package com.google.gwt.sample.stockwatcher.client;

import com.google.gwt.i18n.client.DateTimeFormat;
import java.util.Date;
import com.google.gwt.i18n.client.NumberFormat;
import com.google.gwt.user.client.Random;
import com.google.gwt.user.client.Window;
import com.google.gwt.user.client.Timer;
import java.util.ArrayList;
import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.event.dom.client.ClickHandler;
import com.google.gwt.event.dom.client.KeyCodes;
import com.google.gwt.event.dom.client.KeyDownEvent;
import com.google.gwt.event.dom.client.KeyDownHandler;
import com.google.gwt.user.client.ui.Button;
import com.google.gwt.user.client.ui.FlexTable;
import com.google.gwt.user.client.ui.HorizontalPanel;
import com.google.gwt.user.client.ui.Label;
import com.google.gwt.user.client.ui.RootPanel;
import com.google.gwt.user.client.ui.TextBox;
import com.google.gwt.user.client.ui.VerticalPanel;

public class StockWatcher implements EntryPoint {
	
  private static final int REFRESH_INTERVAL = 5000; // ms
  private VerticalPanel mainPanel = new VerticalPanel();
  private FlexTable stocksFlexTable = new FlexTable();
  private HorizontalPanel addPanel = new HorizontalPanel();
  private TextBox newSymbolTextBox = new TextBox();
  private Button addStockButton = new Button("Add");
  private Label lastUpdatedLabel = new Label();
  private ArrayList<String> stocks = new ArrayList<String>();

  /**
   * Entry point method.
   */
  public void onModuleLoad() {
    // Create table for stock data.
    stocksFlexTable.setText(0, 0, "Symbol");
    stocksFlexTable.setText(0, 1, "Price");
    stocksFlexTable.setText(0, 2, "Change");
    stocksFlexTable.setText(0, 3, "Remove");
    
    // Add styles to elements in the stock list table.
    stocksFlexTable.setCellPadding(6);
    
    // Add styles to elements in the stock list table.
    stocksFlexTable.getRowFormatter().addStyleName(0, "watchListHeader");
    stocksFlexTable.addStyleName("watchList");
    stocksFlexTable.getCellFormatter().addStyleName(0, 1, "watchListNumericColumn");
    stocksFlexTable.getCellFormatter().addStyleName(0, 2, "watchListNumericColumn");
    stocksFlexTable.getCellFormatter().addStyleName(0, 3, "watchListRemoveColumn");

    // Assemble Add Stock panel.
    addPanel.add(newSymbolTextBox);
    addPanel.add(addStockButton);
    addPanel.addStyleName("addPanel");

    // Assemble Main panel.
    mainPanel.add(stocksFlexTable);
    mainPanel.add(addPanel);
    mainPanel.add(lastUpdatedLabel);

    // Associate the Main panel with the HTML host page.
    RootPanel.get("stockList").add(mainPanel);

    // Move cursor focus to the input box.
    newSymbolTextBox.setFocus(true);
    
    // Setup timer to refresh list automatically.
    Timer refreshTimer = new Timer() {
      @Override
      public void run() {
        refreshWatchList();
      }
    };
    refreshTimer.scheduleRepeating(REFRESH_INTERVAL);
    
    // Listen for mouse events on the Add button.
    addStockButton.addClickHandler(new ClickHandler() {
      public void onClick(ClickEvent event) {
        addStock();
      }
    });
    
    // Listen for keyboard events in the input box.
    newSymbolTextBox.addKeyDownHandler(new KeyDownHandler() {
      public void onKeyDown(KeyDownEvent event) {
        if (event.getNativeKeyCode() == KeyCodes.KEY_ENTER) {
          addStock();
        }
      }
    });
  }
  
  /**
   * Add stock to FlexTable. Executed when the user clicks the addStockButton or
   * presses enter in the newSymbolTextBox.
   */
  private void addStock() {
	  final String symbol = newSymbolTextBox.getText().toUpperCase().trim();
      newSymbolTextBox.setFocus(true);

