/*
 * Copyright 2008 Arsen Chaloyan
 *
 * Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/* 
 * Mandatory rules concerning plugin implementation.
 * 1. Each plugin MUST implement a plugin/engine creator function
 *    with the exact signature and name (the main entry point)
 *        MRCP_PLUGIN_DECLARE(mrcp_engine_t*) mrcp_plugin_create(apr_pool_t *pool)
 * 2. Each plugin MUST declare its version number
 *        MRCP_PLUGIN_VERSION_DECLARE
 * 3. One and only one response MUST be sent back to the received request.
 * 4. Methods (callbacks) of the MRCP engine channel MUST not block.
 *   (asynchronous response can be sent from the context of other thread)
 * 5. Methods (callbacks) of the MPF engine stream MUST not block.
 */

#include "mrcp_synth_engine.h"
#include "apt_consumer_task.h"
#include "apt_log.h"

#define SYNTH_ENGINE_TASK_NAME "Demo Synth Engine"

typedef struct demo_synth_engine_t demo_synth_engine_t;
typedef struct demo_synth_channel_t demo_synth_channel_t;
typedef struct demo_synth_msg_t demo_synth_msg_t;

/** Declaration of synthesizer engine methods */
static apt_bool_t demo_synth_engine_destroy(mrcp_engine_t *engine);
static apt_bool_t demo_synth_engine_open(mrcp_engine_t *engine);
static apt_bool_t demo_synth_engine_close(mrcp_engine_t *engine);
static mrcp_engine_channel_t* demo_synth_engine_channel_create(mrcp_engine_t *engine, apr_pool_t *pool);

static const struct mrcp_engine_method_vtable_t engine_vtable = {
	demo_synth_engine_destroy,
	demo_synth_engine_open,
	demo_synth_engine_close,
	demo_synth_engine_channel_create
};


/** Declaration of synthesizer channel methods */
static apt_bool_t demo_synth_channel_destroy(mrcp_engine_channel_t *channel);
static apt_bool_t demo_synth_channel_open(mrcp_engine_channel_t *channel);
static apt_bool_t demo_synth_channel_close(mrcp_engine_channel_t *channel);
static apt_bool_t demo_synth_channel_request_process(mrcp_engine_channel_t *channel, mrcp_message_t *request);

static const struct mrcp_engine_channel_method_vtable_t channel_vtable = {
	demo_synth_channel_destroy,
	demo_synth_channel_open,
	demo_synth_channel_close,
	demo_synth_channel_request_process
};

/** Declaration of synthesizer audio stream methods */
static apt_bool_t demo_synth_stream_destroy(mpf_audio_stream_t *stream);
static apt_bool_t demo_synth_stream_open(mpf_audio_stream_t *stream, mpf_codec_t *codec);
static apt_bool_t demo_synth_stream_close(mpf_audio_stream_t *stream);
static apt_bool_t demo_synth_stream_read(mpf_audio_stream_t *stream, mpf_frame_t *frame);

static const mpf_audio_stream_vtable_t audio_stream_vtable = {
	demo_synth_stream_destroy,
	demo_synth_stream_open,
	demo_synth_stream_close,
	demo_synth_stream_read,
	NULL,
	NULL,
	NULL
};

/** Declaration of demo synthesizer engine */
struct demo_synth_engine_t {
	apt_consumer_task_t    *task;
};

/** Declaration of demo synthesizer channel */
struct demo_synth_channel_t {
	/** Back pointer to engine */
	demo_synth_engine_t   *demo_engine;
	/** Engine channel base */
	mrcp_engine_channel_t *channel;

	/** Active (in-progress) speak request */
	mrcp_message_t        *speak_request;
	/** Pending stop response */
	mrcp_message_t        *stop_response;
	/** Estimated time to complete */
	apr_size_t             time_to_complete;
	/** Is paused */
	apt_bool_t             paused;
	/** Speech source (used instead of actual synthesizing) */
	FILE                  *audio_file;
};

typedef enum {
	DEMO_SYNTH_MSG_OPEN_CHANNEL,
	DEMO_SYNTH_MSG_CLOSE_CHANNEL,
	DEMO_SYNTH_MSG_REQUEST_PROCESS
} demo_synth_msg_type_e;

