &&
      (DATE_STRING_REGEX.test(this.json) ||
      JSON_DATE_REGEX.test(this.json) ||
      PARTIAL_DATE_REGEX.test(this.json));
  }

  /*
   * is this a URL string?
  */
  private get isUrl(): boolean {
    return this.type === 'string' && (this.json.indexOf('http') === 0);
  }

  /*
   * is this an array?
  */
  private get isArray(): boolean {
    return Array.isArray(this.json);
  }

  /*
   * is this an object?
   * Note: In this context arrays are object as well
  */
  private get isObject(): boolean {
    return isObject(this.json);
  }

  /*
   * is this an empty object with no properties?
  */
  private get isEmptyObject(): boolean {
    return !this.keys.length && !this.isArray;
  }

  /*
   * is this an empty object or array?
  */
  private get isEmpty(): boolean {
    return this.isEmptyObject || (this.keys && !this.keys.length && this.isArray);
  }

  /*
   * did we recieve a key argument?
   * This means that the formatter was called as a sub formatter of a parent formatter
  */
  private get hasKey(): boolean {
    return typeof this.key !== 'undefined';
  }

  /*
   * if this is an object, get constructor function name
  */
  private get constructorName(): string {
    return getObjectName(this.json);
  }

  /*
   * get type of this value
   * Possible values: all JavaScript primitive types plus "array" and "null"
  */
  private get type(): string {
    return getType(this.json);
  }

  /*
   * get object keys
   * If there is an empty key we pad it wit quotes to make it visible
  */
  private get keys(): string[] {
    if (this.isObject) {
      return Object.keys(this.json).map((key)=> key ? key : '""');
    } else {
      return [];
    }
  }

  /**
   * Toggles `isOpen` state
   *
  */
  toggleOpen() {
    this.isOpen = !this.isOpen;

    if (this.element) {
      if (this.isOpen) {
        this.appendChildren(this.config.animateOpen);
      } else{
        this.removeChildren(this.config.animateClose);
      }
      this.element.classList.toggle(cssClass('open'));
    }
  }

  /**
  * Open all children up to a certain depth.
  * Allows actions such as expand all/collapse all
  *
  */
  openAtDepth(depth = 1) {
    if (depth < 0) {
      return;
    }

    this.open = depth;
    this.isOpen = (depth !== 0);

    if (this.element) {
      this.removeChildren(false);

      if (depth === 0) {
        this.element.classList.remove(cssClass('open'));
      } else {
        this.appendChildren(this.config.animateOpen);
        this.element.classList.add(cssClass('open'));
      }
    }
  }

  /**
   * Generates inline preview
   *
   * @returns {string}
  */
  getInlinepreview() {
    if (this.isArray) {

      // if array length is greater then 100 it shows "Array[101]"
      if (this.json.length > this.config.hoverPreviewArrayCount) {
        return `Array[${this.json.length}]`;
      } else {
        return `[${this.json.map(getPreview).join(', ')}]`;
      }
    } else {

      const keys = this.keys;

      // the first five keys (like Chrome Developer Tool)
      const narrowKeys = keys.slice(0, this.config.hoverPreviewFieldCount);

      // json value schematic information
      const kvs = narrowKeys.map(key => `${key}:${getPreview(this.json[key])}`);

      // if keys count greater then 5 then show ellipsis
      const ellipsis = keys.length >= this.config.hoverPreviewFieldCount ? '…' : '';

      return `{${kvs.join(', ')}${ellipsis}}`;
    }
  }


  /**
   * Renders an HTML element and installs event listeners
   *
   * @returns {HTMLDivElement}
  */
  render(): HTMLDivElement {

    // construct the root element and assign it to this.element
    this.element = createElement('div', 'row');

    // construct the toggler link
    const togglerLink = createElement('a', 'toggler-link');

    // if this is an object we need a wrapper span (toggler)
    if (this.isObject) {
      togglerLink.appendChild(createElement('span', 'toggler'));
    }

    // if this is child of a parent formatter we need to append the key
    if (this.hasKey) {
      togglerLink.appendChild(createElement('span', 'key', `${this.key}:`));
    }

    // Value for objects and arrays
    if (this.isObject) {

      // construct the value holder element
      const value = createElement('span', 'value');

      // we need a wrapper span for objects
      const objectWrapperSpan = createElement('span');

