// Copyright (C) 2006-2010 David Sugar, Tycho Softworks.
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

#include "server.h"

NAMESPACE_SIPWITCH
using namespace UCOMMON_NAMESPACE;

stack::call::call() : LinkedList(), segments()
{
    arm(stack::resetTimeout());
    count = 0;
    forwarding = diverting = NULL;
    answering = 16; // should set from cfna timer...
    invited = ringing = ringbusy = unreachable = 0;
    phone = false;
    expires = 0l;
    target = source = NULL;
    state = INITIAL;
    enlist(&stack::sip);
    starting = ending = 0l;
    reason = joined = NULL;
    map = NULL;
    timer = Timer::inf;
}

void stack::call::arm(timeout_t timeout)
{
    timer = timeout;
    stack::background::notify();
}

void stack::call::disarm(void)
{
    timer = Timer::inf;
}

void stack::call::terminateLocked(void)
{
    if(state != INITIAL)
        set(TERMINATE, 'q', "bye");
    disconnectLocked();
}

void stack::call::cancelLocked(void)
{
    linked_pointer<segment> sp = segments.begin();
    session *s;

    shell::debug(2, "cancelling call %08x:%u", source->sequence, source->cid);
    while(sp) {
        s = &(sp->sid);
        if(s != source) {
            if(!s->closed) {
                registry::decUse(s->reg, stats::OUTGOING);
                s->closed = true;
            }
            if(s->state == session::REFER)
                s->state = session::CLOSED;
            else if(s->cid > 0 && s->state != session::CLOSED) {
                s->state = session::CLOSED;
                EXOSIP_LOCK
                eXosip_call_terminate(OPTION_CONTEXT s->cid, s->did);
                EXOSIP_UNLOCK
            }
        }
        sp.next();
    }
    invited = ringing = ringbusy = 0;
}

void stack::call::joinLocked(session *join)
{
    linked_pointer<segment> sp = segments.begin();
    session *s;

    if(target)
        return;

    shell::debug(2, "joining call %08x:%u with session %08x:%u",
        source->sequence, source->cid, join->sequence, join->cid);

    String::set(map->target, sizeof(map->target), join->sysident);
    if(!map->active)
        time(&map->active);

    // once we have joined, there is no more forwarding...
    forwarding = diverting = NULL;
    target = join;
    while(sp) {
        s = &(sp->sid);
        if(s != source && s != target) {
            if(!s->closed) {
                registry::decUse(s->reg, stats::OUTGOING);
                s->closed = true;
            }
            if(s->state == session::REFER)
                s->state = session::CLOSED;
            else if(s->cid > 0 && s->state != session::CLOSED) {
                s->state = session::CLOSED;
                EXOSIP_LOCK
                eXosip_call_terminate(OPTION_CONTEXT s->cid, s->did);
                EXOSIP_UNLOCK
            }
        }
        sp.next();
    }
    source->state = target->state = session::OPEN;
}

void stack::call::disconnectLocked(void)
{
    shell::debug(4, "disconnecting call %08x:%u\n", source->sequence, source->cid);

    switch(state) {
    case RINGING:
    case RINGBACK:
    case TRYING:
        reason = "declined";
        reply_source(SIP_DECLINE);
        break;
    case REORDER:
        reason = "rejected";
        break;
    case BUSY:
        reason = "busy";
        reply_source(SIP_BUSY_HERE);
        break;
    case ANSWERED:
    case FAILED:
        reason = "failed";
        break;
    case JOINED:
        reason = "expired";
        break;
    case HOLDING:
    case TERMINATE:
        reason = "terminated";
        break;
    case TRANSFER:
        reason = "transfer";
        break;
    case REDIRECT:
        reason = "redirect";
        break;
    case INITIAL:
    case FINAL:
        break;
    }

    linked_pointer<segment> sp = segments.begin();
    while(sp) {
        if(!sp->sid.closed) {
            if(&(sp->sid) == sp->sid.parent->source)
                registry::decUse(sp->sid.reg, stats::INCOMING);
            else
                registry::decUse(sp->sid.reg, stats::OUTGOING);
            sp->sid.closed = true;
        }
        if(sp->sid.state == session::REFER)
            sp->sid.state = session::CLOSED;
        else if(sp->sid.cid > 0 && sp->sid.state != session::CLOSED) {
            sp->sid.state = session::CLOSED;
            EXOSIP_LOCK
            eXosip_call_terminate(OPTION_CONTEXT sp->sid.cid, sp->sid.did);
            EXOSIP_UNLOCK
        }
        sp.next();
    }

