#define _GNU_SOURCE

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

extern int errno;

struct cmdline *cmd;

int pid_fils, wait_code;

list jobs;

int prompting = 0;
jmp_buf goto_prompt;

char initcd[256], currentcd[256];

int file_in, file_out;

void handler_sigchld(int sig_num)
{
    do
    {
        pid_fils = waitpid(-1, &wait_code, WNOHANG | WUNTRACED | WCONTINUED);
        if ((pid_fils == -1) && (errno != ECHILD))
        { // wait fail ?
            fprintf(stderr, "ERROR: waiting for child failed, (%d) %s\n", errno, strerror(errno));
            exit(errno);
        }

        cell *job = trouver(&jobs, pid_fils);
        if (job != NULL)
        {
            if (prompting)
            {
                printf("\n");
            }

            if (WIFSTOPPED(wait_code))
            {
                printf("[%d] %d stopped: %s\n", job->id, job->pid, job->cmd);
            }
            else if (WIFCONTINUED(wait_code))
            {
                printf("[%d] %d continued: %s\n", job->id, job->pid, job->cmd);
                if (!strcmp(cmd->seq[0][0], "fg"))
                {
                    supprimer(&jobs, job->pid);
                }
            }
            else if (WIFEXITED(wait_code))
            {
                printf("[%d] %d exited: %s\n", job->id, job->pid, job->cmd);
                supprimer(&jobs, job->pid);
            }
            else if (wait_code == SIGKILL)
            {
                printf("[%d] %d killed: %s\n", job->id, job->pid, job->cmd);
                supprimer(&jobs, job->pid);
            }
        }
    } while (pid_fils > 0);

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

void handler_sigint(int sig_num)
{
    printf("\n");
    if (!prompting)
    {
        kill(pid_fils, SIGKILL);
        pause();
    }
    siglongjmp(goto_prompt, sig_num);
}

void handler_sigtstp(int sig_num)
{
    printf("\n");
    if (!prompting)
    {
        ajouter(&jobs, pid_fils, *(cmd->seq));
        kill(pid_fils, SIGSTOP);
        pause();
    }
    siglongjmp(goto_prompt, sig_num);
}

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);

    // main loop
    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->err)
        { // error from readcmd
            fprintf(stderr, "ERROR: readcmd failed, (%d) %s\n", errno, strerror(errno));
            continue;
        }
        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"
            cell *job;
            if (cmd->seq[0][1] == NULL)
            { // no id
                fprintf(stderr, "ERROR: id missing\n");
                continue;
            }
            else
            { // id specified
                job = trouver_id(&jobs, atoi(cmd->seq[0][1]));
            }
            kill(job->pid, SIGCONT);
            pause();
            continue;
        }
        else if (!strcmp(cmd->seq[0][0], "fg"))
        { // "fg"
            cell *job;
            if (cmd->seq[0][1] == NULL)
            { // no id
                fprintf(stderr, "ERROR: id missing\n");
                continue;
            }
            else
            { // id specified
                job = trouver_id(&jobs, atoi(cmd->seq[0][1]));
                pid_fils = job->pid;
            }
            kill(pid_fils, SIGCONT);
            pause();
            waitpid(pid_fils, NULL, 0);
            continue;
        }
        else if (!strcmp(cmd->seq[0][0], "stop"))
        { // "stop"
            cell *job;
            if (cmd->seq[0][1] == NULL)
            { // no id
                fprintf(stderr, "ERROR: id missing\n");
                continue;
            }
            else
            { // id specified
                job = trouver_id(&jobs, atoi(cmd->seq[0][1]));
            }
            kill(job->pid, SIGSTOP);
            pause();
            continue;
        }
        else if (!strcmp(cmd->seq[0][0], "pid"))
        { // "pid"
            printf("pid=%d\n", getpid());
            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_IGN;
            sigaction(SIGTSTP, &action, NULL); // on igonre SIGTSTP
            sigaction(SIGINT, &action, NULL);  // on ignore SIGINT

            if (cmd->in)
            {
                file_in = open(cmd->in, O_RDONLY);
                dup2(file_in, 0);
            }
            if (cmd->out)
            {
                file_out = open(cmd->out, O_CREAT | O_TRUNC | O_WRONLY, 0640);
                dup2(file_out, 1);
            }

            execvp(cmd->seq[0][0], cmd->seq[0]);
            fprintf(stderr, "ERROR: execvp failed, (%d) %s\n", errno, strerror(errno));
            exit(errno); // si execvp échoue on exit avec une erreur
        }
        else
        { // instructions du père
            if (cmd->backgrounded)
            { // background
                int id_fils = ajouter(&jobs, pid_fils, *(cmd->seq));
                printf("[%d] %d\n", id_fils, pid_fils);
            }
            else
            { // foreground
                pid_t id = waitpid(pid_fils, &wait_code, 0);

                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: child failed, (%d) %s\n", wait_code, strerror(wait_code));
                }
            }
        }
    }

    return EXIT_SUCCESS;
}