/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2013, Digium, Inc.
 *
 * David M. Lee, II <dlee@digium.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 *
 * \brief Stasis application control support.
 *
 * \author David M. Lee, II <dlee@digium.com>
 */

#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "$Revision$")

#include "asterisk/stasis_channels.h"

#include "command.h"
#include "control.h"
#include "asterisk/dial.h"
#include "asterisk/bridging.h"
#include "asterisk/bridging_basic.h"
#include "asterisk/bridging_features.h"
#include "asterisk/frame.h"
#include "asterisk/pbx.h"
#include "asterisk/musiconhold.h"

struct stasis_app_control {
	/*! Queue of commands to dispatch on the channel */
	struct ao2_container *command_queue;
	/*!
	 * When set, /c app_stasis should exit and continue in the dialplan.
	 */
	int is_done:1;
	/*!
	 * The associated channel.
	 * Be very careful with the threading associated w/ manipulating
	 * the channel.
	 */
	struct ast_channel *channel;
};

struct stasis_app_control *control_create(struct ast_channel *channel)
{
	struct stasis_app_control *control;

	control = ao2_alloc(sizeof(*control), NULL);
	if (!control) {
		return NULL;
	}

	control->command_queue = ao2_container_alloc_list(
		AO2_ALLOC_OPT_LOCK_MUTEX, 0, NULL, NULL);

	if (!control->command_queue) {
		ao2_cleanup(control);
		return NULL;
	}

	control->channel = channel;

	return control;
}

static struct stasis_app_command *exec_command(
	struct stasis_app_control *control, stasis_app_command_cb command_fn,
	void *data)
{
	RAII_VAR(struct stasis_app_command *, command, NULL, ao2_cleanup);

	command = command_create(command_fn, data);

	if (!command) {
		return NULL;
	}

	/* command_queue is a thread safe list; no lock needed */
	ao2_link(control->command_queue, command);

	ao2_ref(command, +1);
	return command;
}

struct stasis_app_control_dial_data {
	char endpoint[AST_CHANNEL_NAME];
	int timeout;
};

static void *app_control_dial(struct stasis_app_control *control,
	struct ast_channel *chan, void *data)
{
	RAII_VAR(struct ast_dial *, dial, ast_dial_create(), ast_dial_destroy);
	RAII_VAR(struct stasis_app_control_dial_data *, dial_data, data, ast_free);
	enum ast_dial_result res;
	char *tech, *resource;

	struct ast_channel *new_chan;
	struct ast_bridge *bridge;

	tech = dial_data->endpoint;
	if (!(resource = strchr(tech, '/'))) {
		return NULL;
	}
	*resource++ = '\0';

	if (!dial) {
		ast_log(LOG_ERROR, "Failed to create dialing structure.\n");
		return NULL;
	}

	if (ast_dial_append(dial, tech, resource) < 0) {
		ast_log(LOG_ERROR, "Failed to add %s/%s to dialing structure.\n", tech, resource);
		return NULL;
	}

	ast_dial_set_global_timeout(dial, dial_data->timeout);

	res = ast_dial_run(dial, NULL, 0);

	if (res != AST_DIAL_RESULT_ANSWERED || !(new_chan = ast_dial_answered_steal(dial))) {
		return NULL;
	}

	if (!(bridge = ast_bridge_basic_new())) {
		ast_log(LOG_ERROR, "Failed to create basic bridge.\n");
		return NULL;
	}

	ast_bridge_impart(bridge, new_chan, NULL, NULL, 1);
	stasis_app_control_add_channel_to_bridge(control, bridge);

	return NULL;
}

int stasis_app_control_dial(struct stasis_app_control *control, const char *endpoint, int timeout)
{
	struct stasis_app_control_dial_data *dial_data;

	if (!(dial_data = ast_calloc(1, sizeof(*dial_data)))) {
		return -1;
	}

	ast_copy_string(dial_data->endpoint, endpoint, sizeof(dial_data->endpoint));

	if (timeout > 0) {
		dial_data->timeout = timeout * 1000;
	} else if (timeout == -1) {
		dial_data->timeout = -1;
	} else {
		dial_data->timeout = 30000;
	}

	stasis_app_send_command_async(control, app_control_dial, dial_data);

	return 0;
}

int control_is_done(struct stasis_app_control *control)
{
	/* Called from stasis_app_exec thread; no lock needed */
	return control->is_done;
}

struct stasis_app_control_continue_data {
	char context[AST_MAX_CONTEXT];
	char extension[AST_MAX_EXTENSION];
	int priority;
};

static void *app_control_continue(struct stasis_app_control *control,
	struct ast_channel *chan, void *data)
{
	RAII_VAR(struct stasis_app_control_continue_data *, continue_data, data, ast_free);

