/*	Copyright (C) 2021 Gentoo-libre Install

	This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by
	the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

	This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

	You should have received a copy of the GNU General Public License along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/


#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h> //just for ENOENT
#include <sys/stat.h> //just to check for folder
#include "main.h"

int main(int argc, char *argv[])
{
bool decode = false; //decoding is set to false by default (default is to encode)

//malloc the buffer to store the input string in
unsigned char *buffer = malloc(DEFAULT_SIZE*sizeof(unsigned char));
if (!buffer){fprintf(stderr,"Malloc Failed!\n"); exit(1);}
int size = DEFAULT_SIZE-1;//-1 to account for the added NULL char

//wrap encoded lines after COLS character (default 76).
int wrap = WRAP_CHAR;

//Go into stdin mode if there are no cli args
if (argc == 1){stdinMode(buffer, wrap, decode, argv[0]);}//stdinmode is given a pointer to the input string and addittionally the amount of chars to wrap whether default or user set

//arguments processing
int argvPos = 1;

while ((argv[argvPos]) && (argv[argvPos][0] == '-'))
{
if (argv[argvPos][1] == '-')
	{
	if ((memcmp(argv[argvPos],"--wrap=",7)) == 0)
		{
		wrap = atoi(argv[argvPos]+7);//overwrite the default wrap size with the new supplied one
		if (wrap < 0){printf("%s: invalid wrap size: \'%s\'\n", argv[0], argv[argvPos]+7); exit(1);}//if atoi() returns negative, the input wasn't a positive int
		goto nextArgument;
		}

	if ((memcmp(argv[argvPos],"--decode",8)) == 0)
		{
		decode = true;
		goto nextArgument;
		}

	if ((memcmp(argv[argvPos],"--help",6)) == 0)
        	{
		printf("Usage %s [OPTION]... [FILE]\n", argv[0]);
	        printf("Base64 encode FILE, or standard input, to standard output.\n");
		printf("With no FILE, or when FILE is -, read standard input\n\n");
		printf("Mandatory arguments to long options are mandatory for short options too.\n");
		printf("  -d, --decode\t\tdecode data.\n");
		printf("  -w, --wrap=COLS\twrap encoded lines after COLS character (default 76).\n");
                printf("\t\t\t  Use 0 to disable line wrapping\n\n");
		printf("Version: 0.1\n");
		exit(0);
		}
	printf("%s: unrecognized option -- \'%s\'\n", argv[0], argv[argvPos]);//if here is reached, the option wasn't valid
	exit(1);
	}

if ((memcmp(argv[argvPos],"-w",2)) == 0)
	{
	if (!argv[argvPos+1]){printf("%s: option requires an argument -- \'%c\'\n",argv[0],argv[argvPos][1]); exit(1);}//this triggers if -w hasn't been given a value
	wrap = atoi(argv[++argvPos]);//overwrite the default wrap size with the new supplied one
	if (!wrap){printf("%s: invalid wrap size: \'%s\'\n", argv[0], argv[argvPos]); exit(1);}
	goto nextArgument;
	}

if ((memcmp(argv[argvPos],"-d",2)) == 0)
	{
	decode = true;
	goto nextArgument;
	}

if (!argv[argvPos][1]){stdinMode(buffer, wrap, decode, argv[0]);}//if a '-' was detected, but the next char is NULL, '-' was inputted as a file, so stdinMode is activated
printf("%s: invalid option -- \'%c\'\n", argv[0], argv[argvPos][1]);//if here is reached, the option wasn't valid
exit(1);

nextArgument: ++argvPos;//get read to process the next argument
}

if (!argv[argvPos]){stdinMode(buffer, wrap, decode, argv[0]);}//if no more operands were provided after options, go into stdin mode
if (argv[argvPos+1]){printf("%s: extra operand \'%s\'\n", argv[0], argv[argvPos]); exit(1);}//if there are TWO and not ONE addittional argv arg's at this point, the operaterand to the left of the "FILE" is extra


