#include "cdc.h"

#include <memory.h>

#include "../usb_device_types.h"

#include "../usb.h"

#include <blocking_io/blocking_fifo.h>

#include <cmsis_gcc.h>

// state
static USB_CdcState cdcs = { 0 };
static uint8_t tx_buffer[USB_CDC_PCKT_BUFSIZE];

#define USB_CDC_FIFO_MEM_SIZE (3072) // FIXME: ez vagy a blocking FIFO bugos

static uint8_t fifo_mem[USB_CDC_FIFO_MEM_SIZE];
static BFifo fifo;

void usb_cdc_read_callback(const uint8_t * data, uint32_t size);

void usb_cdc_init(const USB_CdcAssignments *as) {
    // clear the structure
    memset(&cdcs, 0, sizeof(USB_CdcState));

    // fill-in default values
    USB_Cdc_LineCodingStruct *lc = &cdcs.line_coding;
    lc->dwDTERate = USB_CDC_DEFAULT_BITRATE;
    lc->bCharFormat = USB_CDC_DEFAULT_CHAR_FORMAT;
    lc->bParityType = USB_CDC_DEFAULT_PARITY_TYPE;
    lc->bDataBits = USB_CDC_DEFAULT_DATA_BITS;

    // fill-in assigments
    cdcs.ep_assignments = *as;

    // initialize buffer
    bfifo_create(&fifo, fifo_mem, USB_CDC_FIFO_MEM_SIZE);

    // from now on CDC is considered initialized
    cdcs.initialized = true;
}

//static uint8_t replyBuf[sizeof(USB_Cdc_LineCodingStruct)];

int usb_cdc_process_and_return(USB_CallbackEvent *cbevt) {
    int ret = -1;
    switch (cbevt->type) {
        case USB_CBEVT_UNKNOWN_REQ: {
            switch (cbevt->setup_request->bRequest) {
                case USB_CDC_SET_LINE_CODING: // set line coding
                    memcpy(&cdcs.line_coding, cbevt->data, sizeof(USB_Cdc_LineCodingStruct));
                    //MSG("%u\n", cdcs.line_coding.dwDTERate);
                    ret = 0;
                    break;
                case USB_CDC_GET_LINE_CODING: // get line coding
                    cbevt->reply_data = (const uint8_t *) &cdcs.line_coding; // expert move: pass the pointer, no copying
                    cbevt->reply_size = sizeof(USB_Cdc_LineCodingStruct);
                    cbevt->reply_valid = true; // the reply has been set to something valid
                    ret = 0;
                    break;
                case USB_CDC_SEND_BREAK: // send break
                    // do nothing
                    ret = 0;
                    break;
                case USB_CDC_SET_CONTROL_LINE_STATE: // set control line state
                    memcpy(&cdcs.control_line_state, cbevt->data, sizeof(USB_Cdc_ControlLineStateStruct));
                    //MSG("%u\n", cdcs.control_line_state.D);
                    ret = 0;
                    break;
                default:
                    break;
            }

            // send a ZLP reply
            if (ret != -1) {
                cbevt->reply_data = NULL;
                cbevt->reply_size = 0;
                cbevt->reply_valid = true;
            }

            break;
        }

        case USB_CBEVT_OUT: {
            if (cbevt->ep == cdcs.ep_assignments.data_ep) {
                //MSG("%c\n", cbevt->data[0]);
                ret = 0;

                usb_cdc_read_callback(cbevt->data, cbevt->size);
                //usbcore_write(cdcs.ep_assignments.data_ep, cbevt->data, cbevt->size); // echo
            }
            break;
        }

        case USB_CBEVT_IN: {
            if (cbevt->ep == cdcs.ep_assignments.control_ep) { // if notification feeding is requested
                usbcore_write(cdcs.ep_assignments.control_ep, NULL, 0); // send ZLP
                ret = 0;
            } else if (cbevt->ep == cdcs.ep_assignments.data_ep) { // if data are requested
                //usbcore_write(cdcs.ep_assignments.data_ep, NULL, 0); // send ZLP
                ret = 0;
                
                // read from the fifo
                uint32_t readSize = bfifo_read(&fifo, tx_buffer, USB_CDC_PCKT_BUFSIZE);
                if (readSize > 0) {
                    uint32_t writeSize = usbcore_write(cdcs.ep_assignments.data_ep, tx_buffer, readSize); // write data acquired from the buffer
                    bfifo_pop(&fifo, writeSize, 0); // pop with no blocking
                }
            }
        }

        default:
            break;
    }

    return ret;
}

// void usb_event_callback(USB_CallbackEvent *cbevt) {
//    usb_cdc_process_and_return(cbevt);
// }

void usb_cdc_write(const uint8_t * data, uint32_t size) {
    if (cdcs.initialized) {
        bfifo_push_all(&fifo, data, size);
    }
}

__attribute__((weak)) void usb_cdc_read_callback(const uint8_t * data, uint32_t size) {
    (void) data;
    (void) size;
    return;
}