const logger = require('./logger.js');
const realpath = require('fs/promises').realpath;
const stat = require('fs/promises').stat;
const http = require('http');
const { HTTP_GET, HTTP_POST } = require('./constants.js');

function timeDiff(startTime) {
    if (startTime instanceof Date) {
        return (new Date().getTime() - startTime.getTime());
    }
    return new Date().getTime - startTime;
}

function clone(object) {
    var clone = {};
    for (key in object) {
        clone[key] = object[key];
    }
    return clone;
}

function httpGET(host, port, path, args) {
    return httpRequest(host, port, path, HTTP_GET, args);
}

function httpPOST(host, port, path, args) {
    return httpRequest(host, port, path, HTTP_POST, args);
}

function httpRequest(host, port, path, method, args) {
    return new Promise(function (resolve, reject) {
        if (!path.startsWith("/")) {
            path = "/" + path;
        }
        logger.debug('sending http \'' + method + '\' request to \'' + host + ':' + port + path + '\'...');
        const request = http.request({
            hostname: host,
            port: port,
            path: path,
            method: method
        }, function (response) {
            if (!response) {
                return reject('error: no response from host for http \'' + method + '\' request \'' + host + ':' + port + path + '\'');
            }
            var responseData = "";
            response.on('data', function (data) {
                responseData += data;
            });
            response.on('end', function () {
                logger.debug('http \'' + method + '\' request \'' + host + ':' + port + path + '\' returned status code \'' + response.statusCode + '\' and data \'' + responseData + '\'');
                var fn = resolve;
                if (response.statusCode != 200) {
                    fn = reject;
                }
                if (!responseData) {
                    return fn();
                }
                try {
                    return fn(JSON.parse(responseData));
                } catch (err) {
                    return fn(responseData);
                }
                
            });
        });
        request.on('error', function (err) {
            return reject('http \'' + method + '\' request \'' + host + ':' + port + path + '\' returned an error >>> ' + err);
        });
        request.end();
    });
}

function toHex(value) {
    var hex = Number(value).toString(16);
    return hex;
}

function sortById(array) {
    return array.sort(function (a, b) {
        return a.id - b.id;
    });
}

function fileExists(file) {
    return new Promise((resolve, reject) => {
        if (file == undefined) {
            reject('can not check the existence of an undefined file');
        }
        resolvePath(file)
            .then((path) => {
                stat(path)
                    .then((stats) => {
                        resolve({path, stats});
                    })
            })
            .catch(reject);
    });
}

function resolvePath(file) {
    return new Promise((resolve, reject) => {
        if (file == undefined) {
            reject('can not resolve a path to an undefined file');
        }
        realpath(file)
            .then(resolve)
            .catch((err) => {
                reject('resolving path \'' + file + '\' encountered an error >>> ' + err);
            });
    });
}

module.exports = {
    timeDiff,
    clone,
    httpGET,
    httpPOST,
    toHex,
    sortById,
    fileExists,
    resolvePath
}