const { EventEmitter } = require('events');

const { ipcMain } = require('electron');

const genUid = require('uid2');

class Server {

constructor (win) {

this.win = win;

this.ipcListener = this.ipcListener.bind(this);

this.emitter = new EventEmitter();

genUid(10, (err, uid) => {

if (this.destroyed) return;

if (err) return this.emitter.emit('error', err);

this.id = uid;

ipcMain.on(uid, this.ipcListener);

// we intentionally subscribe to `on` instead of `once`

// to support reloading the window and re-initializing

// the channel

this.wc.on('did-finish-load', () => {

this.wc.send('init', uid);

});

});

}

get wc () {

return this.win.webContents;

}

ipcListener (event, { ev, data }) {

this.emitter.emit(ev, data);

}

emit (ch, data) {

this.wc.send(this.id, { ch, data });

}

on (ev, fn) {

this.emitter.on(ev, fn);

}

once (ev, fn) {

this.emitter.once(ev, fn);

}

removeListener (ev, fn) {

this.emitter.removeListener(ev, fn);

}

removeAllListeners () {

this.emitter.removeAllListeners();

}

destroy () {

this.removeAllListeners();

this.wc.removeAllListeners();

if (this.id) {

ipcMain.removeListener(this.id, this.ipcListener);

} else {

// mark for `genUid` in constructor

this.destroyed = true;

}

}

}

module.exports = function createRPC (win) {

return new Server(win);

};