/*
 * 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 BLUEKITCHEN
 * GMBH 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__ "ancs_client.c"

#include "btstack_config.h"

#include <stdint.h>
#include <string.h>

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

#include "ble/core.h"
#include "ble/gatt_client.h"
#include "ble/sm.h"
#include "btstack_debug.h"
#include "btstack_event.h"
#include "gap.h"

// ancs_client.h Start
typedef enum ancs_chunk_parser_state {
    W4_ATTRIBUTE_ID,
    W4_ATTRIBUTE_LEN,
    W4_ATTRIBUTE_COMPLETE,
} ancs_chunk_parser_state_t;

typedef enum {
    TC_IDLE,
    TC_W4_ENCRYPTED_CONNECTION,
    TC_W4_SERVICE_RESULT,
    TC_W4_CHARACTERISTIC_RESULT,
    TC_W4_DATA_SOURCE_SUBSCRIBED,
    TC_W4_NOTIFICATION_SOURCE_SUBSCRIBED,
    TC_SUBSCRIBED,
    TC_W4_DISCONNECT
} tc_state_t;

static uint32_t ancs_notification_uid;
static uint16_t gc_handle;
static gatt_client_notification_t ancs_notification_source_notification;
static gatt_client_notification_t ancs_data_source_notification;
static int ancs_service_found;
static gatt_client_service_t  ancs_service;
static gatt_client_characteristic_t ancs_notification_source_characteristic;
static gatt_client_characteristic_t ancs_control_point_characteristic;
static gatt_client_characteristic_t ancs_data_source_characteristic;
static int ancs_characteristcs;
static tc_state_t tc_state = TC_IDLE;

static ancs_chunk_parser_state_t chunk_parser_state;
static uint8_t  ancs_notification_buffer[50];
static uint16_t ancs_bytes_received;
static uint16_t ancs_bytes_needed;
static uint8_t  ancs_attribute_id;
static uint16_t ancs_attribute_len;

static btstack_packet_handler_t client_handler;
static btstack_packet_callback_registration_t hci_event_callback_registration;

static void ancs_client_handle_gatt_client_event(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);

void ancs_client_register_callback(btstack_packet_handler_t handler){
    client_handler = handler; 
}

static void notify_client_text(int event_type){
    if (!client_handler) return;
    uint8_t event[7 + sizeof(ancs_notification_buffer) + 1];
    event[0] = HCI_EVENT_ANCS_META;
    event[1] = 5u + ancs_attribute_len;
    event[2] = event_type;
    little_endian_store_16(event, 3, gc_handle);
    little_endian_store_16(event, 5, ancs_attribute_id);
    (void)memcpy(&event[7], ancs_notification_buffer, ancs_attribute_len);
    // we're nice
    event[7u+ancs_attribute_len] = 0u;
    (*client_handler)(HCI_EVENT_PACKET, 0u, event, event[1u] + 2u);
}

static void notify_client_simple(int event_type){
    if (!client_handler) return;
    uint8_t event[5];
    event[0] = HCI_EVENT_ANCS_META;
    event[1] = 3;
    event[2] = event_type;
    little_endian_store_16(event, 3, gc_handle);
    (*client_handler)(HCI_EVENT_PACKET, 0, event, sizeof(event));
}

static void ancs_chunk_parser_init(void){
    // skip comand id and notification uid
    chunk_parser_state = W4_ATTRIBUTE_ID;
    ancs_bytes_received = 0;
    ancs_bytes_needed = 6;
}

const char * ancs_client_attribute_name_for_id(int id){
    static const char * ancs_attribute_names[] = {
            "AppIdentifier",
            "IDTitle",
            "IDSubtitle",
            "IDMessage",
            "IDMessageSize",
            "IDDate"
    };

    static const uint16_t ANCS_ATTRIBUTE_NAMES_COUNT = sizeof(ancs_attribute_names) / sizeof(char *);

    if (id >= ANCS_ATTRIBUTE_NAMES_COUNT) return NULL;
    return ancs_attribute_names[id];
}

static void ancs_chunk_parser_handle_byte(uint8_t data){
    ancs_notification_buffer[ancs_bytes_received++] = data;
    if (ancs_bytes_received < ancs_bytes_needed) return;
    switch (chunk_parser_state){
        case W4_ATTRIBUTE_ID:
            ancs_attribute_id   = ancs_notification_buffer[ancs_bytes_received-1u];
            ancs_bytes_received = 0;
            ancs_bytes_needed   = 2;
            chunk_parser_state  = W4_ATTRIBUTE_LEN;
            break;
        case W4_ATTRIBUTE_LEN:
            ancs_attribute_len  = little_endian_read_16(ancs_notification_buffer, ancs_bytes_received-2u);
            ancs_bytes_received = 0;
            ancs_bytes_needed   = ancs_attribute_len;
            if (ancs_attribute_len == 0u) {
                ancs_bytes_needed   = 1;
                chunk_parser_state  = W4_ATTRIBUTE_ID;
                break;
            }
            chunk_parser_state  = W4_ATTRIBUTE_COMPLETE;
            break;
        case W4_ATTRIBUTE_COMPLETE:
            ancs_notification_buffer[ancs_bytes_received] = 0;
            notify_client_text(ANCS_SUBEVENT_CLIENT_NOTIFICATION);
            ancs_bytes_received = 0;
            ancs_bytes_needed   = 1;
            chunk_parser_state  = W4_ATTRIBUTE_ID;
            break;
        default:
            btstack_unreachable();
            break;
    }
}

