/* 
 * FreeSWITCH Modular Media Switching Software Library / Soft-Switch Application
 * Copyright (C) 2005-2009, Anthony Minessale II <anthm@freeswitch.org>
 *
 * Version: MPL 1.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is FreeSWITCH Modular Media Switching Software Library / Soft-Switch Application
 *
 * The Initial Developer of the Original Code is
 * Anthony Minessale II <anthm@freeswitch.org>
 * Portions created by the Initial Developer are Copyright (C)
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 * 
 * Anthony Minessale II <anthm@freeswitch.org>
 *
 *
 * mod_loopback.c -- Loopback Endpoint Module
 *
 */
#include <switch.h>

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <string.h>

#define FRAME_QUEUE_LEN 3

SWITCH_MODULE_LOAD_FUNCTION(mod_loopback_load);
SWITCH_MODULE_SHUTDOWN_FUNCTION(mod_loopback_shutdown);
SWITCH_MODULE_DEFINITION(mod_loopback, mod_loopback_load, mod_loopback_shutdown, NULL);

static switch_endpoint_interface_t *loopback_endpoint_interface = NULL;

static switch_memory_pool_t *module_pool = NULL;

typedef enum {
	TFLAG_LINKED = (1 << 0),
	TFLAG_OUTBOUND = (1 << 1),
	TFLAG_WRITE = (1 << 2),
	TFLAG_CNG = (1 << 3),
	TFLAG_BRIDGE = (1 << 4),
	TFLAG_BOWOUT = (1 << 5),
	TFLAG_BLEG = (1 << 6)
} TFLAGS;

struct private_object {
	unsigned int flags;
	switch_mutex_t *flag_mutex;
	switch_mutex_t *mutex;
	switch_core_session_t *session;
	switch_channel_t *channel;
	switch_core_session_t *other_session;
	struct private_object *other_tech_pvt;
	switch_channel_t *other_channel;
	switch_codec_t read_codec;
	switch_codec_t write_codec;
	switch_frame_t read_frame;
	unsigned char databuf[SWITCH_RECOMMENDED_BUFFER_SIZE];

	switch_frame_t *x_write_frame;
	switch_frame_t *write_frame;
	unsigned char write_databuf[SWITCH_RECOMMENDED_BUFFER_SIZE];

	switch_frame_t cng_frame;
	unsigned char cng_databuf[SWITCH_RECOMMENDED_BUFFER_SIZE];
	switch_timer_t timer;
	switch_caller_profile_t *caller_profile;
	int32_t bowout_frame_count;
	char *other_uuid;
	switch_queue_t *frame_queue;
};

typedef struct private_object private_t;

static struct {
	int debug;
} globals;

static switch_status_t channel_on_init(switch_core_session_t *session);
static switch_status_t channel_on_hangup(switch_core_session_t *session);
static switch_status_t channel_on_destroy(switch_core_session_t *session);
static switch_status_t channel_on_routing(switch_core_session_t *session);
static switch_status_t channel_on_exchange_media(switch_core_session_t *session);
static switch_status_t channel_on_soft_execute(switch_core_session_t *session);
static switch_call_cause_t channel_outgoing_channel(switch_core_session_t *session, switch_event_t *var_event,
													switch_caller_profile_t *outbound_profile,
													switch_core_session_t **new_session, switch_memory_pool_t **pool, switch_originate_flag_t flags);
static switch_status_t channel_read_frame(switch_core_session_t *session, switch_frame_t **frame, switch_io_flag_t flags, int stream_id);
static switch_status_t channel_write_frame(switch_core_session_t *session, switch_frame_t *frame, switch_io_flag_t flags, int stream_id);
static switch_status_t channel_kill_channel(switch_core_session_t *session, int sig);

static switch_status_t tech_init(private_t *tech_pvt, switch_core_session_t *session, switch_codec_t *codec)
{
	const char *iananame = "L16";
	int rate = 8000;
	int interval = 20;
	switch_status_t status = SWITCH_STATUS_SUCCESS;
	switch_channel_t *channel = switch_core_session_get_channel(session);
	const switch_codec_implementation_t *read_impl;

	if (codec) {
		iananame = codec->implementation->iananame;
		rate = codec->implementation->samples_per_second;
		interval = codec->implementation->microseconds_per_packet / 1000;
	}
	
	if (switch_core_codec_ready(&tech_pvt->read_codec)) {
		switch_core_codec_destroy(&tech_pvt->read_codec);
	}

