//Ciphers/helperFunctions.hpp
//Matthew Ellison
// Created: 4-29-18
//Modified: 5-8-18
//This file contains the driver function and the test functions for the Cipher program
//This program will use some simple ciphers that are no longer widely used but still fun to play with


#ifndef HELPER_FUNCTIONS_HPP
#define HELPER_FUNCTIONS_HPP


#include "Headers/Caesar.hpp"
#include "Headers/Playfair.hpp"
#include "Headers/Vigenere.hpp"
#include "Headers/Atbash.hpp"
#include "Headers/Morse.hpp"
#include "Headers/Autokey.hpp"
#include <iostream>
#include <fstream>
#include <string>


enum CipherFlagLocation { CAESAR, PLAYFAIR, VIGENERE, ATBASH, MORSE, AUTOKEY, NUM_CIPHERS,
						ENCODE, DECODE, INPUT_FILE, OUTPUT_FILE, SIZE };
std::string flagStrings[SIZE];
//Error handling
bool failFlag = false;		//Set if something fails

//For the getCipher function
typedef std::string (*Fn)(std::ifstream&, bool);



/**
 * @brief Takes all of the arguments that were given to the program and sets boolean flags inside the program that will change behavior
 * 
 * @param argc The number of arguments given
 * @param argv The arguments given
 * @param cipherFlags The array of booleans that represent the possible options passed in
 * @param inputFileString The name of the input file, if given
 * @param outputFileString The name of the output file if given
 */
void getFlags(int argc, char** argv, bool cipherFlags[], std::string& inputFileString, std::string& outputFileString){
	//Cycle through every argument
	bool valid = false;
	for(int cnt = 1;cnt < argc;++cnt){
		//Step through every element in the flagStrings and compare the flags. If the flags do not match or you go out of bounds in argv throw an error
		for(int stringcnt = 0;stringcnt < SIZE;++stringcnt){
			if(argv[cnt] == flagStrings[stringcnt]){
				valid = cipherFlags[stringcnt] = true;
				//If the flag showed an input file get the file name if possible
				if(stringcnt == INPUT_FILE){
					//Make sure there is enough room in argv for the file name
					if((cnt + 1) < argc){
						inputFileString = argv[++cnt];
					}
				}
				//If the flag showed an output file get the file name if possible
				else if(stringcnt == OUTPUT_FILE){
					//Make sure there is enough room in argv for the file name
					if((cnt + 1) < argc){
						outputFileString = argv[++cnt];
					}
				}
				break;
			}
		}
		//If the flag was not valid throw an error
		if(!valid){
			std::cout << argv[cnt] << " is an invalid flag" << std::endl;
			return;
		}
		valid = false;
	}
}

/**
 * @brief Checks that the flags given are valid
 * 
 * @param flags All of the flags that the program can have
 * @return true If valid options were chosen
 * @return false If invalid options were chosen
 */
bool checkFlags(bool flags[]){
	int counter = 0;
	bool correct = false;
	//Run through each flag and counter how many are true
	for(int cnt = 0;cnt < NUM_CIPHERS;++cnt){
		if(flags[cnt]){
			++counter;
		}
	}

	//Check if a valid number of flags were true
	if(counter == 1){
		correct = true;
	}

	//Check if either encode or decode is set, but not both
	if((flags[ENCODE] && flags[DECODE]) || (!flags[ENCODE] && !flags[DECODE])){
		correct = false;
	}

	return correct;
}

/**
 * @brief Set the array of strings that controls what each flag should look
 * 
 */
void setFlagStrings(){
	flagStrings[CAESAR] = "-c";
	flagStrings[PLAYFAIR] = "-p";
	flagStrings[VIGENERE] = "-v";
	flagStrings[ATBASH] = "-a";
	flagStrings[MORSE] = "-m";
	flagStrings[AUTOKEY] = "-u";
	flagStrings[ENCODE] = "-e";
	flagStrings[DECODE] = "-d";
	flagStrings[INPUT_FILE] = "-i";
	flagStrings[OUTPUT_FILE] = "-o";
}

