/**
 * The MIT License (MIT)
 *
 * Copyright (c) 2015 Jordan Thomas
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

"use strict";


/**
 * Returns the similarity of the given strings.
 *
 * @param a {string} a string
 * @param b {string} a string
 * @param caseSensitive {boolean} whether the calculation should be case-sensitive
 * @returns {number} the similarity of the given strings
 */
export const jaroWinkler = function (a, b, caseSensitive = true) {
    // Convert to lowercase if not case-sensitive
    if (!caseSensitive) {
        a = a.toLowerCase();
        b = b.toLowerCase();
    }

    if (a.length === 0 || b.length === 0) return 0;
    if (a === b) return 1;


    // Calculate difference
    const range = Math.floor(Math.max(a.length, b.length) / 2) - 1;
    const aMatches = [];
    const bMatches = [];
    let low;
    let high;
    let m = 0;

    // Find matches
    for (let i = 0; i < a.length; i++) {
        low = (i >= range) ? i - range : 0;
        high = (i + range <= b.length) ? (i + range) : (b.length - 1);

        for (let j = low; j <= high; j++) {
            if (aMatches[i] !== true && bMatches[j] !== true && a[i] === b[j]) {
                aMatches[i] = true;
                bMatches[j] = true;
                m++;
                break;
            }
        }
    }

    // Short-circuit if not matches found
    if (m === 0) return 0;

    // Count transpositions
    let k = 0;
    let numTrans = 0;

    for (let i = 0; i < a.length; i++) {
        if (aMatches[i] === true) {
            let j;
            for (j = k; j < b.length; j++) {
                if (bMatches[j] === true) {
                    k = j + 1;
                    break;
                }
            }

            if (a[i] !== b[j]) numTrans++;
        }
    }

    let weight = (m / a.length + m / b.length + (m - numTrans / 2) / m) / 3;
    let l = 0;
    const p = 0.1;

    if (weight > 0.7) {
        while (a[l] === b[l] && l < 4)
            l++;

        weight += l * p * (1 - weight);
    }

    return weight;
};