/**
 * @license
 * Copyright Paperbits. All Rights Reserved.
 *
 * Use of this source code is governed by a Commercial license that can be found in the LICENSE file and at https://paperbits.io/license/commercial.
 */

/**
 * Compares two specificity vectors, returning the winning one.
 *
 * @param {Array} vector a
 * @param {Array} vector b
 * @return {Array}
 * @api public
 */
function compareSpecificity(a, b) {
    let i;

    for (i = 0; i < 4; i++) {
        if (a[i] === b[i]) {
            continue;
        }
        if (a[i] > b[i]) {
            return a;
        }
        return b;
    }

    return b;
}

/**
 * CSS property constructor.
 *
 * @param {String} property
 * @param {String} value
 * @param {Selector} selector the property originates from
 */
export function cssProperty(prop, value, selector) {
    let o = {};

    /**
     * Compares with another Property based on Selector#specificity.
     */
    const compare = (property) => {
        const a = selector.specificity();
        const b = property.selector.specificity();
        const winner = compareSpecificity(a, b);

        if (winner === a && a !== b) {
            return o;
        }
        return property;
    };

    o = {
        prop: prop,
        value: value,
        selector: selector,
        compare: compare
    };

    return o;
}