class Trade {
    constructor() {
        // A list of all the open trades.
        this.trades = [];
        /* HTML elements that interact with this class. */
        // The html element that displays the quote value to execute the trade at.
        this.priceInput_el = null;
        // The html element that displays the actual quote value of the base asset.
        this.currentPrice_el = null;
        // The html element that displays the quantity to executed the trade at.
        this.qtyInput_el = null;
        // The html element that displays the value of the trade. (quantity * price)
        this.tradeValue_el = null;
        // The html element that displays the orderType of the trade. (Market|Limit)
        this.orderType_el = null;
        // The html element that displays the target for the trade ['binance'|'test_exchange'].
        this.target_el = null;
        // The html element that displays the side to trade. [buy|sell]
        this.side_el = null;
        // The html element that displays the form dialog for a new trade.
        this.formDialog_el = null;
        // The html element that displays the active trades.
        this.activeTLst_el = null;
    }
    connectElements({price='price', currentPrice='currentPrice', quantity='quantity',
                     tradeValue='tradeValue', orderType='orderType', target='tradeTarget',
                     side='side', ntf='new_trade_form', atl='activeTradesLst'}={}){
        /*
            Sets a reference to the dom elements that interact with this class.
            Overwriting the default id's allows for instance specific binding.
        */
        this.priceInput_el = document.getElementById(price);
        this.currentPrice_el = document.getElementById(currentPrice);
        this.qtyInput_el = document.getElementById(quantity);
        this.tradeValue_el = document.getElementById(tradeValue);
        this.orderType_el = document.getElementById(orderType);
        this.target_el = document.getElementById(target);
        this.side_el = document.getElementById(side);
        this.formDialog_el = document.getElementById(ntf);
        this.activeTLst_el = document.getElementById(atl);
    }
    initialize(){
        /* Set the values and behavior of elements this class interacts with. */

        // Bind this instance with the html element ment to interact with it.
        this.connectElements();
        // Store this object pointer for referencing inside callbacks and event handlers.
        var that = this;
        // Assign the quote value of the asset to the current price display element.
        window.UI.data.price_history.then((ph) => {
            // Assign the last closing price in the price history to the price input element.
            that.priceInput_el.value = ph[ph.length-1].close;
            // Set the current price display to the same value.
            that.currentPrice_el.value = that.priceInput_el.value;
        });
        // Set the trade value to zero. This will update when price and quantity inputs are received.
        this.tradeValue_el.value = 0;
        // Toggle current price or input-field for value updates depending on orderType.
        function update_tradeValue(){
            if ( that.orderType_el.value == 'MARKET')
                {that.tradeValue_el.value = that.qtyInput_el.value * that.currentPrice_el.value;}
            else
                {that.tradeValue_el.value = that.qtyInput_el.value * that.priceInput_el.value;}
        }
        // Market orders are executed at the current price. To avoid confusion.
        // Grey out this price input when orderType is set to Market.
        this.orderType_el.addEventListener('change', function(){
            if(this.value == 'MARKET')
            {
                that.currentPrice_el.style.display = "inline-block";
                that.priceInput_el.style.display = "none";
            }
            else if(this.value == 'LIMIT')
            {
                that.currentPrice_el.style.display = "none";
                that.priceInput_el.style.display = "inline-block";
            }
            update_tradeValue();
        });
        // Update the trade value display everytime the price input changes.
        this.priceInput_el.addEventListener('change', update_tradeValue);
        // Update the trade value display everytime the quantity input changes.
        this.qtyInput_el.addEventListener('change', update_tradeValue);
        // Send a request to the server for any loaded data.
        window.UI.data.comms.sendToApp('request', 'trades');
    }
    // Call to display the 'Create new trade' dialog.
    open_tradeForm() { this.formDialog_el.style.display = "grid"; }
    // Call to hide the 'Create new signal' dialog.
    close_tradeForm() { this.formDialog_el.style.display = "none"; }