	if (switch_core_codec_ready(&tech_pvt->write_codec)) {
		switch_core_codec_destroy(&tech_pvt->write_codec);
	}

	switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "%s setup codec %s/%d/%d\n", switch_channel_get_name(channel), iananame, rate, interval);
	
	status = switch_core_codec_init(&tech_pvt->read_codec,
									iananame,
									NULL,
									rate,
									interval,
									1, 
									SWITCH_CODEC_FLAG_ENCODE | SWITCH_CODEC_FLAG_DECODE,
									NULL, 
									switch_core_session_get_pool(session));

	if (status != SWITCH_STATUS_SUCCESS || !tech_pvt->read_codec.implementation || !switch_core_codec_ready(&tech_pvt->read_codec)) {
		goto end;
	}

	status = switch_core_codec_init(&tech_pvt->write_codec,
									iananame,
									NULL,
									rate,
									interval,
									1, 
									SWITCH_CODEC_FLAG_ENCODE | SWITCH_CODEC_FLAG_DECODE,
									NULL, 
									switch_core_session_get_pool(session));
	

	if (status != SWITCH_STATUS_SUCCESS) {
		switch_core_codec_destroy(&tech_pvt->read_codec);
		goto end;
	}

	tech_pvt->read_frame.data = tech_pvt->databuf;
	tech_pvt->read_frame.buflen = sizeof(tech_pvt->databuf);
	tech_pvt->read_frame.codec = &tech_pvt->read_codec;
	

	tech_pvt->cng_frame.data = tech_pvt->cng_databuf;
	tech_pvt->cng_frame.buflen = sizeof(tech_pvt->cng_databuf);
	//switch_set_flag((&tech_pvt->cng_frame), SFF_CNG);
	tech_pvt->cng_frame.datalen = 2;

	tech_pvt->bowout_frame_count = (tech_pvt->read_codec.implementation->actual_samples_per_second / 
							 tech_pvt->read_codec.implementation->samples_per_packet) * 3;

	switch_core_session_set_read_codec(session, &tech_pvt->read_codec);
	switch_core_session_set_write_codec(session, &tech_pvt->write_codec);
	
	if (tech_pvt->flag_mutex) {
		switch_core_timer_destroy(&tech_pvt->timer);
	}

	read_impl = tech_pvt->read_codec.implementation;

	switch_core_timer_init(&tech_pvt->timer, "soft", 
						   read_impl->microseconds_per_packet / 1000, 
						   read_impl->samples_per_packet *4,
						   switch_core_session_get_pool(session));
	

	if (!tech_pvt->flag_mutex) {
		switch_mutex_init(&tech_pvt->flag_mutex, SWITCH_MUTEX_NESTED, switch_core_session_get_pool(session));
		switch_mutex_init(&tech_pvt->mutex, SWITCH_MUTEX_NESTED, switch_core_session_get_pool(session));
		switch_core_session_set_private(session, tech_pvt);
		switch_queue_create(&tech_pvt->frame_queue, FRAME_QUEUE_LEN, switch_core_session_get_pool(session));
		tech_pvt->session = session;
		tech_pvt->channel = switch_core_session_get_channel(session);
	}

 end:

	return status;
}

/* 
   State methods they get called when the state changes to the specific state 
   returning SWITCH_STATUS_SUCCESS tells the core to execute the standard state method next
   so if you fully implement the state you can return SWITCH_STATUS_FALSE to skip it.
*/
static switch_status_t channel_on_init(switch_core_session_t *session)
{
	switch_channel_t *channel, *b_channel;
	private_t *tech_pvt = NULL, *b_tech_pvt = NULL;
	switch_core_session_t *b_session;
	char name[128];
	switch_caller_profile_t *caller_profile;

	tech_pvt = switch_core_session_get_private(session);
	switch_assert(tech_pvt != NULL);

	channel = switch_core_session_get_channel(session);
	switch_assert(channel != NULL);
	


	if (switch_test_flag(tech_pvt, TFLAG_OUTBOUND) && !switch_test_flag(tech_pvt, TFLAG_BLEG)) {
		
		if (!(b_session = switch_core_session_request(loopback_endpoint_interface, SWITCH_CALL_DIRECTION_INBOUND, NULL))) {
			switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_CRIT, "Failure.\n");
			goto end;
		}
	
		if (switch_core_session_read_lock(b_session) != SWITCH_STATUS_SUCCESS) {
			switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_CRIT, "Failure.\n");
			switch_core_session_destroy(&b_session);
			goto end;
		}
		