static void ancs_client_handle_notification(uint8_t * packet, uint16_t size){
    UNUSED(size);

    uint16_t  value_handle = little_endian_read_16(packet, 4);
    uint16_t  value_length = little_endian_read_16(packet, 6);
    uint8_t * value = &packet[8];

    log_info("ANCS Notification, value handle %u", value_handle);

    if (value_handle == ancs_data_source_characteristic.value_handle){
        int i;
        for (i=0;i<value_length;i++) {
            ancs_chunk_parser_handle_byte(value[i]);
        }
    } else if (value_handle == ancs_notification_source_characteristic.value_handle){
        ancs_notification_uid = little_endian_read_32(value, 4);
        log_info("Notification received: EventID %02x, EventFlags %02x, CategoryID %02x, CategoryCount %u, UID %04x",
                 value[0], value[1], value[2], value[3], (int) ancs_notification_uid);
        static uint8_t get_notification_attributes[] = {0, 0,0,0,0,  0,  1,32,0,  2,32,0, 3,32,0, 4, 5};
        little_endian_store_32(get_notification_attributes, 1, ancs_notification_uid);
        ancs_notification_uid = 0;
        ancs_chunk_parser_init();
        gatt_client_write_value_of_characteristic(ancs_client_handle_gatt_client_event, gc_handle, ancs_control_point_characteristic.value_handle,
                                                  sizeof(get_notification_attributes), get_notification_attributes);
    } else {
        log_info("Unknown Source: ");
        log_info_hexdump(value , value_length);
    }
}

static void ancs_client_handle_gatt_client_event(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){

    UNUSED(packet_type);
    UNUSED(channel);

    static const uint8_t ancs_notification_source_uuid[] = {0x9F,0xBF,0x12,0x0D,0x63,0x01,0x42,0xD9,0x8C,0x58,0x25,0xE6,0x99,0xA2,0x1D,0xBD};
    static const uint8_t ancs_control_point_uuid[] =       {0x69,0xD1,0xD8,0xF3,0x45,0xE1,0x49,0xA8,0x98,0x21,0x9B,0xBD,0xFD,0xAA,0xD9,0xD9};
    static const uint8_t ancs_data_source_uuid[] =         {0x22,0xEA,0xC6,0xE9,0x24,0xD6,0x4B,0xB5,0xBE,0x44,0xB3,0x6A,0xCE,0x7C,0x7B,0xFB};

    gatt_client_characteristic_t characteristic;

    switch(tc_state){
        case TC_W4_SERVICE_RESULT:
            switch(hci_event_packet_get_type(packet)){
                case GATT_EVENT_SERVICE_QUERY_RESULT:
                    gatt_event_service_query_result_get_service(packet, &ancs_service);
                    ancs_service_found = 1;
                    break;
                case GATT_EVENT_QUERY_COMPLETE:
                    if (!ancs_service_found){
                        log_info("ANCS Service not found");
                        tc_state = TC_IDLE;
                        break;
                    }
                    tc_state = TC_W4_CHARACTERISTIC_RESULT;
                    log_info("ANCS Client - Discover characteristics for ANCS SERVICE ");
                    gatt_client_discover_characteristics_for_service(ancs_client_handle_gatt_client_event, gc_handle, &ancs_service);
                    break;
                default:
                    break;
            }
            break;

