shell.h

#ifndef SHELL_H
#define SHELL_H

#define _GNU_SOURCE
#include "stdio.h"
#include "stdlib.h"
#include "string.h"
#include "unistd.h"
#include "sys/types.h"
#include "sys/wait.h"
#include "signal.h"
#include "fcntl.h"


#define MAX_CMD_BUFFER 255

extern volatile sig_atomic_t pid_foreground; 
//volatile to avoid unexpected changes from a handler
//sig_atomic_t is a type of integer that can be safely read/written in a signal handler
//called pid_foreground because it is meant to track the ID of the child process currently running in the foreground.



typedef enum {RUNNING, STOPPED, DONE} job_status;

typedef struct job {
    pid_t pid;
    int id;
    char *line;
    job_status status;
    struct job *next;
} job;

extern int latest_exit_status; //tracks latest command's exit status to support echo $? (part of Milestone 4)
extern job *job_list;

void sigint_handler(int signal);
void sigtstp_handler(int signal);
void sigchld_handler(int signal);

job *add_job(pid_t pid, const char *line, job_status status);
void remove_job(job *j);
job* find_job(int id);
void update_job_status(pid_t pid, job_status status);
void notify_job(job *j, const char *status_line);
void list_jobs();

void parse_command(char *line, char **args, char **input_file, char **output_file, int *bgCheck);
void apply_redirection(char *input_file, char *output_file);
void restore_redirection();

#endif