package org.cfml.util;

import java.util.*;
import java.util.regex.*;

import org.cfml.Code;
import org.cfml.instr.Instruction;

public class InstructionFinder {
	private Code code;
	private int position = 0;

	public InstructionFinder(Code c) {
		code = c;
	}

	public void setCode(Code c) {
		code = c;
		position = 0;
	}

	public Code code() {
		return code;
	}

	public Instruction[][] find(String regex) {
		return find(regex, null);
	}

	public Instruction[][] find(String regex, MatchVerifier mv) {
		Instruction[] instructions = code.instructions();
		StringBuffer sb = new StringBuffer();
		if(instructions.length > 0) {
			sb.append(instructions[0].name());
			for(int i = 1; i < instructions.length; i++)
				sb.append(' ' + instructions[i].name());
		}
		Matcher m = Pattern.compile(regex).matcher(sb);
		List<Instruction[]> matches = new Vector<Instruction[]>();
		int found = 0;
		while(m.find()) {
			if(m.start() != 0 && sb.charAt(m.start() - 1) != ' ')
				continue;
			int start = sb.substring(0, m.start()).split(" ").length;
			if(m.start() == 0 && start == 1)
				start = 0;
			Instruction[] match = new Instruction[sb.substring(0, m.end()).split(" ").length - start];
			System.arraycopy(instructions, start, match, 0, match.length);
			if(mv != null && !mv.verify(match))
				continue;
			matches.add(match);
			found++;
		}
		return matches.toArray(new Instruction[found][]);
	}

	public Instruction[] findNext(String regex) {
		return findNext(regex, null);
	}

	public Instruction[] findNext(String regex, MatchVerifier mv) {
		Instruction[] instructions = code.instructions();
		StringBuffer sb = new StringBuffer();
		if(instructions.length > position) {
			sb.append(instructions[position].name());
			for(int i = position + 1; i < instructions.length; i++)
				sb.append(' ' + instructions[i].name());
		}
		Matcher m = Pattern.compile(regex).matcher(sb);
		while(m.find()) {
			if(m.start() != 0 && sb.charAt(m.start() - 1) != ' ')
				continue;
			int start = sb.substring(0, m.start()).split(" ").length;
			if(m.start() == 0 && start == 1)
				start = 0;
			Instruction[] match = new Instruction[sb.substring(0, m.end()).split(" ").length - start];
			System.arraycopy(instructions, position + start, match, 0, match.length);
			if(mv != null && !mv.verify(match))
				continue;
			position = position + start + match.length;
			return match;
		}
		return null;
	}

	public static interface MatchVerifier {
		public boolean verify(Instruction[] match);
	}
}