		switch_core_session_add_stream(b_session, NULL);
		b_channel = switch_core_session_get_channel(b_session);
		b_tech_pvt = (private_t *) switch_core_session_alloc(b_session, sizeof(*b_tech_pvt));

		switch_snprintf(name, sizeof(name), "loopback/%s-b", tech_pvt->caller_profile->destination_number);
		switch_channel_set_name(b_channel, name);
		if (tech_init(b_tech_pvt, b_session, switch_core_session_get_read_codec(session)) != SWITCH_STATUS_SUCCESS) {
			switch_channel_hangup(channel, SWITCH_CAUSE_DESTINATION_OUT_OF_ORDER);
			switch_core_session_destroy(&b_session);
			goto end;
		}
		
		caller_profile = switch_caller_profile_clone(b_session, tech_pvt->caller_profile);
		caller_profile->source = switch_core_strdup(caller_profile->pool, modname);
		switch_channel_set_caller_profile(b_channel, caller_profile);
		b_tech_pvt->caller_profile = caller_profile;
		switch_channel_set_state(b_channel, CS_INIT);

		tech_pvt->other_session = b_session;
		tech_pvt->other_tech_pvt = b_tech_pvt;
		tech_pvt->other_channel = b_channel;

		//b_tech_pvt->other_session = session;
		//b_tech_pvt->other_tech_pvt = tech_pvt;
		//b_tech_pvt->other_channel = channel;

		b_tech_pvt->other_uuid = switch_core_session_strdup(b_session, switch_core_session_get_uuid(session));
		
		switch_set_flag_locked(tech_pvt, TFLAG_LINKED);
		switch_set_flag_locked(b_tech_pvt, TFLAG_LINKED);
		switch_set_flag_locked(b_tech_pvt, TFLAG_BLEG);

		
		switch_channel_set_flag(channel, CF_ACCEPT_CNG);	
		//switch_ivr_transfer_variable(session, tech_pvt->other_session, "process_cdr");
		switch_ivr_transfer_variable(session, tech_pvt->other_session, NULL);
		
		switch_channel_set_variable(channel, "other_loopback_leg_uuid", switch_channel_get_uuid(b_channel));
		switch_channel_set_variable(b_channel, "other_loopback_leg_uuid", switch_channel_get_uuid(channel));

		if (switch_core_session_thread_launch(b_session) != SWITCH_STATUS_SUCCESS) {
			switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_CRIT, "Error spawning thread\n");
			switch_channel_hangup(channel, SWITCH_CAUSE_DESTINATION_OUT_OF_ORDER);
			goto end;
		}
	} else if ((tech_pvt->other_session = switch_core_session_locate(tech_pvt->other_uuid))) {
		tech_pvt->other_tech_pvt = 	switch_core_session_get_private(tech_pvt->other_session);
		tech_pvt->other_channel = switch_core_session_get_channel(tech_pvt->other_session);
	}
	
	if (!tech_pvt->other_session) {
		switch_clear_flag_locked(tech_pvt, TFLAG_LINKED);
		switch_channel_hangup(channel, SWITCH_CAUSE_DESTINATION_OUT_OF_ORDER);
		goto end;
	}

	switch_channel_set_variable(channel, "loopback_leg", switch_test_flag(tech_pvt, TFLAG_BLEG) ? "B" : "A");
	switch_channel_set_state(channel, CS_ROUTING);

 end:

	return SWITCH_STATUS_SUCCESS;
}

static void do_reset(private_t *tech_pvt)
{
	switch_clear_flag_locked(tech_pvt, TFLAG_WRITE);
	switch_set_flag_locked(tech_pvt, TFLAG_CNG);
	
	switch_mutex_lock(tech_pvt->mutex);
	if (tech_pvt->other_tech_pvt) {
		switch_clear_flag_locked(tech_pvt->other_tech_pvt, TFLAG_WRITE);
		switch_set_flag_locked(tech_pvt->other_tech_pvt, TFLAG_CNG);
	}
	switch_mutex_unlock(tech_pvt->mutex);
}

static switch_status_t channel_on_routing(switch_core_session_t *session)
{
	switch_channel_t *channel = NULL;
	private_t *tech_pvt = NULL;

	channel = switch_core_session_get_channel(session);
	assert(channel != NULL);

	tech_pvt = switch_core_session_get_private(session);
	assert(tech_pvt != NULL);

	do_reset(tech_pvt);

	switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "%s CHANNEL ROUTING\n", switch_channel_get_name(channel));
	
	return SWITCH_STATUS_SUCCESS;
}

static switch_status_t channel_on_execute(switch_core_session_t *session)
{
	switch_channel_t *channel = NULL;
	private_t *tech_pvt = NULL;

	channel = switch_core_session_get_channel(session);
	assert(channel != NULL);

	tech_pvt = switch_core_session_get_private(session);
	assert(tech_pvt != NULL);

	switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "%s CHANNEL EXECUTE\n", switch_channel_get_name(channel));
	
	return SWITCH_STATUS_SUCCESS;
}

static switch_status_t channel_on_destroy(switch_core_session_t *session)
{
	switch_channel_t *channel = NULL;
	private_t *tech_pvt = NULL;
	void *pop;

	channel = switch_core_session_get_channel(session);
	switch_assert(channel != NULL);

	tech_pvt = switch_core_session_get_private(session);

	if (tech_pvt) {
		switch_core_timer_destroy(&tech_pvt->timer);
		
		if (switch_core_codec_ready(&tech_pvt->read_codec)) {
			switch_core_codec_destroy(&tech_pvt->read_codec);
		}
		
		if (switch_core_codec_ready(&tech_pvt->write_codec)) {
			switch_core_codec_destroy(&tech_pvt->write_codec);
		}

		if (tech_pvt->write_frame) {
			switch_frame_free(&tech_pvt->write_frame);
		}

		while (switch_queue_trypop(tech_pvt->frame_queue, &pop) == SWITCH_STATUS_SUCCESS && pop) {
			switch_frame_t *frame = (switch_frame_t *) pop;
			switch_frame_free(&frame);
		}
	}


	return SWITCH_STATUS_SUCCESS;
}


static switch_status_t channel_on_hangup(switch_core_session_t *session)
{
	switch_channel_t *channel = NULL;
	private_t *tech_pvt = NULL;

	channel = switch_core_session_get_channel(session);
	switch_assert(channel != NULL);

	tech_pvt = switch_core_session_get_private(session);
	switch_assert(tech_pvt != NULL);
	switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "%s CHANNEL HANGUP\n", switch_channel_get_name(channel));

	switch_clear_flag_locked(tech_pvt, TFLAG_LINKED);

	switch_mutex_lock(tech_pvt->mutex);
	if (tech_pvt->other_tech_pvt) {
		switch_clear_flag_locked(tech_pvt->other_tech_pvt, TFLAG_LINKED);
		tech_pvt->other_tech_pvt = NULL;
	}
	
	if (tech_pvt->other_session) {
		switch_channel_hangup(tech_pvt->other_channel, switch_channel_get_cause(channel));
		switch_core_session_rwunlock(tech_pvt->other_session);
		tech_pvt->other_channel = NULL;
		tech_pvt->other_session = NULL;
	}
	switch_mutex_unlock(tech_pvt->mutex);
	
	return SWITCH_STATUS_SUCCESS;
}

static switch_status_t channel_kill_channel(switch_core_session_t *session, int sig)
{
	switch_channel_t *channel = NULL;
	private_t *tech_pvt = NULL;

	channel = switch_core_session_get_channel(session);
	switch_assert(channel != NULL);

	tech_pvt = switch_core_session_get_private(session);
	switch_assert(tech_pvt != NULL);

	switch (sig) {
	case SWITCH_SIG_BREAK:
		switch_set_flag_locked(tech_pvt, TFLAG_CNG);
		switch_mutex_lock(tech_pvt->mutex);
		if (tech_pvt->other_tech_pvt) {
			switch_set_flag_locked(tech_pvt->other_tech_pvt, TFLAG_CNG);
		}
		switch_mutex_unlock(tech_pvt->mutex);
		break;
	case SWITCH_SIG_KILL:
		switch_channel_hangup(channel, SWITCH_CAUSE_NORMAL_CLEARING);
		switch_clear_flag_locked(tech_pvt, TFLAG_LINKED);
		switch_mutex_lock(tech_pvt->mutex);
		if (tech_pvt->other_tech_pvt) {
			switch_clear_flag_locked(tech_pvt->other_tech_pvt, TFLAG_LINKED);
		}
		switch_mutex_unlock(tech_pvt->mutex);
		break;
	default:
		break;
	}

	switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "%s CHANNEL KILL\n", switch_channel_get_name(channel));

