coynzer.BTCTicker

//reference System.dll, System.Drawing.dll, LEDmatrix.dll

/* LICENSE

This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License (GPL) as published by
the Free Software Foundation; either version 2 of the License, or (at
your option) any later version. The full text of versions 2 and 3 of
the GPL can be found respectively in the files LICENSE-GPLV2 and
LICENSE-GPLV3.

This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
Public License for more details.

You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/

/*
 * Written by coynzer, https://bitcointalk.org/index.php?action=profile;u=153694
 *
 * Version 0.1
 *
 * I don't think I will do a lot of support for this code, either it works for you or it doesn't. No guarantees given whatsoever.
 * However, if you have any questions or problems you could try asking in the respective forum post and might get help:
 * https://bitcointalk.org/index.php?topic=310184.0
 *
 * This plug-in will turn your USB message board into a BTC exchange rater ticker. The ticker is using the
 * last price from Mt.Gox for the selected currency.
 *
 * If you want to add a new currency first the easiest way is to copy an existing block, e.g. that for USD starting with this line:
 *   public class USD : LedProgramBase
 * The end of the block is the line with a single "}" on the same level as where the above line is. Create a copy that whole block
 * directly after it.
 * The part "USD" on this line is the name that will be shown in the selection box, e.g. if you call your currency "XYZ" it
 * will be shown as "BTCTicker.XYZ". Please note that you may not use spaces or special characters in this name.
 *
 * In the last step you have to tell the new ticker which exchange rate to fetch from Mt.Gox, e.g. in the code you
 * copied it is BTC to USD which is expressed in the concatenated string "BTCUSD" in the code below:
 *   Ticker ticker = new Ticker("BTCUSD");
 * If you want to get the rate for BTC to XYZ instead you would replace that with "BTCXYZ". In the future it should also
 * be possible to use something as "BTCLTC". You can see a list of available tickers here;
 * https://bitbucket.org/nitrous/mtgox-api/overview#markdown-header-streamlist_public
 *
 * Now after you have done your changes you can save the file and click the "Reload" button in the USB LED Driver program
 * and your new ticker should be available from the drop-down list.
 */


using System;
using System.Diagnostics;
using System.Drawing;
using System.Globalization;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Text.RegularExpressions;
using LedMatrixComms;

namespace BTCTicker
{

    public class Ticker
    {
        #region Settings
        public static int RefreshInterval = 5000; // minimum refresh exchange interval in milliseconds
        public static int DrawInterval = 500; // animation draw interval in milliseconds

        static bool AnimationEnabled = true; // set to "false" if you want to disable animation when the exchange rate changes
        const string TickerBaseUrl = "https://data.mtgox.com/api/2/$CURRENCY$/money/ticker_fast"; // base Mt.Gox ticker URL with a $CURRENCY$ variable
        const string TickerRegexString = @"\""last\""\:\{\""value\""\:\""(?<VALUE>\d+\.\d+)\""\,"; // don't change this if you don't know what you are doing
        const int AnimationBaseY = -3; // don't change this if you don't know what you are doing
        #endregion Settings

        #region Private objects
        Font drawFont = new Font(FontFamily.GenericSansSerif, 9f, GraphicsUnit.Pixel);
        SolidBrush drawBrush = new SolidBrush(Color.Black);
        Regex tickerRegex = new Regex(TickerRegexString);
        string tickerUrl = "";
        WebClient webClient = new WebClient();
        string lastPriceString = " ";
        string priceString = "1";
        double lastPrice = 0;
        double price = 1;
        int animationPosition = 0;
        Stopwatch lastRefresh = new Stopwatch();
        #endregion Private objects

        public Ticker(string currency)
        {
            tickerUrl = TickerBaseUrl.Replace("$CURRENCY$", currency);
        }

        private void getCurrentPrice()
        {
            string errorString = "Err01";
            try
            {
                string jsonSring = webClient.DownloadString(tickerUrl);
                errorString = "Err02";
                Match regexMatch = tickerRegex.Match(jsonSring);
                errorString = "Err03";
                string regexValue = regexMatch.Groups["VALUE"].Value;
                errorString = "Err04";
                double priceValue = Convert.ToDouble(regexValue, CultureInfo.InvariantCulture);
                errorString = "Err05";
                int lenght = Math.Truncate(priceValue).ToString().Length;
                if (lenght > 4)
                {
                    priceString = errorString;
                    price = double.NaN;
                    return;
                }
                errorString = "Err06";
                int fractionDigits = Math.Max(0, (4 - lenght));
                errorString = "Err07";
                double priceValueRounded = Math.Round(priceValue, fractionDigits);
                errorString = "Err08";
                priceString = priceValueRounded.ToString(CultureInfo.InvariantCulture);
                price = priceValueRounded;
            }
            catch
            {
                priceString = errorString;
                price = double.NaN;
            }

