#define _GNU_SOURCE

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/wait.h>
#include <string.h>
#include <signal.h>
#include <errno.h>
#include <setjmp.h>
#include "readcmd.h"

extern int errno;
struct cmdline *cmd;
int pid_fils;
int prompting = 0;
jmp_buf goto_prompt;
char initcd[256], currentcd[256];

void handler_sigchld(int sig_num)
{
    if (prompting)
    {
        printf("\n");
        siglongjmp(goto_prompt, sig_num);
    }
}

int main(int argc, char *argv[])
{
    getcwd(initcd, sizeof(initcd));

    // gestion des signaux
    struct sigaction action;
    sigemptyset(&action.sa_mask);
    action.sa_flags = SA_SIGINFO | SA_RESTART;
    action.sa_handler = handler_sigchld;
    sigaction(SIGCHLD, &action, NULL);

    // loop principal
    while (1)
    {
        sigsetjmp(goto_prompt, 1);

        prompting = 1;
        getcwd(currentcd, sizeof(currentcd));
        printf("%s >>> ", currentcd);
        cmd = readcmd();
        prompting = 0;

        if (cmd == NULL)
        { // EOF
            break;
        }
        else if (cmd->seq[0] == NULL)
        { // empty
            continue;
        }
        else if (!strcmp(cmd->seq[0][0], "exit"))
        { // "exit"
            break;
        }
        else if (!strcmp(cmd->seq[0][0], "cd"))
        { // "cd"
            int ret = 0;
            if (cmd->seq[0][1] == NULL)
            { // no path
                ret = chdir(initcd);
            }
            else
            { // with path
                ret = chdir(cmd->seq[0][1]);
            }
            if (ret)
            { // wrong path
                fprintf(stderr, "ERROR: cd failed, (%d) %s\n", errno, strerror(errno));
            }
            continue;
        }

        pid_fils = fork();
        if (pid_fils == -1)
        { // fork fail ?
            fprintf(stderr, "ERROR: forking failed, (%d) %s\n", errno, strerror(errno));
            exit(errno);
        }

        if (pid_fils == 0)
        { // instructions du fils
            execvp(cmd->seq[0][0], cmd->seq[0]);
            exit(errno); // si execlp échoue on exit avec une erreur
        }
        else
        { // instructions du père
            if (!cmd->backgrounded)
            { // background
                int wait_code;
                pid_t id = waitpid(pid_fils, &wait_code, 0); // on attend la fin de l'exec du fils

                if (id == -1)
                { // wait fail ?
                    fprintf(stderr, "ERROR: waiting for %d failed, (%d) %s\n", wait_code, errno, strerror(errno));
                    exit(errno);
                }

                if (wait_code)
                { // execvp fail ?
                    fprintf(stderr, "ERROR: %d's execution failed, (%d) %s\n", pid_fils, wait_code, strerror(wait_code));
                }
            }
        }
    }

    return EXIT_SUCCESS;
}