Formula Parsing

Core/ProfitTrailer/StrategyHelper.cs

@@ -12,9 +12,212 @@ using Core.Main;
 using Core.Helper;
 using Core.Main.DataObjects.PTMagicData;
 using Newtonsoft.Json;
+using System.Text.RegularExpressions;
 
 namespace Core.ProfitTrailer
 {
+  public class OperandToken : Token
+    {
+    }
+    public class OrToken : OperandToken
+    {
+    }
+
+    public class AndToken : OperandToken
+    {
+    }
+
+    public class BooleanValueToken : Token
+    { 
+    }
+
+    public class FalseToken : BooleanValueToken
+    {
+    }
+
+    public class TrueToken : BooleanValueToken
+    {
+    }
+
+    public class ParenthesisToken : Token
+    {
+    }
+
+    public class ClosedParenthesisToken : ParenthesisToken
+    {
+    }
+
+    public class OpenParenthesisToken : ParenthesisToken
+    {
+    }
+
+    public class NegationToken : Token
+    {
+    }
+
+    public abstract class Token
+    {
+    }
+
+    public class Tokenizer
+    {
+        private readonly StringReader _reader;
+        private string _text;
+
+        public Tokenizer(string text)
+        {
+            _text = text;
+            _reader = new StringReader(text);
+        }
+
+        public IEnumerable<Token> Tokenize()
+        {
+            var tokens = new List<Token>();
+            while (_reader.Peek() != -1)
+            {
+                while (Char.IsWhiteSpace((char) _reader.Peek()))
+                {
+                    _reader.Read();
+                }
+
+                if (_reader.Peek() == -1)
+                    break;
+
+                var c = (char) _reader.Peek();
+                switch (c)
+                {
+                    case '!':
+                        tokens.Add(new NegationToken());
+                        _reader.Read();
+                        break;
+                    case '(':
+                        tokens.Add(new OpenParenthesisToken());
+                        _reader.Read();
+                        break;
+                    case ')':
+                        tokens.Add(new ClosedParenthesisToken());
+                        _reader.Read();
+                        break;
+                    default:
+                        if (Char.IsLetter(c))
+                        {
+                            var token = ParseKeyword();
+                            tokens.Add(token);
+                        }
+                        else
+                        {
+                            var remainingText = _reader.ReadToEnd() ?? string.Empty;
+                            throw new Exception(string.Format("Unknown grammar found at position {0} : '{1}'", _text.Length - remainingText.Length, remainingText));
+                        }
+                        break;
+                }
+            }
+            return tokens;
+        }
+
+        private Token ParseKeyword()
+        {
+            var text = new StringBuilder();
+            while (Char.IsLetter((char) _reader.Peek()))
+            {
+                text.Append((char) _reader.Read());
+            }
+
+            var potentialKeyword = text.ToString().ToLower();
+
+            switch (potentialKeyword)
+            {
+                case "true":
+                    return new TrueToken();
+                case "false":
+                    return new FalseToken();
+                case "and":
+                    return new AndToken();
+                case "or":
+                    return new OrToken();
+                default:
+                    throw new Exception("Expected keyword (True, False, and, or) but found "+ potentialKeyword);
+            }
+        }
+    }
+    public class Parser
+    {
+        private readonly IEnumerator<Token> _tokens;
+
+        public Parser(IEnumerable<Token> tokens)
+        {
+            _tokens = tokens.GetEnumerator();
+            _tokens.MoveNext();
+        }
+
+        public bool Parse()
+        {
+            while (_tokens.Current != null)
+            {
+                var isNegated = _tokens.Current is NegationToken;
+                if (isNegated)
+                    _tokens.MoveNext();
+
+                var boolean = ParseBoolean();
+                if (isNegated)
+                    boolean = !boolean;
+
+                while (_tokens.Current is OperandToken)
+                {
+                    var operand = _tokens.Current;
+                    if (!_tokens.MoveNext())
+                    {
+                        throw new Exception("Missing expression after operand");
+                    }
+                    var nextBoolean = ParseBoolean();
+
+                    if (operand is AndToken)
+                        boolean = boolean && nextBoolean;
+                    else
+                        boolean = boolean || nextBoolean;
+
+                }
+
+                return boolean;
+            }
+
+            throw new Exception("Empty expression");
+        }
+
+        private bool ParseBoolean()
+        {
+            if (_tokens.Current is BooleanValueToken)
+            {
+                var current = _tokens.Current;
+                _tokens.MoveNext();
+
+                if (current is TrueToken)
+                    return true;
+
+                return false;
+            }
+            if (_tokens.Current is OpenParenthesisToken)
+            {
+                _tokens.MoveNext();
+
+                var expInPars = Parse();
+
+                if (!(_tokens.Current is ClosedParenthesisToken))
+                    throw new Exception("Expecting Closing Parenthesis");
+                    
+                _tokens.MoveNext(); 
+
+                return expInPars;
+            }
+            if (_tokens.Current is ClosedParenthesisToken)
+                throw new Exception("Unexpected Closed Parenthesis");
+
+            // since its not a BooleanConstant or Expression in parenthesis, it must be a expression again
+            var val = Parse();
+            return val;
+        }
+    }
+
   public static class StrategyHelper
   {
     public static string GetStrategyShortcut(string strategyName, bool onlyValidStrategies)
@@ -36,7 +239,6 @@ namespace Core.ProfitTrailer
       }
 
       // buy/sell strategies beginning with PT 2.3.3 contain the stragegy designation letter followed by a colon and space.
-
       // remove the letter and colon, change to shortcut, then reapply the letter and colon
       if (strategyName.Contains(":"))
       {
@@ -317,10 +519,22 @@ namespace Core.ProfitTrailer
 
           if (!isValidStrategy )
           {
-            // Temporary until a fix for formula true/false
+            // Parse Formulas
             if (strategy.Name.Contains("FORMULA"))
             {
-              strategyText += "<span class=\"label label-warning\" data-toggle=\"tooltip\" data-placement=\"top\" title=\"AND/OR FORMULA\">FORM</span> ";
+              string expression = strategy.Name.Remove(0, 10);
+              expression = expression.Replace("<span class=\"tdgreen\">","true").Replace("<span class=\"red\">","false").Replace("</span>","").Replace("&&","and").Replace("||","or");
+              expression = Regex.Replace(expression, @"[ABCDEFGHIJKLMNOPQRSTUVWXYZ]", String.Empty);
+              var tokens = new Tokenizer(expression).Tokenize();
+              var parser = new Parser(tokens);
+              if (parser.Parse()) {
+                strategyText += "<span class=\"label label-success\" data-toggle=\"tooltip\" data-placement=\"top\" title=\"CONDITIONAL FORMULA\">(FORM)</span> ";
+              }
+              else
+              {
+                strategyText += "<span class=\"label label-danger\" data-toggle=\"tooltip\" data-placement=\"top\" title=\"CONDITIONAL FORMULA\">(FORM)</span> ";  
+              }
+              
             }
             else
             {