/*
 * Copyright (C) 2014 BlueKitchen GmbH
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 * 4. Any redistribution, use, or modification is done solely for
 *    personal benefit and not for any commercial purpose or for
 *    monetary gain.
 *
 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS
 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * Please inquire about commercial licensing options at 
 * contact@bluekitchen-gmbh.com
 *
 */

#define __BTSTACK_FILE__ "heart_rate_service_server.c"

/**
 * Implementation of the GATT Battery Service Server 
 * To use with your application, add '#import <heart_rate_service.gatt' to your .gatt file
 */

#include "bluetooth.h"
#include "btstack_defines.h"
#include "ble/att_db.h"
#include "ble/att_server.h"
#include "btstack_util.h"
#include "bluetooth_gatt.h"
#include "btstack_debug.h"

#include "ble/gatt-service/heart_rate_service_server.h"

typedef enum {
	HEART_RATE_SERVICE_VALUE_FORMAT,
	HEART_RATE_SERVICE_SENSOR_CONTACT_STATUS,
	HEART_RATE_SERVICE_ENERGY_EXPENDED_STATUS,
	HEART_RATE_SERVICE_RR_INTERVAL
} heart_rate_service_flag_bit_t;

typedef struct {
	hci_con_handle_t con_handle;

	// characteristic: Heart Rate Mesurement 
	uint16_t measurement_value_handle;
	uint8_t  flags;
	uint16_t measurement_bpm;
	uint16_t energy_expended_kJ; // kilo Joules
	int rr_interval_count;
	int rr_offset;
	uint16_t * rr_intervals;
	heart_rate_service_sensor_contact_status_t sensor_contact;

	// characteristic descriptor: Client Characteristic Configuration
	uint16_t measurement_client_configuration_descriptor_handle;
	uint16_t measurement_client_configuration_descriptor_notify;
	btstack_context_callback_registration_t measurement_callback;

	// characteristic: Body Sensor Location 
	uint16_t sensor_location_value_handle;
	heart_rate_service_body_sensor_location_t sensor_location;
	
	// characteristic: Hear Rate Control Point
	// uint8_t reset_energy_expended;
	uint16_t control_point_value_handle;
	
} heart_rate_t;

static att_service_handler_t heart_rate_service;
static heart_rate_t heart_rate;

static btstack_packet_handler_t heart_rate_service_callback;

static uint16_t heart_rate_service_read_callback(hci_con_handle_t con_handle, uint16_t attribute_handle, uint16_t offset, uint8_t * buffer, uint16_t buffer_size){
	UNUSED(con_handle);
	UNUSED(attribute_handle);
	UNUSED(offset);
	UNUSED(buffer_size);

	if (attribute_handle == heart_rate.measurement_client_configuration_descriptor_handle){
		if (buffer){
			little_endian_store_16(buffer, 0, heart_rate.measurement_client_configuration_descriptor_notify);
		}
		return 2;
	}
	
	if (attribute_handle == heart_rate.sensor_location_value_handle){
		if (buffer){
			buffer[0] = heart_rate.sensor_location;
		}
		return 1;
	}
	return 0;
}

static int heart_rate_service_write_callback(hci_con_handle_t con_handle, uint16_t attribute_handle, uint16_t transaction_mode, uint16_t offset, uint8_t *buffer, uint16_t buffer_size){
	UNUSED(transaction_mode);
	UNUSED(offset);
	UNUSED(buffer_size);

	if (attribute_handle == heart_rate.measurement_client_configuration_descriptor_handle){
		heart_rate.measurement_client_configuration_descriptor_handle = little_endian_read_16(buffer, 0);
		heart_rate.con_handle = con_handle;
	}
	return 0;
}


void heart_rate_service_server_init(heart_rate_service_body_sensor_location_t location){
	heart_rate_t * instance = &heart_rate;

	instance->sensor_location = location;

	// get service handle range
	uint16_t start_handle = 0;
	uint16_t end_handle   = 0xffff;
	int service_found = gatt_server_get_get_handle_range_for_service_with_uuid16(ORG_BLUETOOTH_SERVICE_HEART_RATE, &start_handle, &end_handle);
	if (!service_found) return;

