#ifndef CH32_USB_DRV
#define CH32_USB_DRV

#include "../../usb_common_types.h"

#include "../../usb_driver_common.h"

// maximum number of endpoints that can be supported
#define USB_MAX_NUM_OF_ENDPOINTS (8)

// number of supported endpoints
#ifndef USB_NUM_OF_ENDPOINTS // number of endpoints can be overridden to conserve memory
#define USB_NUM_OF_ENDPOINTS (USB_MAUSB_MAX_NUM_OF_ENDPOINTS) // set it to the maximum that this type of module can support
#else
#if USB_MAX_NUM_OF_ENDPOINTS > USB_MAX_NUM_OF_ENDPOINTS // do not allow greater number of endpoints than what the device supports
#undef USB_NUM_OF_ENDPOINTS
#define USB_NUM_OF_ENDPOINTS (USB_MUSB_MAX_NUM_OF_ENDPOINTS)
#endif
#endif

// non isochronous transfers
#define USB_MAX_FS_PCKT_SIZE_NON_ISOCHRONOUS (64)

// isochronous transfers
#define USB_MAX_FS_PCKT_SIZE_ISOCHRONOUS (1023)

// endpoint configuration structure
typedef struct {
    uint16_t max_packet_size; // maximum packet size
    bool8_t responding_NAK;   // indicates if endpoint responds with NAK
    uint8_t type;             // endpoint type
    uint8_t service_interval; // service interval

    // calculated values

    uint8_t is_configured;   // the endpoint is in use
    uint16_t buffer_address; // address in the FIFO
    bool8_t zlp_next;        // indicates, that ZLP should be transmitted at the end of the current transfer (for IN endpoints)
    bool8_t autoarm;         // automatically arm endpoint (for OUT endpoints)
    bool8_t txp;             // transfer in progress
} USBDRV_EpConfig;

typedef enum {
    USB_EVT_USB_RESET, // bus reset received
    USB_EVT_TRANSFER_COMPLETION,
} USBDRV_EventCode;

// USB device state
typedef struct {
    USBDRV_EpConfig ep_OUT[USB_NUM_OF_ENDPOINTS]; // OUT endpoint configs
    USBDRV_EpConfig ep_IN[USB_NUM_OF_ENDPOINTS];  // IN endpoint configs
    uint8_t *buf;                                 // pointer to the receive buffer (this way declaration can be separated)
    uint8_t address;                              // device address
    bool address_pending;                         // address change is pending
} USBDRV_GlobalState;

// event data
typedef union {
    struct {
        uint8_t pckt_status; // read packet status
        uint8_t data_pid;    // data PID
        uint8_t byte_count;  // byte count
        uint8_t ep_num;      // read endpoint number
    } rx;                    // receive event data
} USBDRV_EventData;

// event compound for queueing
typedef struct {
    uint32_t code;         // event code
    USBDRV_EventData data; // accompaining event data
} USBDRV_EventCompound;

// ------------

/**
 * Fully initialize USB driver.
 */
void usbdrv_init();

/**
 * Reset USB driver.
 */
void usbdrv_reset();

/**
 * Init driver's global state.
 */
void usbdrv_init_global_state();

/**
 * Initialize driver interface.
 */
void usbdrv_init_intf();

/**
 * USB peripheral initialization.
 *
 * @param reset only perform an after-reset reinitialization
 */
void usbdrv_periph_init(bool reset);

/**
 * Clear all TX and RX FIFOs.
 */
void usbdrv_clear_all_fifos();

/**
 * Power down or up the USB peripheral. Also control built-in transciever.
 *
 * @param en power on/off
 */
void usbdrv_power_and_connect(bool en);

/**
 * Configure USB Endpoint.
 *
 * @param ep index of the endpoint
 * @param dir direction of the endpoint to be configured
 * @param cfg pointer to the configuration details
 */
void usbdrv_configure_endpoint(uint8_t ep, uint8_t dir, const USBDRV_EpConfig *cfg);