	return SWITCH_STATUS_SUCCESS;
}

static switch_status_t channel_on_soft_execute(switch_core_session_t *session)
{
	switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "CHANNEL TRANSMIT\n");
	return SWITCH_STATUS_SUCCESS;
}

static switch_status_t channel_on_exchange_media(switch_core_session_t *session)
{
	switch_channel_t *channel = NULL;
	private_t *tech_pvt = NULL;

	channel = switch_core_session_get_channel(session);
	assert(channel != NULL);

	tech_pvt = switch_core_session_get_private(session);
	assert(tech_pvt != NULL);

	switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "CHANNEL LOOPBACK\n");

	return SWITCH_STATUS_SUCCESS;
}

static switch_status_t channel_on_reset(switch_core_session_t *session)
{
	private_t *tech_pvt = (private_t *) switch_core_session_get_private(session);
	switch_assert(tech_pvt != NULL);

	do_reset(tech_pvt);
	switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "%s RESET\n", switch_channel_get_name(switch_core_session_get_channel(session)));

	return SWITCH_STATUS_SUCCESS;
}

static switch_status_t channel_on_hibernate(switch_core_session_t *session)
{
	switch_assert(switch_core_session_get_private(session));

	switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "%s HIBERNATE\n", switch_channel_get_name(switch_core_session_get_channel(session)));

	return SWITCH_STATUS_SUCCESS;
}

static switch_status_t channel_on_consume_media(switch_core_session_t *session)
{
	switch_channel_t *channel = NULL;
	private_t *tech_pvt = NULL;

	channel = switch_core_session_get_channel(session);
	assert(channel != NULL);

	tech_pvt = switch_core_session_get_private(session);
	assert(tech_pvt != NULL);

	switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "CHANNEL CONSUME_MEDIA\n");

	return SWITCH_STATUS_SUCCESS;
}

static switch_status_t channel_send_dtmf(switch_core_session_t *session, const switch_dtmf_t *dtmf)
{
	private_t *tech_pvt = NULL;

	tech_pvt = switch_core_session_get_private(session);
	switch_assert(tech_pvt != NULL);

	if (tech_pvt->other_channel) {
		switch_channel_queue_dtmf(tech_pvt->other_channel, dtmf);
	}

	return SWITCH_STATUS_SUCCESS;
}

static switch_status_t channel_read_frame(switch_core_session_t *session, switch_frame_t **frame, switch_io_flag_t flags, int stream_id)
{
	switch_channel_t *channel = NULL;
	private_t *tech_pvt = NULL;
	switch_status_t status = SWITCH_STATUS_FALSE;
	switch_mutex_t *mutex = NULL;
	void *pop = NULL;

	channel = switch_core_session_get_channel(session);
	switch_assert(channel != NULL);

	tech_pvt = switch_core_session_get_private(session);
	switch_assert(tech_pvt != NULL);

	if (!switch_test_flag(tech_pvt, TFLAG_LINKED)) {
		goto end;
	}
	
	*frame = NULL;
	
	if (!switch_channel_ready(channel)) {
		goto end;
	}

	switch_core_timer_next(&tech_pvt->timer);
	
	mutex = tech_pvt->mutex;
	switch_mutex_lock(mutex);

	if (switch_queue_trypop(tech_pvt->frame_queue, &pop) == SWITCH_STATUS_SUCCESS && pop) {
		if (tech_pvt->write_frame) {
			switch_frame_free(&tech_pvt->write_frame);
		}
		tech_pvt->write_frame = (switch_frame_t *) pop;
		tech_pvt->write_frame->codec = &tech_pvt->read_codec;
		*frame = tech_pvt->write_frame;
	} else {
		switch_set_flag(tech_pvt, TFLAG_CNG);
	}
	
	if (switch_test_flag(tech_pvt, TFLAG_CNG)) {
		unsigned char data[SWITCH_RECOMMENDED_BUFFER_SIZE];
		uint32_t flag = 0;
		switch_status_t encode_status;
		uint32_t rate = tech_pvt->read_codec.implementation->actual_samples_per_second;