/**
 * @brief Run the appropriate commands to use a Caesar cipher
 * 
 * @param infile The input file if one was provided
 * @param encode Whether the encoding flag was set. True if encoding, false if decoding
 * @return The new message
 */
std::string runCaesar(std::ifstream& infile, bool encode){
	std::string inputString, cipherString;
	int offset;
	Caesar cipher;
	//Check if the input file is open
	if(infile.is_open()){
		infile >> offset;
		infile.ignore(10000, '\n');	//Get rid of the \n that is right after the offset
		std::getline(infile, inputString);
		if(infile.fail()){
			failFlag = true;
			cipherString = "Input file has an incorrect format\n";
		}
	}
	//Otherwise prompt for the appropriate strings
	else{
		std::cout << "Enter the cipher offset: ";
		std::cin >> offset;
		if(std::cin.fail()){
			std::cin.ignore(10000, '\n');
			std::cin.clear();
			std::cout << "That is an invalid offset\nEnter the cipher offset: ";
			std::cin >> offset;
		}
		std::cout << "Enter the input string: ";
		std::cin.ignore(10000, '\n');
		std::getline(std::cin, inputString);
	}

	//Check if there was an error reading the file
	if(failFlag){
		return cipherString;
	}
	//Run the correct cipher
	if(encode){
		cipherString = cipher.encode(offset, inputString);
	}
	else{
		cipherString = cipher.decode(offset, inputString);
	}

	return cipherString;
}

/**
 * @brief Run the appropriate commands to use a Playfair cipher
 * 
 * @param infile The input file if one was provided
 * @param encode Whether the encoding flag was set. True if encoding, false if decoding
 * @return The new message
 */
std::string runPlayfair(std::ifstream& infile, bool encode){
	std::string keyword, inputString, cipherString;
	Playfair cipher;
	//Check if the input file is open
	if(infile.is_open()){
		std::getline(infile, keyword);
		std::getline(infile, inputString);
		if(infile.fail()){
			failFlag = true;
			cipherString = "Input file has an incorrect format\n";
		}
	}
	//Otherwise prompt for the appropriate strings
	else{
		std::cout << "Enter the keyword: ";
		std::getline(std::cin, keyword);
		std::cout << "Enter the input string: ";
		std::getline(std::cin, inputString);
	}

	//Check if there was an error reading the file
	if(failFlag){
		return cipherString;
	}
	//Run the correct cipher
	if(encode){
		cipherString = cipher.encode(keyword, inputString);
	}
	else{
		cipherString = cipher.decode(keyword, inputString);
	}

	return cipherString;
}

/**
 * @brief Run the appropriate commands to use a Vigenere cipher
 * 
 * @param infile The input file if one was provided
 * @param encode Whether the encoding flag was set. True if encoding, false if decoding
 * @return The new message
 */
std::string runVigenere(std::ifstream& infile, bool encode){
	std::string keyword, inputString, cipherString;
	Vigenere cipher;
	//Check if the input file is open
	if(infile.is_open()){
		std::getline(infile, keyword);
		std::getline(infile, inputString);
		if(infile.fail()){
			failFlag = true;
			cipherString = "Input file has an incorrect format\n";
		}
	}
	//Otherwise prompt for the appropriate strings
	else{
		std::cout << "Enter the keyword: ";
		std::getline(std::cin, keyword);
		std::cout << "Enter the input string: ";
		std::getline(std::cin, inputString);
	}