    if(state != INITIAL && state != FINAL) {
        time(&ending);
        set(FINAL, 'q', "exit");
    }

    arm(stack::resetTimeout());
}

void stack::call::closingLocked(session *s)
{
    assert(s != NULL);

    if(invited)
        --invited;

    if(!invited) {
        if(!stack::forward(this))
            disconnectLocked();
        if(state == RINGING) {
            arm(1000);
            reply_source(SIP_CALL_IS_BEING_FORWARDED);
        }
    }
}

void stack::call::reply_source(int error)
{
    osip_message_t *reply = NULL;

    shell::debug(3, "sip: sending source reply %d", error);

    if(error == SIP_CALL_IS_BEING_FORWARDED && answering)
        answering = 16;

    EXOSIP_LOCK
    eXosip_call_build_answer(OPTION_CONTEXT source->tid, error, &reply);
    if(reply != NULL) {
        stack::siplog(reply);
        eXosip_call_send_answer(OPTION_CONTEXT source->tid, error, reply);
    }
    else {
        shell::debug(3, "sip: source reply %d failed", error);
        eXosip_call_send_answer(OPTION_CONTEXT source->tid, SIP_BAD_REQUEST, NULL);
    }
    EXOSIP_UNLOCK
}

void stack::call::set(state_t flag, char id, const char *text)
{
    state = flag;
    if(!map)
        return;

    map->state[0] = id;
    String::set(map->state + 1, sizeof(map->state) - 1, text);
}

void stack::call::bye(thread *thread, session *s)
{
    bool closing = false;

    Mutex::protect(this);
    s->tid = 0; // cleared already....

    switch(state) {
    case JOINED:
    case ANSWERED:
    case HOLDING:
        if(s == source || s == target) {
            s->state = session::CLOSED;
            terminateLocked();
        }
        break;
    case TRYING:
    case RINGING:
    case RINGBACK:
        if(s == source) {
            s->state = session::CLOSED;
            disconnectLocked();
        }
        else
            closing = true;
    default:
        break;
    }
    Mutex::release(this);
    if(closing)
        stack::close(s);
}

void stack::call::ring(thread *thread, session *s)
{
    assert(thread != NULL);

    Mutex::protect(this);
    switch(state) {
    case TRYING:
    case INITIAL:
    case BUSY:
        // we offset the first ring by 1 second because some servers
        // send a 180 immediately followed by a 200 because they do
        // artificial ringback within a connected session (asterisk for
        // example).  Also, we might get a 200 OK accept from another
        // invited ua, and so we do not want to start a partial ring
        // followed by a connect...
        set(RINGING, 'r', "ringin");
        arm(1000);
    case RINGING:
        if(s && s != source && s->state != session::RING) {
            ++ringing;
            s->state = session::RING;
        }
        else if(!s)
            ++ringing;
    default:
        break;
    }
    Mutex::release(this);
}

void stack::call::failed(thread *thread, session *s)
{
    assert(thread != NULL);

    Mutex::protect(this);
    switch(state) {
    case FINAL:
    case TERMINATE:
    case FAILED:
        Mutex::release(this);
        return;
    default:
        break;
    }

    if(s->state == session::RING)
        --ringing;
    else if(s->state == session::BUSY)
        --ringbusy;
    else if(s->state == session::REFER)
        s->state = session::CLOSED;
    if(s->state != session::CLOSED)
        s->state = session::OPEN;

    switch(state) {
    case RINGING:
        if(!ringing && ringbusy)
            set(BUSY, 'b', "busy");
        else if(!ringing) {
            arm(stack::resetTimeout());
            set(FAILED, '*', "failed");
        }
        break;
    case INITIAL:
    case ANSWERED:
        set(FAILED, '*', "failed");
        arm(stack::resetTimeout());
        break;
    case BUSY:
        if(!ringbusy) {
            set(FAILED, '*', "failed");
            arm(stack::resetTimeout());
        }
    default:
        break;
    }
    Mutex::release(this);
    stack::close(s);
}

void stack::call::reinvite(thread *thread, session *s)
{
    osip_message_t *reply = NULL;
    osip_body_t *body = NULL;
    int did = source->did;
    session *update = source;
    bool holding = false;
    char *sdp;
    int error = 200;

    assert(thread != NULL);
    assert(s != NULL);

