// Loaded from https://deno.land/x/cliffy@v0.12.1/packages/x/normalCase.ts


import camelCaseRegexp from 'https://deno.land/x/case/vendor/camelCaseRegexp.ts';
import camelCaseUpperRegexp from 'https://deno.land/x/case/vendor/camelCaseUpperRegexp.ts';

import nonWordRegexp from 'https://deno.land/x/case/vendor/nonWordRegexp.ts';
import lowerCase from './lowerCase.ts';

export default function normalCase( str: string, locale?: string, replacement?: string ): string {

    if ( str == null ) {
        return '';
    }

    replacement = typeof replacement !== 'string' ? ' ' : replacement;

    function replace( match: string, index: number, value: string ): string {
        if ( index === 0 || index === value.length - match.length ) {
            return '';
        }

        return replacement || '';
    }

    str = String( str )
        // Support camel case ("camelCase" -> "camel Case").
        .replace( camelCaseRegexp, '$1 $2' )
        // Support odd camel case ("CAMELCase" -> "CAMEL Case").
        .replace( camelCaseUpperRegexp, '$1 $2' )
        // Remove all non-word characters and replace with a single space.
        .replace( nonWordRegexp, replace );

    // Lower case the entire string.
    return lowerCase( str, locale );
}