"use strict";

const XHR = ("onload" in new XMLHttpRequest()) ? XMLHttpRequest : XDomainRequest;

const HOST = 'https://javascriptru.firebaseio.com';

export default class Model {

constructor(opts, data) {

this._resource = opts.resource;

this._key = opts.key;

this.setData(data)

}

setData(data) {

this.data = data;

}

getData() {

return this.data;

}

setKey(key) {

alert('New key set: ' + key);

this._key = key;

}

fetch(done, fail) {

this._request('GET', null, (xhr) => {

this.setData(JSON.parse(xhr.responseText));

done && done(this, xhr);

}, fail);

}

save(done, fail) {

let method = this._key ? 'PUT' : 'POST';

this._request(method, this.data, (xhr) => {

if (method === 'POST') {

this.setKey(JSON.parse(xhr.responseText).name);

} else if (method === 'PUT') {

this.setData(JSON.parse(xhr.responseText));

}

done && done(this, xhr, method);

}, fail);

}

_getUrl() {

let url = `${HOST}/${this._resource}`;

if (this._key) {

url += `/${this._key}`;

}

return `${url}.json`;

}

_request(method, data, callback, errback) {

let xhr = new XHR(),

model = this;

xhr.open(method, this._getUrl(), true);

xhr.onload = function (event) {

callback.call(this, this, event, model);

};

xhr.onerror = function (event) {

//TODO: Do smth on errors

};

xhr.send(JSON.stringify(data || {}));

}

}