#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>

#include <pcilib.h>
#include <pcilib/bar.h>

#include <libsocket/libinetsocket.h>

#define REG_FREQ_7BIT 0x91A0
#define REG_BUSY_1BIT 0x91A4

#pragma inline
void write_reg_32(volatile void *bar, int addr, uint32_t value) {
    *((volatile uint32_t *) (((char*)bar) + addr)) = value;
}


#pragma inline
uint32_t read_reg_32(volatile void *bar, int addr) {
    return *((volatile uint32_t *) (((char*)bar) + addr));
}


int main(int argc, char *argv[]) {
    pcilib_t *pci;

    pci = pcilib_open("/dev/fpga0", PCILIB_MODEL_DETECT);
    if (!pci) {
        printf("pcilib_open failed\n");
        exit(-1);
    }

    volatile void *bar = pcilib_resolve_bar_address(pci, PCILIB_BAR0, 0);
    if (!bar) {
        printf("Failed to map PCI BAR for access\n");
        pcilib_close(pci);
        exit(-1);
    }


    int socket;
    int ret;

    socket = create_inet_server_socket("0.0.0.0", "56000", LIBSOCKET_TCP, LIBSOCKET_IPv4, 0);

    if (socket < 0) {
        printf("Failed to create server listening socket\n");
        exit(-1);
    }
    printf("Ethernet socket created on port 56000.\n");
    

    while (1) {
        int peer_socket;
        char *peer_addr = calloc(16,1);
        
        printf("Waiting for incoming connection...\n");
        peer_socket = accept_inet_stream_socket(socket, peer_addr, 16, 0, 0, 0, 0);

        if (peer_socket < 0) {
            printf("Failed to accpet client connection\n");
            destroy_inet_socket(socket);
            exit(-1);
        }

        printf("Got connection from: %s\n", peer_addr);


        unsigned char *buf = calloc(1, 1);

        uint32_t val = 0;

        //We use 7-bit encoding. So any value larger than 127 is "invalid"
        //and can be used it for signalling.
        //We use 0xFF as the disconnect signal
        while (val != 0xFF) {

            //read() returns 0 in case of error
            ret = read (peer_socket, buf, 1);
            val = (*buf)&0xFF;

            if ((val == 0xFF) || (ret == 0)) {
                break;
            }

            printf("Received: %u\n", val);

            uint32_t busy = read_reg_32(bar, REG_BUSY_1BIT); 
            
            if ((busy&0x1) == 0) {

                //Value needs to be stored in bits 1 - 7, because bit 0 is
                //used as a busy-bit
                uint32_t write_val = val << 1;
                write_val = write_val & 0xFF;

                write_reg_32(bar, REG_FREQ_7BIT, val);
            }

        }

        printf("Client disconnected.\n");
        destroy_inet_socket(peer_socket);
        free(buf);
        free(peer_addr);
    }

    destroy_inet_socket(socket);

    printf("All went well\n");
    pcilib_close(pci);
    return 0;
}