	/* Called from stasis_app_exec thread; no lock needed */
	ast_explicit_goto(control->channel, continue_data->context, continue_data->extension, continue_data->priority);

	control->is_done = 1;

	return NULL;
}

int stasis_app_control_continue(struct stasis_app_control *control, const char *context, const char *extension, int priority)
{
	struct stasis_app_control_continue_data *continue_data;

	if (!(continue_data = ast_calloc(1, sizeof(*continue_data)))) {
		return -1;
	}
	ast_copy_string(continue_data->context, S_OR(context, ""), sizeof(continue_data->context));
	ast_copy_string(continue_data->extension, S_OR(extension, ""), sizeof(continue_data->extension));
	if (priority > 0) {
		continue_data->priority = priority;
	} else {
		continue_data->priority = -1;
	}

	stasis_app_send_command_async(control, app_control_continue, continue_data);

	return 0;
}

struct stasis_app_control_mute_data {
	enum ast_frame_type frametype;
	unsigned int direction;
};

static void *app_control_mute(struct stasis_app_control *control,
	struct ast_channel *chan, void *data)
{
	RAII_VAR(struct stasis_app_control_mute_data *, mute_data, data, ast_free);
	SCOPED_CHANNELLOCK(lockvar, chan);

	ast_channel_suppress(control->channel, mute_data->direction, mute_data->frametype);

	return NULL;
}

int stasis_app_control_mute(struct stasis_app_control *control, unsigned int direction, enum ast_frame_type frametype)
{
	struct stasis_app_control_mute_data *mute_data;

	if (!(mute_data = ast_calloc(1, sizeof(*mute_data)))) {
		return -1;
	}

	mute_data->direction = direction;
	mute_data->frametype = frametype;

	stasis_app_send_command_async(control, app_control_mute, mute_data);

	return 0;
}

static void *app_control_unmute(struct stasis_app_control *control,
	struct ast_channel *chan, void *data)
{
	RAII_VAR(struct stasis_app_control_mute_data *, mute_data, data, ast_free);
	SCOPED_CHANNELLOCK(lockvar, chan);

	ast_channel_unsuppress(control->channel, mute_data->direction, mute_data->frametype);

	return NULL;
}

int stasis_app_control_unmute(struct stasis_app_control *control, unsigned int direction, enum ast_frame_type frametype)
{
	struct stasis_app_control_mute_data *mute_data;

	if (!(mute_data = ast_calloc(1, sizeof(*mute_data)))) {
		return -1;
	}

	mute_data->direction = direction;
	mute_data->frametype = frametype;

	stasis_app_send_command_async(control, app_control_unmute, mute_data);

	return 0;
}

char *stasis_app_control_get_channel_var(struct stasis_app_control *control, const char *variable)
{
	RAII_VAR(struct ast_str *, tmp, ast_str_create(32), ast_free);
	SCOPED_CHANNELLOCK(lockvar, control->channel);

	if (!tmp) {
		return NULL;
	}

	if (variable[strlen(variable) - 1] == ')') {
		if (ast_func_read2(control->channel, variable, &tmp, 0)) {
			return NULL;
		}
	} else {
		if (!ast_str_retrieve_variable(&tmp, 0, control->channel, NULL, variable)) {
			return NULL;
		}
	}

	return ast_strdup(ast_str_buffer(tmp));
}

int stasis_app_control_set_channel_var(struct stasis_app_control *control, const char *variable, const char *value)
{
	return pbx_builtin_setvar_helper(control->channel, variable, value);
}

static void *app_control_hold(struct stasis_app_control *control,
	struct ast_channel *chan, void *data)
{
	ast_indicate(control->channel, AST_CONTROL_HOLD);