		*frame = &tech_pvt->cng_frame;
		tech_pvt->cng_frame.codec = &tech_pvt->read_codec;
		tech_pvt->cng_frame.datalen = tech_pvt->read_codec.implementation->decoded_bytes_per_packet;
		memset(tech_pvt->cng_frame.data, 0, tech_pvt->cng_frame.datalen);
		memset(&data, 0, sizeof(data));

		if (strcasecmp(tech_pvt->read_codec.implementation->iananame, "L16")) {
			encode_status = switch_core_codec_encode(&tech_pvt->read_codec,
											  NULL,
											  data,
											  sizeof(data),
											  tech_pvt->read_codec.implementation->actual_samples_per_second,

											  tech_pvt->cng_frame.data,
											  &tech_pvt->cng_frame.datalen,											  
											  &rate,
											  &flag);
			if (encode_status != SWITCH_STATUS_SUCCESS) {
				switch_channel_hangup(channel, SWITCH_CAUSE_DESTINATION_OUT_OF_ORDER);
			}
													 
		}

		//switch_set_flag((&tech_pvt->cng_frame), SFF_CNG);
		switch_clear_flag_locked(tech_pvt, TFLAG_CNG);
	}


	if (*frame) {
		status = SWITCH_STATUS_SUCCESS;
	} else {
		status = SWITCH_STATUS_FALSE;
	}	

 end:

	if (mutex) {
		switch_mutex_unlock(mutex);
	}

	return status;
}

static switch_status_t channel_write_frame(switch_core_session_t *session, switch_frame_t *frame, switch_io_flag_t flags, int stream_id)
{
	switch_channel_t *channel = NULL;
	private_t *tech_pvt = NULL;
	switch_status_t status = SWITCH_STATUS_FALSE;
	
	channel = switch_core_session_get_channel(session);
	switch_assert(channel != NULL);

	tech_pvt = switch_core_session_get_private(session);
	switch_assert(tech_pvt != NULL);

	if (switch_test_flag(frame, SFF_CNG) || switch_test_flag(tech_pvt, TFLAG_CNG) || switch_test_flag(tech_pvt, TFLAG_BOWOUT)) {
		return SWITCH_STATUS_SUCCESS;
	}

	switch_mutex_lock(tech_pvt->mutex);
	if (!switch_test_flag(tech_pvt, TFLAG_BOWOUT) && 
		tech_pvt->other_tech_pvt && 
		switch_test_flag(tech_pvt, TFLAG_BRIDGE) && 
		switch_test_flag(tech_pvt->other_tech_pvt, TFLAG_BRIDGE) && 
		switch_channel_test_flag(tech_pvt->channel, CF_BRIDGED) &&
		switch_channel_test_flag(tech_pvt->other_channel, CF_BRIDGED) &&
		switch_channel_test_flag(tech_pvt->channel, CF_ANSWERED) &&
		switch_channel_test_flag(tech_pvt->other_channel, CF_ANSWERED) &&
		!--tech_pvt->bowout_frame_count <= 0
		) {
		const char *a_uuid = switch_channel_get_variable(channel, SWITCH_SIGNAL_BOND_VARIABLE);
		const char *b_uuid = switch_channel_get_variable(tech_pvt->other_channel, SWITCH_SIGNAL_BOND_VARIABLE);
		const char *vetoa, *vetob;

		switch_set_flag_locked(tech_pvt, TFLAG_BOWOUT);
		switch_set_flag_locked(tech_pvt->other_tech_pvt, TFLAG_BOWOUT);

		vetoa = switch_channel_get_variable(tech_pvt->channel, "loopback_bowout");
		vetob = switch_channel_get_variable(tech_pvt->other_tech_pvt->channel, "loopback_bowout");
		
		if ((!vetoa || switch_true(vetoa)) && (!vetob || switch_true(vetob))) {
			switch_clear_flag_locked(tech_pvt, TFLAG_WRITE);
			switch_clear_flag_locked(tech_pvt->other_tech_pvt, TFLAG_WRITE);
			
			if (a_uuid && b_uuid) {
				switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, 
								  "%s detected bridge on both ends, attempting direct connection.\n", switch_channel_get_name(channel));
				
				/* channel_masquerade eat your heart out....... */
				switch_ivr_uuid_bridge(a_uuid, b_uuid);
				switch_mutex_unlock(tech_pvt->mutex);
				return SWITCH_STATUS_SUCCESS;
			}
		}
	}

	if (switch_test_flag(tech_pvt, TFLAG_LINKED) && tech_pvt->other_tech_pvt) { 
		switch_frame_t *clone;

		if (frame->codec->implementation != tech_pvt->write_codec.implementation) {
			/* change codecs to match */
			tech_init(tech_pvt, session, frame->codec);
			tech_init(tech_pvt->other_tech_pvt, tech_pvt->other_session, frame->codec);
		}