/**
 * Deconfigure a specific USB Endpoint.
 *
 * @param ep index of the endpoint
 * @param dir direction of the endpoint to be deconfigured
 */
void usbdrv_deconfigure_endpoint(uint8_t ep, uint8_t dir);

/**
 * Stall a particular USB Endpoint.
 *
 * @param ep index of the endpoint to be stalled
 * @param dir direction of the endpoint
 * @param stall enable/disable stalling
 */
void usbdrv_stall_endpoint(uint8_t ep, uint8_t dir, bool stall);

/**
 * Setup and prepare Endpoint to transfer data towards the host.
 * May be called multiple times in a single transmission, since
 * large messages do not have to fit into a single buffer.
 *
 * @param ep index of the Endpoint
 * @param data pointer to the data
 * @param len length of the data to be read
 * @return number of bytes read from the data buffer
 */
uint32_t usbdrv_arm_IN_endpoint(uint8_t ep, const uint8_t *data, uint16_t len);

/**
 * Prepare Endpoint to expect data reception from the host.
 *
 * @param ep index of the Endpoint
 * @param size expected reception length
 * @return message length that the endpoint can support during next reception
 */
uint32_t usbdrv_arm_OUT_endpoint(uint8_t ep, uint16_t size);

/**
 * Enable or disable OUT Endpoint auto arming.
 * Right after a transaction completes the USB core
 * automatically prepares the endpoint for the next
 * reception if this feature is enabled.
 *
 * @param ep index of the Endpoint
 */
void usbdrv_autoarm_OUT_endpoint(uint8_t ep);

/**
 * Mask or unmask Endpoint interrupt generation.
 *
 * @param ep index of the Endpoint
 * @param dir direction of the Endpoint
 * @param en enable/disable interrupt
 */
void usbdrv_enable_endpoint_interrupt(uint8_t ep, uint8_t dir, bool en);

/**
 * Preload Endpoint config. Do not write configuration
 * to the hardware right away, just buffer them in.
 *
 * @param ep index of the Endpoint
 * @param dir direction of the Endpint
 * @param cfg pointer to Endpoint configuration
 */
void usbdrv_preload_endpoint_config(uint8_t ep, uint8_t dir, const USBDRV_EpConfig *cfg);

/**
 * Clear ALL Endpoints' preload configurations.
 * Does NOT clear configuration in the hardware!
 */
void usbdrv_clear_endpoint_config();

/**
 * Apply preloaded Endpoint configuration, write
 * Endpoint config to the hardware.
 */
void usbdrv_apply_endpoint_config();

/**
 * Select a specific configuration from the descriptor
 * dump, preload Endpoint settings and finally apply them.
 *
 * @param config_index configuration index
 */
void usbdrv_fetch_endpoint_configuration(uint8_t config_index);

/**
 * Construct FIFO considering configured Endpoints.
 */
void usbdrv_allocate_buffers();

/**
 * Apply an initial EP0 setup.
 */
void usbdrv_initial_ep0_setup();

/**
 * Set USB device address.
 *
 * @param addr device address
 */
void usbdrv_set_address(uint8_t addr);

/**
 * Get driver interface.
 *
 * @return pointer to the driver interface
 */
UsbDrv_DrvIntf *usbdrv_get_intf();

/**
 * Register callback for IN transaction complete.
 *
 * @param ep index of the Endpoint
 * @param cb pointer to the callback function
 */
void usbdrv_register_IN_complete_cb(uint8_t ep, UsbDrv_IN_cb cb);

/**
 * Get Endpoint interrupt flag.
 *
 * @param ep index of the Endpoint
 * @param dir direction of the Endpoint
 * @return flag was set
 */
bool usbdrv_get_endpoint_interrupt_flag(uint8_t ep, uint8_t dir);

#endif /* CH32_USB_DRV */