package de.skuzzle.polly.core.parser;

import java.util.Collection;
import java.util.EnumMap;
import java.util.Map;
import java.util.Set;
import java.util.TreeSet;

/**
 * This class maps token types which represent operators to a certain precedence level.
 * 
 * @author Simon Taddiken
 */
public class PrecedenceTable {

    public enum PrecedenceLevel {
        RELATION, DISJUNCTION, CONJUNCTION, SECTERM, TERM, FACTOR, POSTFIX, DOTDOT, UNARY;
    }
    
    private Map<PrecedenceLevel, Set<TokenType>> levels;
    
    
    
    public PrecedenceTable() {
        this.levels = new EnumMap<PrecedenceLevel, Set<TokenType>>(PrecedenceLevel.class);
        for (PrecedenceLevel lvl : PrecedenceLevel.values()) {
            this.levels.put(lvl, new TreeSet<TokenType>());
        }
        
        this.add(PrecedenceLevel.RELATION, TokenType.EGT);
        this.add(PrecedenceLevel.RELATION, TokenType.ELT);
        this.add(PrecedenceLevel.RELATION, TokenType.EQ);
        this.add(PrecedenceLevel.RELATION, TokenType.NEQ);
        this.add(PrecedenceLevel.RELATION, TokenType.GT);
        this.add(PrecedenceLevel.RELATION, TokenType.LT);
        this.add(PrecedenceLevel.RELATION, TokenType.EQUIVALENCE);
        this.add(PrecedenceLevel.RELATION, TokenType.IMPLICATION);
        
        this.add(PrecedenceLevel.DISJUNCTION, TokenType.BOOLEAN_OR);
        this.add(PrecedenceLevel.DISJUNCTION, TokenType.INT_OR);
        this.add(PrecedenceLevel.DISJUNCTION, TokenType.XOR);
        this.add(PrecedenceLevel.DISJUNCTION, TokenType.AND_OR);
        
        this.add(PrecedenceLevel.CONJUNCTION, TokenType.BOOLEAN_AND);
        this.add(PrecedenceLevel.CONJUNCTION, TokenType.INT_AND);
        
        this.add(PrecedenceLevel.SECTERM, TokenType.ADD);
        this.add(PrecedenceLevel.SECTERM, TokenType.ADDWAVE);
        this.add(PrecedenceLevel.SECTERM, TokenType.SUB);
        this.add(PrecedenceLevel.SECTERM, TokenType.WAVE);
        this.add(PrecedenceLevel.SECTERM, TokenType.GT); // ISSUE #12: parser makes effort to recognize a rightshift here
        //this.add(PrecedenceLevel.SECTERM, TokenType.URIGHT_SHIFT);
        this.add(PrecedenceLevel.SECTERM, TokenType.LEFT_SHIFT);
        
        // ISSUE 0000099: Add open brace and identifier to TERM precedence level so they
        //                are recognized as multiplications
        this.add(PrecedenceLevel.TERM, TokenType.OPENBR);
        this.add(PrecedenceLevel.TERM, TokenType.IDENTIFIER);
        
        this.add(PrecedenceLevel.TERM, TokenType.MUL);
        this.add(PrecedenceLevel.TERM, TokenType.DIV);
        this.add(PrecedenceLevel.TERM, TokenType.INTDIV);
        this.add(PrecedenceLevel.TERM, TokenType.MOD);
        
        this.add(PrecedenceLevel.FACTOR, TokenType.POWER);
        
        this.add(PrecedenceLevel.POSTFIX, TokenType.OPENSQBR);
        this.add(PrecedenceLevel.POSTFIX, TokenType.QUESTION);
        this.add(PrecedenceLevel.POSTFIX, TokenType.QUEST_EXCALAMTION);
        this.add(PrecedenceLevel.POSTFIX, TokenType.TRANSPOSE);
        
        this.add(PrecedenceLevel.DOTDOT, TokenType.DOTDOT);
        
        this.add(PrecedenceLevel.UNARY, TokenType.SUB);
        this.add(PrecedenceLevel.UNARY, TokenType.EXCLAMATION);
    }
    
    
    
    public boolean match(Token t, PrecedenceLevel level) {
        return this.levels.get(level).contains(t.getType());
    }
    
    
    public void add(PrecedenceLevel level, TokenType t) {
        this.levels.get(level).add(t);
    }
    
    public Collection<TokenType> getLevel(PrecedenceLevel level) {
        return this.levels.get(level);
    }
}