import {isArray, isString} from './predicate';


// ------------ @author Daniel de Oliveira -----------------



function makeValueForCurrentKey(resultSegment: any) {
    return (resultSegment
        || resultSegment === ''
        || resultSegment === 0
        || resultSegment === false)
        ? resultSegment
        : undefined;
}


const isObject_ = (o: any) => o instanceof Object;


// library internal
export function getElForPathIn(object: any, path: string): any {

    if (!path || path.length < 1) return undefined;
    return _getElForPathIn(object, convertPath(path));
}


export function _getElForPathIn(object: any, path: Array<string|number>): any {

    const key = path[0];

    if (path.length === 1) {

        if (isString(key)) {
            if (isObject_(object)) return makeValueForCurrentKey(object[key]);
            else return undefined;
        } else {
            if (isArray(object)) return makeValueForCurrentKey(object[key]);
            else return undefined;
        }

    } else {
        path.shift();
        return object[key]
            ? _getElForPathIn(object[key], path)
            : undefined;
    }
}


function convertPath(path: string) {

    const segments = [];
    let current = '';
    for (let i = 0; i < path.length; i++) {
        if (path[i] !== '[' && path[i] !== '.' && path[i] !== ']') {
            current += path[i];
        } else {
            if (path[i] === ']') {
                segments.push(parseInt(current));
            } else {
                if (current) segments.push(current);
            }
            current = '';
        }
    }
    if (current) segments.push(current);
    return segments;
}