/*
 * 10/28/2004
 * DefaultTokenFactory.java - Default token factory.
 * This library is distributed under a modified BSD license. See the included
 * RSyntaxTextArea.License.txt file for details.
 */
package org.fife.ui.rsyntaxtextarea;

import javax.swing.text.Segment;

/**
 * This class generates tokens for a {@link TokenMaker}. This class is here
 * because it reuses tokens when they aren't needed anymore to prevent This
 * class doesn't actually create new tokens every time <code>createToken</code>
 * is called. Instead, it internally keeps a stack of available already-created
 * tokens. When more tokens are needed to properly display a line, more tokens
 * are added to the available stack. This saves from needless repetitive memory
 * allocation. However, it makes it IMPERATIVE that users call
 * <code>resetTokenList</code> when creating a new token list so that the token
 * maker can keep an accurate list of available tokens.
 * <p>
 *
 * NOTE: This class should only be used by {@link TokenMaker}; nobody else needs
 * it!
 *
 * @author Robert Futrell
 * @version 0.1
 */
class DefaultTokenFactory implements TokenFactory {

	private int size;
	private int increment;
	private TokenImpl[] tokenList;
	private int currentFreeToken;
	protected static final int DEFAULT_START_SIZE = 30;
	protected static final int DEFAULT_INCREMENT = 10;

	/**
	 * Constructor.
	 */
	DefaultTokenFactory() {
		this(DEFAULT_START_SIZE, DEFAULT_INCREMENT);
	}

	/**
	 * Constructor.
	 *
	 * @param size      The initial number of tokens in this factory.
	 * @param increment How many tokens to increment by when the stack gets empty.
	 */
	DefaultTokenFactory(int size, int increment) {
		this.size = size;
		this.increment = increment;
		this.currentFreeToken = 0;
		// Give us some tokens to initially work with.
		tokenList = new TokenImpl[size];
		for (int i = 0; i < size; i++) {
			tokenList[i] = new TokenImpl();
		}
	}

	/**
	 * Adds tokens to the internal token list. This is called whenever a request is
	 * made and no more tokens are available.
	 */
	private void augmentTokenList() {
		TokenImpl[] temp = new TokenImpl[size + increment];
		System.arraycopy(tokenList, 0, temp, 0, size);
		size += increment;
		tokenList = temp;
		for (int i = 0; i < increment; i++) {
			tokenList[size - i - 1] = new TokenImpl();
		}
		// System.err.println("... size up to: " + size);
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public TokenImpl createToken() {
		TokenImpl token = tokenList[currentFreeToken];
		token.reset();
		if (++currentFreeToken == size) {
			augmentTokenList();
		}
		return token;
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public TokenImpl createToken(final Segment line, final int beg, final int end, final int startOffset,
			final int type) {
		return createToken(line.array, beg, end, startOffset, type);
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public TokenImpl createToken(final char[] line, final int beg, final int end, final int startOffset,
			final int type) {
//		if (tokenList.length - 1 > currentFreeToken)
//			return null;
		TokenImpl token = tokenList[currentFreeToken];
		token.set(line, beg, end, startOffset, type);
		currentFreeToken++;
		if (currentFreeToken == size) {
			augmentTokenList();
		}
		return token;
	}

	/**
	 * Resets the state of this token maker. This method should be called by the
	 * <code>TokenMaker</code> every time a token list is generated for a new line
	 * so the tokens can be reused.
	 */
	@Override
	public void resetAllTokens() {
		currentFreeToken = 0;
	}
}