/** Declaration of demo synthesizer task message */
struct demo_synth_msg_t {
	demo_synth_msg_type_e  type;
	mrcp_engine_channel_t *channel; 
	mrcp_message_t        *request;
};


static apt_bool_t demo_synth_msg_signal(demo_synth_msg_type_e type, mrcp_engine_channel_t *channel, mrcp_message_t *request);
static apt_bool_t demo_synth_msg_process(apt_task_t *task, apt_task_msg_t *msg);

/** Declare this macro to set plugin version */
MRCP_PLUGIN_VERSION_DECLARE

/** Declare this macro to use log routine of the server, plugin is loaded from */
MRCP_PLUGIN_LOGGER_IMPLEMENT

/** Create demo synthesizer engine */
MRCP_PLUGIN_DECLARE(mrcp_engine_t*) mrcp_plugin_create(apr_pool_t *pool)
{
	/* create demo engine */
	demo_synth_engine_t *demo_engine = apr_palloc(pool,sizeof(demo_synth_engine_t));
	apt_task_t *task;
	apt_task_vtable_t *vtable;
	apt_task_msg_pool_t *msg_pool;

	/* create task/thread to run demo engine in the context of this task */
	msg_pool = apt_task_msg_pool_create_dynamic(sizeof(demo_synth_msg_t),pool);
	demo_engine->task = apt_consumer_task_create(demo_engine,msg_pool,pool);
	if(!demo_engine->task) {
		return NULL;
	}
	task = apt_consumer_task_base_get(demo_engine->task);
	apt_task_name_set(task,SYNTH_ENGINE_TASK_NAME);
	vtable = apt_task_vtable_get(task);
	if(vtable) {
		vtable->process_msg = demo_synth_msg_process;
	}

	/* create engine base */
	return mrcp_engine_create(
				MRCP_SYNTHESIZER_RESOURCE, /* MRCP resource identifier */
				demo_engine,               /* object to associate */
				&engine_vtable,            /* virtual methods table of engine */
				pool);                     /* pool to allocate memory from */
}

/** Destroy synthesizer engine */
static apt_bool_t demo_synth_engine_destroy(mrcp_engine_t *engine)
{
	demo_synth_engine_t *demo_engine = engine->obj;
	if(demo_engine->task) {
		apt_task_t *task = apt_consumer_task_base_get(demo_engine->task);
		apt_task_destroy(task);
		demo_engine->task = NULL;
	}
	return TRUE;
}

/** Open synthesizer engine */
static apt_bool_t demo_synth_engine_open(mrcp_engine_t *engine)
{
	demo_synth_engine_t *demo_engine = engine->obj;
	if(demo_engine->task) {
		apt_task_t *task = apt_consumer_task_base_get(demo_engine->task);
		apt_task_start(task);
	}
	return TRUE;
}

/** Close synthesizer engine */
static apt_bool_t demo_synth_engine_close(mrcp_engine_t *engine)
{
	demo_synth_engine_t *demo_engine = engine->obj;
	if(demo_engine->task) {
		apt_task_t *task = apt_consumer_task_base_get(demo_engine->task);
		apt_task_terminate(task,TRUE);
	}
	return TRUE;
}

/** Create demo synthesizer channel derived from engine channel base */
static mrcp_engine_channel_t* demo_synth_engine_channel_create(mrcp_engine_t *engine, apr_pool_t *pool)
{
	mpf_stream_capabilities_t *capabilities;
	mpf_termination_t *termination; 

	/* create demo synth channel */
	demo_synth_channel_t *synth_channel = apr_palloc(pool,sizeof(demo_synth_channel_t));
	synth_channel->demo_engine = engine->obj;
	synth_channel->speak_request = NULL;
	synth_channel->stop_response = NULL;
	synth_channel->time_to_complete = 0;
	synth_channel->paused = FALSE;
	synth_channel->audio_file = NULL;
	
	capabilities = mpf_source_stream_capabilities_create(pool);
	mpf_codec_capabilities_add(
			&capabilities->codecs,
			MPF_SAMPLE_RATE_8000 | MPF_SAMPLE_RATE_16000,
			"LPCM");

	/* create media termination */
	termination = mrcp_engine_audio_termination_create(
			synth_channel,        /* object to associate */
			&audio_stream_vtable, /* virtual methods table of audio stream */
			capabilities,         /* stream capabilities */
			pool);                /* pool to allocate memory from */