    Mutex::protect(this);
    if(s == source) {
        update = target;
        if(target)
            did = target->did;
        else
            goto unconnected;
    }

    s->tid = thread->sevent->tid;

    body = NULL;
    osip_message_get_body(thread->sevent->request, 0, &body);

    switch(state) {
    case RINGING:
    case RINGBACK:
    case TRYING:
    case ANSWERED:
        if(s == source) {
unconnected:
            Mutex::release(this);
            EXOSIP_LOCK
            eXosip_call_build_answer(OPTION_CONTEXT source->tid, 500, &reply);
            if(reply != NULL) {
                osip_message_set_header(reply, "Reply-After", "8");
                stack::siplog(reply);
                eXosip_call_send_answer(OPTION_CONTEXT source->tid, 500, reply);
            }
            EXOSIP_UNLOCK
            return;
        }
        if(state != ANSWERED && state != RINGBACK) {
            joinLocked(s);
            if(state != ANSWERED)
                set(RINGBACK, 'r', "ringback");
        }
        if(thread->header_expires) {
            time(&expires);
            expires += thread->header_expires;
            arm((timeout_t)(thread->header_expires * 1000l));
        }
        Mutex::release(this);
        EXOSIP_LOCK
        eXosip_call_build_answer(OPTION_CONTEXT source->tid, 200, &reply);
        if(reply != NULL) {
            osip_message_set_require(reply, "100rel");
            osip_message_set_header(reply, "RSeq", "1");
            if(body && body->body) {
                sdp = media::reinvite(s, body->body);
                if(sdp) {
                    osip_message_set_body(reply, sdp, strlen(sdp));
                    osip_message_set_content_type(reply, "application/sdp");
                }
                else
                    error = SIP_TEMPORARILY_UNAVAILABLE;
            }
            stack::siplog(reply);
            eXosip_call_send_answer(OPTION_CONTEXT source->tid, error, reply);
        }
        EXOSIP_UNLOCK
        return;
    case HOLDING:
    case JOINED:
        if(holding)
            set(HOLDING, 'h', "holding");
        else
            set(JOINED, 'j', "joined");
        if(thread->header_expires) {
            time(&expires);
            expires += thread->header_expires;
            arm((timeout_t)(thread->header_expires * 1000l));
        }
        Mutex::release(this);

        EXOSIP_LOCK
        eXosip_call_build_request(OPTION_CONTEXT did, "INVITE", &reply);
        if(reply != NULL) {
            if(stack::sip_protocol == IPPROTO_UDP)
                osip_message_set_supported(reply, "100rel,replaces");
            if(body && body->body) {
                osip_message_set_body(reply, body->body, strlen(body->body));
                osip_message_set_content_type(reply, "application/sdp");
            }
            stack::siplog(reply);
            eXosip_call_send_request(OPTION_CONTEXT did, reply);
            update->state = session::REINVITE;
        }
        EXOSIP_UNLOCK
        if(!reply)
            goto failed;
        return;
    default:
        break;
    }
    Mutex::release(this);
failed:
    shell::debug(2, "reinvite failed for call %08x:%u",
            source->sequence, source->cid);
        failed(thread, s);
}

void stack::call::answer(thread *thread, session *s)
{
    osip_message_t *reply = NULL;
    int did, tid;

    assert(thread != NULL);
    assert(s != NULL);

    Mutex::protect(this);
    if(s == source || (target != NULL && target != s)) {
        Mutex::release(this);
        shell::debug(2, "cannot answer call %08x:%u from specified session",
            source->sequence, source->cid);
        return;
    }
    switch(state) {
    case RINGING:
    case RINGBACK:
    case TRYING:
        joinLocked(s);
        set(ANSWERED, 'a', "answered");
        arm(16000l);
    case ANSWERED:
        if(thread->sevent->did > -1)
            s->did = thread->sevent->did;
        tid = source->tid;
        break;
    case JOINED:
    case HOLDING:
        // if already joined, then we assume that the target ua never
        // saw the ack the originating ua had sent although we did, and
        // so we resend it.
        if(thread->sevent->did > -1)
            s->did = thread->sevent->did;
        did = target->did;
        Mutex::release(this);
        EXOSIP_LOCK
        eXosip_call_send_ack(OPTION_CONTEXT did, NULL);
        EXOSIP_UNLOCK
        return;
    default:
        Mutex::release(this);
        shell::debug(2, "cannot answer non-ringing call %08x:%u",
            source->sequence, source->cid);
        return;
    }
    Mutex::release(this);
    EXOSIP_LOCK
    eXosip_call_build_answer(OPTION_CONTEXT tid, SIP_OK, &reply);
    if(reply != NULL) {
        osip_message_set_body(reply, s->sdp, strlen(s->sdp));
        osip_message_set_content_type(reply, "application/sdp");
        stack::siplog(reply);
        eXosip_call_send_answer(OPTION_CONTEXT tid, SIP_OK, reply);
        EXOSIP_UNLOCK
    }
    else {
        EXOSIP_UNLOCK
        shell::debug(2, "answer failed for call %08x:%u",
            source->sequence, source->cid);
        failed(thread, source);
    }
}

