//
//#region Imports ...
const XValueTools = require('../tools/x-value.tools');
const XBaseDescriptor = require('./x-base.descriptor');
const XKeyValueDescriptor = require('./x-key-value.descriptor');
//#endregion

/**
 * check an object is valid ContentDescriptor object ...
 * 
 * @param {any} object proposed object to check ...
 * @returns 
 */
function isDescriptor(object) {
    //
    let result = false;
    result = object &&
        object.hasOwnProperty('type') &&
        object.hasOwnProperty('childs') &&
        Array.isArray(object.childs) &&
        (
            object.childs.length > 0 ?
                object.childs.every(ch => XKeyValueDescriptor.isDescriptor(ch)) :
                true
        );

    //
    return result;
}

/**
 * converts an instance of Descriptor to Expression ...
 * 
 * @param descriptor an instance of ContentDescriptor ...
 * @param {string} assignSymbol property assign symbol ...
 * @returns creator string ...
 */
function toExpression(
    descriptor = createDescriptor(),
    assignSymbol = ':',
    separator = ','
) {
    //
    let result = '';

    //
    // Validate Arg ...
    if (!isDescriptor(descriptor)) {
        return result;
    }

    //
    // Normalize Property Assign Symbol ...
    assignSymbol = !XValueTools.isValidArg(assignSymbol) ?
        ':' :
        assignSymbol;

    //
    const isArrayType = descriptor.type === XBaseDescriptor.ContentTypes.Array;
    const isObjectType = descriptor.type === XBaseDescriptor.ContentTypes.Object;

    //
    result += (
        isObjectType ? '{\n' :
            isArrayType ? '[\n' :
                ''
    );

    //
    for (let i = 0; i < descriptor.childs.length; i++) {
        //
        const keyVal = descriptor.childs[i];
        const keyValExpression = XKeyValueDescriptor.toExpression(keyVal, assignSymbol);

        //
        if (separator === ';') {
            //
            result += keyValExpression + (
                i === descriptor.childs.length - 1 ?
                    separator :
                    `${separator}\n`
            );
        } else {
            //
            result += keyValExpression + (
                i === descriptor.childs.length - 1 ?
                    '' :
                    `${separator}\n`
            );
        }
    }

    //
    result += (
        isObjectType ? '\n}' :
            isArrayType ? '\n]' :
                ''
    );

    //
    return result;
}

/**
 * retrieve base or filled ContentDescriptor object instance ...
 * 
 * @param {any} value value provider object instance ...
 * @returns an instance of ContentDescriptor ...
 */
function createDescriptor(value) {
    //
    let result = {
        type: XBaseDescriptor.ContentTypes.Unknown,
        childs: [
            XKeyValueDescriptor.createDescriptor()
        ]
    };
    result.childs.pop();

    //
    //#region Apply Value ...
    if (value) {
        //
        //#region type ...
        if (XBaseDescriptor.isValidContentType(value.type)) {
            result.type = value.type;
        }
        //#endregion

        //
        //#region childs ...
        if (
            XValueTools.hasChildArray(value.childs) &&
            value.childs.every(ch => XKeyValueDescriptor.isDescriptor(ch))
        ) {
            result.childs = [
                ...value.childs
            ];
        }
        //#endregion
    }
    //#endregion

    //
    return result;
}

//
// Module Exports ...
module.exports = {
    isDescriptor,
    toExpression,
    createDescriptor,
}