//CipherStreamJava/src/main/java/com/mattrixwv/CipherStreamJava/polySubstitution/Trifid.java
//Mattrixwv
// Created: 03-03-22
//Modified: 03-03-22
package com.mattrixwv.cipherstream.polysubstitution;


import java.util.ArrayList;
import java.util.StringJoiner;

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.exceptions.InvalidBaseException;


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

	//A class representing the location of a character in the grid
	private class CharLocation{
		private int x;
		private int y;
		private int z;
		public CharLocation(int x, int y, int z){
			this.x = x;
			this.y = y;
			this.z = z;
		}
		public int getX(){
			return x;
		}
		public int getY(){
			return y;
		}
		public int getZ(){
			return z;
		}
		public String toString(){
			return "[" + (z + 1) + ", " + (x + 1) + ", " + (y + 1) + "]";
		}
	}

	//Fields
	private String inputString;		//The message that needs to be encoded/decoded
	private String outputString;	//The encoded/decoded message
	private String keyword;			//The keyword used to create the grid
	private int groupSize;			//The size of the groups used to break up the input
	private char[][][] grid;		//The grid used to encode/decode the message
	private char fillIn;	//The character added to the alphabet to meet the 27 character requirement
	private boolean preserveCapitals;	//Persist capitals in the output string
	private boolean preserveWhitespace;	//Persist whitespace in the output string
	private boolean preserveSymbols;	//Persist symbols in the output string

	//Makes sure the fillIn is a valid character
	private void setFillIn(char fillIn) throws InvalidCharacterException{
		//Make sure the character is a printing character
		if((fillIn < ' ') || (fillIn > '~')){
			throw new InvalidCharacterException("Fill in character must be a printing character");
		}
		//Make sure the character is not a letter
		if(Character.isAlphabetic(fillIn)){
			throw new InvalidCharacterException("Fill in must not be a letter");
		}

		logger.debug("Setting fill in {}", fillIn);

		//Save the fillIn character
		this.fillIn = fillIn;
	}
	//Strips invalid characters from the keyword and creates the grid
	private void setKeyword(String keyword) throws InvalidKeywordException{
		//Ensure the keyword isn't null
		if(keyword == null){
			throw new InvalidKeywordException("Keyword cannot be null");
		}

		logger.debug("Original keyword {}", keyword);

		//Change everything to uppercase
		logger.debug("Removing case");
		keyword = keyword.toUpperCase();

		//Remove everything except capital letters
		logger.debug("Removing all invalid characters");
		keyword = keyword.replaceAll("[^A-Z" + fillIn + "]", "");

		//Add all letters in the alphabet and fillIn to the key
		logger.debug("Appending entire alphabet to keyword");
		keyword += "ABCDEFGHIJKLMNOPQRSTUVWXYZ" + fillIn;

		//Remove all duplicate characters
		logger.debug("Removing duplicated characters");
		StringBuilder uniqueKey = new StringBuilder();
		keyword.chars().distinct().forEach(c -> uniqueKey.append((char)c));
		this.keyword = uniqueKey.toString();

		logger.debug("Cleaned keyword {}", this.keyword);

		//Create the grid from the sanitized keyword
		createGrid();
	}
	//Creates the grid from the keyword
	private void createGrid(){
		logger.debug("Creating grid from keyword");

		for(int layerCnt = 0;layerCnt < grid.length;++layerCnt){
			for(int rowCnt = 0;rowCnt < grid[layerCnt].length;++rowCnt){
				for(int colCnt = 0;colCnt < grid[layerCnt][rowCnt].length;++colCnt){
					int loc = 0;
					loc = colCnt + (rowCnt * grid[layerCnt][rowCnt].length) + (layerCnt * grid[layerCnt].length * grid[layerCnt][rowCnt].length);
					grid[layerCnt][rowCnt][colCnt] = keyword.charAt(loc);
				}
			}
		}

		logger.debug("Completed grid\n{}", getGrid());
	}
	//Ensures groupSize constraints
	private void setGroupSize(int groupSize) throws InvalidBaseException{
		if(groupSize <= 0){
			throw new InvalidBaseException("Group size must be > 0");
		}

		logger.debug("Setting group size");

		this.groupSize = groupSize;
	}
	//Ensures inputString constraints
	private void setInputString(String inputString) throws InvalidInputException{
		//Ensure the input string isn't null
		if(inputString == null){
			throw new InvalidInputException("Input cannot be null");
		}

		logger.debug("Original input string '{}'", inputString);