void stack::call::message_reply(thread *thread, session *s)
{
    assert(thread != NULL);
    assert(s != NULL);

    int tid;

    Mutex::protect(this);
    tid = s->tid;
    Mutex::release(this);

    if(tid < 1)
        return;

    EXOSIP_LOCK
    eXosip_call_send_answer(OPTION_CONTEXT tid, thread->sevent->response->status_code, NULL);
    EXOSIP_UNLOCK
}


void stack::call::relay(thread *thread, session *s)
{
    assert(thread != NULL);
    assert(s != NULL);

    int status = thread->sevent->response->status_code;
    int tid = -1;
    osip_body_t *body = NULL;
    osip_message_t *reply = NULL;

    Mutex::protect(this);
    if(s == source && target)
        tid = target->tid;
    else if(s == target)
        tid = source->tid;

    osip_message_get_body(thread->sevent->response, 0, &body);

    switch(s->state) {
    case session::REFER:
        if(status == SIP_ACCEPTED) {
            set(TRANSFER, 'x', "transfer");
            disconnectLocked();
            Mutex::release(this);
            return;
        }
        s->state = session::OPEN;
        break;
    case session::REINVITE:
        if(status != SIP_ACCEPTED)
            s->state = session::OPEN;
    default:
        break;
    }
    Mutex::release(this);
    if(tid < 1)
        return;

    EXOSIP_LOCK
    eXosip_call_build_answer(OPTION_CONTEXT tid, status, &reply);
    if(reply) {
        if(stack::sip_protocol == IPPROTO_UDP)
            osip_message_set_require(reply, "100rel");
        osip_message_set_header(reply, "RSeq", "1");
        if(body && body->body) {
            osip_message_set_body(reply, body->body, strlen(body->body));
            osip_message_set_content_type(reply, "application/sdp");
        }
        eXosip_call_send_answer(OPTION_CONTEXT tid, status, reply);
    }
    EXOSIP_UNLOCK
}

void stack::call::confirm(thread *thread, session *s)
{
    assert(thread != NULL);
    assert(s != NULL);

    osip_message_t *ack = NULL;
    time_t now;
    int did = -1;

    Mutex::protect(this);
    if(target == NULL) {
        Mutex::release(this);
        shell::debug(2, "cannot confirm call %08x:%u from session %08x:%u\n",
            source->sequence, source->cid, s->sequence, s->cid);
        return;
    }
    switch(state)
    {
    case ANSWERED:
    case JOINED:
        set(JOINED, 'j', "joined");
        source->state = target->state = session::OPEN;
        if(thread->sevent->did > -1)
            s->did = thread->sevent->did;
        if(expires) {
            time(&now);
            arm((timeout_t)((expires - now) * 1000l));
        }
        else
            arm((timeout_t)DAY_TIMEOUT);
    case HOLDING:
        if(s == source)
            did = target->did;
        else if(s == target)
            did = source->did;
        break;
    default:
        Mutex::release(this);
        shell::debug(2, "cannot confirm unanswered call %08x:%u",
            source->sequence, source->cid);
        return;
    }
    Mutex::release(this);
    EXOSIP_LOCK
    eXosip_call_build_ack(OPTION_CONTEXT did, &ack);
    if(ack) {
        stack::siplog(ack);
        eXosip_call_send_ack(OPTION_CONTEXT did, ack);
    }
    else {
        shell::debug(2, "confirm failed to send for call %08x:%u",
            source->sequence, source->cid);
    }
    EXOSIP_UNLOCK
}

void stack::call::busy(thread *thread, session *s)
{
    assert(thread != NULL);