	return NULL;
}

void stasis_app_control_hold(struct stasis_app_control *control)
{
	stasis_app_send_command_async(control, app_control_hold, NULL);
}

static void *app_control_unhold(struct stasis_app_control *control,
	struct ast_channel *chan, void *data)
{
	ast_indicate(control->channel, AST_CONTROL_UNHOLD);

	return NULL;
}

void stasis_app_control_unhold(struct stasis_app_control *control)
{
	stasis_app_send_command_async(control, app_control_unhold, NULL);
}

static void *app_control_moh_start(struct stasis_app_control *control,
	struct ast_channel *chan, void *data)
{
	char *moh_class = data;

	ast_moh_start(chan, moh_class, NULL);

	ast_free(moh_class);
	return NULL;
}

void stasis_app_control_moh_start(struct stasis_app_control *control, const char *moh_class)
{
	char *data = NULL;

	if (!ast_strlen_zero(moh_class)) {
		data = ast_strdup(moh_class);
	}

	stasis_app_send_command_async(control, app_control_moh_start, data);
}

static void *app_control_moh_stop(struct stasis_app_control *control,
	struct ast_channel *chan, void *data)
{
	ast_moh_stop(chan);
	return NULL;
}

void stasis_app_control_moh_stop(struct stasis_app_control *control)
{
	stasis_app_send_command_async(control, app_control_moh_stop, NULL);
}

struct ast_channel_snapshot *stasis_app_control_get_snapshot(
	const struct stasis_app_control *control)
{
	RAII_VAR(struct stasis_message *, msg, NULL, ao2_cleanup);
	struct stasis_caching_topic *caching_topic;
	struct ast_channel_snapshot *snapshot;

	caching_topic = ast_channel_topic_all_cached();
	ast_assert(caching_topic != NULL);

	msg = stasis_cache_get(caching_topic, ast_channel_snapshot_type(),
		stasis_app_control_get_channel_id(control));
	if (!msg) {
		return NULL;
	}

	snapshot = stasis_message_data(msg);
	ast_assert(snapshot != NULL);

	ao2_ref(snapshot, +1);
	return snapshot;
}

void *stasis_app_send_command(struct stasis_app_control *control,
	stasis_app_command_cb command_fn, void *data)
{
	RAII_VAR(struct stasis_app_command *, command, NULL, ao2_cleanup);

	if (control == NULL) {
		return NULL;
	}

	command = exec_command(control, command_fn, data);
	if (!command) {
		return NULL;
	}

	return command_join(command);
}

int stasis_app_send_command_async(struct stasis_app_control *control,
	stasis_app_command_cb command_fn, void *data)
{
	RAII_VAR(struct stasis_app_command *, command, NULL, ao2_cleanup);

	if (control == NULL) {
		return -1;
	}

	command = exec_command(control, command_fn, data);
	if (!command) {
		return -1;
	}

	return 0;
}

const char *stasis_app_control_get_channel_id(
	const struct stasis_app_control *control)
{
	return ast_channel_uniqueid(control->channel);
}

void stasis_app_control_publish(
	struct stasis_app_control *control, struct stasis_message *message)
{
	if (!control || !control->channel || !message) {
		return;
	}
	stasis_publish(ast_channel_topic(control->channel), message);
}

int stasis_app_control_queue_control(struct stasis_app_control *control,
	enum ast_control_frame_type frame_type)
{
	return ast_queue_control(control->channel, frame_type);
}

int control_dispatch_all(struct stasis_app_control *control,
	struct ast_channel *chan)
{
	int count = 0;
	struct ao2_iterator i;
	void *obj;

	ast_assert(control->channel == chan);

	i = ao2_iterator_init(control->command_queue, AO2_ITERATOR_UNLINK);

	while ((obj = ao2_iterator_next(&i))) {
		RAII_VAR(struct stasis_app_command *, command, obj, ao2_cleanup);
		command_invoke(command, control, chan);
		++count;
	}

	ao2_iterator_destroy(&i);
	return count;
}

/* Must be defined here since it must operate on the channel outside of the queue */
int stasis_app_control_remove_channel_from_bridge(
	struct stasis_app_control *control, struct ast_bridge *bridge)
{
	return ast_bridge_remove(bridge, control->channel);
}