		//Apply removal options
		if(!preserveCapitals){
			logger.debug("Removing case");
			inputString = inputString.toUpperCase();
		}
		if(!preserveWhitespace){
			if(Character.isWhitespace(fillIn)){
				throw new InvalidInputException("If fillIn is whitespace, whitespace must be preserved");
			}
			logger.debug("Removing whitespace");
			inputString = inputString.replaceAll("\\s", "");
		}
		if(!preserveSymbols){
			logger.debug("Removing symbols");
			inputString = inputString.replaceAll("[^a-zA-Z" + fillIn + "\\s]", "");
		}

		//Save the string
		logger.debug("Cleaned input string '{}'", inputString);
		this.inputString = inputString;

		//Ensure the string isn't blank
		if(this.inputString.isBlank()){
			throw new InvalidInputException("Input must contain at least 1 letter");
		}
	}
	//Returns the inputString with only letters
	private String getCleanInputString(){
		logger.debug("Cleaning input string for encoding");
		return inputString.toUpperCase().replaceAll("[^A-Z" + fillIn + "]", "");
	}
	//Returns the location of the given character in the grid
	private CharLocation findChar(char letter) throws InvalidCharacterException{
		logger.debug("Finding character {} in grid", letter);

		for(int layer = 0;layer < grid.length;++layer){
			for(int row = 0;row < grid[layer].length;++row){
				for(int col = 0;col < grid[layer][row].length;++col){
					if(grid[layer][row][col] == letter){
						logger.debug("Found at {} {} {}", layer, row, col);

						return new CharLocation(row, col, layer);
					}
				}
			}
		}

		//If it was not found something went wrong
		throw new InvalidCharacterException("The character '" + letter + "' was not found in the grid");
	}
	//Return the character from the location provided
	private char getChar(CharLocation location) throws InvalidCharacterException{
		if(location.getX() > 2){
			throw new InvalidCharacterException("x cannot be larget than 2");
		}
		if(location.getY() > 2){
			throw new InvalidCharacterException("y cannot be larget than 2");
		}
		if(location.getZ() > 2){
			throw new InvalidCharacterException("z cannot be larget than 2");
		}

		logger.debug("Getting character at {} {} {}", location.getZ(), location.getX(), location.getY());

		return grid[location.getZ()][location.getX()][location.getY()];
	}
	//Adds all non-letter characters back to the output string
	private void formatOutput(String outputString){
		logger.debug("Formatting output");

		//Keep track of where you are in the output
		int outputCnt = 0;
		StringBuilder output = new StringBuilder();
		//Check every character in the input and apply the correct rules to the output
		for(char ch : inputString.toCharArray()){
			logger.debug("Working character {}", ch);
			if(Character.isUpperCase(ch)){
				logger.debug("Formatting uppercase");
				output.append(Character.toUpperCase(outputString.charAt(outputCnt++)));
			}
			else if(Character.isLowerCase(ch)){
				logger.debug("Formatting lowercase");
				output.append(Character.toLowerCase(outputString.charAt(outputCnt++)));
			}
			else{
				logger.debug("Appending symbol");
				output.append(ch);
			}
		}

		//Save the output
		logger.debug("Formatted output '{}'", output);
		this.outputString = output.toString();
	}
	//Encodes inputString using a polybius square and stores the result in outputString
	private void encode() throws InvalidCharacterException{
		logger.debug("Encoding");

		//Step through every element in the sanitized inputString encoding the letters
		logger.debug("Conveting letters to coordinates");
		ArrayList<CharLocation> locations = new ArrayList<>();
		for(char ch : getCleanInputString().toCharArray()){
			//Get the location of the char in the grid
			CharLocation location = findChar(ch);
			locations.add(location);
		}

