/**
 * Partial polyfill of `SVGTransformList`
 * @module SVGTransformList
 *
 * @license MIT
 *
 * @copyright 2010 Alexis Deveria, 2010 Jeff Schiller
 */

import {NS} from './namespaces.js';
import {supportsNativeTransformLists} from './browser.js';

const svgroot = document.createElementNS(NS.SVG, 'svg');

/**
 * Helper function to convert `SVGTransform` to a string.
 * @param {SVGTransform} xform
 * @returns {string}
 */
function transformToString (xform) {
  const m = xform.matrix;
  let text = '';
  switch (xform.type) {
  case 1: // MATRIX
    text = 'matrix(' + [m.a, m.b, m.c, m.d, m.e, m.f].join(',') + ')';
    break;
  case 2: // TRANSLATE
    text = 'translate(' + m.e + ',' + m.f + ')';
    break;
  case 3: // SCALE
    if (m.a === m.d) {
      text = 'scale(' + m.a + ')';
    } else {
      text = 'scale(' + m.a + ',' + m.d + ')';
    }
    break;
  case 4: { // ROTATE
    let cx = 0;
    let cy = 0;
    // this prevents divide by zero
    if (xform.angle !== 0) {
      const K = 1 - m.a;
      cy = (K * m.f + m.b * m.e) / (K * K + m.b * m.b);
      cx = (m.e - m.b * cy) / K;
    }
    text = 'rotate(' + xform.angle + ' ' + cx + ',' + cy + ')';
    break;
  }
  }
  return text;
}

/**
 * Map of SVGTransformList objects.
 */
let listMap_ = {};

/**
* @interface module:SVGTransformList.SVGEditTransformList
* @property {Integer} numberOfItems unsigned long
*/
/**
* @function module:SVGTransformList.SVGEditTransformList#clear
* @returns {undefined}
*/
/**
* @function module:SVGTransformList.SVGEditTransformList#initialize
* @param {SVGTransform} newItem
* @returns {SVGTransform}
*/
/**
* (DOES NOT THROW DOMException, INDEX_SIZE_ERR)
* @function module:SVGTransformList.SVGEditTransformList#getItem
* @param {Integer} index unsigned long
* @returns {SVGTransform}
*/
/**
* (DOES NOT THROW DOMException, INDEX_SIZE_ERR)
* @function module:SVGTransformList.SVGEditTransformList#insertItemBefore
* @param {SVGTransform} newItem
* @param {Integer} index unsigned long
* @returns {SVGTransform}
*/
/**
* (DOES NOT THROW DOMException, INDEX_SIZE_ERR)
* @function module:SVGTransformList.SVGEditTransformList#replaceItem
* @param {SVGTransform} newItem
* @param {Integer} index unsigned long
* @returns {SVGTransform}
*/
/**
* (DOES NOT THROW DOMException, INDEX_SIZE_ERR)
* @function module:SVGTransformList.SVGEditTransformList#removeItem
* @param {Integer} index unsigned long
* @returns {SVGTransform}
*/
/**
* @function module:SVGTransformList.SVGEditTransformList#appendItem
* @param {SVGTransform} newItem
* @returns {SVGTransform}
*/
/**
* NOT IMPLEMENTED
* @ignore
* @function module:SVGTransformList.SVGEditTransformList#createSVGTransformFromMatrix
* @param {SVGMatrix} matrix
* @returns {SVGTransform}
*/
/**
* NOT IMPLEMENTED
* @ignore
* @function module:SVGTransformList.SVGEditTransformList#consolidate
* @returns {SVGTransform}
*/

/**
* SVGTransformList implementation for Webkit.
* These methods do not currently raise any exceptions.
* These methods also do not check that transforms are being inserted.  This is basically
* implementing as much of SVGTransformList that we need to get the job done.
* @implements {module:SVGTransformList.SVGEditTransformList}
*/
export class SVGTransformList {// eslint-disable-line no-shadow
  /**
  * @param {Element} elem
  */
  constructor (elem) {
    this._elem = elem || null;
    this._xforms = [];
    // TODO: how do we capture the undo-ability in the changed transform list?
    this._update = function () {
      let tstr = '';
      // /* const concatMatrix = */ svgroot.createSVGMatrix();
      for (let i = 0; i < this.numberOfItems; ++i) {
        const xform = this._list.getItem(i);
        tstr += transformToString(xform) + ' ';
      }
      this._elem.setAttribute('transform', tstr);
    };
    this._list = this;
    this._init = function () {
      // Transform attribute parser
      let str = this._elem.getAttribute('transform');
      if (!str) { return; }

      // TODO: Add skew support in future
      const re = /\s*((scale|matrix|rotate|translate)\s*\(.*?\))\s*,?\s*/;
      let m = true;
      while (m) {
        m = str.match(re);
        str = str.replace(re, '');
        if (m && m[1]) {
          const x = m[1];
          const bits = x.split(/\s*\(/);
          const name = bits[0];
          const valBits = bits[1].match(/\s*(.*?)\s*\)/);
          valBits[1] = valBits[1].replace(/(\d)-/g, '$1 -');
          const valArr = valBits[1].split(/[, ]+/);
          const letters = 'abcdef'.split('');
          const mtx = svgroot.createSVGMatrix();
          Object.values(valArr).forEach(function (item, i) {
            valArr[i] = parseFloat(item);
            if (name === 'matrix') {
              mtx[letters[i]] = valArr[i];
            }
          });
          const xform = svgroot.createSVGTransform();
          const fname = 'set' + name.charAt(0).toUpperCase() + name.slice(1);
          const values = name === 'matrix' ? [mtx] : valArr;

          if (name === 'scale' && values.length === 1) {
            values.push(values[0]);
          } else if (name === 'translate' && values.length === 1) {
            values.push(0);
          } else if (name === 'rotate' && values.length === 1) {
            values.push(0, 0);
          }
          xform[fname](...values);
          this._list.appendItem(xform);
        }
      }
    };
    this._removeFromOtherLists = function (item) {
      if (item) {
        // Check if this transform is already in a transformlist, and
        // remove it if so.
        Object.values(listMap_).some((tl) => {
          for (let i = 0, len = tl._xforms.length; i < len; ++i) {
            if (tl._xforms[i] === item) {
              tl.removeItem(i);
              return true;
            }
          }
          return false;
        });
      }
    };

    this.numberOfItems = 0;
  }
  /**
  * @returns {undefined}
  */
  clear () {
    this.numberOfItems = 0;
    this._xforms = [];
  }

