class Data {
    constructor() {
        // The user name
        this.user_name = bt_data.user_name;

        // The id's of the HTML elements that contain sections of the user interface.
        this.chart1_id = 'chart';
        this.chart2_id = 'chart2';
        this.chart3_id = 'chart3';

        /* Set into memory configuration data from the server. */
        // The assets being traded.
        this.trading_pair = bt_data.trading_pair;
        // The time period of the charts.
        this.interval = bt_data.interval;
        // All the indicators available.
        this.indicators = bt_data.indicators;

        /* Comms handles communication with the servers. Register
           callbacks to handle various incoming messages.*/
        this.comms = new Comms();
        this.comms.registerCallback('candle_update', this.candle_update)
        this.comms.registerCallback('candle_close', this.candle_close)
        this.comms.registerCallback('indicator_update', this.indicator_update)
        // Open the connection to our local server.
        this.comms.setAppCon();
        /* Open connection for streaming candle data wth the exchange.
           Pass it the time period of candles to stream. */
        this.comms.setExchangeCon(this.interval, this.trading_pair);

        //Request historical price data from the server.
        this.price_history = this.comms.getPriceHistory(this.user_name);

        //last price from price history.
        this.price_history.then((value) => {  this.last_price = value[value.length-1].close;   });

        // Request from the server initialization data for the indicators.
        this.indicator_data = this.comms.getIndicatorData(this.user_name);

        // Call back for indicator updates.
        this.i_updates = null;
    }

    candle_update(new_candle){
        // This is called everytime a candle update comes from the local server.
	    window.UI.charts.update_main_chart(new_candle);
        //console.log('Candle update:');
        this.last_price = new_candle.close;
    }
    registerCallback_i_updates(call_back){
        this.i_updates = call_back;
    }
    indicator_update(data){
        // This is called everytime an indicator update come in.
        window.UI.data.i_updates(data);
    }

    candle_close(new_candle){
        // This is called everytime a candle closes.
        //console.log('Candle close:');
        //console.log(new_candle);
    }
}