	/* create engine channel base */
	synth_channel->channel = mrcp_engine_channel_create(
			engine,               /* engine */
			&channel_vtable,      /* virtual methods table of engine channel */
			synth_channel,        /* object to associate */
			termination,          /* associated media termination */
			pool);                /* pool to allocate memory from */

	return synth_channel->channel;
}

/** Destroy engine channel */
static apt_bool_t demo_synth_channel_destroy(mrcp_engine_channel_t *channel)
{
	/* nothing to destroy */
	return TRUE;
}

/** Open engine channel (asynchronous response MUST be sent)*/
static apt_bool_t demo_synth_channel_open(mrcp_engine_channel_t *channel)
{
	return demo_synth_msg_signal(DEMO_SYNTH_MSG_OPEN_CHANNEL,channel,NULL);
}

/** Close engine channel (asynchronous response MUST be sent)*/
static apt_bool_t demo_synth_channel_close(mrcp_engine_channel_t *channel)
{
	return demo_synth_msg_signal(DEMO_SYNTH_MSG_CLOSE_CHANNEL,channel,NULL);
}

/** Process MRCP channel request (asynchronous response MUST be sent)*/
static apt_bool_t demo_synth_channel_request_process(mrcp_engine_channel_t *channel, mrcp_message_t *request)
{
	return demo_synth_msg_signal(DEMO_SYNTH_MSG_REQUEST_PROCESS,channel,request);
}

/** Process SPEAK request */
static apt_bool_t demo_synth_channel_speak(mrcp_engine_channel_t *channel, mrcp_message_t *request, mrcp_message_t *response)
{
	char *file_path = NULL;
	demo_synth_channel_t *synth_channel = channel->method_obj;
	synth_channel->time_to_complete = 0;
	if(channel->engine) {
		const mpf_codec_descriptor_t *descriptor = mrcp_engine_source_stream_codec_get(channel);
		char *file_name = apr_psprintf(channel->pool,"demo-%dkHz.pcm",
			descriptor ? descriptor->sampling_rate/1000 : 8);
		file_path = apt_datadir_filepath_get(channel->engine->dir_layout,file_name,channel->pool);
	}
	if(file_path) {
		synth_channel->audio_file = fopen(file_path,"rb");
		if(synth_channel->audio_file) {
			apt_log(APT_LOG_MARK,APT_PRIO_INFO,"Set [%s] as Speech Source",file_path);
		}
		else {
			apt_log(APT_LOG_MARK,APT_PRIO_INFO,"No Speech Source [%s] Found",file_path);
			/* calculate estimated time to complete */
			if(mrcp_generic_header_property_check(request,GENERIC_HEADER_CONTENT_LENGTH) == TRUE) {
				mrcp_generic_header_t *generic_header = mrcp_generic_header_get(request);
				if(generic_header) {
					synth_channel->time_to_complete = generic_header->content_length * 10; /* 10 msec per character */
				}
			}
		}
	}
	
	response->start_line.request_state = MRCP_REQUEST_STATE_INPROGRESS;
	/* send asynchronous response */
	mrcp_engine_channel_message_send(channel,response);
	synth_channel->speak_request = request;
	return TRUE;
}

/** Process STOP request */
static apt_bool_t demo_synth_channel_stop(mrcp_engine_channel_t *channel, mrcp_message_t *request, mrcp_message_t *response)
{
	demo_synth_channel_t *synth_channel = channel->method_obj;
	/* store the request, make sure there is no more activity and only then send the response */
	synth_channel->stop_response = response;
	return TRUE;
}

/** Process PAUSE request */
static apt_bool_t demo_synth_channel_pause(mrcp_engine_channel_t *channel, mrcp_message_t *request, mrcp_message_t *response)
{
	demo_synth_channel_t *synth_channel = channel->method_obj;
	synth_channel->paused = TRUE;
	/* send asynchronous response */
	mrcp_engine_channel_message_send(channel,response);
	return TRUE;
}

/** Process RESUME request */
static apt_bool_t demo_synth_channel_resume(mrcp_engine_channel_t *channel, mrcp_message_t *request, mrcp_message_t *response)
{
	demo_synth_channel_t *synth_channel = channel->method_obj;
	synth_channel->paused = FALSE;
	/* send asynchronous response */
	mrcp_engine_channel_message_send(channel,response);
	return TRUE;
}

