#define _GNU_SOURCE

#include "signals.h"
#include "log.h"

#include <string.h>
#include <signal.h>
#include <stdlib.h>
#include <assert.h>

struct signals {
    /** The libevent base to use */
    struct event_base *ev_base;
    
    /** Information about up to MAX_SIGNALS signals */
    struct signal {
        /** The event we use to handle the signal */
        struct event *ev;

    } sig_list[MAX_SIGNALS];
    
    /** Number of used sig_list slots */
    int sig_count;
};

void signals_loopexit (int signal, short event, void *arg) 
{
    struct signals *signals = arg;

    (void) event;

    log_info("caught %s: exiting", strsignal(signal));
    
    if (event_base_loopexit(signals->ev_base, NULL))
        FATAL("event_base_loopexit");
}

void signals_ignore (int signal, short event, void *arg)
{
    struct signals *signals = arg;
    
    (void) signal;
    (void) event;
    (void) arg;
    (void) signals;
    
    /* ignore */
}

err_t signals_create (struct signals **signals_ptr, struct event_base *ev_base)
{
    struct signals *signals;

    if ((signals = calloc(1, sizeof(*signals))) == NULL)
        return ERR_CALLOC;
    
    // simple attributes
    signals->ev_base = ev_base;

    // done
    *signals_ptr = signals;

    return SUCCESS;
}

err_t signals_add (struct signals *signals, int sigval, void (*sig_handler)(evutil_socket_t, short, void *), void *arg) 
{
    struct signal *sig_info;
    
    // find our sig_info
    assert(signals->sig_count < MAX_SIGNALS);
    sig_info = signals->sig_list + (signals->sig_count++);
    
    // set up the libevent signal events
    if ((sig_info->ev = evsignal_new(signals->ev_base, sigval, sig_handler, arg)) == NULL)
        return ERR_EVENT_NEW;

    if (evsignal_add(sig_info->ev, NULL))
        return ERR_EVENT_ADD;

    // ok
    return SUCCESS;
}

struct signals *signals_default (struct event_base *ev_base) 
{
    struct signals *signals = NULL;
    
    // alloc signals
    if (signals_create(&signals, ev_base))
        return NULL;
    
    // add the set of default signals
    if (    signals_add(signals,    SIGPIPE,    &signals_ignore,        signals)
        ||  signals_add(signals,    SIGINT,     &signals_loopexit,      signals)
    ) 
        goto error;
    
    // ok
    return signals;

error:
    if (signals)
        signals_free(signals);

    return NULL;
}   

void signals_free (struct signals *signals) 
{
    int i;
    
    // free all events
    for (i = 0; i < signals->sig_count; i++) {
        if (evsignal_del(signals->sig_list[i].ev))
            log_warn("evsignal_del failed");
    }
    
    // free the info itself
    free(signals);
}