		//Split the locations up by group
		logger.debug("Splitting locations into groups");
		int numGroups = inputString.length() / groupSize;
		if(numGroups == 0){
			numGroups = 1;
		}
		ArrayList<ArrayList<CharLocation>> groups = new ArrayList<>(numGroups);
		for(int cnt = 0;cnt < numGroups;++cnt){
			groups.add(new ArrayList<>());
		}
		int groupCnt = -1;
		for(int locCnt = 0;locCnt < locations.size();++locCnt){
			//If you've reached the end of the group move to the next one
			if((locCnt % groupSize) == 0){
				++groupCnt;
			}
			groups.get(groupCnt).add(locations.get(locCnt));
		}

		//Split the coordinates into rows
		logger.debug("Splitting groups into rows");
		ArrayList<Integer> coordinates = new ArrayList<>(locations.size() * 3);
		for(ArrayList<CharLocation> group : groups){
			//Split the coordinates up into 3 rows
			ArrayList<Integer> layers = new ArrayList<>(group.size());
			ArrayList<Integer> rows = new ArrayList<>(group.size());
			ArrayList<Integer> cols = new ArrayList<>(group.size());
			for(CharLocation loc : group){
				layers.add(loc.getZ());
				rows.add(loc.getX());
				cols.add(loc.getY());
			}
			coordinates.addAll(layers);
			coordinates.addAll(rows);
			coordinates.addAll(cols);
		}
		//Create new locations from the rows of coordinates
		logger.debug("Converting split locations into new locations");
		ArrayList<CharLocation> newLocations = new ArrayList<>(locations.size());
		for(int cnt = 0;cnt < coordinates.size();){
			int z = coordinates.get(cnt++);
			int x = coordinates.get(cnt++);
			int y = coordinates.get(cnt++);
			newLocations.add(new CharLocation(x, y, z));
		}

		//Get the new letters from the grid
		logger.debug("Converting new locations into characters");
		StringBuilder output = new StringBuilder();
		for(CharLocation loc : newLocations){
			output.append(getChar(loc));
		}

		//Format the output
		formatOutput(output.toString());
	}
	//Decodes inputString using a polybius square and stores the result in outputString
	private void decode() throws InvalidCharacterException{
		logger.debug("Decoding");

		//Step through every element in the sanitized inputString encoding the letters
		logger.debug("Converting letters to coordinates");
		ArrayList<CharLocation> locations = new ArrayList<>();
		for(char ch : getCleanInputString().toCharArray()){
			//Get the location of the char in the grid
			CharLocation location = findChar(ch);
			locations.add(location);
		}

		//Split the locations up by group
		logger.debug("Splitting locations into groups");
		int numGroups = inputString.length() / groupSize;
		if(numGroups == 0){
			numGroups = 1;
		}
		ArrayList<ArrayList<CharLocation>> groups = new ArrayList<>(numGroups);
		for(int cnt = 0;cnt < numGroups;++cnt){
			groups.add(new ArrayList<>());
		}
		int groupCnt = -1;
		for(int locCnt = 0;locCnt < locations.size();++locCnt){
			//If you've reached the end of the group move to the next one
			if((locCnt % groupSize) == 0){
				++groupCnt;
			}
			groups.get(groupCnt).add(locations.get(locCnt));
		}

		//Split the coordinates into rows by group and create the original grid locations
		logger.debug("Putting locations into rows");
		ArrayList<CharLocation> originalLocations = new ArrayList<>(locations.size());
		for(ArrayList<CharLocation> group : groups){
			//Read all of the coordinates from the group out into a row
			ArrayList<Integer> coordinates = new ArrayList<>(group.size() * 3);
			for(CharLocation loc : group){
				coordinates.add(loc.getZ());
				coordinates.add(loc.getX());
				coordinates.add(loc.getY());
			}