/** Process SET-PARAMS request */
static apt_bool_t demo_synth_channel_set_params(mrcp_engine_channel_t *channel, mrcp_message_t *request, mrcp_message_t *response)
{
	mrcp_synth_header_t *req_synth_header;
	/* get synthesizer header */
	req_synth_header = mrcp_resource_header_get(request);
	if(req_synth_header) {
		/* check voice age header */
		if(mrcp_resource_header_property_check(request,SYNTHESIZER_HEADER_VOICE_AGE) == TRUE) {
			apt_log(APT_LOG_MARK,APT_PRIO_INFO,"Set Voice Age [%"APR_SIZE_T_FMT"]",
				req_synth_header->voice_param.age);
		}
		/* check voice name header */
		if(mrcp_resource_header_property_check(request,SYNTHESIZER_HEADER_VOICE_NAME) == TRUE) {
			apt_log(APT_LOG_MARK,APT_PRIO_INFO,"Set Voice Name [%s]",
				req_synth_header->voice_param.name);
		}
	}
	
	/* send asynchronous response */
	mrcp_engine_channel_message_send(channel,response);
	return TRUE;
}

/** Process GET-PARAMS request */
static apt_bool_t demo_synth_channel_get_params(mrcp_engine_channel_t *channel, mrcp_message_t *request, mrcp_message_t *response)
{
	mrcp_synth_header_t *req_synth_header;
	/* get synthesizer header */
	req_synth_header = mrcp_resource_header_get(request);
	if(req_synth_header) {
		mrcp_synth_header_t *res_synth_header = mrcp_resource_header_prepare(response);
		/* check voice age header */
		if(mrcp_resource_header_property_check(request,SYNTHESIZER_HEADER_VOICE_AGE) == TRUE) {
			res_synth_header->voice_param.age = 25;
			mrcp_resource_header_property_add(response,SYNTHESIZER_HEADER_VOICE_AGE);
		}
		/* check voice name header */
		if(mrcp_resource_header_property_check(request,SYNTHESIZER_HEADER_VOICE_NAME) == TRUE) {
			apt_string_set(&res_synth_header->voice_param.name,"David");
			mrcp_resource_header_property_add(response,SYNTHESIZER_HEADER_VOICE_NAME);
		}
	}

	/* send asynchronous response */
	mrcp_engine_channel_message_send(channel,response);
	return TRUE;
}

/** Dispatch MRCP request */
static apt_bool_t demo_synth_channel_request_dispatch(mrcp_engine_channel_t *channel, mrcp_message_t *request)
{
	apt_bool_t processed = FALSE;
	mrcp_message_t *response = mrcp_response_create(request,request->pool);
	switch(request->start_line.method_id) {
		case SYNTHESIZER_SET_PARAMS:
			processed = demo_synth_channel_set_params(channel,request,response);
			break;
		case SYNTHESIZER_GET_PARAMS:
			processed = demo_synth_channel_get_params(channel,request,response);
			break;
		case SYNTHESIZER_SPEAK:
			processed = demo_synth_channel_speak(channel,request,response);
			break;
		case SYNTHESIZER_STOP:
			processed = demo_synth_channel_stop(channel,request,response);
			break;
		case SYNTHESIZER_PAUSE:
			processed = demo_synth_channel_pause(channel,request,response);
			break;
		case SYNTHESIZER_RESUME:
			processed = demo_synth_channel_resume(channel,request,response);
			break;
		case SYNTHESIZER_BARGE_IN_OCCURRED:
			processed = demo_synth_channel_stop(channel,request,response);
			break;
		case SYNTHESIZER_CONTROL:
			break;
		case SYNTHESIZER_DEFINE_LEXICON:
			break;
		default:
			break;
	}
	if(processed == FALSE) {
		/* send asynchronous response for not handled request */
		mrcp_engine_channel_message_send(channel,response);
	}
	return TRUE;
}

/** Callback is called from MPF engine context to destroy any additional data associated with audio stream */
static apt_bool_t demo_synth_stream_destroy(mpf_audio_stream_t *stream)
{
	return TRUE;
}

/** Callback is called from MPF engine context to perform any action before open */
static apt_bool_t demo_synth_stream_open(mpf_audio_stream_t *stream, mpf_codec_t *codec)
{
	return TRUE;
}

/** Callback is called from MPF engine context to perform any action after close */
static apt_bool_t demo_synth_stream_close(mpf_audio_stream_t *stream)
{
	return TRUE;
}

