#ifndef SMALLSH_H
#define SMALLSH_H

// Name:   Damian Amerman-Smith
// ID:     934-403-184
// Email:  amermand@oregonstate.edu

#include <sys/types.h>

// Holds required infractructure for implementing "status" and managing background processes
struct smallsh {
    // Necessary infrastructure for implementing "status"
    bool use_status;    // Determines if the last foregrounded process via a status or a signal
    int exit_status;    // Holds the last foreground exit status
    int term_sig;       // Holds the last foreground termination signal

    // Linked-list of backgrounded processes that get waitpid(...WNOHANG)-ed
    // before each terminal prompt
    struct process* head_proc;
    struct process* tail_proc;
    int num_background;         // Amount of processes held in the background

    //Holds most recently forked process for use by catch_children() 
    struct process* child;

    bool foreground_only;       // Ignores requests to background processes
};


// Holds process info for management by parent shell
// Backgrounded process are held in a linked list by smallsh struct until
// finishing execution
struct process {
    pid_t pid;                  // This process's Process ID
    struct Command* command;    // The command the process is to execute
    struct process* next;       // Pointer for linked-list functionality
};


// Holds the details of a command that get passed to child processes
struct Command {
    char* command;          // Holds the first key term of a command
    int argc;               // Number of arguments
    char** argv;            // Array of arguments
    bool input_redirect;    // Determines if stdin or input_file is used
    bool output_redirect;   // Determines if stdout or output_fle is used
    char* input_file;       // Filepath of input
    char* output_file;      // Filepath of output
    bool backgrounded;      // If ran in background (true) or shell waits for it (false)
};

// Function declarations for smallsh.c
struct smallsh* create_shell();                                             // Initializes shell struct
struct process* create_process(struct Command* command);                    // Initializes process struct
bool run_process(struct smallsh* smallsh, struct process* process);         // Forks off child processes to run tasks,
                                                                            // tracking backgrounded children
void add_to_background(struct smallsh* smallsh, struct process* process);   // Adds a new backgrounded process to smallsh's backlog
void delete_command(struct Command* command);                               // Frees allocated memory within a command
void delete_process(struct process* process);                               // Frees allocated memory within a process
char* get_substring(char* input, int beginning, int length);                // Helper function to replace instances of "$$" with the
                                                                            // process's PID
struct Command* parse_command(char* input);                                 // Parses incoming text into the command given

// To silence compilation warnings
char* strtok_r(char* str, const char* delim, char** saveptr);
pid_t waitpid(pid_t pid, int* status, int options);
int kill(pid_t pid, int sig);
char* itoa(int value, char* string, int radix);

#endif