import * as d3Format from "d3-format";

/**
 * Creates a function which produces formatted versions of the provided numerical value.
 * @param specifier - d3 format specifier (https://github.com/d3/d3-format)
 */
export function createNumericalFormatter(specifier = ",.2s"){

    const formatter = d3Format.format(specifier);

    return (n) => {

        // todo: when upgrade to newest d3-format, delete the n==0 check, change the specifier to $,.2~s
        if (n === 0){
            return "0";
        }
        else if (Math.abs(n) < 1) {
            return n.toString();
        }
        else{
            const s = formatter(n);
            return s.replace("G", "B");
        }
    };
}

/**
 * Creates a function which produces currency formatted versions of the provided numerical value.
 * @param specifier - d3 format specifier (https://github.com/d3/d3-format)
 */
export function createCurrencyFormatter(specifier = "$,.2s"){

    const formatter = d3Format.format(specifier);

    return (n) => {

        // todo: when upgrade to newest d3-format, delete the n==0 check, change the specifier to $,.2~s
        if (n === 0){
            return "$0";
        }
        else if (Math.abs(n) < 1) {
            return `$${n}`;
        }
        else{
            const s = formatter(n);
            if (n < 0) {
                return '(' + s.replace("G", "B").replace("-", "") + ')';
            } else {
                return s.replace("G", "B");
            }
        }

    };
}

/**
 * Produces currency formatted versions of the provided numerical value.
 * @param value - numerical value to format
 * @param config - toLocaleString config override
 * @param rounding - A divisor to round the provided value
 */
export function formatCurrencyRounding(value, config = {}, rounding = 1){

    const localStringConfig = {
            style: "currency", currency: "USD", minimumFractionDigits: 0, maximumFractionDigits: 0
        }
    ;

    for (const c in config){

        if (config.hasOwnProperty(c)){
            localStringConfig[c] = config[c];
        }
    }

    const valueRounded = value / rounding,
        valueFormatted = valueRounded.toLocaleString("en-US", localStringConfig);

    return valueFormatted;
}