	// get Heart Rate Mesurement characteristic value handle and client configuration handle
	instance->measurement_value_handle = gatt_server_get_value_handle_for_characteristic_with_uuid16(start_handle, end_handle, ORG_BLUETOOTH_CHARACTERISTIC_HEART_RATE_MEASUREMENT);
	instance->measurement_client_configuration_descriptor_handle = gatt_server_get_client_configuration_handle_for_characteristic_with_uuid16(start_handle, end_handle, ORG_BLUETOOTH_CHARACTERISTIC_HEART_RATE_MEASUREMENT);
	// get Body Sensor Location characteristic value handle and client configuration handle
	instance->sensor_location_value_handle = gatt_server_get_value_handle_for_characteristic_with_uuid16(start_handle, end_handle, ORG_BLUETOOTH_CHARACTERISTIC_SENSOR_LOCATION);
	// get Hear Rate Control Point characteristic value handle and client configuration handle
	instance->control_point_value_handle = gatt_server_get_value_handle_for_characteristic_with_uuid16(start_handle, end_handle, ORG_BLUETOOTH_CHARACTERISTIC_HEART_RATE_CONTROL_POINT);
	
	// register service with ATT Server
	heart_rate_service.start_handle   = start_handle;
	heart_rate_service.end_handle     = end_handle;
	heart_rate_service.read_callback  = &heart_rate_service_read_callback;
	heart_rate_service.write_callback = &heart_rate_service_write_callback;
	
	att_server_register_service_handler(&heart_rate_service);
}


static void heart_rate_service_can_send_now(void * context){
	heart_rate_t * instance = (heart_rate_t *) context;
	instance->flags |= (1 << HEART_RATE_SERVICE_VALUE_FORMAT);
	instance->flags |= (instance->sensor_contact << HEART_RATE_SERVICE_SENSOR_CONTACT_STATUS);
	if (instance->energy_expended_kJ){
		instance->flags |= (1 << HEART_RATE_SERVICE_ENERGY_EXPENDED_STATUS);
	}
	if (instance->rr_interval_count){
		instance->flags |= (1 << HEART_RATE_SERVICE_RR_INTERVAL);
	}

	uint8_t value[100];
	int pos = 0;

	value[pos++] = instance->flags;
	little_endian_store_16(value, pos, instance->measurement_bpm);
	pos += 2;
	if (instance->energy_expended_kJ){
		little_endian_store_16(value, pos, instance->energy_expended_kJ);
		pos += 2;
	}

	// TODO: get actual MTU from ATT server
	uint16_t bytes_left = btstack_min(sizeof(value), l2cap_max_mtu() - 3 - pos);

	while (bytes_left > 2 && instance->rr_interval_count){
		little_endian_store_16(value, pos, instance->rr_intervals[0]);
		pos +=2;
		bytes_left -= 2;
		instance->rr_intervals++;
		instance->rr_interval_count--;
	}

	att_server_notify(instance->con_handle, instance->measurement_value_handle, &value[0], pos);

	if (instance->rr_interval_count){
		instance->measurement_callback.callback = &heart_rate_service_can_send_now;
		instance->measurement_callback.context  = (void*) instance;
		att_server_register_can_send_now_callback(&instance->measurement_callback, instance->con_handle);
	} 
}

void heart_rate_service_add_energy_expended(uint16_t energy_expended_kJ){
	heart_rate_t * instance = &heart_rate;
	// limit energy expended to 0xffff
	if ( instance->energy_expended_kJ <= 0xffff - energy_expended_kJ){
		instance->energy_expended_kJ += energy_expended_kJ;
	} else {
		instance->energy_expended_kJ = 0xffff;
	}

	if (instance->measurement_client_configuration_descriptor_notify){
		instance->measurement_callback.callback = &heart_rate_service_can_send_now;
		instance->measurement_callback.context  = (void*) instance;
		att_server_register_can_send_now_callback(&instance->measurement_callback, instance->con_handle);
	}
}

void heart_rate_service_server_update_heart_rate_values(uint16_t bits_per_minute, 
	heart_rate_service_sensor_contact_status_t sensor_contact, int rr_interval_count, uint16_t * rr_intervals){

	heart_rate_t * instance = &heart_rate;
	
	instance->measurement_bpm = bits_per_minute;
	instance->sensor_contact = sensor_contact;
	instance->rr_interval_count = rr_interval_count;
	instance->rr_intervals = rr_intervals;
	instance->rr_offset = 0;

	if (instance->measurement_client_configuration_descriptor_notify){
		instance->measurement_callback.callback = &heart_rate_service_can_send_now;
		instance->measurement_callback.context  = (void*) instance;
		att_server_register_can_send_now_callback(&instance->measurement_callback, instance->con_handle);
	}
}