/**
 * SMS services.
 */

"use strict";

const http = require("http");
const URL = require("url");


/**
 * 创建一个 Sender
 * @param url 发送短信的 API 的 URL
 * @param timeout 请求超时时间, 单位ms, default 500ms
 * @param keepAlive 是否使用 keepAlive 连接池
 * @constructor
 */
function SMSSender (url, timeout, keepAlive){
    if (!(this instanceof SMSSender)) {
        return new SMSSender(url, timeout, keepAlive);
    }
    this.requesetOptions = Object.assign(URL.parse(url), {
        "method": "POST",
        "timeout": timeout || 500, // 500ms timeout default
        "agent": keepAlive ? new http.Agent({"keepAlive": true}) : false // 低频用 false, 高频用 keepAliveAgent
    });
}

/**
 * 发送短信, 文档: https://github.com/guanghetv/SMSNotify
 * @param {String|String[]} phoneNum 电话号码, 大陆的可以不带 +86, 其他地区的必须有国家/地区代码
 * @param {String} templateName 模板名称, 请从文档末尾的列表中选择需要的
 * @param {Object} params 模板对应的参数表
 * @return {Promise}
 */
SMSSender.prototype.sendMessage = function (phoneNum, templateName, params) {
    let self = this;
    return new Promise(function (resolve) {
        let request = http.request(self.requesetOptions, resp => {
            let body;
            resp.on("data", chunk => body = chunk.toString());
            resp.on("end", () => {
                if (resp.statusCode >= 400) {
                    resolve({"ok": false, "message": body});
                } else {
                    resolve({"ok": true});
                }
            });
        });
        request.on("error", err => {if (!request.timeouted) console.error(err)});
        request.on("timeout", () => {
            request.timeouted = true;
            request.abort();
            resolve({"ok": false, "message": "request timeout"});
        });
        request.end(JSON.stringify({
            "phone": phoneNum,
            "template": templateName,
            "params": params
        }));
    });
};


module.exports = SMSSender;