'use strict';

var index = require('../../utils/es/index.js');

/**
 * Scale the image so the given width and height keeping the aspect ratio. Some parts of the image may be clipped.
 * @param {number} w the width to resize the image to
 * @param {number} h the height to resize the image to
 * @param {number} alignBits (optional) A bitmask for horizontal and vertical alignment
 * @param {string} mode (optional) a scaling method (e.g. Jimp.RESIZE_BEZIER)
 * @param {function(Error, Jimp)} cb (optional) a callback for when complete
 * @returns {Jimp} this for chaining of methods
 */
var cover = (() => ({
  cover(w, h, alignBits, mode, cb) {
    if (typeof w !== "number" || typeof h !== "number") {
      return index.throwError.call(this, "w and h must be numbers", cb);
    }
    if (alignBits && typeof alignBits === "function" && typeof cb === "undefined") {
      cb = alignBits;
      alignBits = null;
      mode = null;
    } else if (typeof mode === "function" && typeof cb === "undefined") {
      cb = mode;
      mode = null;
    }
    alignBits = alignBits || this.constructor.HORIZONTAL_ALIGN_CENTER | this.constructor.VERTICAL_ALIGN_MIDDLE;
    const hbits = alignBits & (1 << 3) - 1;
    const vbits = alignBits >> 3;

    // check if more flags than one is in the bit sets
    if (!(hbits !== 0 && !(hbits & hbits - 1) || vbits !== 0 && !(vbits & vbits - 1))) return index.throwError.call(this, "only use one flag per alignment direction", cb);
    const alignH = hbits >> 1; // 0, 1, 2
    const alignV = vbits >> 1; // 0, 1, 2

    const f = w / h > this.bitmap.width / this.bitmap.height ? w / this.bitmap.width : h / this.bitmap.height;
    this.scale(f, mode);
    this.crop((this.bitmap.width - w) / 2 * alignH, (this.bitmap.height - h) / 2 * alignV, w, h);
    if (index.isNodePattern(cb)) {
      cb.call(this, null, this);
    }
    return this;
  }
}));

module.exports = cover;
