#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>

#define BUFSIZE 1024    // size of read/write buffers
#define PREAD 0         // index of read end of pipe
#define PWRITE 1        // index of write end of pipe
#define NAME_MAX 255    // max len of commands and args
#define ARG_MAX 255     // max number of arguments
#define MAX_LINE 1024   // maximum length of input lines
#define MAX_CHILD 1024  // maximum number of children in commando
#define STATUS_LEN 10   // length of the str_status field in childcmd

// block options to update_cmd_status() indicating whether to block or
// not on waiting for child; passed to wait()
#define NOBLOCK (WCONTINUED | WUNTRACED | WNOHANG)
#define DOBLOCK (WCONTINUED | WUNTRACED)

#define eprintf(...) fprintf(stderr, __VA_ARGS__)

// cmd_t: struct to represent a running command/child process.
typedef struct {
    char name[NAME_MAX + 1];  // name of command like "ls" or "gcc"
    char *argv[ARG_MAX + 1];  // argv for running child, NULL terminated
    pid_t pid;                // PID of child
    int out_pipe[2];          // pipe for child output
    int finished;             // 1 if child process finished, 0 otherwise
    int status;               // return value of child, -1 if not finished
    char str_status[STATUS_LEN +
                    1];  // describes child status such as RUN or EXIT(..)
    void *output;        // saved output from child, NULL initially
    int output_size;     // number of bytes in output
} cmd_t;

// cmdctl_t: struct for tracking multiple commands
typedef struct {
    cmd_t *cmd[MAX_CHILD];  // array of pointers to cmd_t
    int size;               // number of cmds in the array
} cmdctl_t;

// util.c
void parse_into_tokens(char input_command[], char *tokens[], int *ntok);
void pause_for(long nanos, int secs);

// cmd.c
cmd_t *cmd_new(char *argv[]);
void cmd_free(cmd_t *cmd);
void cmd_info(cmd_t *cmd);
void cmd_start(cmd_t *cmd);
void cmd_fetch_output(cmd_t *cmd);
void cmd_print_output(cmd_t *cmd);
void cmd_update_state(cmd_t *cmd, int nohang);

// cmdctl.c
void cmdctl_print(cmdctl_t *ctl);
void cmdctl_add(cmdctl_t *ctl, cmd_t *cmd);
void cmdctl_update_state(cmdctl_t *ctl, int nohang);
void cmdctl_freeall(cmdctl_t *ctl);