//CipherStreamJava/src/main/java/com/mattrixwv/CipherStreamJava/combination/ADFGX.java
//Mattrixwv
// Created: 01-25-22
//Modified: 07-09-22
package com.mattrixwv.cipherstream.combination;


import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.mattrixwv.cipherstream.exceptions.InvalidCharacterException;
import com.mattrixwv.cipherstream.exceptions.InvalidInputException;
import com.mattrixwv.cipherstream.exceptions.InvalidKeywordException;
import com.mattrixwv.cipherstream.polysubstitution.Columnar;
import com.mattrixwv.cipherstream.polysubstitution.PolybiusSquare;


public class ADFGX{
	private static final Logger logger = LoggerFactory.getLogger(ADFGX.class);

	//Internal fields
	private String inputString;		//The string that needs encoded/decoded
	private String outputString;	//The string that is output after encoding/decoding
	private String squareKeyword;	//The keyword used in the Polybius Square
	private String keyword;			//The keyword used in the Columnar cipher
	private boolean preserveCapitals;	//Whether to respect capitals in the output string
	private boolean preserveWhitespace;	//Whether to respect whitespace in the output string
	private boolean preserveSymbols;	//Whether to respect symbols in the output string
	//Internal ciphers
	private PolybiusSquare polybiusSquare;	//The first step in encoding
	private Columnar columnar;	//The second step in encoding


	//Ensures Polybius keyword constraints
	private void setSquareKeyword(String squareKeyword) throws InvalidKeywordException{
		if(squareKeyword == null){
			throw new InvalidKeywordException("Square keyword cannot be null");
		}

		logger.debug("squareKeyword = {}", squareKeyword);
		this.squareKeyword = squareKeyword;
	}
	//Ensures Columnar keyword constraints
	private void setKeyword(String keyword) throws InvalidKeywordException{
		if(keyword == null){
			throw new InvalidKeywordException("Keyword cannot be null");
		}

		logger.debug("keyword = {}", keyword);
		this.keyword = keyword;
	}
	//Ensures inputString constraints
	private void setInputString(String inputString) throws InvalidInputException{
		if(inputString == null){
			throw new InvalidInputException("Input cannot be null");
		}

		logger.debug("original input string '{}'", inputString);
		if(!preserveCapitals){
			logger.debug("Removing capitals");

			inputString = inputString.toUpperCase();
		}
		if(!preserveWhitespace){
			logger.debug("Removing whitespace");

			inputString = inputString.replaceAll("\\s", "");
		}
		if(!preserveSymbols){
			logger.debug("Removing symbols");

			inputString = inputString.replaceAll("[^a-zA-Z\\s]", "");
		}

		this.inputString = inputString;

		if(this.inputString.isBlank()){
			throw new InvalidInputException("Input cannot be blank");
		}
		logger.debug("cleaned input string '{}'", inputString);
	}
	//Format the output string with capitals, symbols, and numbers that are in the input string
	private void formatOutputStringEncode(){
		logger.debug("Formatting output string to match input string");

		StringBuilder output = new StringBuilder();
		int outputLocation = 0;
		for(char ch : inputString.toCharArray()){
			logger.debug("Input character {}", ch);
			if(Character.isUpperCase(ch)){
				logger.debug("Converting output to uppercase");

				output.append(Character.toUpperCase(outputString.charAt(outputLocation++)));
				output.append(Character.toUpperCase(outputString.charAt(outputLocation++)));
			}
			else if(Character.isLowerCase(ch)){
				logger.debug("Converting output to lowercase");

				output.append(Character.toLowerCase(outputString.charAt(outputLocation++)));
				output.append(Character.toLowerCase(outputString.charAt(outputLocation++)));
			}
			else{
				logger.debug("Appending symbol to output");

				output.append(ch);
			}
		}

		logger.debug("Saving output string '{}'", outputString);
		outputString = output.toString();
	}
	private void formatOutputStringDecode(){
		logger.debug("Formatting output string to match input string");
		StringBuilder output = new StringBuilder();
		int outputLocation = 0;
		for(int inputLocation = 0;inputLocation < inputString.length();++inputLocation){
			char ch = inputString.charAt(inputLocation);
			logger.debug("Input character {}", ch);
			if(Character.isUpperCase(ch)){
				logger.debug("Converting output to uppercase");