		if (switch_queue_size(tech_pvt->other_tech_pvt->frame_queue) < FRAME_QUEUE_LEN) {
			if (switch_frame_dup(frame, &clone) != SWITCH_STATUS_SUCCESS) {
				abort();
			}

			if (switch_queue_trypush(tech_pvt->other_tech_pvt->frame_queue, clone) != SWITCH_STATUS_SUCCESS) {
				switch_frame_free(&clone);
			}

			switch_set_flag_locked(tech_pvt->other_tech_pvt, TFLAG_WRITE);
		}
		
		status = SWITCH_STATUS_SUCCESS;
	}

	switch_mutex_unlock(tech_pvt->mutex);

	return status;
}

static switch_status_t channel_receive_message(switch_core_session_t *session, switch_core_session_message_t *msg)
{
	switch_channel_t *channel;
	private_t *tech_pvt;

	channel = switch_core_session_get_channel(session);
	switch_assert(channel != NULL);

	tech_pvt = switch_core_session_get_private(session);
	switch_assert(tech_pvt != NULL);
	
	switch (msg->message_id) {
	case SWITCH_MESSAGE_INDICATE_ANSWER:
		if (tech_pvt->other_channel && !switch_test_flag(tech_pvt, TFLAG_OUTBOUND)) {
			switch_channel_mark_answered(tech_pvt->other_channel);
		}
		break;
	case SWITCH_MESSAGE_INDICATE_PROGRESS:
		if (tech_pvt->other_channel && !switch_test_flag(tech_pvt, TFLAG_OUTBOUND)) {
			switch_channel_mark_pre_answered(tech_pvt->other_channel);
		}
		break;
	case SWITCH_MESSAGE_INDICATE_BRIDGE:
		{
			switch_set_flag_locked(tech_pvt, TFLAG_BRIDGE);			
		}
		break;
	case SWITCH_MESSAGE_INDICATE_UNBRIDGE:
		{
			switch_clear_flag_locked(tech_pvt, TFLAG_BRIDGE);
		}
		break;
	default:
		break;
	}

	switch (msg->message_id) {
	case SWITCH_MESSAGE_INDICATE_BRIDGE:
	case SWITCH_MESSAGE_INDICATE_UNBRIDGE:
	case SWITCH_MESSAGE_INDICATE_AUDIO_SYNC:
		{
			void *pop;

			while (switch_queue_trypop(tech_pvt->frame_queue, &pop) == SWITCH_STATUS_SUCCESS && pop) {
				switch_frame_t *frame = (switch_frame_t *) pop;
				switch_frame_free(&frame);
			}

			while (switch_queue_trypop(tech_pvt->other_tech_pvt->frame_queue, &pop) == SWITCH_STATUS_SUCCESS && pop) {
				switch_frame_t *frame = (switch_frame_t *) pop;
				switch_frame_free(&frame);
			}

			switch_core_timer_sync(&tech_pvt->timer);

		}
		break;
    default:
        break;
    }
	

	return SWITCH_STATUS_SUCCESS;
}

static switch_call_cause_t channel_outgoing_channel(switch_core_session_t *session, switch_event_t *var_event,
													switch_caller_profile_t *outbound_profile,
													switch_core_session_t **new_session, switch_memory_pool_t **pool, switch_originate_flag_t flags)
{
	char name[128];

	if (session) {
		switch_channel_t *channel = switch_core_session_get_channel(session);
		switch_channel_clear_flag(channel, CF_PROXY_MEDIA);
		switch_channel_clear_flag(channel, CF_PROXY_MODE);
		switch_channel_pre_answer(channel);
	}

	if ((*new_session = switch_core_session_request(loopback_endpoint_interface, SWITCH_CALL_DIRECTION_OUTBOUND, pool)) != 0) {
		private_t *tech_pvt;
		switch_channel_t *channel;
		switch_caller_profile_t *caller_profile;

		switch_core_session_add_stream(*new_session, NULL);

		if ((tech_pvt = (private_t *) switch_core_session_alloc(*new_session, sizeof(private_t))) != 0) {
			channel = switch_core_session_get_channel(*new_session);
			switch_snprintf(name, sizeof(name), "loopback/%s-a", outbound_profile->destination_number);
			switch_channel_set_name(channel, name);
			if (tech_init(tech_pvt, *new_session, session ? switch_core_session_get_read_codec(session) : NULL) != SWITCH_STATUS_SUCCESS) {
				switch_core_session_destroy(new_session);
				return SWITCH_CAUSE_DESTINATION_OUT_OF_ORDER;
			}
		} else {
			switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_CRIT, "Hey where is my memory pool?\n");
			switch_core_session_destroy(new_session);
			return SWITCH_CAUSE_DESTINATION_OUT_OF_ORDER;
		}
		
