import { Pipe, PipeTransform } from '@angular/core';

// enums
import { eStringPlaceholder, eUnit } from '../enums';

@Pipe({
    name: 'formatCurrency',
    standalone: true,
})
export class FormatCurrencyPipe implements PipeTransform {
    transform(currency: number, useAbbreviation?: boolean): string {
        if (!currency) return eUnit.DOLLAR_SIGN + 0;

        if (useAbbreviation) return this.nFormatter(currency);

        return (
            eUnit.DOLLAR_SIGN +
            currency.toFixed(2).replace(/(\d)(?=(\d{3})+(?!\d))/g, '$1,')
        );
    }

    private nFormatter(num: number): string {
        const si = [
            { value: 1, symbol: eStringPlaceholder.EMPTY },
            { value: 1e3, symbol: 'K' },
            { value: 1e6, symbol: 'M' },
            { value: 1e9, symbol: 'G' },
            { value: 1e12, symbol: 'T' },
            { value: 1e15, symbol: 'P' },
            { value: 1e18, symbol: 'E' },
        ];
        const decimalPlaces = 2;
        const regex = /\.0+$|(\.[0-9]*[1-9])0+$/;
        let index;
        for (index = si.length - 1; index > 0; index--) {
            if (num >= si[index].value) break;
        }
        return (
            eUnit.DOLLAR_SIGN +
            (num / si[index].value)
                .toFixed(decimalPlaces)
                .replace(regex, '$1') +
            si[index].symbol
        );
    }
}