            // code for testing the animation (uncomment this and comment all lines above to use it)
//          Random random = new Random();
//          price = Convert.ToDouble(random.Next(90, 110));
//          priceString = price.ToString(CultureInfo.InvariantCulture);
        }

        public void DrawPrice(Graphics g)
        {
            if ((!lastRefresh.IsRunning) || (lastRefresh.ElapsedMilliseconds > RefreshInterval) && (animationPosition == 0))
            {
                getCurrentPrice();
                if (AnimationEnabled)
                {
                    if (!double.IsNaN(price))
                    {
                        if (price > lastPrice)
                            animationPosition = 1;
                        else if (price < lastPrice)
                            animationPosition = -1;
                        else
                            animationPosition = 0;
                    }
                    lastRefresh.Reset();
                    lastRefresh.Start();
                }
                else
                {
                    if (lastPriceString != priceString)
                    {
                        // clear the display
                        g.Clear(Color.White);
                        drawPriceText(g, priceString, AnimationBaseY);
                        lastPriceString = priceString;
                        lastPrice = price;
                    }
                    lastRefresh.Reset();
                    lastRefresh.Start();
                    return;
                }

            }

            if (animationPosition == 0)
                return;

            // clear the display
            g.Clear(Color.White);
            drawPriceText(g, lastPriceString, AnimationBaseY + animationPosition);
            if (animationPosition > 0)
            {
                drawPriceText(g, priceString, AnimationBaseY + animationPosition - 8);
                animationPosition++;
            }
            else if (animationPosition < 0)
            {
                drawPriceText(g, priceString, AnimationBaseY + animationPosition + 8);
                animationPosition--;
            }
            if (Math.Abs(animationPosition) == 9)
            {
                animationPosition = 0;
                lastPriceString = priceString;
                lastPrice = price;
            }
        }

        private void drawPriceText(Graphics g, string priceText, int yPos)
        {
            // if this an error message just draw it without using the spacing logics below
            int xPos = -2;
            if (priceText.StartsWith("Err"))
            {
                g.DrawString(priceText, drawFont, drawBrush, xPos, yPos);
                return;
            }

            // spacing logic starts here
            // the digit "4" is one pixel wider than all others - we will try use extra space from "." and "1" which are not as wide as others

            int pixelWidth = 0;
            for (int charIndex = 0; charIndex < priceText.Length; charIndex++)
            {
                if (charIndex > 0)
                    pixelWidth++; // add leading pixel space

                switch (priceText[charIndex])
                {
                    case '.':
                        pixelWidth += 1;
                        break;
                    case '1':
                        pixelWidth += 2;
                        break;
                    default:
                        pixelWidth += 4;
                        break;
                }
            }
            int pixelBuffer = 21 - pixelWidth; // calculate spare pixels we can use for extra space after the number 4, which is one pixel wider than all other numbers
            bool lastIs4 = (priceText[priceText.Length - 1] == '4');
            if (lastIs4) // if "4" is the last digit we MUST give it the extra pixel so reserve that in the buffer already
                pixelBuffer--;


            for (int charIndex = 0; charIndex < priceText.Length; charIndex++)
            {
                if (priceText[charIndex] == '1')
                    xPos -= 1;
                if (priceText[charIndex] == '.')
                    xPos -= 1;
                g.DrawString(priceText.Substring(charIndex, 1), drawFont, drawBrush, xPos, yPos);
                if (priceText[charIndex] == '.')
                    xPos += 3;
                else if (priceText[charIndex] == '1')
                    xPos += 4;
                else if ((priceText[charIndex] == '4') && (pixelBuffer > 0) && (charIndex < (priceText.Length - 1)))
                {
                    // if this a "4" and we still got spare pixels in the buffer then use it here
                    xPos += 6;
                    pixelBuffer--;
                }
                else
                    xPos += 5;
                if ((charIndex == (priceText.Length - 1)) && (lastIs4)) // if the following last character is a "4" add the extra pixel space we reserved
                    xPos++;
            }
        }
    }


    #region Currency implementations
    public class USD : LedProgramBase
    {
        Ticker ticker = new Ticker("BTCUSD");

        public override int Speed()
        {
            return Ticker.DrawInterval;
        }

        public override void Setup(LedUsbDevice device)
        {
        }

        protected override void Update(Graphics g)
        {
            ticker.DrawPrice(g);
        }
    }

    public class EUR : LedProgramBase
    {
        Ticker ticker = new Ticker("BTCEUR");

        public override int Speed()
        {
            return Ticker.DrawInterval;
        }

        public override void Setup(LedUsbDevice device)
        {
        }

        protected override void Update(Graphics g)
        {
            ticker.DrawPrice(g);
        }
    }

    public class CAD : LedProgramBase
    {
        Ticker ticker = new Ticker("BTCCAD");

        public override int Speed()
        {
            return Ticker.DrawInterval;
        }

        public override void Setup(LedUsbDevice device)
        {
        }

        protected override void Update(Graphics g)
        {
            ticker.DrawPrice(g);
        }
    }

    public class GBP : LedProgramBase
    {
        Ticker ticker = new Ticker("BTCGBP");

        public override int Speed()
        {
            return Ticker.DrawInterval;
        }

        public override void Setup(LedUsbDevice device)
        {
        }

        protected override void Update(Graphics g)
        {
            ticker.DrawPrice(g);
        }
    }
    #endregion Currency implementations

}