      // get constructor name and append it to wrapper span
      var constructorName = createElement('span', 'constructor-name', this.constructorName);
      objectWrapperSpan.appendChild(constructorName);

      // if it's an array append the array specific elements like brackets and length
      if (this.isArray) {
        const arrayWrapperSpan = createElement('span');
        arrayWrapperSpan.appendChild(createElement('span', 'bracket', '['));
        arrayWrapperSpan.appendChild(createElement('span', 'number', (this.json.length)));
        arrayWrapperSpan.appendChild(createElement('span', 'bracket', ']'));
        objectWrapperSpan.appendChild(arrayWrapperSpan);
      }

      // append object wrapper span to toggler link
      value.appendChild(objectWrapperSpan);
      togglerLink.appendChild(value);

    // Primitive values
    } else {

      // make a value holder element
      const value = this.isUrl ? createElement('a') : createElement('span');

      // add type and other type related CSS classes
      value.classList.add(cssClass(this.type));
      if (this.isDate) {
        value.classList.add(cssClass('date'));
      }
      if (this.isUrl) {
        value.classList.add(cssClass('url'));
        value.setAttribute('href', this.json);
      }

      // Append value content to value element
      const valuePreview = getValuePreview(this.json, this.json);
      value.appendChild(document.createTextNode(valuePreview));

      // append the value element to toggler link
      togglerLink.appendChild(value);
    }

    // if hover preview is enabled, append the inline preview element
    if (this.isObject && this.config.hoverPreviewEnabled) {
      const preview = createElement('span', 'preview-text');
      preview.appendChild(document.createTextNode(this.getInlinepreview()));
      togglerLink.appendChild(preview);
    }

    // construct a children element
    const children = createElement('div', 'children');

    // set CSS classes for children
    if (this.isObject) {
      children.classList.add(cssClass('object'));
    }
    if (this.isArray) {
      children.classList.add(cssClass('array'));
    }
    if (this.isEmpty) {
      children.classList.add(cssClass('empty'));
    }

    // set CSS classes for root element
    if (this.config && this.config.theme) {
      this.element.classList.add(cssClass(this.config.theme));
    }
    if (this.isOpen) {
      this.element.classList.add(cssClass('open'));
    }

    // append toggler and children elements to root element
    this.element.appendChild(togglerLink);
    this.element.appendChild(children);

    // if formatter is set to be open call appendChildren
    if (this.isObject && this.isOpen) {
      this.appendChildren();
    }

    // add event listener for toggling
    if (this.isObject) {
      togglerLink.addEventListener('click', this.toggleOpen.bind(this));
    }

    return this.element as HTMLDivElement;
  }

  /**
   * Appends all the children to children element
   * Animated option is used when user triggers this via a click
  */
  appendChildren(animated: boolean = false) {
    const children = this.element.querySelector(`div.${cssClass('children')}`);

    if (!children || this.isEmpty) { return; }

    if (animated) {
      let index = 0;
      const addAChild = ()=> {
        const key = this.keys[index];
        const formatter = new JSONFormatter(this.json[key], this.open - 1, this.config, key);
        children.appendChild(formatter.render());

        index += 1;

        if (index < this.keys.length) {
          if (index > MAX_ANIMATED_TOGGLE_ITEMS) {
            addAChild();
          } else {
            requestAnimationFrame(addAChild);
          }
        }
      };

      requestAnimationFrame(addAChild);

    } else {
      this.keys.forEach(key => {
        const formatter = new JSONFormatter(this.json[key], this.open - 1, this.config, key);
        children.appendChild(formatter.render());
      });
    }
  }

  /**
   * Removes all the children from children element
   * Animated option is used when user triggers this via a click
  */
  removeChildren(animated: boolean = false) {
    const childrenElement = this.element.querySelector(`div.${cssClass('children')}`) as HTMLDivElement;

    if (animated) {
      let childrenRemoved = 0;
      const removeAChild = ()=> {
        if (childrenElement && childrenElement.children.length) {
          childrenElement.removeChild(childrenElement.children[0]);
          childrenRemoved += 1;
          if (childrenRemoved > MAX_ANIMATED_TOGGLE_ITEMS) {
            removeAChild();
          } else {
            requestAnimationFrame(removeAChild);
          }
        }
      };
      requestAnimationFrame(removeAChild);
    } else {
      if (childrenElement) {
        childrenElement.innerHTML = '';
      }
    }
  }
}