    Mutex::protect(this);
    switch(state) {
    case INITIAL:
        if(!s) {
            set(BUSY, 'b', "busy");
            disconnectLocked();
            Mutex::release(this);
            return;
        }
    case FINAL:
    case HOLDING:
    case JOINED:
    case ANSWERED:
    case FAILED:
        Mutex::release(this);
        return;
    default:
        break;
    }

    if(s && s != source) {
        if(s->state == session::RING)
            --ringing;
        if(s->state != session::BUSY) {
            ++ringbusy;
            s->state = session::BUSY;
        }
    }
    else if(!s)
        ++ringbusy;

    switch(state) {
    case INITIAL:
    case RINGING:
    case RINGBACK:
        // we goto busy in this special case, otherwise stack::close handles na
        if(!ringing && ringbusy && invited == 1 && s != source) {
            if(forwarding) {
                forwarding = "busy";
                if(s)
                    s->state = session::CLOSED;
                if(s && !s->closed) {
                    registry::decUse(s->reg, stats::OUTGOING);
                    s->closed = true;
                }
                ringbusy = invited = 0;
                if(stack::forward(this)) {
                    if(state == RINGING)
                        arm(1000);
                    Mutex::release(this);
                    if(state == RINGING)
                        reply_source(SIP_CALL_IS_BEING_FORWARDED);
                    return;
                }
            }
            set(BUSY, 'b', "busy");
            disconnectLocked();
        }
    default:
        break;
    }

    Mutex::release(this);
    if(s)
        stack::close(s);
    else
        stack::close(source);
}

void stack::call::trying(thread *thread)
{
    // if we are in initial state, then send call trying, otherwise
    // turn-over state and set timer to wait for all invites to become
    // busy or one or more to start ringing...
    //
    if(state == INITIAL) {
        shell::debug(3, "sip: sending initial ring %d", SIP_RINGING);
        reply_source(SIP_RINGING);
        time_t now;
        time(&now);
        if(answering)
            answering -= (unsigned)(now - starting);
    }

    Mutex::protect(this);
    set(TRYING, 't', "trying");
    arm(4000);
    Mutex::release(this);
}

timeout_t stack::call::getTimeout(void)
{
    timeout_t current;
    Mutex::protect(this);
    current = timer.get();
    if(current < 2) {
        timer = Timer::inf;
        expired();
    }
    Mutex::release(this);
    return current;
}

void stack::call::expired(void)
{
    linked_pointer<segment> sp;

    switch(state) {
    case TRANSFER:
    case HOLDING:   // hold-recall timer expired...

    case RINGING:   // re-generate ring event to origination...
                    // also controls call-forward no-answer timing...

            if(answering == 1 && forwarding) {
                forwarding = "na";
                cancelLocked();
                if(stack::forward(this)) {
                    arm(1000);
                    reply_source(SIP_CALL_IS_BEING_FORWARDED);
                    return;
                }
                disconnectLocked();
                break;
            }
            if(answering)
                --answering;
            arm(1000);
            reply_source(SIP_RINGING);
            return;
    case REDIRECT:  // FIXME: add refer select of next segment if list....

    case RINGBACK:
    case BUSY:      // invite expired
    case JOINED:    // active call session expired without re-invite
    case ANSWERED:
    case REORDER:
    case TRYING:
    case FAILED:
            disconnectLocked();
            break;
    case FINAL:     // session expired that expects to be recycled.
    case INITIAL:   // never used session recycled.
        // The call record is garbage collected
        shell::debug(4, "expiring call %08x:%u\n", source->sequence, source->cid);
        stack::destroy(this);
        return;
    default:
        break;
    }
}

cdr *stack::call::log(void)
{
    if(!starting)
        return NULL;

    if(!reason)
        reason = "unknown";

    if(!ending)
        time(&ending);

    if(!joined && target)
        joined = target->sysident;

    if(!joined)
        joined = "n/a";

    cdr *node = cdr::get();
    node->type = cdr::STOP;
    node->starting = starting;
    node->sequence = source->sequence;
    node->cid = source->cid;
    node->duration = (unsigned long)(ending - starting);
    String::set(node->uuid, sizeof(node->uuid), source->uuid);
    String::set(node->reason, sizeof(node->reason), reason);
    String::set(node->ident, sizeof(node->ident), source->sysident);
    String::set(node->dialed, sizeof(node->dialed), dialed);
    String::set(node->joined, sizeof(node->joined), joined);
    String::set(node->display, sizeof(node->display), source->display);
    if(target)
        snprintf(node->network, sizeof(node->network), "%s/%s", source->network, target->network);
    else
        String::set(node->network, sizeof(node->network), source->network);
    starting = 0l;
    return node;
}

END_NAMESPACE