package bjc.rgens.text.markov;

import java.io.IOException;
import java.io.Reader;
import java.util.HashMap;
import java.util.Map;

/**
 * Create a Markov generate from a provided source.
 *
 * @author bjculkin
 *
 */
public class StandaloneTextGenerator {
	/**
	 * Build a markov generator from a provided source.
	 *
	 * @param order
	 *                The markov order to use.
	 *
	 * @param reader
	 *                The source to seed the generator from.
	 *
	 * @return The markov generator for the provided text.
	 */
	public static StandaloneMarkov generateMarkovMap(int order, Reader reader) {
		Map<String, Markov> hash = new HashMap<>();

		Character next = null;

		try {
			next = (char) reader.read();
		} catch (IOException e1) {
			System.out.println("IOException in stepping through the reader");

			e1.printStackTrace();

			System.exit(1);
		}

		StringBuilder origFileBuffer = new StringBuilder();

		while (next != null && Character.isDefined(next)) {
			Character.toString(next);
			origFileBuffer.append(next);

			try {
				next = (char) reader.read();
			} catch (IOException e) {
				System.out.println("IOException in stepping through the reader");

				e.printStackTrace();
			}

		}

		String origFile = origFileBuffer.toString();
		String firstSub = origFile.substring(0, order);

		for (int i = 0; i < origFile.length() - order; i++) {
			String sub = origFile.substring(i, i + order);
			Character suffix = origFile.charAt(i + order);

			if (hash.containsKey(sub)) {
				Markov marvin = hash.get(sub);
				marvin.add(suffix);
				hash.put(sub, marvin);
			} else {
				Markov marvin = new Markov(sub, suffix);
				hash.put(sub, marvin);
			}
		}

		return new StandaloneMarkov(order, hash, firstSub);
	}
}