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package se.l4.commons.serialization.format;

import java.io.IOException;

public abstract class AbstractStreamingInput
	implements StreamingInput
{
	private Object value;
	private Token token;
	
	protected int level;
	
	public AbstractStreamingInput()
	{
	}
	
	protected void setValue(Object value)
	{
		this.value = value;
	}
	
	@Override
	public Token next()
		throws IOException
	{
		Token token = next0();
		switch(token)
		{
			case OBJECT_END:
			case LIST_END:
				level--;
				break;
			case OBJECT_START:
			case LIST_START:
				level++;
				break;
			default: // Do nothing
		}
		
		return this.token = token;
	}
	
	protected abstract Token next0()
		throws IOException;
	
	protected IOException raiseException(String message)
	{
		return new IOException(message);
	}
	
	@Override
	public Token next(Token expected)
		throws IOException
	{
		Token t = next();
		if(t != expected)
		{
			throw raiseException("Expected "+ expected + " but got " + t);
		}
		return t;
	}
	
	@Override
	public void skipValue()
		throws IOException
	{
		if(token != Token.KEY)
		{
			throw raiseException("Value skipping can only be used with when token is " + Token.KEY);
		}
		
		switch(peek())
		{
			case LIST_START:
			case LIST_END:
			case OBJECT_START:
			case OBJECT_END:
				next();
				skip();
				break;
			default:
				next();
		}
	}
	
	@Override
	public void skip()
		throws IOException
	{
		Token start = token;
		Token stop;
		switch(token)
		{
			case LIST_START:
				stop = Token.LIST_END;
				break;
			case OBJECT_START:
				stop = Token.OBJECT_END;
				break;
			case VALUE:
				return;
			default:
				throw raiseException("Can only skip when start of object, start of list or value, token is now " + token);
		}
		
		int currentLevel = level;
		Token next = peek();
		while(true)
		{
			// Loop until no more tokens or if we stopped and the level has been reset
			if(next == null)
			{
				throw raiseException("No more tokens, but end of skipped value not found. Started at " + start + " and tried to find " + stop);
			}
			else if(next == stop && level == currentLevel)
			{
				// Consume this last token
				next();
				break;
			}

			// Read peeked value and peek for next one
			next();
			next = peek(); 
		}
	}
	
	@Override
	public Token current()
	{
		return token;
	}
	
	@Override
	public Object getValue()
	{
		return value;
	}
	
	@Override
	public String getString()
	{
		return (String) value;
	}

	@Override
	public boolean getBoolean()
	{
		return (Boolean) value;
	}
	
	@Override
	public double getDouble()
	{
		return ((Number) value).doubleValue();
	}
	
	@Override
	public float getFloat()
	{
		return ((Number) value).floatValue();
	}
	
	@Override
	public long getLong()
	{
		return ((Number) value).longValue();
	}
	
	@Override
	public int getInt()
	{
		return ((Number) value).intValue();
	}
	
	@Override
	public short getShort()
	{
		return ((Number) value).shortValue();
	}
	
	@Override
	public byte[] getByteArray()
	{
		return (byte[]) value;
	}
}