    // Call to display the 'Trade details' dialog.
    open_tradeDetails_Form() { document.getElementById("trade_details_form").style.display = "grid"; }
    // Call to hide the 'Create new signal' dialog.
    close_tradeDetails_Form() { document.getElementById("trade_details_form").style.display = "none"; }

    submitNewTrade(){
        // Collect all the input fields.
        var target = this.target_el.value;                // The target to trade ['binance'|'test_exchange'].
        var symbol = window.UI.data.trading_pair;         // The symbol to trade at.
        var price = this.priceInput_el.value;             // The price to trade at this is ignored in a market trade.
        var side = this.side_el.value;                    // The side to trade at.
        var orderType = this.orderType_el.value;          // The orderType for the trade.
        var quantity = this.qtyInput_el.value;            // The base quantity to trade.
        var data = {
                        target, symbol, price, side, orderType, quantity
                    };
       	window.UI.data.comms.sendToApp( "new_trade", data);
       	this.close_tradeForm();
    }
    set_data(trades){
        console.log('incoming trades!!!');
        console.log(trades);
        // Create a list item for every trade and add it to a UL element.
        var ul = this.activeTLst_el;

        // loop through a provided list of trades and attributes.
        for (let trade in trades){
            // Create a Json object from each trade.
            if (typeof(trades[trade]) == 'string')
                    // During initialization the object received from the server is in string form.
                    var obj = JSON.parse(trades[trade]);
                else
                    // When trades are created this function receives a javascript object.
                    var obj=trades[trade];
            // Keep a local record of the trade.
            this.trades.push(obj);
            // Define the function that is called when closing an individual trade.
            let click_func = "window.UI.trade.closeTrade('" + obj.unique_id + "')";

            // Create a close button for every individual trade.
            let close_btn = '<button onclick="' + click_func + '" style="color:red;width:32;height:22;margin-right:18;">&#10008;</button>';
            // Format some markup to display the attributes of the trade.
            //let trade_id = " <span>" + obj.unique_id + ": </span>";
            let trade_qty = "<span id='" + obj.unique_id + "_qty'>" + obj.stats.qty_filled + "</span>";
            let trade_profit = "<span id='" + obj.unique_id + "_profit'>" + obj.stats.profit + "</span>";
            let trade_pct = "<span id='" + obj.unique_id + "_pct'>" + obj.stats.profit_pct + "</span>";
            let trade_icon = "<button class='trade_details' onclick='UI.trade.open_tradeDetails_Form()'>" + "</button>";
            // Stick all the html together.
            let html = trade_icon;
            html += "<span>QTY:" + trade_qty + "</span>";
            html += "<span>P/L:" + trade_profit + "</span>";
            html += "<span>P/L %:" + trade_pct + "</span>";
            html += close_btn;
            // Put it in a div.
            html = "<div class='trade_cont'>" + html + "</div>"
            // Create the list item.
            let li = document.createElement("li");
            // Give it an id.
            li.id = obj.unique_id + '_item';
            // Inject the html.
            li.innerHTML= html;
            // And add it the the UL we created earlier.
            ul.appendChild(li);
        }
       console.log('pushed trades!!!');
        console.log(this.trades);

    }
    closeTrade(tradeId){
        // Requests that the server close a specific trade.
        window.UI.data.comms.sendToApp('close_trade', tradeId);
        // Get the trade element from the UI
        let child = document.getElementById(tradeId + '_item');
        // Ask the parent of the trade element to remove its child(trade) from the document.
        child.parentNode.removeChild(child);
    }
    update_received(trade_updts){
//        if ( 'cmd' in trade_updts) {
//            let alert =
//            window.UI.alerts.publish_alerts('trade', trade_updts);
//            this.executeCmd(trade_updts.cmd);
//        }
        console.log('Received trade update.');
        console.log('Updating trade updating local list.');
        this.trades = trade_updts;
        for (let trade in this.trades){
            console.log('dont forget to update the html.');
            console.log(trade);
        }
    }

}