			//Read out the coordinates into new locations
			logger.debug("Converting locations into new locations");
			ArrayList<CharLocation> originalGroup = new ArrayList<>(group.size());
			for(int cnt = 0;cnt < group.size();++cnt){
				originalGroup.add(new CharLocation(0, 0, 0));
			}
			int coordinateCnt = 0;
			for(CharLocation loc : originalGroup){
				loc.z = coordinates.get(coordinateCnt++);
			}
			for(CharLocation loc : originalGroup){
				loc.x = coordinates.get(coordinateCnt++);
			}
			for(CharLocation loc : originalGroup){
				loc.y = coordinates.get(coordinateCnt++);
			}
			originalLocations.addAll(originalGroup);
		}

		//Get the original letters from the grid
		logger.debug("Converting new locations into letters");
		StringBuilder output = new StringBuilder();
		for(CharLocation loc : originalLocations){
			output.append(getChar(loc));
		}

		//Format the output
		formatOutput(output.toString());
	}


	//Constructor
	public Trifid() throws InvalidCharacterException{
		preserveCapitals = false;
		preserveWhitespace = false;
		preserveSymbols = false;
		setFillIn('+');
	}
	public Trifid(boolean preserveCapitals, boolean preserveWhitespace, boolean preserveSymbols) throws InvalidCharacterException{
		this.preserveCapitals = preserveCapitals;
		this.preserveWhitespace = preserveWhitespace;
		this.preserveSymbols = preserveSymbols;
		setFillIn('+');
	}
	public Trifid(boolean preserveCapitals, boolean preserveWhitespace, boolean preserveSymbols, char fillIn) throws InvalidCharacterException{
		this.preserveCapitals = preserveCapitals;
		this.preserveWhitespace = preserveWhitespace;
		this.preserveSymbols = preserveSymbols;
		setFillIn(fillIn);
	}

	//Encodes inputString using keyword and groupSize and returns the result
	public String encode(String keyword, String inputString) throws InvalidBaseException, InvalidKeywordException, InvalidInputException, InvalidCharacterException{
		return encode(keyword, inputString.length(), inputString);
	}
	public String encode(String keyword, int groupSize, String inputString) throws InvalidBaseException, InvalidKeywordException, InvalidInputException, InvalidCharacterException{
		//Set the parameters
		reset();
		setKeyword(keyword);
		setGroupSize(groupSize);
		setInputString(inputString);

		//Encode and return the message
		encode();
		return outputString;
	}
	//Decodes inputString using keyword and groupSize and returns the result
	public String decode(String keyword, String inputString) throws InvalidBaseException, InvalidKeywordException, InvalidInputException, InvalidCharacterException{
		return decode(keyword, inputString.length(), inputString);
	}
	public String decode(String keyword, int groupSize, String inputString) throws InvalidBaseException, InvalidKeywordException, InvalidInputException, InvalidCharacterException{
		//Set the parameters
		reset();
		setKeyword(keyword);
		setGroupSize(groupSize);
		setInputString(inputString);

		//Decode and return the message
		decode();
		return outputString;
	}

	//Makes sure all variables are empty
	public void reset(){
		logger.debug("Resetting fields");

		inputString = "";
		outputString = "";
		keyword = "";
		groupSize = Integer.MAX_VALUE;
		grid = new char[3][3][3];
	}
	//Gets
	public String getInputString(){
		return inputString;
	}
	public String getOutputString(){
		return outputString;
	}
	public String getKeyword(){
		return keyword;
	}
	public int getGroupSize(){
		return groupSize;
	}
	public char getFillIn(){
		return fillIn;
	}
	public String getGrid(){
		logger.debug("Creating string from grid");

		StringJoiner layers = new StringJoiner("\n\n");

		for(char[][] layer : grid){
			StringJoiner gridJoiner = new StringJoiner("\n");
			for(char[] row : layer){
				StringJoiner rowJoiner = new StringJoiner(" ", "[", "]");
				for(char ch : row){
					rowJoiner.add(Character.toString(ch));
				}
				gridJoiner.add(rowJoiner.toString());
			}
			layers.add(gridJoiner.toString());
		}

		return layers.toString();
	}
}