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

/**
 * check an object is valid key/value object ...
 * @param {any} object proposed object to check ...
 * @returns 
 */
function isDescriptor(object) {
    //
    let result = false;
    result = object &&
        object.hasOwnProperty('key') &&
        object.hasOwnProperty('type') &&
        object.hasOwnProperty('value');

    //
    return result;
}

/**
 * retrieve base or filled KeyValueProvider object instance ...
 * 
 * @param {any} value value provider object instance ...
 * @returns an instance of KeyValueDescriptor ...
 */
function createDescriptor(value) {
    //
    const result = {
        key: '',
        value: undefined,
        type: XBaseDescriptor.ContentTypes.Unknown,
    };

    //
    //#region Apply Value ...
    if (value) {
        //
        //#region key ...
        if (XValueTools.isValidArg(value.key)) {
            result.key = value.key;
        }
        //#endregion

        //
        //#region type ...
        if (
            XValueTools.isValidArg(value.type) &&
            XBaseDescriptor.isValidContentType(value.type)
        ) {
            result.type = value.type;
        }
        //#endregion

        //
        //#region value ...
        if (value.value) {
            result.value = value.value;
        }
        //#endregion
    }
    //#endregion

    //
    return result;
}

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

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

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

    //
    // Handle Key ...
    if (descriptor.key !== XBaseDescriptor.ExpressionKeys.IGNORED_KEY) {
        result += descriptor.key + assignSymbol + ' ';
    }

    //
    // Handle Value ...
    const valueExpression = XBaseDescriptor.toExpression(descriptor);
    result += valueExpression;

    //
    return result;
}

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