      // Stock code must be between 1 and 10 chars that are numbers, letters, or dots.
      if (!symbol.matches("^[0-9A-Z\\.]{1,10}$")) {
        Window.alert("'" + symbol + "' is not a valid symbol.");
        newSymbolTextBox.selectAll();
        return;
      }

      newSymbolTextBox.setText("");
      
      // Don't add the stock if it's already in the table.
      if (stocks.contains(symbol))
        return;
      
      // Add the stock to the table.
      int row = stocksFlexTable.getRowCount();
      stocks.add(symbol);
      stocksFlexTable.setText(row, 0, symbol);
      stocksFlexTable.setWidget(row, 2, new Label());
      stocksFlexTable.getCellFormatter().addStyleName(row, 1, "watchListNumericColumn");
      stocksFlexTable.getCellFormatter().addStyleName(row, 2, "watchListNumericColumn");
      stocksFlexTable.getCellFormatter().addStyleName(row, 3, "watchListRemoveColumn");
      
      // Add a button to remove this stock from the table.
      Button removeStockButton = new Button("x");
      removeStockButton.addStyleDependentName("remove");
      removeStockButton.addClickHandler(new ClickHandler() {
        public void onClick(ClickEvent event) {
          int removedIndex = stocks.indexOf(symbol);
          stocks.remove(removedIndex);
          stocksFlexTable.removeRow(removedIndex + 1);
        }
      });
      stocksFlexTable.setWidget(row, 3, removeStockButton);
      
      // Get the stock price.
      refreshWatchList();   
  }
  
  /**
   * Generate random stock prices.
   */
  private void refreshWatchList() {
    final double MAX_PRICE = 100.0; // $100.00
    final double MAX_PRICE_CHANGE = 0.02; // +/- 2%

    StockPrice[] prices = new StockPrice[stocks.size()];
    for (int i = 0; i < stocks.size(); i++) {
      double price = Random.nextDouble() * MAX_PRICE;
      double change = price * MAX_PRICE_CHANGE
          * (Random.nextDouble() * 2.0 - 1.0);

      prices[i] = new StockPrice(stocks.get(i), price, change);
   }
      updateTable(prices);  
  }

  /**
   * Update the Price and Change fields all the rows in the stock table.
   *
   * @param prices Stock data for all rows.
   */
  private void updateTable(StockPrice[] prices) {
    for (int i = 0; i < prices.length; i++) {
      updateTable(prices[i]);
    }

    // Display timestamp showing last refresh.
    DateTimeFormat dateFormat = DateTimeFormat.getFormat(
      DateTimeFormat.PredefinedFormat.DATE_TIME_MEDIUM);
    lastUpdatedLabel.setText("Last update : " + 
        dateFormat.format(new Date()));
  }
  
  /**
   * Update a single row in the stock table.
   *
   * @param price Stock data for a single row.
   */
  private void updateTable(StockPrice price) {
   // Make sure the stock is still in the stock table.
   if (!stocks.contains(price.getSymbol())) {
     return;
   }

   int row = stocks.indexOf(price.getSymbol()) + 1;

   // Format the data in the Price and Change fields.
   String priceText = NumberFormat.getFormat("#,##0.00").format(
       price.getPrice());
   NumberFormat changeFormat = NumberFormat.getFormat("+#,##0.00;-#,##0.00");
   String changeText = changeFormat.format(price.getChange());
   String changePercentText = changeFormat.format(price.getChangePercent());

   // Populate the Price and Change fields with new data.
   stocksFlexTable.setText(row, 1, priceText);
   Label changeWidget = (Label)stocksFlexTable.getWidget(row, 2);
   changeWidget.setText(changeText + " (" + changePercentText + "%)");
   // stocksFlexTable.setText(row, 2, changeText + " (" + changePercentText + "%)");
   
   // Change the color of text in the Change field based on its value.	
   String changeStyleName = "noChange";
   if (price.getChangePercent() < -0.1f) {
	 changeStyleName = "negativeChange";
   }
   else if (price.getChangePercent() > 0.1f) {
	 changeStyleName = "positiveChange";
   }
   changeWidget.setStyleName(changeStyleName);
  }
}