/*************************************************************
 *
 *  Copyright (c) 2017 The MathJax Consortium
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

/**
 * @fileoverview  Implements a bounding-box object and operations on it
 *
 * @author dpvc@mathjax.org (Davide Cervone)
 */

import {BIGDIMEN, length2em} from '../../util/lengths.js';

/**
 *  CSS styles that affect BBoxes
 */
export const BBoxStyleAdjust = [
    ['borderTopWidth', 'h'],
    ['borderRightWidth', 'w'],
    ['borderBottomWidth', 'd'],
    ['borderLeftWidth', 'w', 0],
    ['paddingTop', 'h'],
    ['paddingRight', 'w'],
    ['paddingBottom', 'd'],
    ['paddingLeft', 'w', 0]
];

/**
 *  The data used to initialize a BBox
 */
export type BBoxData = {
    w?: number,
    h?: number,
    d?: number
};

/*****************************************************************/
/**
 *  The BBox class
 */

export class BBox {
    /**
     * Constant for pwidth of full width box
     */
    public static fullWidth = '100%';

    /**
     *  These are the data stored for a bounding box
     */
    public w: number;
    public h: number;
    public d: number;
    public scale: number;
    public rscale: number; // scale relative to the parent's scale
    public L: number;      // extra space on the left
    public R: number;      // extra space on the right
    public pwidth: string; // percentage width (for tables)
    public ic: number;     // italic correction
    public sk: number;     // skew

    /**
     * @return {BBox}  A BBox initialized to zeros
     */
    public static zero() {
        return new BBox({h: 0, d: 0, w: 0});
    }

    /**
     * @return {BBox}  A BBox with height and depth not set
     */
    public static empty() {
        return new BBox();
    }

    /**
     * @param {BBoxData} def  The data with which to initialize the BBox
     *
     * @return {BBox}  The newly created BBox
     *
     * @constructor
     */
    constructor(def: BBoxData = {w: 0, h: -BIGDIMEN, d: -BIGDIMEN}) {
        this.w = def.w || 0;
        this.h = ('h' in def ? def.h : -BIGDIMEN);
        this.d = ('d' in def ? def.d : -BIGDIMEN);
        this.L = this.R = this.ic = this.sk = 0;
        this.scale = this.rscale = 1;
        this.pwidth = '';
    }

    /**
     * Set up a bbox for append() and combine() operations
     * @return {BBOX}  the boox itself (for chaining calls)
     */
    public empty() {
        this.w = 0;
        this.h = this.d = -BIGDIMEN;
        return this;
    }

    /**
     * Convert any unspecified values into zeros
     */
    public clean () {
        if (this.w === -BIGDIMEN) this.w = 0;
        if (this.h === -BIGDIMEN) this.h = 0;
        if (this.d === -BIGDIMEN) this.d = 0;
    }

    /**
     * @param {number} scale  The scale to use to modify the bounding box size
     */
    public rescale(scale: number) {
        this.w *= scale;
        this.h *= scale;
        this.d *= scale;
    }

    /**
     * @param {BBox} cbox  A bounding to combine with this one
     * @param {number} x   An x-offest for the child bounding box
     * @param {number} y   A y-offset for the child bounding box
     */
    public combine(cbox: BBox, x: number = 0, y: number = 0) {
        let rscale = cbox.rscale;
        let w = x + rscale * (cbox.w + cbox.L + cbox.R);
        let h = y + rscale * cbox.h;
        let d = rscale * cbox.d - y;
        if (w > this.w) this.w = w;
        if (h > this.h) this.h = h;
        if (d > this.d) this.d = d;
    }

    /**
     * @param {BBox} cbox  A bounding box to be added to the right of this one
     */
    public append(cbox: BBox) {
        let scale = cbox.rscale;
        this.w += scale * (cbox.w + cbox.L + cbox.R);
        if (scale * cbox.h > this.h) {
            this.h = scale * cbox.h;
        }
        if (scale * cbox.d > this.d) {
            this.d = scale * cbox.d;
        }
    }

    /**
     * @param {BBox} cbox  The bounding box to use to overwrite this one
     */
    public updateFrom(cbox: BBox) {
        this.h = cbox.h;
        this.d = cbox.d;
        this.w = cbox.w;
        if (cbox.pwidth) {
            this.pwidth = cbox.pwidth;
        }
    }

}