//Ciphers/SourceFiles/Vigenere.cpp
//Matthew Ellison
// Created: 4-29-18
//Modified: 5-16-18
//This file contains the implementation of the Vigenere class

#include "../Headers/Vigenere.hpp"
#include <string>
#include <vector>
#include <cctype>


/**
 * @brief The current library's version number
 * 
 */
const std::string Vigenere::version = "1.0";

/**
 * @brief Construct a new Vigenere object
 * 
 */
Vigenere::Vigenere(){
	reset();
}

/**
 * @brief Destroy the Vigenere object
 * 
 */
Vigenere::~Vigenere(){
}

/**
 * @brief Removes all invalid characters from input and sets it to inputString
 * 
 * @param input The string you want to encode/decode
 */
void Vigenere::setInputString(std::string input){
	//Loop through every character in input. Remove all whitespace and punctuation and make sure all letters are capital and add it to inputString
	for(unsigned int cnt = 0;cnt < input.size();++cnt){
		char letter = input[cnt];
		if(isupper(letter)){
			inputString += letter;
		}
		else if(islower(letter)){
			inputString += toupper(letter);
		}
		//If the letter is whitespace or punctuation do nothing
	}
}

/**
 * @brief Returns the string you wish to encode/decode
 * 
 * @return The string you wish to encode/decode
 */
std::string Vigenere::getInputString() const{
	return inputString;
}

/**
 * @brief Returns the encoded/decoded message
 * 
 * @return The encoded/decoded message
 */
std::string Vigenere::getOutputString() const{
	return outputString;
}

/**
 * @brief Removes all invalid characters from key and sets it to keyword
 * 
 * @param key The keyword used for the cipher
 */
void Vigenere::setKeyword(std::string key){
	//Loop through every letter in the key and make sure all of them are uppercase letters
	for(unsigned int cnt = 0;cnt < key.size();++cnt){
		char letter = key[cnt];
		if(isupper(letter)){
			keyword += letter;
		}
		else if(islower(letter)){
			keyword += toupper(letter);
		}
		//If it is not a letter ignore it
	}
	//Make sure offset is empty before adding to it
	offset.clear();
	setOffset();
}

/**
 * @brief Returns the keyword you are using for the cipher
 * 
 * @return The keyword you are using for the cipher
 */
std::string Vigenere::getKeyword() const{
	return keyword;
}

/**
 * @brief Uses keyword to set the offsets of the letters used during encoding/decoding
 * 
 */
void Vigenere::setOffset(){
	//Reserve the correct size to increase speed later
	offset.reserve(keyword.size());

	//Loop through every letter in keyword and get the offset from A
	for(char letter : keyword){
		offset.push_back((letter - 'A') % 26);
	}
}

/**
 * @brief Returns the vector that holds the offsets of the letters used during encoding/decoding
 * 
 * @return A the vector holding offsets of the letters used during encoding/decoding
 * @note Used mostly for debuging
 */
std::vector<unsigned int> Vigenere::getOffsets() const{
	return offset;
}

/**
 * @brief Encodes the inputString using the Vigenere cipher and saves the result in outputString
 * 
 * @return The encoded message
 */
std::string Vigenere::encode(){
	//Reserve the correct size for the output string to increase speed for longer messages
	outputString.reserve(inputString.size());

	//Step through every charater in the inputString and advance it the correct amount, according to offset
	for(unsigned int cnt = 0;cnt < inputString.size();++cnt){
		char letter = (inputString[cnt] + offset[cnt % offset.size()]);	//By using % you allow it to loop without having a separate counter
		//Make sure the character is still a letter, if not, wrap around
		if(letter < 'A'){
			letter += 26;
		}
		else if(letter > 'Z'){
			letter -= 26;
		}
		outputString += letter;
	}

	return outputString;
}

/**
 * @brief Sets all of the variables for the cipher and returns the result
 * 
 * @param key The keyword used in the cipher
 * @param input The message that you wish to encode
 * @return The encoded message
 */
std::string Vigenere::encode(std::string key, std::string input){
	reset();
	setKeyword(key);
	//Throw an error if there is no keyword
	//Would be better to throw an error here
	if(keyword == ""){
		return "Error! Empty keyword\n";
	}
	setInputString(input);
	return encode();
}

/**
 * @brief Decodes the inputString using the Vigenere cipher and saves the result in outputString
 * 
 * @return The decoded message
 */
std::string Vigenere::decode(){
	//Reserve the correct size for the output string to increase speed for longer messages
	outputString.reserve(inputString.size());

	//Step through every charater in the inputString and reduce it the correct amount, according to offset
	for(unsigned int cnt = 0;cnt < inputString.size();++cnt){
		char letter = (inputString[cnt] - offset[cnt % offset.size()]);	//By using % you allow it to loop without having a separate counter
		if(letter < 'A'){
			letter += 26;
		}
		else if(letter > 'Z'){
			letter -= 26;
		}
		outputString += letter;
	}

	return outputString;
}

/**
 * @brief Sets all of the variables for the cipher and returns the result
 * 
 * @param key The keyword used in the cipher
 * @param input The message that you wish to decode
 * @return The decoded message
 */
std::string Vigenere::decode(std::string key, std::string input){
	reset();
	setKeyword(key);
	//Throw an error if there is no keyword
	//Would be better to throw an error here
	if(keyword == ""){
		return "Error! Empty keyword\n";
	}
	setInputString(input);
	return decode();
}

/**
 * @brief Makes sure all of the variables are empty
 * 
 */
void Vigenere::reset(){
	inputString = outputString = keyword = "";
	offset.clear();
}

/**
 * @brief Returns a string containing the version information
 * 
 * @return The version information
 */
std::string Vigenere::getVersion(){
	return version;
}