/**
 * @author brun0ne [brunonblok@gmail.com]
 * @copyright Crown Copyright 2023
 * @license Apache-2.0
 */

import Operation from "../Operation.mjs";
import OperationError from "../errors/OperationError.mjs";

/**
 * PHP Serialize operation
 */
class PHPSerialize extends Operation {

    /**
     * PHPSerialize constructor
     */
    constructor() {
        super();

        this.name = "PHP Serialize";
        this.module = "Default";
        this.description = "Performs PHP serialization on JSON data.<br><br>This function does not support <code>object</code> tags.<br><br>Since PHP doesn't distinguish dicts and arrays, this operation is not always symmetric to <code>PHP Deserialize</code>.<br><br>Example:<br><code>[5,&quot;abc&quot;,true]</code><br>becomes<br><code>a:3:{i:0;i:5;i:1;s:3:&quot;abc&quot;;i:2;b:1;}<code>";
        this.infoURL = "https://www.phpinternalsbook.com/php5/classes_objects/serialization.html";
        this.inputType = "JSON";
        this.outputType = "string";
        this.args = [];
    }

    /**
     * @param {JSON} input
     * @param {Object[]} args
     * @returns {string}
     */
    run(input, args) {
        /**
         * Determines if a number is an integer
         * @param {number} value 
         * @returns {boolean}
         */
        function isInteger(value) {
            return typeof value === "number" && parseInt(value.toString(), 10) === value;
        }

        /**
         * Serialize basic types
         * @param {string | number | boolean} content 
         * @returns {string}
         */
        function serializeBasicTypes(content) {
            const basicTypes = {
                "string": "s",
                "integer": "i",
                "float": "d",
                "boolean": "b"
            };
        
            /**
             * Booleans
             * cast to 0 or 1
             */
            if (typeof content === "boolean"){
                return `${basicTypes["boolean"]}:${content ? 1 : 0}`;
            }
            
            /**
             * Numbers
             */
            if (typeof content === "number"){
                if (isInteger(content)){
                    return `${basicTypes["integer"]}:${content.toString()}`
                }
                else {
                    return `${basicTypes["float"]}:${content.toString()}`
                }
            }
        
            /**
             * Strings
             */
            if (typeof content === "string")
                return `${basicTypes["string"]}:${content.length}:"${content}"`;
            
            /** This should be unreachable */
            throw new OperationError(`Encountered a non-implemented type: ${typeof content}`);
        }

        /**
         * Recursively serialize
         * @param {*} object 
         * @returns {string}
         */
        function serialize(object) {
            /**
             * Null
             */
            if (object == null) {
                return `N;`
            }
        
            /**
             * Basic types
             */
            if (typeof object !== "object"){
                return `${serializeBasicTypes(object)};`;
            }
        
            /**
             * Arrays
             */
            else if (object instanceof Array) {
                const serializedElements = [];
        
                for (let i = 0; i < object.length; i++) {
                    serializedElements.push(`${serialize(i)}${serialize(object[i])}`);
                }
        
                return `a:${object.length}:{${serializedElements.join("")}}`
            }
        
            /**
             * Objects
             * Note: the output cannot be guaranteed to be in the same order as the input 
             */
            else if (object instanceof Object) {
                const serializedElements = [];
                const keys = Object.keys(object);
        
                for (const key of keys) {
                    serializedElements.push(`${serialize(key)}${serialize(object[key])}`);
                }
        
                return `a:${keys.length}:{${serializedElements.join("")}}`
            }

            /** This should be unreachable */
            throw new OperationError(`Encountered a non-implemented type: ${typeof object}`);
        }

        return serialize(input);
    }
}

export default PHPSerialize;