#ifndef CLASS_EEM
#define CLASS_EEM

#include <stdint.h>

#include "../usb_callback_event.h"

#include <blocking_io/blocking_fifo.h>

#include <etherlib/etherlib.h>

#define USB_EEM_FIFO_SIZE (8192)

typedef enum {
    EEM_ECHO = 0, // Echo
    EEM_ECHO_RESPONSE, // Echo response
    EEM_SUSPEND_HINT, // Suspend hint
    EEM_RESPONSE_HINT, // Response hint
    EEM_RESPONSE_COMPLETE_HINT, // Response complete hint
    EEM_TICKLE, // Tickle
} USB_EemCmd;

typedef enum {
    EEM_IDLE = 0, // IDLE state, a new transfer may be initiated
    EEM_TRANSFER_IN_PROGRESS // transfer is in progress, new transfers have to wait
} USB_EemFsmState;

typedef enum {
    EEM_EVT_NONE = 0, // no event
    EEM_EVT_NETBOUND_PCKT_RECEIVED, // a USB packet has been received for a netbound Ethernet frame
    // EEM_EVT_HOSTBOUND_FRAME_IN_QUEUE, // a new hostbound frame is in the queue
    EEM_EVT_HOSTBOUND_TRANSFER_DONE, // the previous hostbound transfer has completed
} USB_EemEvent;

/**
 * Ethernet frame prepended with EEM header
*/
typedef struct {
    uint16_t header; ///< EEM header (CRC present?, Frame Length)
    uint8_t payload[]; ///< Actual payload
} USB_EemFrame;

typedef struct {
    EthInterface * intf; // interface for packet interception and injection
    uint8_t data_ep; // bulk data in and out endpoint pair
    osMessageQueueId_t eventQueue; // event queue
    // BFifo hostbFifo; // Hostbound FIFO
    BFifo netbFifo; // Network bound FIFO
    USB_EemFsmState netbState; // state of host bound operations
    uint16_t netbFrameSize; // size of network bound packet
    uint16_t netbSizeLeft; // number of bytes expected from the host sending into current network bound packet
    bool netbAutoArm; // signal, that the netbound endpoint should be autoarmed or not
    USB_EemFsmState hostbState; // state of network bound operations
    osMessageQueueId_t hostbFrameQ; // queue for hostbound message pointers
    USB_EemFrame * hostbFrame; // hostbound frame
    uint16_t hostbFrameLength; // hostbound frame length
    uint16_t hostbFrameIndex; // read index in hostbound frame
    bool echoRespQueued; // indicates if an EchoResponse was queued
    bool initialized; // EEM is initialized
    osThreadId_t th; // EEM thread
} USB_EemState;

/**
 * Initialize USB EEM module.
 * @param data_ep data endpoint number
*/
void usb_eem_init(uint8_t data_ep);

/**
 * Callback function for data reception and transmission.
 * @param cbevt pointer to callback event structure
 * @return function returns how to proceed with packet processing 
*/
int usb_eem_process_and_return(USB_CallbackEvent * cbevt);

/**
 * Set Ethernet interface.
 * @param pointer to Ethernet interface
*/
void usb_eem_set_intf(EthInterface * intf);

#endif /* CLASS_EEM */