/** Callback is called from MPF engine context to read/get new frame */
static apt_bool_t demo_synth_stream_read(mpf_audio_stream_t *stream, mpf_frame_t *frame)
{
	demo_synth_channel_t *synth_channel = stream->obj;
	/* check if STOP was requested */
	if(synth_channel->stop_response) {
		/* send asynchronous response to STOP request */
		mrcp_engine_channel_message_send(synth_channel->channel,synth_channel->stop_response);
		synth_channel->stop_response = NULL;
		synth_channel->speak_request = NULL;
		synth_channel->paused = FALSE;
		if(synth_channel->audio_file) {
			fclose(synth_channel->audio_file);
			synth_channel->audio_file = NULL;
		}
		return TRUE;
	}

	/* check if there is active SPEAK request and it isn't in paused state */
	if(synth_channel->speak_request && synth_channel->paused == FALSE) {
		/* normal processing */
		apt_bool_t completed = FALSE;
		if(synth_channel->audio_file) {
			/* read speech from file */
			apr_size_t size = frame->codec_frame.size;
			if(fread(frame->codec_frame.buffer,1,size,synth_channel->audio_file) == size) {
				frame->type |= MEDIA_FRAME_TYPE_AUDIO;
			}
			else {
				completed = TRUE;
			}
		}
		else {
			/* fill with silence in case no file available */
			if(synth_channel->time_to_complete >= CODEC_FRAME_TIME_BASE) {
				memset(frame->codec_frame.buffer,0,frame->codec_frame.size);
				frame->type |= MEDIA_FRAME_TYPE_AUDIO;
				synth_channel->time_to_complete -= CODEC_FRAME_TIME_BASE;
			}
			else {
				completed = TRUE;
			}
		}
		
		if(completed) {
			/* raise SPEAK-COMPLETE event */
			mrcp_message_t *message = mrcp_event_create(
								synth_channel->speak_request,
								SYNTHESIZER_SPEAK_COMPLETE,
								synth_channel->speak_request->pool);
			if(message) {
				/* get/allocate synthesizer header */
				mrcp_synth_header_t *synth_header = mrcp_resource_header_prepare(message);
				if(synth_header) {
					/* set completion cause */
					synth_header->completion_cause = SYNTHESIZER_COMPLETION_CAUSE_NORMAL;
					mrcp_resource_header_property_add(message,SYNTHESIZER_HEADER_COMPLETION_CAUSE);
				}
				/* set request state */
				message->start_line.request_state = MRCP_REQUEST_STATE_COMPLETE;

				synth_channel->speak_request = NULL;
				if(synth_channel->audio_file) {
					fclose(synth_channel->audio_file);
					synth_channel->audio_file = NULL;
				}
				/* send asynch event */
				mrcp_engine_channel_message_send(synth_channel->channel,message);
			}
		}
	}
	return TRUE;
}

static apt_bool_t demo_synth_msg_signal(demo_synth_msg_type_e type, mrcp_engine_channel_t *channel, mrcp_message_t *request)
{
	apt_bool_t status = FALSE;
	demo_synth_channel_t *demo_channel = channel->method_obj;
	demo_synth_engine_t *demo_engine = demo_channel->demo_engine;
	apt_task_t *task = apt_consumer_task_base_get(demo_engine->task);
	apt_task_msg_t *msg = apt_task_msg_get(task);
	if(msg) {
		demo_synth_msg_t *demo_msg;
		msg->type = TASK_MSG_USER;
		demo_msg = (demo_synth_msg_t*) msg->data;

		demo_msg->type = type;
		demo_msg->channel = channel;
		demo_msg->request = request;
		status = apt_task_msg_signal(task,msg);
	}
	return status;
}

static apt_bool_t demo_synth_msg_process(apt_task_t *task, apt_task_msg_t *msg)
{
	demo_synth_msg_t *demo_msg = (demo_synth_msg_t*)msg->data;
	switch(demo_msg->type) {
		case DEMO_SYNTH_MSG_OPEN_CHANNEL:
			/* open channel and send asynch response */
			mrcp_engine_channel_open_respond(demo_msg->channel,TRUE);
			break;
		case DEMO_SYNTH_MSG_CLOSE_CHANNEL:
			/* close channel, make sure there is no activity and send asynch response */
			mrcp_engine_channel_close_respond(demo_msg->channel);
			break;
		case DEMO_SYNTH_MSG_REQUEST_PROCESS:
			demo_synth_channel_request_dispatch(demo_msg->channel,demo_msg->request);
			break;
		default:
			break;
	}
	return TRUE;
}