#ifndef MESSAGES_H
#define MESSAGES_H

#include <stdint.h>

#ifdef __cplusplus
extern "C" {
#endif

/***********************
 * Message Definitions *
 ***********************/

#define MSG_HEADER           0x1234

#define MSG_CTL_VALID_DEVICE 0x0001  // device id is valid
#define MSG_CTL_VALID_WORLD  0x0002  // world time is valid
#define MSG_CTL_VALID_START  0x0004  // start time is valid
#define MSG_CTL_VALID_PERIOD 0x0008  // period is valid
#define MSG_CTL_RELAY_MODE   0x4000  // relay output messages
#define MSG_CTL_BEGIN_SYNC   0x8000  // begin time sync

#pragma pack(1)

typedef enum {
	MSG_ID_INIT,       // Device initialization
	MSG_ID_SYNC,       // Time synchronization
	MSG_ID_EVENT,      // Event occurred
	MSG_MAX_ID,        // Maximum message ID
} msgid_t;

typedef struct {
	uint32_t seconds;  // Seconds since 1970
	uint32_t nanosec;  // Nanoseconds since 'seconds'
} ntime_t;

typedef struct {
	uint16_t header;   // Message Header
	uint16_t msgid;    // Message ID
	uint16_t length;   // Body length
	uint16_t cksum;    // Body checksum
} header_t;

typedef struct {
	uint16_t control;  // Message control bits
	uint16_t device;   // Device ID to use
	ntime_t  world;    // World time (since 1970)
	ntime_t  start;    // Transmit start time
	ntime_t  period;   // Transmit period
} init_msg_t;

typedef struct {
	ntime_t  time;     // Time of previous message
} sync_msg_t;

typedef struct {
	uint16_t device;   // Device ID
	uint16_t event;    // Event ID
	ntime_t  world;    // UTC Time of event
	ntime_t  local;    // Time since turn-on
} event_msg_t;

#pragma pack()

/******************
 * Message Parser *
 ******************/

typedef void (*handler_t)(header_t *head, void *body);

typedef struct {
	int       index;
	int       state;
	uint8_t   buffer[256];
	handler_t handler[MSG_MAX_ID];
} parser_t;

void msg_register(parser_t *parser, int msgid, handler_t handler);

void msg_receive(parser_t *parser, int byte);

#ifdef __cplusplus
}
#endif

#endif