#include "rc.h"
#include "parse.h"
#include "exec.h"

#include <signal.h>
#include <termios.h>

// -----------------------------------------------------------------------
// globals

Thread *runner = nil;
Shell shell    = { 0 };

// -----------------------------------------------------------------------
// functions

void
initshell(int *iflag)
{
    if((*iflag=isatty(0))){
        while(tcgetpgrp(0) != (shell.pid = getpgrp()))
            kill(-shell.pid, SIGTTIN);

        /* ignore job control signals */
        signal(SIGINT,  SIG_IGN);
        signal(SIGQUIT, SIG_IGN);
        signal(SIGTSTP, SIG_IGN);
        signal(SIGTTIN, SIG_IGN);
        signal(SIGTTOU, SIG_IGN);
        /* NOTE: if SIGCHLD is set to SIG_IGN then
         *  1. children that terminate do not become zombies
         *  2. call a to wait() will block until all children have terminated
         *  3. the call to wait will fail with errno == ECHILD
         *  see for discussion:
         *      https://stackoverflow.com/questions/1608017/no-child-process-error-from-waitpid-when-waiting-for-process-group 
         */
        // signal(SIGCHLD, SIG_IGN);

        /* take control */
        shell.pid = getpid();
        if(setpgid(shell.pid, shell.pid)<0)
            fatal("could not put shell in its own process group");

        tcsetpgrp(shell.pid, shell.pid);
    }
}

// -----------------------------------------------------------------------
// main point of entry

static void
usage(void)
{
    print(shell.err, "usage: %s [-cei] [file]", argv0);
    exit(2);
}

int
main(int argc, char *argv[])
{
    int flag;
    char *exe, *cmd = nil;
    shell.err = openfd(2);

    initenv();
    initpath();
    initkeywords();
    inithistory();
    initshell(&flag);

    ARGBEGIN{
    case 'e': shell.noerror = 1;     break;
    case 'i': shell.interactive = 1; break;
    case 'I': shell.interactive = 0; break;
    case 'c':
        cmd = EARGF(usage());
        panicf("not implemented");
        break;
    default:
        usage();
    }ARGEND;

    if(!argc){
        shell.interactive |= flag;
        exe = "/dev/stdin";
    }else
        exe = *argv++, argc--;

    initlexer(shell.interactive);

    /* enablevi(); */
    xboot(exe, argc, argv);
    /* unreachable */
}