import java.util.ArrayList;

/**
 * Derived class that represents a repeat statement in the SILLY language.
 *   @author Dave Reed
 *   @version 2/8/15
 */
public class Repeat extends Statement {
    private Expression expr;
    private ArrayList<Statement> stmts;  
    
    /**
     * Reads in a repeat statement from the specified stream
     *   @param input the stream to be read from
     */
	public Repeat(TokenStream input) throws Exception {
        Token keyword = input.next();
        if (!keyword.toString().equals("repeat")) {
	        throw new Exception("SYNTAX ERROR: Malformed while statement");
	    }

	    this.expr = new Expression(input);
        this.stmts = new ArrayList<Statement>();
        
        while (!input.lookAhead().toString().equals("end")) {
            this.stmts.add(Statement.getStatement(input));
        } 
        input.next(); 
	}
    
    /**
	 * Executes the current repeat statement.
	 */
	public void execute() throws Exception {
		Object val = this.expr.evaluate().getValue();
	    if (val instanceof Integer) {
	    	int numReps = ((Integer) val).intValue();
		    for (int i = 0; i < numReps; i++) {
		        for (Statement stmt : this.stmts) {
		            stmt.execute();
		        }
		    }
	    }
	    else {
	    	throw new Exception("RUNTIME ERROR: Repeat expression must be an integer");
	    }
	}
	
	/**
	 * Converts the current repeat statement into a String.
	 *   @return the String representation of this statement
	 */
    public String toString() {
        String str = "repeat " + this.expr + "\n";
        for (Statement stmt : this.stmts) {
            str += "    " + stmt + "\n";
        }
        return str + "end";
    }
}