/*
    Copyright (c) 2012-2013 Martin Sustrik  All rights reserved.
    Copyright (c) 2013 GoPivotal, Inc.  All rights reserved.
    Copyright 2016 Garrett D'Amore <garrett@damore.org>

    Permission is hereby granted, free of charge, to any person obtaining a copy
    of this software and associated documentation files (the "Software"),
    to deal in the Software without restriction, including without limitation
    the rights to use, copy, modify, merge, publish, distribute, sublicense,
    and/or sell copies of the Software, and to permit persons to whom
    the Software is furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included
    in all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
    IN THE SOFTWARE.
*/

#include "binproc.h"
#include "sinproc.h"
#include "cinproc.h"
#include "ins.h"

#include "../../utils/err.h"
#include "../../utils/cont.h"
#include "../../utils/fast.h"
#include "../../utils/alloc.h"

#define NN_BINPROC_STATE_IDLE 1
#define NN_BINPROC_STATE_ACTIVE 2
#define NN_BINPROC_STATE_STOPPING 3

#define NN_BINPROC_SRC_SINPROC 1

/*  Implementation of nn_ep interface. */
static void nn_binproc_stop (struct nn_ep *);
static void nn_binproc_destroy (struct nn_ep *);
static const struct nn_ep_vfptr nn_binproc_vfptr = {
    nn_binproc_stop,
    nn_binproc_destroy
};

/*  Private functions. */
static void nn_binproc_handler (struct nn_fsm *self, int src, int type,
    void *srcptr);
static void nn_binproc_shutdown (struct nn_fsm *self, int src, int type,
    void *srcptr);
static void nn_binproc_connect (struct nn_ins_item *self,
    struct nn_ins_item *peer);


int nn_binproc_create (struct nn_ep *ep)
{
    int rc;
    struct nn_binproc *self;

    self = nn_alloc (sizeof (struct nn_binproc), "binproc");
    alloc_assert (self);

    nn_ins_item_init (&self->item, ep);
    nn_fsm_init_root (&self->fsm, nn_binproc_handler, nn_binproc_shutdown,
        nn_ep_getctx (ep));
    self->state = NN_BINPROC_STATE_IDLE;
    nn_list_init (&self->sinprocs);

    /*  Start the state machine. */
    nn_fsm_start (&self->fsm);

    /*  Register the inproc endpoint into a global repository. */
    rc = nn_ins_bind (&self->item, nn_binproc_connect);
    if (rc < 0) {
        nn_list_term (&self->sinprocs);

        /*  TODO: Now, this is ugly! We are getting the state machine into
            the idle state manually. How should it be done correctly? */
        self->fsm.state = 1;
        nn_fsm_term (&self->fsm);

        nn_ins_item_term (&self->item);
        nn_free (self);
        return rc;
    }

    nn_ep_tran_setup (ep, &nn_binproc_vfptr, self);
    return 0;
}

static void nn_binproc_stop (struct nn_ep *ep)
{
    struct nn_binproc *binproc;

    binproc = nn_ep_tran_private (ep);

    nn_fsm_stop (&binproc->fsm);
}

static void nn_binproc_destroy (struct nn_ep *ep)
{
    struct nn_binproc *binproc;

    binproc = nn_ep_tran_private (ep);

    nn_list_term (&binproc->sinprocs);
    nn_fsm_term (&binproc->fsm);
    nn_ins_item_term (&binproc->item);

    nn_free (binproc);
}

static void nn_binproc_connect (struct nn_ins_item *self,
    struct nn_ins_item *peer)
{
    struct nn_binproc *binproc;
    struct nn_cinproc *cinproc;
    struct nn_sinproc *sinproc;

    binproc = nn_cont (self, struct nn_binproc, item);
    cinproc = nn_cont (peer, struct nn_cinproc, item);

    nn_assert_state (binproc, NN_BINPROC_STATE_ACTIVE);