//file processing mode
int result;
int i = 0; //keeps track of buffer to write
FILE *fp;
struct stat sb;//struct used by stat()

if (stat(argv[argvPos], &sb) == 0 && S_ISDIR(sb.st_mode)){fprintf(stderr, "%s: read error: Is a directory\n", argv[0]); free(buffer); exit(1);}//check if cli argv is a folder

fp = fopen(argv[argvPos],"rb");//rb for reading binary
if (!fp)//if file failed to open
	{
	if (errno == ENOENT){fprintf(stderr,"%s: %s: No such file or directory\n", argv[0], argv[argvPos]); free(buffer); exit(1);}//ENOENT is returned if there is no such file or directory
	fprintf(stderr, "%s: %s: Could not open\n", argv[0], argv[argvPos]); free(buffer); exit(1);//all other errors are blanket handled
	}

result = fread(buffer+i, 1, sizeof(unsigned char)*DEFAULT_SIZE-1, fp);//attempt to read up to DEFAULT_SIZE from file. (-1 to account for NULL char to be added)
if (!result){fclose(fp); free(buffer); exit(1);}//fread will fail if file is empty, so just exit.
i+=result;//add result to i so chars in buffer aren't overwritten next fread()

readAgain: if (result == (sizeof(unsigned char)*DEFAULT_SIZE-1))//if the file is longer than DEFAULT_SIZE, result will be the size of DEFAULT_SIZE
		{
		size += DEFAULT_SIZE;//increase size of buffer by DEFAULT_SIZE each time
		buffer = realloc(buffer,size*sizeof(unsigned char));
		if (!buffer){fprintf(stderr,"Realloc Failed!\n"); exit(1);}

		result = fread(buffer+i, 1, sizeof(unsigned char)*DEFAULT_SIZE-1, fp);//attempt to read up to DEFAULT_SIZE from file
	        if (!result){goto perfectSize;}//the previous fread() was the perfect size, so jump to processing
		i+=result;//add result to i so chars in buffer aren't overwritten next fread()
		goto readAgain;//repeat until result is less than DEFAULT_SIZE
		}

perfectSize: buffer[i] = '\0';//add null char since function expects it

if (!decode)
	{
	char *output = base64Encode(buffer, i);
	if (!output){fprintf(stderr, "Malloc Failed!\n"); exit(1);}
	if (wrap == 0){result = fwrite(output, 1, sizeof(unsigned char)*strlen(output), stdout); goto exit;}//if wrap is set to 0, do no wrapping.

	int charactersLeft = strlen(output);//the total number of characters to print is strlen(output_
	int x = 0;//position to print from in string so wrap printing works

	while (charactersLeft > wrap)//keep looping until all of the wrap length writes are done
		{
		result = fwrite(output+x, 1, sizeof(unsigned char)*wrap, stdout);//write wrap number of characters at a time
		if (!result){fprintf(stderr, "Fwrite Failed!\n"); exit(1);}//fwrite to stdout should not fail. It's best to just exit if it does.
		putchar('\n');//add a newline to finish off the wrapped line
		x += wrap;//increase the printing position to the next position
		charactersLeft -= wrap;//decrease charactersLeft by how many were printed
		}

	if (charactersLeft == 0){goto exit;}//if the printed number of characters was perfect, don't print an extra newline

	result = fwrite(output+x, 1, sizeof(unsigned char)*charactersLeft, stdout);//print any remaining characters that are smaller in number than wrap.
	if (!result){fprintf(stderr, "Fwrite Failed!\n"); exit(1);}//fwrite to stdout should not fail. It's best to just exit if it does.
	putchar('\n');//add a newline to finish off the wrapped line
	goto exit;
	}

if (decode)
	{
	int outputLength = base64Decode(buffer, i);
	if (!outputLength){fprintf(stderr,"%s: invalid input\n", argv[0]); free(buffer); exit(1);}//base64 returns -1 if input string was invalid
	result = fwrite(buffer, 1, sizeof(unsigned char)*outputLength, stdout);
	goto exit;
	}

exit: fclose(fp);//close the file
free(buffer);
return 0;
}