        case TC_W4_CHARACTERISTIC_RESULT:
            switch(hci_event_packet_get_type(packet)){
                case GATT_EVENT_CHARACTERISTIC_QUERY_RESULT:
                    gatt_event_characteristic_query_result_get_characteristic(packet, &characteristic);
                    if (memcmp(characteristic.uuid128, ancs_notification_source_uuid, 16) == 0){
                        log_info("ANCS Notification Source found, attribute handle %u", characteristic.value_handle);
                        ancs_notification_source_characteristic = characteristic;
                        ancs_characteristcs++;
                        break;
                    }
                    if (memcmp(characteristic.uuid128, ancs_control_point_uuid, 16) == 0){
                        log_info("ANCS Control Point found, attribute handle %u", characteristic.value_handle);
                        ancs_control_point_characteristic = characteristic;
                        ancs_characteristcs++;
                        break;
                    }
                    if (memcmp(characteristic.uuid128, ancs_data_source_uuid, 16) == 0){
                        log_info("ANCS Data Source found, attribute handle %u", characteristic.value_handle);
                        ancs_data_source_characteristic = characteristic;
                        ancs_characteristcs++;
                        break;
                    }
                    break;
                case GATT_EVENT_QUERY_COMPLETE:
                    log_info("ANCS Characteristcs count %u", ancs_characteristcs);
                    tc_state = TC_W4_NOTIFICATION_SOURCE_SUBSCRIBED;
                    gatt_client_listen_for_characteristic_value_updates(&ancs_notification_source_notification, &ancs_client_handle_gatt_client_event, gc_handle, &ancs_notification_source_characteristic);
                    gatt_client_write_client_characteristic_configuration(ancs_client_handle_gatt_client_event, gc_handle, &ancs_notification_source_characteristic,
                                                                          GATT_CLIENT_CHARACTERISTICS_CONFIGURATION_NOTIFICATION);
                    break;
                default:
                    break;
            }
            break;
        case TC_W4_NOTIFICATION_SOURCE_SUBSCRIBED:
            switch(hci_event_packet_get_type(packet)){
                case GATT_EVENT_QUERY_COMPLETE:
                    log_info("ANCS Notification Source subscribed");
                    tc_state = TC_W4_DATA_SOURCE_SUBSCRIBED;
                    gatt_client_listen_for_characteristic_value_updates(&ancs_data_source_notification, &ancs_client_handle_gatt_client_event, gc_handle, &ancs_data_source_characteristic);
                    gatt_client_write_client_characteristic_configuration(ancs_client_handle_gatt_client_event, gc_handle, &ancs_data_source_characteristic,
                                                                          GATT_CLIENT_CHARACTERISTICS_CONFIGURATION_NOTIFICATION);
                    break;
                default:
                    break;
            }
            break;
        case TC_W4_DATA_SOURCE_SUBSCRIBED:
            switch(hci_event_packet_get_type(packet)){
                case GATT_EVENT_QUERY_COMPLETE:
                    log_info("ANCS Data Source subscribed");
                    tc_state = TC_SUBSCRIBED;
                    notify_client_simple(ANCS_SUBEVENT_CLIENT_CONNECTED);
                    break;
                default:
                    break;
            }
            break;
        case TC_SUBSCRIBED:
            switch(hci_event_packet_get_type(packet)){
                case GATT_EVENT_NOTIFICATION:
                case GATT_EVENT_INDICATION:
                    ancs_client_handle_notification(packet, size);
                    break;
                default:
                    break;
            }
            break;
        default:
            break;
    }
}

static void handle_hci_event(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){

    UNUSED(packet_type); // ok: only hci events
    UNUSED(channel);     // ok: there is no channel
    UNUSED(size);        // ok: fixed format events read from HCI buffer

    static const uint8_t ancs_service_uuid[] =             {0x79,0x05,0xF4,0x31,0xB5,0xCE,0x4E,0x99,0xA4,0x0F,0x4B,0x1E,0x12,0x2D,0x00,0xD0};

    int connection_encrypted;

    // handle connect / disconncet events first
    switch (hci_event_packet_get_type(packet)) {
        case HCI_EVENT_LE_META:
            switch (packet[2]) {
                case HCI_SUBEVENT_LE_CONNECTION_COMPLETE:
                    gc_handle = hci_subevent_le_connection_complete_get_connection_handle(packet);
                    log_info("Connection handle 0x%04x, request encryption", gc_handle);

                    // we need to be paired to enable notifications
                    tc_state = TC_W4_ENCRYPTED_CONNECTION;
                    ancs_service_found = false;
                    sm_request_pairing(gc_handle);
                    break;
                default:
                    break;
            }
            return;

        case HCI_EVENT_ENCRYPTION_CHANGE:
        case HCI_EVENT_ENCRYPTION_CHANGE_V2:
            if (gc_handle != hci_event_encryption_change_get_connection_handle(packet)) return;
            connection_encrypted = hci_event_encryption_change_get_encryption_enabled(packet);
            log_info("Encryption state change: %u", connection_encrypted);
            if (!connection_encrypted) return;
            if (tc_state != TC_W4_ENCRYPTED_CONNECTION) return;

            // let's start
            log_info("\nANCS Client - CONNECTED, discover ANCS service");
            tc_state = TC_W4_SERVICE_RESULT;
            gatt_client_discover_primary_services_by_uuid128(ancs_client_handle_gatt_client_event, gc_handle, ancs_service_uuid);
            return;
            
        case HCI_EVENT_DISCONNECTION_COMPLETE:
            if (hci_event_disconnection_complete_get_connection_handle(packet) != gc_handle) break;
            if (tc_state == TC_SUBSCRIBED){
                notify_client_simple(ANCS_SUBEVENT_CLIENT_DISCONNECTED);
            }
            tc_state = TC_IDLE;
            gc_handle = 0;
            return;

        default:
            break;
    }
}

void ancs_client_init(void){
    hci_event_callback_registration.callback = &handle_hci_event;
    hci_add_event_handler(&hci_event_callback_registration);
}

// unit test only
#if defined __cplusplus
extern "C"
#endif
void ancs_client_set_invalid_parser_state(void);
void ancs_client_set_invalid_parser_state(void){
    chunk_parser_state = (ancs_chunk_parser_state_t) 0x17;
}