/*
   This example code is in the Public Domain (or CC0 licensed, at your option.)

   Unless required by applicable law or agreed to in writing, this
   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
   CONDITIONS OF ANY KIND, either express or implied.
*/

#ifndef __ESP_EDDYSTONE_PROTOCOL_H__
#define __ESP_EDDYSTONE_PROTOCOL_H__

#include "stdbool.h"
#include "stdint.h"

/* Eddystone definitions */
#define EDDYSTONE_SERVICE_UUID          0xFEAA

#define EDDYSTONE_FRAME_TYPE_UID        0x00
#define EDDYSTONE_FRAME_TYPE_URL        0x10
#define EDDYSTONE_FRAME_TYPE_TLM        0x20
#define EDDYSTONE_FRAME_TYPE_EID        0x30

#define EDDYSTONE_UID_FRAME_LEN         0x17
#define EDDYSTONE_TLM_FRAME_LEN         0x11
#define EDDYSTONE_URL_MAX_LEN           18


/* Eddystone UID frame */
typedef struct {
    int8_t    ranging_data;     /*<! calibrated Tx power at 0m */
    uint8_t   namespace_id[10];
    uint8_t   instance_id[6];
    uint8_t   reserved[2];
} __attribute__((packed))esp_eddystone_uid_t;

/* Eddystone URL frame */
typedef struct { 
    int8_t    tx_power;         /*<! calibrated Tx power at 0m */    
    uint8_t   url_scheme;       /*<! encoded scheme prefix */
    uint8_t   encoded_url[0];   /*<! length 1-17 */
} __attribute__((packed))esp_eddystone_url_t;

/* Eddystone TLM frame */
typedef struct {
    uint8_t    version;        /*<! TLM version,0x00 for now */
    uint16_t   batt;           /*<! battery voltage, 1mV/bit */
    uint16_t   temp;           /*<! beacon temperature */
    uint32_t   adv_count;      /*<! adv pdu count since power-on or reboot */
    uint32_t   time;           /*<! time sence power-on or reboot, a 0.1 second resolution counter */
} __attribute__((packed)) esp_eddystone_tlm_t;

/*  AD Structure of flags */
typedef struct {
    uint8_t     len;
    uint8_t     type;
    uint8_t     flags;
} __attribute__((packed)) esp_eddystone_flags_t;

/* AD Structure of complete 16-bit service uuid */
typedef struct {
    uint8_t     len;
    uint8_t     type;
    uint16_t    uuid;       /*<! complete list of 16-bit service UUIDs data type value */
} __attribute__((packed)) esp_eddystone_uuid_t;

/* AD Structure of eddystone frame*/
typedef struct {
    uint8_t     len;        /*<! length of eddystone data */
    uint8_t     type;       /*<! service data type,must be 0x16 */
    uint16_t    uuid;       /*<! 16-bit eddystone uuid */
    uint8_t     frame_type;
    union {
        esp_eddystone_uid_t     uid;
        esp_eddystone_url_t     url;
        esp_eddystone_tlm_t     tlm;
    } u[0];
} __attribute__((packed)) esp_eddystone_frame_t;

/* eddystone packet type */
typedef struct {
    esp_eddystone_flags_t   flags;
    esp_eddystone_uuid_t    uuid;
    esp_eddystone_frame_t   frame;
} __attribute__((packed)) esp_eddystone_packet_t;

/* 
 * URLs are written only with the graphic printable characters of the US-ASCII coded character set. 
 * The octets 00-20 and 7F-FF hexadecimal are not used. 
 * See “Excluded US-ASCII Characters” in RFC 2936.
 *
 */
static inline bool esp_eddystone_is_char_invalid(int ch)
{
    return (ch >= 0x00 && ch <= 0x20) || (ch >= 0x7f && ch <= 0xff);
}

#endif /* __ESP_EDDYSTONE_PROTOCOL_H__ */