#ifndef FLATUSB_USB_DRIVER_INTERFACE
#define FLATUSB_USB_DRIVER_INTERFACE

#include <stdbool.h>
#include <stdint.h>

typedef enum {
    USB_SPD_UKWN = 0,
    USB_SPD_LOW = 1,
    USB_SPD_FULL = 2,
    USB_SPD_HIGH = 3
} USBDRV_LineSpeed;

typedef void (*USBDRV_IN_cb)(uint8_t ep);

typedef struct {
    // USB CORE -> USB DRIVER
    void (*init)();                                                    // initialize USB driver
    void (*reset)();                                                   // reset USB driver
    void (*stall)(uint8_t ep, uint8_t dir, bool stall);                // stall the endpoint
    uint32_t (*arm_IN)(uint8_t ep, const uint8_t *data, uint16_t len); // arm IN endpoint
    uint32_t (*arm_OUT)(uint8_t ep, uint16_t len);                     // arm OUT endpoint
    void (*set_address)(uint8_t addr);                                 // set device address
    void (*set_config)(uint8_t ci);                                    // make the chosen setting operational
    void (*autoarm)(uint8_t ep);                                       // enable OUT autoarm
    void (*en_ep_irq)(uint8_t ep, uint8_t dir, bool en);               // enable endpoint interrupt
    void (*reg_IN_cb)(uint8_t ep, USBDRV_IN_cb cb);                    // register a callback for IN transaction complete

    // USB DRIVER -> USB CORE
    void (*rst_notify)();             // notify USB core of a bus issued reset
    void (*enum_notify)(uint8_t spd); // notify the USB core that speed negotiation has concluded
} USB_DrvIntf;

#ifndef USBDBGMSG
#define USBMSG(...)
#endif

// callback codes
typedef enum {
    USB_CBC_OUT,          // OUT done!
    USB_CBC_IN_DONE,      // IN done!
    USB_CBC_IN_FIFOEMPTY, // could not serve IN request, since Tx FIFO was empty
} USBDRV_CallbackCode;

// callback compound
typedef struct {
    uint8_t ep : 4;      // endpoint number
    uint8_t dir : 1;     // direction
    uint8_t code : 3;    // event code
    uint16_t size;       // data size
    const uint8_t *data; // data
} USBDRV_CallbackCompound;

typedef enum { UST_SETUP,
               UST_DATA } USBDRV_ControlTfStage;

#endif /* FLATUSB_USB_DRIVER_INTERFACE */