1 files changed, 310 insertions, 0 deletions
diff --git a/base/src/bjc/dicelang/dice/DiceBox.java b/base/src/bjc/dicelang/dice/DiceBox.java
new file mode 100644
index 0000000..8d00d96
--- /dev/null
+++ b/base/src/bjc/dicelang/dice/DiceBox.java
@@ -0,0 +1,310 @@
+package bjc.dicelang.dice;
+
+import java.util.Random;
+import java.util.function.Predicate;
+import java.util.regex.Pattern;
+
+/**
+ * Contains static methods for producing dice from strings.
+ *
+ * @author Ben Culkin
+ */
+public class DiceBox {
+	static final Random rng = new Random();
+
+	/**
+	 * Parse a die expression from a string.
+	 *
+	 * @param expString
+	 *                The string to parse.
+	 *
+	 * @return The die expression from the string, or null if it wasn't one
+	 */
+	public static DieExpression parseExpression(final String expString) {
+		try {
+			return doParseExpression(expString);
+		} catch (Exception ex) {
+			/*
+			 * @TODO 10/08/17 Ben Culkin :DieErrors :ErrorRefactor
+			 * 	Use different types of exceptions to provide
+			 * 	better error messages. 
+			 */
+			String exMessage = ex.getMessage();
+
+			System.out.printf("ERROR: Could not parse die expression (Cause: %s)\n", exMessage);
+			ex.printStackTrace();
+
+			return null;
+		}
+	}
+
+	private static DieExpression doParseExpression(final String expString) {
+		/* Only bother with valid expressions. */
+		if (!isValidExpression(expString)) {
+			return null;
+		}
+
+		if (scalarDiePattern.matcher(expString).matches()) {
+			/* Parse scalar die. */
+			/* @TODO 10/08/17 Ben Culkin :SubstringIndexOf
+			 * 	This substring/index of call should be
+			 * 	abstracted into its own method so as to make the
+			 * 	code more explanatory and ensure that things
+			 * 	like the return code of indexOf are correctly
+			 * 	checked.
+			 */
+			final String dieString = expString.substring(0, expString.indexOf('s'));
+
+			final long lar = Long.parseLong(dieString);
+
+			final Die scal = new ScalarDie(lar);
+
+			return new DieExpression(scal);
+		} else if (simpleDiePattern.matcher(expString).matches()) {
+			/* Parse simple die groups. */
+			final String[] dieParts = expString.split("d");
+
+			final long right = Long.parseLong(dieParts[1]);
+			final long left;
+
+			if (dieParts[0].equals("")) {
+				/* Handle short-form expressions. */
+				left = 1;
+			} else {
+				left = Long.parseLong(dieParts[0]);
+			}
+
+			final Die scal = new SimpleDie(left, right);
+
+			return new DieExpression(scal);
+		} else if (fudgeDiePattern.matcher(expString).matches()) {
+			/* Parse fudge dice. */
+			/* :SubstringIndexOf */
+			final String nDice = expString.substring(0, expString.indexOf('d'));
+			final Die fudge    = new FudgeDie(Long.parseLong(nDice));
+
+			return new DieExpression(fudge);
+		} else if (compoundDiePattern.matcher(expString).matches()) {
+			/* Parse compound die expressions. */
+			final String[] dieParts = expString.split("c");
+
+			/* @TODO 10/08/17 :SplitParse
+			 * 	Should this split string/parse split parts be
+			 * 	abstracted into something else that handles
+			 * 	doing the splitting correctly, as well as
+			 * 	making sure that the resulting DieExpressions
+			 * 	are of the right type?
+			 */
+			final DieExpression left  = parseExpression(dieParts[0]);
+			final DieExpression right = parseExpression(dieParts[1]);
+
+			/* :ErrorRefactor */
+			if (left.isList) {
+				System.out.printf("ERROR: Expected a scalar die expression for lhs of compound die, got a list expression instead (%s)\n",
+				                  left);
+			} else if (right.isList) {
+				System.out.printf("ERROR: Expected a scalar die expression for rhs of compound die, got a list expression instead (%s)\n",
+				                  right);
+			}
+
+			final Die compound = new CompoundDie(left.scalar, right.scalar);
+
+			return new DieExpression(new CompoundDie(left.scalar, right.scalar));
+		} else if (compoundingDiePattern.matcher(expString).matches()) {
+			/* Parse compounding die expressions. */
+			final String[] dieParts = expString.split("!!");
+
+			final DieExpression left    = parseExpression(dieParts[0]);
+			final Predicate<Long> right = deriveCond(dieParts[1]);
+
+			final Die scal = new CompoundingDie(left.scalar, right, dieParts[1]);
+
+			return new DieExpression(scal);
+		} else if (explodingDiePattern.matcher(expString).matches()) {
+			/* Parse exploding die expressions. */
+			final String[] dieParts = expString.split("!");
+
+			final DieExpression left    = parseExpression(dieParts[0]);
+			final Predicate<Long> right = deriveCond(dieParts[1]);
+
+			final DieList lst = new ExplodingDice(left.scalar, right, dieParts[1], false);
+
+			return new DieExpression(lst);
+		} else if (penetratingDiePattern.matcher(expString).matches()) {
+			/* Parse penetrating die expressions. */
+			final String[] dieParts = expString.split("p!");
+
+			final DieExpression left    = parseExpression(dieParts[0]);
+			final Predicate<Long> right = deriveCond(dieParts[1]);
+
+			final DieList lst = new ExplodingDice(left.scalar, right, dieParts[1], true);
+
+			return new DieExpression(lst);
+		} else if (diceListPattern.matcher(expString).matches()) {
+			/* Parse simple die lists. */
+			final String[] dieParts = expString.split("dl");
+
+			final DieExpression left  = parseExpression(dieParts[0]);
+			final DieExpression right = parseExpression(dieParts[1]);
+
+			final DieList lst = new SimpleDieList(left.scalar, right.scalar);
+			return new DieExpression(lst);
+		}
+
+		/* Unhandled type of die expression. */
+		System.out.printf("INTERNAL ERROR: Valid die expression '%s' not parsed\n", expString);
+		return null;
+	}
+
+	/* The strings and patterns used for matching. */
+	/* @TODO 10/08/17 Ben Culkin :RegexResource
+	 * 	These regexes and patterns should be moved to something
+	 * 	external, probably using the SimpleProperties-based system that
+	 * 	BJC-Utils2 uses.
