package com.cp.brainfuck;

import java.util.Stack;
import java.util.EmptyStackException;
import java.util.ArrayList;
import com.cp.ircbot.bot.IRCBot;

public class BrainfuckInterpreter
{
    private ArrayList<BrainfuckThread> threads;
    private IRCBot bot;

    public BrainfuckInterpreter(IRCBot bot)
    {
        this.bot = bot;
        threads = new ArrayList<BrainfuckThread>();
    }

    public ArrayList<String> cleanup()
    {
        ArrayList<BrainfuckThread> toRemove = new ArrayList<BrainfuckThread>();
        ArrayList<String> output = new ArrayList<String>();
        for (BrainfuckThread thread : threads)
        {
            if (!thread.isRunning())
                toRemove.add(thread);
        }
        for (BrainfuckThread thread : toRemove)
        {
            if (!thread.getOutput().getOutput().equals(""))
            {
                output.add(thread.getOutput().getOutput());
            }
        }
        threads.removeAll(toRemove);
        return output;
    }

    public BrainfuckThread execute(String brainfuck) throws BrainfuckParseError
    {
        return execute(brainfuck.toCharArray());
    }

    public BrainfuckThread execute(char[] brainfuck) throws BrainfuckParseError
    {
        char[] segments = parse(brainfuck);
        BrainfuckThread thread = new BrainfuckThread(brainfuck, segments, new BrainfuckWriter());
        threads.add(thread);
        return thread;
    }

    private char[] parse(char[] brainfuck) throws BrainfuckParseError
    {
        char[] codeStack = new char[brainfuck.length];
        Stack<Integer> stack = new Stack<Integer>();
        for (int index = 0; index < brainfuck.length; index++)
        {
            switch (brainfuck[index])
            {
                case '[':
                    stack.push(index);
                    break;
                case ']':
                    try
                    {
                        int x = stack.pop();
                        codeStack[x] = (char) index;
                        codeStack[index] = (char) x;
                    } catch (EmptyStackException e)
                    {
                        throw new BrainfuckParseError("Unbalanced brackets");
                    }
                    break;
            }
        }
        if (!stack.isEmpty())
            throw new BrainfuckParseError("Unclosed bracket");
        return codeStack;
    }

}