#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"
#include "jobs.h"

int prompting = 0;
int job_id = 1;
list jobs;
pid_t pidFils;
struct cmdline *cmd;

jmp_buf start;

void handler_print(int signal_num, siginfo_t *info)
{
    cell* job = trouver(&jobs, info->si_pid);
    if (job)
    { // pid dans la lite des proccess en fond
        if (job->state)
        {
            job->state = 0;
            siglongjmp(start, signal_num);
        }
        
        if (prompting)
        { // si il n'y a pas d'execution de proccess actuellement
            printf("\n");
        }

        printf("[%d] (%d) done: %s\n", job->id, job->pid, job->cmd);
        supprimer(&jobs, job->pid);
        job_id--;

        if (prompting)
        { // on réaffiche un prompt si besoin
            siglongjmp(start, signal_num);
        }
    }
}

void handler_restart(int signal_num)
{
    printf("\n");
    siglongjmp(start, signal_num);
}

void handler_stop(int signal_num)
{
    if (!prompting)
    {
        kill(pidFils, SIGTSTP);
        ajouter(&jobs, pidFils, job_id++, *(cmd->seq), 1);
        printf("[%d] (%d) suspended: %s\n", job_id, pidFils, *(cmd->seq));
        siglongjmp(start, signal_num);
    }
    else
    {
        handler_restart(signal_num);
    }
}

int main(int argc, char *argv[])
{
    extern int errno;

    initialiser(&jobs);

    // gestion des signaux
    struct sigaction action;
    sigemptyset(&action.sa_mask);
    action.sa_flags = SA_SIGINFO | SA_RESTART;
    action.sa_handler = handler_print;
    sigaction(SIGCHLD, &action, NULL);
    action.sa_handler = handler_restart;
    sigaction(SIGINT, &action, NULL);
    action.sa_handler = handler_stop;
    sigaction(SIGTSTP, &action, NULL);

    // variables pour afficher le path
    char initcd[256], currentcd[256];
    getcwd(initcd, 256);

    // loop principal
    while (1)
    {
        if (sigsetjmp(start, 1) == 2)
        { // si on provient du jump
            continue;
        }

        getcwd(currentcd, 256);
        printf("%s >>> ", currentcd);

        prompting = 1;
        cmd = readcmd();
        prompting = 0;

        if (cmd == NULL)
        { // on quitte le shell, EOF
            break;
        }
        else if (cmd->seq[0] == NULL)
        { // ligne vide, on skip
            continue;
        }
        else if (!strcmp(cmd->seq[0][0], "bg"))
        {
            kill(pidFils, SIGCONT);
            continue;
        }
        else if (!strcmp(cmd->seq[0][0], "exit"))
        {
            break;
        }
        else if (!strcmp(cmd->seq[0][0], "cd"))
        { // cd
            int ret = 0;
            if (cmd->seq[0][1] == NULL)
            { // vide, sans path
                ret = chdir(initcd);
            }
            else
            { // avec un path
                ret = chdir(cmd->seq[0][1]);
            }
            if (ret)
            { // si le path n'existe pas
                fprintf(stderr, "ERROR: cd failed, (%d) %s\n", errno, strerror(errno));
            }
            continue;
        }
        else if (!strcmp(cmd->seq[0][0], "jobs"))
        { // on affiche tous les process de fond
            afficher(&jobs);
            continue;
        }

        pidFils = fork();

        if (pidFils == -1)
        { // si le fork échoue
            fprintf(stderr, "ERROR: forking failed, (%d) %s\n", errno, strerror(errno));
            exit(errno);
        }

        if (pidFils == 0)
        { // instructions du fils
            if (cmd->backgrounded)
            {
                action.sa_handler = SIG_IGN;
                sigaction(SIGINT, &action, NULL); // on ignore SIGINT
            }
            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)
            { // on sauvegarde le pid, si background
                ajouter(&jobs, pidFils, job_id++, *(cmd->seq), 0);
                printf("[%d] %d\n", job_id, pidFils);
            }
            else
            { // on attend le fils, si foreground
                int codeTerm;
                pid_t idFils = waitpid(pidFils, &codeTerm, 0); // on attend la fin de l'exec du fils

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

                if (codeTerm)
                { // si l'exec a échoué
                    fprintf(stderr, "ERROR: %d's execution failed, (%d) %s\n", pidFils, codeTerm, strerror(codeTerm));
                }
            }
        }
    }

    liberer(&jobs);
    return EXIT_SUCCESS;
}