#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <sys/wait.h>
#include <sys/types.h>
#include <pty.h>
#include <sysexits.h>
#include <fcntl.h>
#include <readline/readline.h>
#include <readline/history.h>

#define BUFCHUNKSIZE 4096
#define BUFSAFEPAD 8
#define KNRM  "\x1B[0m"
#define KRED  "\x1B[31m"
#define KGRN  "\x1B[32m"
#define KYEL  "\x1B[33m"
#define KBLU  "\x1B[34m"
#define KMAG  "\x1B[35m"
#define KCYN  "\x1B[36m"
#define KWHT  "\x1B[37m"
#define BKRED  "\x1B[41m"
#define BKGRN  "\x1B[42m"
#define BKYEL  "\x1B[43m"
#define BKBLU  "\x1B[44m"
#define BKMAG  "\x1B[45m"
#define BKCYN  "\x1B[46m"
#define BKWHT  "\x1B[47m"


#if defined(DEBUG) && DEBUG > 0
	#define DEBUG_PRINT(fmt, args...) fprintf(stderr, "DEBUG: %s:%d:%s(): " fmt, \
		__FILE__, __LINE__, __func__, ##args)
	#define COLORTEST() fprintf(stderr, "Color Palate:\n" \
		KRED"KRED"KGRN"KGRN"KYEL"KYEL"KBLU"KBLU"KMAG"KMAG"KCYN"KCYN"KWHT"KWHT"KNRM"\n" \
		KRED"▒▒▒▒"KGRN"▒▒▒▒"KYEL"▒▒▒▒"KBLU"▒▒▒▒"KMAG"▒▒▒▒"KCYN"▒▒▒▒"KWHT"▒▒▒▒"KNRM"\n" \
		KRED"████"KGRN"████"KYEL"████"KBLU"████"KMAG"████"KCYN"████"KWHT"████"KNRM"\n" \
		BKRED"KRED"BKGRN"KGRN"BKYEL"KYEL"BKBLU"KBLU"BKMAG"KMAG"BKCYN"KCYN"BKWHT"KWHT"KNRM"\n" \
		) 
#else
	#define DEBUG_PRINT(fmt, args...) /* Don't do anything in release builds */
	#define COLORTEST()
#endif

void child_process(char *argv[]){
	execl(argv[1], argv[1], NULL);
}


size_t getuserinput(char* input_buffer, size_t max_buffer_size, int fd) {
	int in_char;
	size_t total_read_length;
	ssize_t read_result;
	//read_result = read(fd, &in_char, 1);
	while (1) {
		printf("reading char\n");
		in_char = fgetc(stdin);
		printf("read char\n");
	}
	//if (inchar < 0){
	//	//error condition
	//	exit(1);
	//}
	return 1;
}


// go through the buffer and find the lines to be edited and print them after
int processbufferpop(char *roll_buffer, size_t read_length) {
	//this is where some optimization could come in with using malloc and then freeing subset of memory; dog garn dynamic memory allocation
	int found_index;
	char *found_char = strchr(roll_buffer, '\n');
	if (found_char != NULL){
			found_index = found_char - roll_buffer;
			char to_process_string[];

	} else {
		//no more instances

	}

	write(STDOUT_FILENO, roll_buffer, read_length);
	write(STDOUT_FILENO, "\n", 1);
	
	return 0;	
}


int main(int argc, char *argv[]) {
	COLORTEST();
	int master;
	pid_t child_pid;
	//struct winsize win = {
	//	.ws_col = 80, .ws_row = 24,
	//	.ws_xpixel = 480, .ws_ypixel = 192,
	//};

	if (argc < 2) {
		printf("Usage: %s cmd [args...]\n", argv[0]);
		exit(EX_USAGE);
	}

	child_pid = forkpty(&master, NULL, NULL, NULL);
	if (child_pid == -1) {
		perror("forkpty failed");
		exit(EX_OSERR);
	}
	if (child_pid == 0) {
		child_process(argv);
		exit(0);
	}

	//remainder is main is the parent process for processing input and shit
	fcntl(master, F_SETFL, O_NONBLOCK);
	char *child_out_roll_buffer = (char*) malloc(sizeof(char) * (BUFCHUNKSIZE+BUFSAFEPAD+1));
	
	usleep(500*1000);
	while(1){
		//	  ideally I would want to read from the pipe and buffer the output, rewriting the line on change
		//	  whenever it sees a newline, it should send it to the processor and print to stdout, with that newline
		//	  
		//CHILD OUTPUT HANDLING
		memset(child_out_roll_buffer, 0, BUFCHUNKSIZE+BUFSAFEPAD);
		int cont_read_offset_index = 0;		//when we need to continue reading after process leaves us with half filled buffer
							// treating the buffer as kind of a FIFO stack thing
							// strip lines from top and then move leftover to top,
							// then start reading where we left off
		while(1){
			ssize_t read_count = read(master, &child_out_roll_buffer[cont_read_offset_index], BUFCHUNKSIZE - cont_read_offset_index);
			if (read_count == 0 ) {
				DEBUG_PRINT("EOF\n");
				exit(0);			
			}
			if (read_count == -1){
				if(errno == EAGAIN){ //errored because read would block
					break;
				} else {
					DEBUG_PRINT("I/O \"Error\" (Child Exited?) %d\n", errno);
					exit(0);
				}
			}
			//process da block then write it
			cont_read_offset_index = processbufferpop(child_out_roll_buffer, read_count);
			
		}

		//INPUT HANDLING
		memset(child_out_roll_buffer, 0, BUFCHUNKSIZE);
		strncpy(child_out_roll_buffer, readline(KGRN"~>"KNRM), BUFCHUNKSIZE-1);
		
		//printf("%s\n", child_out_roll_buffer);
		write(master, child_out_roll_buffer, strlen(child_out_roll_buffer));
		write(master, "\n", 1);

		//memset(child_out_roll_buffer, 0, BUFCHUNKSIZE);
		//ssize_t count = strlen(child_out_roll_buffer);
		usleep(200*1000);
	}
}