+	 */
+	/* Defines a comparison predicate. */
+	private static final String comparePoint = "[<>=]\\d+";
+
+	/*
+	 * Defines a scalar die.
+	 *
+	 * This is just a number.
+	 */
+	private static final String     scalarDie        = "[\\+\\-]?\\d+sd";
+	private static final Pattern    scalarDiePattern = Pattern.compile(
+	                        String.format("\\A%s\\Z", scalarDie));
+
+	/*
+	 * Defines a simple die.
+	 *
+	 * This is a group of one or more dice of the same size.
+	 */
+	private static final String     simpleDie               = "(?:\\d+)?d\\d+";
+	private static final Pattern    simpleDiePattern        = Pattern.compile("\\A" +
+	                simpleDie + "\\Z");
+
+	/*
+	 * Defines a fudge die.
+	 *
+	 * This is like a simple die, but all the die give -1, 0, or 1 as
+	 * results.
+	 */
+	private static final String     fudgeDie        = "(?:\\d+)?dF";
+	private static final Pattern    fudgeDiePattern = Pattern.compile("\\A" + fudgeDie +
+	                "\\Z");
+
+	/*
+	 * Defines a compound die.
+	 *
+	 * This is like using two d10's to simulate a d100
+	 */
+	private static final String     compoundDie             = simpleDie + "c(?:(?:" +
+	                simpleDie + ")|(?:\\d+))";
+	private static final Pattern    compoundDiePattern      = Pattern.compile("\\A" +
+	                compoundDie + "\\Z");
+
+	/*
+	 * Defines a compound group.
+	 *
+	 * This is used for forming die list type expressions.
+	 */
+	private static final String compoundGroup = "(?:(?:" + scalarDie + ")|(?:" + simpleDie +
+	                ")|(?:" + compoundDie
+	                + ")|(?:" + fudgeDie + "))";
+
+	/*
+	 * Defines a compounding die.
+	 *
+	 * This is like an exploding die, but is a single die, not a group of
+	 * them.
+	 */
+	private static final String     compoundingDie          = compoundGroup + "!!" +
+	                comparePoint;
+	private static final Pattern    compoundingDiePattern   = Pattern.compile("\\A" +
+	                compoundingDie + "\\Z");
+
+	/*
+	 * Defines an exploding die.
+	 *
+	 * This is a die that you reroll the component of if it meets a certain
+	 * condition.
+	 */
+	private static final String     explodingDie            = compoundGroup + "!" +
+	                comparePoint;
+	private static final Pattern    explodingDiePattern     = Pattern.compile("\\A" +
+	                explodingDie + "\\Z");
+
+	/*
+	 * Defines a penetrating die.
+	 *
+	 * This is like an exploding die, but the exploded result gets a -1
+	 * penalty.
+	 */
+	private static final String     penetratingDie          = compoundGroup + "!" +
+	                comparePoint;
+	private static final Pattern    penetratingDiePattern   = Pattern.compile("\\A" +
+	                penetratingDie + "\\Z");
+
+	/*
+	 * Defines a die list.
+	 *
+	 * This is an array of dice of the specified size.
+	 */
+	private static final String     diceList        = compoundGroup + "dl" + compoundGroup;
+	private static final Pattern    diceListPattern = Pattern.compile("\\A" + diceList +
+	                "\\Z");
+
+	/**
+	 * Check if a given string is a valid die expression.
+	 *
+	 * @param exp
+	 *                The string to check validity of.
+	 *
+	 * @return Whether or not the string is a valid command.
+	 */
+	public static boolean isValidExpression(final String exp) {
+		/* @NOTE
+		 * 	Should this matcher/matches expression be abstracted in
+		 * 	some way?
+		 */
+		if (scalarDiePattern.matcher(exp).matches()) {
+			return true;
+		} else if (simpleDiePattern.matcher(exp).matches()) {
+			return true;
+		} else if (fudgeDiePattern.matcher(exp).matches()) {
+			return true;
+		} else if (compoundDiePattern.matcher(exp).matches()) {
+			return true;
+		} else if (compoundingDiePattern.matcher(exp).matches()) {
+			return true;
+		} else if (explodingDiePattern.matcher(exp).matches()) {
+			return true;
+		} else if (penetratingDiePattern.matcher(exp).matches()) {
+			return true;
+		} else if (diceListPattern.matcher(exp).matches()) {
+			return true;
+		} else {
+			return false;
+		}
+	}
+
+	/* Derive a predicate from a compare point */
+	private static Predicate<Long> deriveCond(final String patt) {
+		final long num = Long.parseLong(patt.substring(1));
+
+		/* @NOTE
+		 * 	Should this be extended in some way, to provide other
+		 * 	operators?
+		 */
+		switch (patt.charAt(0)) {
+		case '<':
+			return (roll) -> (roll < num);
+		case '=':
+			return (roll) -> (roll == num);
+		case '>':
+			return (roll) -> (roll > num);
+		default:
+			return (roll) -> (false);
+		}
+	}
+}