	//Check if there was an error reading the file
	if(failFlag){
		return cipherString;
	}
	//Run the correct cipher
	if(encode){
		cipherString = cipher.encode(keyword, inputString);
	}
	else{
		cipherString = cipher.decode(keyword, inputString);
	}

	return cipherString;
}

/**
 * @brief Run the appropriate commands to use an Atbash cipher
 * 
 * @param infile The input file if one was provided
 * @param encode Whether the encoding flag was set. True if encoding, false if decoding
 * @return The new message
 */
std::string runAtbash(std::ifstream& infile, bool encode){
	std::string inputString, cipherString;
	Atbash cipher;
	//Check if the input file is open
	if(infile.is_open()){
		std::getline(infile, inputString);
		if(infile.fail()){
			failFlag = true;
			cipherString = "Input file has an incorrect format\n";
		}
	}
	//Otherwise prompt for the appropriate strings
	else{
		std::cout << "Enter the input string: ";
		std::getline(std::cin, inputString);
	}

	//Check if there was an error reading the file
	if(failFlag){
		return cipherString;
	}
	//Run the correct cipher
	if(encode){
		cipherString = cipher.encode(inputString);
	}
	else{
		cipherString = cipher.decode(inputString);
	}

	return cipherString;
}

/**
 * @brief Run the appropriate commands to use Morse code
 * 
 * @param infile The input file if one was provided
 * @param encode Whether the encoding flag was set. True if encoding, false if decoding
 * @return The new message
 */
std::string runMorse(std::ifstream& infile, bool encode){
	std::string inputString, cipherString;
	Morse cipher;
	//Check if the input file is open
	if(infile.is_open()){
		std::getline(infile, inputString);
		if(infile.fail()){
			failFlag = true;
			cipherString = "Input file has an incorrect format\n";
		}
	}
	//Otherwise prompt for the appropriate strings
	else{
		std::cout << "Enter the input string: ";
		std::getline(std::cin, inputString);
	}

	//Check if there was an error reading the file
	if(failFlag){
		return cipherString;
	}
	//Run the correct cipher
	if(encode){
		cipherString = cipher.encode(inputString);
	}
	else{
		cipherString = cipher.decode(inputString);
	}

	return cipherString;
}

/**
 * @brief Run the appropriate commands to use an Autokey cipher
 * 
 * @param infile The input file if one was provided
 * @param encode Whether the encoding flag was set. True if encoding, false if decoding
 * @return The new message
 */
std::string runAutokey(std::ifstream& infile, bool encode){
	std::string keyword, inputString, cipherString;
	Autokey cipher;
	//Check if the input file is open
	if(infile.is_open()){
		std::getline(infile, keyword);
		std::getline(infile, inputString);
		if(infile.fail()){
			failFlag = true;
			cipherString = "Input file has an incorrect format\n";
		}
	}
	//Otherwise prompt for the appropriate strings
	else{
		std::cout << "Enter the keyword: ";
		std::getline(std::cin, keyword);
		std::cout << "Enter the input string: ";
		std::getline(std::cin, inputString);
	}

	//Check if there was an error reading the file
	if(failFlag){
		return cipherString;
	}
	//Run the correct cipher
	if(encode){
		cipherString = cipher.encode(keyword, inputString);
	}
	else{
		cipherString = cipher.decode(keyword, inputString);
	}

	return cipherString;
}

/**
 * @brief Uses the flags to determine which cipher needs to be run
 * 
 * @param cipherFlags The possible flags given to the program
 * @return The appropriate run___ function based on the flags
 */
//Returns the correct function for the flags that are set
Fn getCipher(const bool cipherFlags[]){
	if(cipherFlags[CAESAR]){
		return runCaesar;
	}
	else if(cipherFlags[PLAYFAIR]){
		return runPlayfair;
	}
	else if(cipherFlags[VIGENERE]){
		return runVigenere;
	}
	else if(cipherFlags[ATBASH]){
		return runAtbash;
	}
	else if(cipherFlags[MORSE]){
		return runMorse;
	}
	else if(cipherFlags[AUTOKEY]){
		return runAutokey;
	}
	//If it didn't trip one of the flags, there was an error before this
	else{
		std::cout << "There was an error selecting the appropriate function";
		exit(0);
	}
}

#endif //HELPER_FUNCTIONS_HPP