    sinproc = nn_alloc (sizeof (struct nn_sinproc), "sinproc");
    alloc_assert (sinproc);
    nn_sinproc_init (sinproc, NN_BINPROC_SRC_SINPROC,
        binproc->item.ep, &binproc->fsm);
    nn_list_insert (&binproc->sinprocs, &sinproc->item,
        nn_list_end (&binproc->sinprocs));
    nn_sinproc_connect (sinproc, &cinproc->fsm);

    nn_ep_stat_increment (binproc->item.ep, NN_STAT_ACCEPTED_CONNECTIONS, 1);
}

static void nn_binproc_shutdown (struct nn_fsm *self, int src, int type,
    void *srcptr)
{
    struct nn_binproc *binproc;
    struct nn_list_item *it;
    struct nn_sinproc *sinproc;

    binproc = nn_cont (self, struct nn_binproc, fsm);

    if (nn_slow (src == NN_FSM_ACTION && type == NN_FSM_STOP)) {

        /*  First, unregister the endpoint from the global repository of inproc
            endpoints. This way, new connections cannot be created anymore. */
        nn_ins_unbind (&binproc->item);

        /*  Stop the existing connections. */
        for (it = nn_list_begin (&binproc->sinprocs);
              it != nn_list_end (&binproc->sinprocs);
              it = nn_list_next (&binproc->sinprocs, it)) {
            sinproc = nn_cont (it, struct nn_sinproc, item);
            nn_sinproc_stop (sinproc);
        }

        binproc->state = NN_BINPROC_STATE_STOPPING;
        goto finish;
    }
    if (binproc->state == NN_BINPROC_STATE_STOPPING) {
        nn_assert (src == NN_BINPROC_SRC_SINPROC && type == NN_SINPROC_STOPPED);
        sinproc = (struct nn_sinproc*) srcptr;
        nn_list_erase (&binproc->sinprocs, &sinproc->item);
        nn_sinproc_term (sinproc);
        nn_free (sinproc);
finish:
        if (!nn_list_empty (&binproc->sinprocs))
            return;
        binproc->state = NN_BINPROC_STATE_IDLE;
        nn_fsm_stopped_noevent (&binproc->fsm);
        nn_ep_stopped (binproc->item.ep);
        return;
    }

    nn_fsm_bad_state(binproc->state, src, type);
}

static void nn_binproc_handler (struct nn_fsm *self, int src, int type,
    void *srcptr)
{
    struct nn_binproc *binproc;
    struct nn_sinproc *peer;
    struct nn_sinproc *sinproc;

    binproc = nn_cont (self, struct nn_binproc, fsm);

    switch (binproc->state) {

/******************************************************************************/
/*  IDLE state.                                                               */
/******************************************************************************/
    case NN_BINPROC_STATE_IDLE:
        switch (src) {

        case NN_FSM_ACTION:
            switch (type) {
            case NN_FSM_START:
                binproc->state = NN_BINPROC_STATE_ACTIVE;
                return;
            default:
                nn_fsm_bad_action (binproc->state, src, type);
            }

        default:
            nn_fsm_bad_source (binproc->state, src, type);
        }

/******************************************************************************/
/*  ACTIVE state.                                                             */
/******************************************************************************/
    case NN_BINPROC_STATE_ACTIVE:
        switch (src) {

        case NN_SINPROC_SRC_PEER:
            switch (type) {
            case NN_SINPROC_CONNECT:
                peer = (struct nn_sinproc*) srcptr;
                sinproc = nn_alloc (sizeof (struct nn_sinproc), "sinproc");
                alloc_assert (sinproc);
                nn_sinproc_init (sinproc, NN_BINPROC_SRC_SINPROC,
                    binproc->item.ep, &binproc->fsm);
                nn_list_insert (&binproc->sinprocs, &sinproc->item,
                    nn_list_end (&binproc->sinprocs));
                nn_sinproc_accept (sinproc, peer);
                return;
            default:
                nn_fsm_bad_action (binproc->state, src, type);
            }

        case NN_BINPROC_SRC_SINPROC:
            return;

        default:
            nn_fsm_bad_source (binproc->state, src, type);
        }

/******************************************************************************/
/*  Invalid state.                                                            */
/******************************************************************************/
    default:
        nn_fsm_bad_state (binproc->state, src, type);
    }
}