		if (outbound_profile) {
			char *dialplan = NULL, *context = NULL;

			caller_profile = switch_caller_profile_clone(*new_session, outbound_profile);
			caller_profile->source = switch_core_strdup(caller_profile->pool, modname);
			if ((context = strchr(caller_profile->destination_number, '/'))) {
				*context++ = '\0';
				
				if ((dialplan = strchr(context, '/'))) {
					*dialplan++ = '\0';
				}

				if (!switch_strlen_zero(context)) {
					caller_profile->context = switch_core_strdup(caller_profile->pool, context);
				}

				if (!switch_strlen_zero(dialplan)) {
					caller_profile->dialplan = switch_core_strdup(caller_profile->pool, dialplan);
				}
			}
			
			if (switch_strlen_zero(caller_profile->context)) {
				caller_profile->context = switch_core_strdup(caller_profile->pool, "default");
			}

			if (switch_strlen_zero(caller_profile->dialplan)) {
				caller_profile->dialplan = switch_core_strdup(caller_profile->pool, "xml");
			}

			switch_snprintf(name, sizeof(name), "loopback/%s-a", caller_profile->destination_number);
			switch_channel_set_name(channel, name);
			switch_channel_set_flag(channel, CF_OUTBOUND);
			switch_set_flag_locked(tech_pvt, TFLAG_OUTBOUND);
			switch_channel_set_caller_profile(channel, caller_profile);
			tech_pvt->caller_profile = caller_profile;
		} else {
			switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Doh! no caller profile\n");
			switch_core_session_destroy(new_session);
			return SWITCH_CAUSE_DESTINATION_OUT_OF_ORDER;
		}
		
		switch_channel_set_state(channel, CS_INIT);
		
		return SWITCH_CAUSE_SUCCESS;
	}

	return SWITCH_CAUSE_DESTINATION_OUT_OF_ORDER;
}

static switch_state_handler_table_t channel_event_handlers = {
	/*.on_init */ channel_on_init,
	/*.on_routing */ channel_on_routing,
	/*.on_execute */ channel_on_execute,
	/*.on_hangup */ channel_on_hangup,
	/*.on_exchange_media */ channel_on_exchange_media,
	/*.on_soft_execute */ channel_on_soft_execute,
	/*.on_consume_media */ channel_on_consume_media,
	/*.on_hibernate */ channel_on_hibernate,
	/*.on_reset */ channel_on_reset,
	/*.on_park*/ NULL,
    /*.on_reporting*/ NULL,
    /*.on_destroy*/ channel_on_destroy

};

static switch_io_routines_t channel_io_routines = {
	/*.outgoing_channel */ channel_outgoing_channel,
	/*.read_frame */ channel_read_frame,
	/*.write_frame */ channel_write_frame,
	/*.kill_channel */ channel_kill_channel,
	/*.send_dtmf */ channel_send_dtmf,
	/*.receive_message */ channel_receive_message
};

SWITCH_MODULE_LOAD_FUNCTION(mod_loopback_load)
{
	if (switch_core_new_memory_pool(&module_pool) != SWITCH_STATUS_SUCCESS) {
		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_CRIT, "OH OH no pool\n");
		return SWITCH_STATUS_TERM;
	}

	memset(&globals, 0, sizeof(globals));

	/* connect my internal structure to the blank pointer passed to me */
	*module_interface = switch_loadable_module_create_module_interface(pool, modname);
	loopback_endpoint_interface = switch_loadable_module_create_interface(*module_interface, SWITCH_ENDPOINT_INTERFACE);
	loopback_endpoint_interface->interface_name = "loopback";
	loopback_endpoint_interface->io_routines = &channel_io_routines;
	loopback_endpoint_interface->state_handler = &channel_event_handlers;

	/* indicate that the module should continue to be loaded */
	return SWITCH_STATUS_SUCCESS;
}

SWITCH_MODULE_SHUTDOWN_FUNCTION(mod_loopback_shutdown)
{
	return SWITCH_STATUS_SUCCESS;
}

/* For Emacs:
 * Local Variables:
 * mode:c
 * indent-tabs-mode:t
 * tab-width:4
 * c-basic-offset:4
 * End:
 * For VIM:
 * vim:set softtabstop=4 shiftwidth=4 tabstop=4 expandtab:
 */