  /**
  * @param {SVGTransform} newItem
  * @returns {SVGTransform}
  */
  initialize (newItem) {
    this.numberOfItems = 1;
    this._removeFromOtherLists(newItem);
    this._xforms = [newItem];
  }

  /**
  * @param {Integer} index unsigned long
  * @throws {Error}
  * @returns {SVGTransform}
  */
  getItem (index) {
    if (index < this.numberOfItems && index >= 0) {
      return this._xforms[index];
    }
    const err = new Error('DOMException with code=INDEX_SIZE_ERR');
    err.code = 1;
    throw err;
  }

  /**
  * @param {SVGTransform} newItem
  * @param {Integer} index unsigned long
  * @returns {SVGTransform}
  */
  insertItemBefore (newItem, index) {
    let retValue = null;
    if (index >= 0) {
      if (index < this.numberOfItems) {
        this._removeFromOtherLists(newItem);
        const newxforms = new Array(this.numberOfItems + 1);
        // TODO: use array copying and slicing
        let i;
        for (i = 0; i < index; ++i) {
          newxforms[i] = this._xforms[i];
        }
        newxforms[i] = newItem;
        for (let j = i + 1; i < this.numberOfItems; ++j, ++i) {
          newxforms[j] = this._xforms[i];
        }
        this.numberOfItems++;
        this._xforms = newxforms;
        retValue = newItem;
        this._list._update();
      } else {
        retValue = this._list.appendItem(newItem);
      }
    }
    return retValue;
  }

  /**
  * @param {SVGTransform} newItem
  * @param {Integer} index unsigned long
  * @returns {SVGTransform}
  */
  replaceItem (newItem, index) {
    let retValue = null;
    if (index < this.numberOfItems && index >= 0) {
      this._removeFromOtherLists(newItem);
      this._xforms[index] = newItem;
      retValue = newItem;
      this._list._update();
    }
    return retValue;
  }

  /**
  * @param {Integer} index unsigned long
  * @throws {Error}
  * @returns {SVGTransform}
  */
  removeItem (index) {
    if (index < this.numberOfItems && index >= 0) {
      const retValue = this._xforms[index];
      const newxforms = new Array(this.numberOfItems - 1);
      let i;
      for (i = 0; i < index; ++i) {
        newxforms[i] = this._xforms[i];
      }
      for (let j = i; j < this.numberOfItems - 1; ++j, ++i) {
        newxforms[j] = this._xforms[i + 1];
      }
      this.numberOfItems--;
      this._xforms = newxforms;
      this._list._update();
      return retValue;
    }
    const err = new Error('DOMException with code=INDEX_SIZE_ERR');
    err.code = 1;
    throw err;
  }

  /**
  * @param {SVGTransform} newItem
  * @returns {SVGTransform}
  */
  appendItem (newItem) {
    this._removeFromOtherLists(newItem);
    this._xforms.push(newItem);
    this.numberOfItems++;
    this._list._update();
    return newItem;
  }
}

/**
* @function module:SVGTransformList.resetListMap
* @returns {undefined}
*/
export const resetListMap = function () {
  listMap_ = {};
};

/**
 * Removes transforms of the given element from the map.
 * @function module:SVGTransformList.removeElementFromListMap
 * @param {Element} elem - a DOM Element
 * @returns {undefined}
 */
export let removeElementFromListMap = function (elem) { // eslint-disable-line import/no-mutable-exports
  if (elem.id && listMap_[elem.id]) {
    delete listMap_[elem.id];
  }
};

/**
* Returns an object that behaves like a `SVGTransformList` for the given DOM element.
* @function module:SVGTransformList.getTransformList
* @param {Element} elem - DOM element to get a transformlist from
* @todo The polyfill should have `SVGAnimatedTransformList` and this should use it
* @returns {SVGAnimatedTransformList|SVGTransformList}
*/
export const getTransformList = function (elem) {
  if (!supportsNativeTransformLists()) {
    const id = elem.id || 'temp';
    let t = listMap_[id];
    if (!t || id === 'temp') {
      listMap_[id] = new SVGTransformList(elem);
      listMap_[id]._init();
      t = listMap_[id];
    }
    return t;
  }
  if (elem.transform) {
    return elem.transform.baseVal;
  }
  if (elem.gradientTransform) {
    return elem.gradientTransform.baseVal;
  }
  if (elem.patternTransform) {
    return elem.patternTransform.baseVal;
  }

  return null;
};

/**
* @callback module:SVGTransformList.removeElementFromListMap
* @param {Element} elem
*/
/**
* Replace `removeElementFromListMap` for unit-testing.
* @function module:SVGTransformList.changeRemoveElementFromListMap
* @param {module:SVGTransformList.removeElementFromListMap} cb Passed a single argument `elem`
* @returns {undefined}
*/

export const changeRemoveElementFromListMap = function (cb) { // eslint-disable-line promise/prefer-await-to-callbacks
  removeElementFromListMap = cb;
};