#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"

extern int errno;

struct cmdline *cmd;

int pid_fils;

int job_id = 0;
list jobs;

int prompting = 0;
jmp_buf goto_prompt;

char initcd[256], currentcd[256];

void handler_sigchld(int sig_num, siginfo_t *info)
{
    cell *job = trouver(&jobs, info->si_pid);
    if (job && !job->state)
    {
        if (prompting)
        {
            printf("\n");
        }

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

        if (prompting)
        {
            siglongjmp(goto_prompt, sig_num);
        }
    }
}

void handler_sigint(int sig_num)
{
    printf("\n");
    siglongjmp(goto_prompt, sig_num);
}

void handler_sigtstp(int sig_num)
{
    if (!prompting)
    {
        kill(pid_fils, SIGTSTP);
        cell *job = ajouter(&jobs, pid_fils, ++job_id, *(cmd->seq), 1);
        printf("[%d] %d suspended: %s\n", job_id, pid_fils, job->cmd);
        siglongjmp(goto_prompt, sig_num);
    }
    else
    {
        handler_sigint(sig_num);
    }
}

void attendre(int pid)
{
    int wait_code;
    pid_t id = waitpid(pid, &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, wait_code, strerror(wait_code));
    }
}

int main(int argc, char *argv[])
{
    initialiser(&jobs);
    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);
    action.sa_handler = handler_sigint;
    sigaction(SIGINT, &action, NULL);
    action.sa_handler = handler_sigtstp;
    sigaction(SIGTSTP, &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;
        }
        else if (!strcmp(cmd->seq[0][0], "jobs"))
        { // "jobs"
            afficher(&jobs);
            continue;
        }
        else if (!strcmp(cmd->seq[0][0], "bg"))
        { // "bg"
            kill(pid_fils, SIGCONT);
            continue;
        }
        else if (!strcmp(cmd->seq[0][0], "fg"))
        { // "fg"
            cell *job;
            if (cmd->seq[0][1] == NULL)
            { // no id
                fprintf(stderr, "ERROR: fg id error");
                continue;
            }
            else
            { // id specified
                job = &(jobs[atoi(cmd->seq[0][1]) - 1]);
            }
            kill(job->pid, SIGCONT);
            printf("[%d] %d continued: %s\n", job->id, job->pid, job->cmd);
            supprimer(&job, job->pid);
            job_id--;
            attendre(job->pid);
            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
            action.sa_handler = SIG_DFL;
            sigaction(SIGTSTP, &action, NULL); // on default SIGTSTP
            sigaction(SIGCONT, &action, NULL); // on default SIGCONT

            if (cmd->backgrounded)
            { // background
                action.sa_handler = SIG_IGN;
                sigaction(SIGINT, &action, NULL);  // on ignore SIGINT
                sigaction(SIGTSTP, &action, NULL); // on ignore SIGTSTP
            }

            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
                ajouter(&jobs, pid_fils, ++job_id, *(cmd->seq), 0);
                printf("[%d] %d\n", job_id, pid_fils);
            }
            else
            { // foreground
                attendre(pid_fils);
            }
        }
    }

    return EXIT_SUCCESS;
}