#include<stdio.h>
#include<unistd.h>
#include<stdlib.h>
#include<signal.h>
#include<string.h>
#include<time.h>
#include<wait.h>
#include "string_helpers.h"
#include "string_helpers.h"
#include "string_helpers.h"
#include "string_helpers.h"
#include "string_helpers.h"
#include "string_helpers.h"
#include "string_helpers.h"

char debug = 0;
void handle_ctrlc(int signal){
	write(1, "^C", 2);
	fsync(1);
}

int main(){
	size_t linebuffer_limit = 1024;
	char *linebuffer = malloc(linebuffer_limit);
	char working_directory[512];
	getcwd(working_directory, 512);
	ssize_t readlen;
	struct sigaction ctrlc_action;
	char *user_home = "/home/seth/"; // TODO:  Set this automatically
	ctrlc_action.sa_handler = handle_ctrlc;
	sigaction(SIGINT, &ctrlc_action, 0);
	while(1){
		write(1, working_directory, strlen(working_directory));
		write(1, "$: ", 3);
		fsync(1);
		readlen = read(0, linebuffer, linebuffer_limit);
		if(readlen == -1){
			write(1, "\n", 1);
			continue;
		} 
		if(readlen == 0)
			break;
		linebuffer[readlen-1] = 0;
		if(debug) printf("You entered:  \"%s\" (%ld bytes)\n", linebuffer, readlen);
		/* Shell expansions */
		for(size_t i = 0; linebuffer[i]; i++){
			if(linebuffer[i] == '~'){
				int length = strlen(user_home);
				move_right(linebuffer + i, length - 2);
				strncpy(linebuffer + i, user_home, length - 1);				
			}
		}
		/* Shell Builtins */
		if(!strncmp(linebuffer, "cd ", 3)){
			chdir(linebuffer + 3);
			getcwd(working_directory, 512);
			continue;
		}
		if(!strncmp(linebuffer, "debug", 5)){
			debug = !debug;
			continue;
		}
		if(!strncmp(linebuffer, "exit", 4)){
			break;
		}
		/* Most shells have a few more builtins than that */

		/* Maybe the user specified a program */
		handle_pipes(linebuffer, 0);
		/* What if there's a pipe? */
		
		char *secondcmd;
		if(secondcmd = strstr(linebuffer, "|")){
			*secondcmd = 0; // This'll overwrite the | with a terminator
			char *end_of_first = secondcmd - 1;
			while(*end_of_first == ' '){
				*end_of_first = 0;
				--end_of_first;
			}
			while(*++secondcmd == ' ') *secondcmd = ' ';

			printf("First command:  \"%s\"\n", linebuffer);
			printf("Second command:  \"%s\"\n", secondcmd);
			int pipefd[2];
			pipe(pipefd);
			// Run first command
			pid_t pid = fork();
			if(!pid) { // Set up and exec the first command, the one in linebuffer
				size_t length;
				char **argv = split(linebuffer, &length);
				dup2(pipefd[1], 1);
				close(pipefd[0]);
				execvp(linebuffer, argv);
				free(argv);
				perror("exec");
				return 1;
			}
			// Run second command
			handle_pipes
			pid_t pid2 = fork();
			if(!pid2){ // Set up and exec the second command, the one in secondcmd
				size_t length;
				char **argv = split(secondcmd, &length);
				dup2(pipefd[0], 0);
				close(pipefd[1]);
				execvp(secondcmd, argv);
				free(argv);
				perror("exec");
				return 1;
			}
			close(pipefd[0]);
			close(pipefd[1]);
			wait(0);
			wait(0);
			continue;
		}
		

		/* Should this code be part of the pipe handling above? */
		pid_t pid = fork();
		if(!pid){ // We're the child
			size_t length;
			char **argv = split(linebuffer, &length);
			if(debug) {
				printf("About to run:  %s\n", linebuffer);
				for(int i = 0; argv[i]; i++)
					printf("argv[%d] = %s\n", i, argv[i]);
			}
			execvp(linebuffer, argv);
			free(argv);
			/* Child is not coming back from this unless execvp fails (nonexistant file specified, etc) */
			perror("exec");
			return 1;
		} else {
			pid_t finished_child = wait(0);
			if(debug) printf("Child %d finished\n", finished_child);
		}

	}

	write(1, "\n", 1);
	free(linebuffer);
	return 0;
}

void handle_pipes(char *linebuffer, int input){
	char *secondcmd;
	if(secondcmd = strstr(linebuffer, "|")){
		*secondcmd = 0; // This'll overwrite the | with a terminator
		char *end_of_first = secondcmd - 1;
		while(*end_of_first == ' '){
			*end_of_first = 0;
			--end_of_first;
		}
		while(*++secondcmd == ' ') *secondcmd = ' ';

		printf("First command:  \"%s\"\n", linebuffer);
		printf("Second command:  \"%s\"\n", secondcmd);
		int pipefd[2];
		pipe(pipefd);
		// Run first command
		pid_t pid = fork();
		if(!pid) { // Set up and exec the first command, the one in linebuffer
			size_t length;
			char **argv = split(linebuffer, &length);
			dup2(pipefd[1], 1);
			close(pipefd[0]);
			execvp(linebuffer, argv);
			free(argv);
			perror("exec");
			return; // Will probably make it go all goofy
		}
		// Run second command
		close(pipefd[1]);
		handle_pipes(secondcmd, pipefd[0]);
		wait(0);
		return;
	}
	pid_t pid = fork();
	if(!pid) { // Set up and exec the first command, the one in linebuffer
		size_t length;
		char **argv = split(linebuffer, &length);
		dup2(input, 1);
		execvp(linebuffer, argv);
		free(argv);
		perror("exec");
		return 1;
	}
		wait(0);

}