				output.append(Character.toUpperCase(outputString.charAt(outputLocation++)));
				++inputLocation;
			}
			else if(Character.isLowerCase(ch)){
				logger.debug("Converting output to lowercase");

				output.append(Character.toLowerCase(outputString.charAt(outputLocation++)));
				++inputLocation;
			}
			else{
				logger.debug("Appending symbol to output");

				output.append(ch);
			}
		}

		logger.debug("Saving output string '{}'", output);
		outputString = output.toString();
	}
	//Encodes the inputString and stores the result in outputString
	private void encode() throws InvalidCharacterException, InvalidInputException, InvalidKeywordException{
		//Encode the input with polybius
		logger.debug("Encoding using Polybius Square");
		String polybiusOutput = polybiusSquare.encode(squareKeyword, inputString);
		squareKeyword = polybiusSquare.getKeyword();
		//Change polybius to use the correct symbols
		logger.debug("Replacing coordinates with letters");
		polybiusOutput = polybiusOutput.replace("1", "A").replace("2", "D").replace("3", "F").replace("4", "G").replace("5", "X");

		//Encode polybius's output with columnar
		logger.debug("Encoding using columnar");
		String columnarOutput = columnar.encode(keyword, polybiusOutput);
		keyword = columnar.getKeyword();
		outputString = columnarOutput;

		//Add whatever is needed to the output string
		formatOutputStringEncode();
	}
	//Decodes the inputString and stores the result in outputString
	private void decode() throws InvalidKeywordException, InvalidCharacterException, InvalidInputException{
		//Decode the input with columnar
		logger.debug("Decoding using columnar");
		String columnarOutput = columnar.decode(keyword, inputString);
		keyword = columnar.getKeyword();

		//Change the symbols to the correct ones for polybius
		logger.debug("Replacing letters with coordinates");
		columnarOutput = columnarOutput.replace("A", "1").replace("D", "2").replace("F", "3").replace("G", "4").replace("X", "5");
		//Decode with polybius
		logger.debug("Decoding using Polybius Square");
		String polybiusOutput = polybiusSquare.decode(squareKeyword, columnarOutput);
		squareKeyword = polybiusSquare.getKeyword();
		outputString = polybiusOutput;

		//Add whatever is needed to the output string
		formatOutputStringDecode();
	}


	//Constructor
	public ADFGX() throws InvalidCharacterException{
		preserveCapitals = false;
		preserveWhitespace = false;
		preserveSymbols = false;
		reset();
	}
	public ADFGX(boolean preserveCapitals, boolean preserveWhitespace, boolean preserveSymbols) throws InvalidCharacterException{
		this.preserveCapitals = preserveCapitals;
		this.preserveWhitespace = preserveWhitespace;
		this.preserveSymbols = preserveSymbols;
		reset();
	}

	//Encodes inputString using keyword and returns the result
	public String encode(String squareKeyword, String keyword, String inputString) throws InvalidKeywordException, InvalidInputException, InvalidCharacterException{
		setSquareKeyword(squareKeyword);
		setKeyword(keyword);
		setInputString(inputString);
		encode();
		return outputString;
	}
	//Decodes inputString using keyword and returns the result
	public String decode(String squareKeyword, String keyword, String inputString) throws InvalidKeywordException, InvalidInputException, InvalidCharacterException{
		setSquareKeyword(squareKeyword);
		setKeyword(keyword);
		setInputString(inputString);
		decode();
		return outputString;
	}

	//Returns the cleaned inputString
	public String getInputString(){
		return inputString;
	}
	//Returns the outputString
	public String getOutputString(){
		return outputString;
	}
	//Returns the cleaned Polybius Square keyword
	public String getSquareKeyword(){
		return squareKeyword;
	}
	//Returns the cleaned Columnar keyword
	public String getKeyword(){
		return keyword;
	}
	//Makes sure all of the variables are empty
	public void reset() throws InvalidCharacterException{
		logger.debug("Resetting fields");

		polybiusSquare = new PolybiusSquare(false, false);
		columnar = new Columnar(false, false, false, true, 'B');
		inputString = "";
		outputString = "";
		squareKeyword = "";
		keyword = "";
	}
}