import java.io.*;
import java.util.*;
public class HuffmanLibrary {
	  public static String readFileAsString (String filename) throws FileNotFoundException {
		  Scanner sc = new Scanner( new File(filename));
		  String book = "";
		  while (sc.hasNextLine()){
			  book+=sc.nextLine();
			  book+= " "; //line breaks dont have spaces so i added them
		  }
		  return book;

	  }
	  public static HLinkedList createHlist(String filecontents){
		  HLinkedList list = new HLinkedList();
		  for (int i = 0; i < filecontents.length(); i++){
			  list.addchar(filecontents.charAt(i)); //puts all the characters in the linked list add method
		  }
		  return list;
	  }
	  public static HLinkedList getSortedLinkedList(HLinkedList list){
		  list.sort(); //the sort method is in the linked list class
		  return list;
	  }
	  public static HTree createHuffmanTree(HLinkedList list){
		  return new HTree(list); //the tree is created in the tree constructor
	  }
	  public static void updateCodeValues(HLinkedList list, HTree tree){
		  HTreeNode r = tree.getRoot();
		  codeHelper("",r,list);
	  }
	  private static void codeHelper(String encode, HTreeNode node, HLinkedList list){
		  if(node == null)return;
		  if(node.left == null && node.right==null){//recursive method for encoding each letter
			  list.find(node.getchar()).code = encode;
		  }
		  codeHelper(encode + 0, node.left, list);
		  codeHelper(encode + 1, node.right, list);
	  }

	  public static void Huffman_coder(String input_file, String output_file) throws Exception{
		  String book = readFileAsString (input_file);//read to stri
		  HLinkedList l = createHlist(book);//make Hlist
		  HTree t = createHuffmanTree(l);//make the tree this changes the original hlist
		  HLinkedList l2 = createHlist(book);//another hlist is made to replace it
		  updateCodeValues(l2,t);
		  String codebook = "";
		  for (int i = 0; i < book.length(); i ++){
			  codebook+=l2.find(book.charAt(i)).code;
			  //codebook+=(int)(math.rand()*2) :D
		  }
		  BinaryFileWriter.createBinaryFile(codebook, output_file);


	  }

}