#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <unistd.h>
#include <locale.h>
#include <libserialport.h>

#include <sys/time.h>

#ifdef __GNUC__
#define A_UNUSED __attribute__((unused))
#else
#define A_UNUSED
#endif

struct sp_port *serial_guess_port(void)
{
    struct sp_port **ports;

    if (sp_list_ports(&ports) != SP_OK || ports[0] == NULL) {
        puts("No serial devices detected");
        return NULL;
    }

    if (ports[1] != NULL) {
        puts("Please select a port");
        return NULL;
    }

    return ports[0];
}

char *program_name;

void serial_error(char *message)
{
    char *error = sp_last_error_message();
    fprintf(stderr, "%s: %s: %s\n", program_name, message, error);
    sp_free_error_message(error);
}

int main(int argc, char *argv[])
{
    program_name = argv[0];
    setlocale(LC_ALL, "");

    long save = 0;
    if (argc > 1) {
        save = strtol(argv[1], NULL, 0);
    }

    struct sp_port *port;

    if (!(port = serial_guess_port())) return 1;
    puts(sp_get_port_name(port));

    if (sp_open(port, SP_MODE_READ_WRITE) != SP_OK ||
            sp_set_baudrate(port, 2000000) != SP_OK ||
            sp_set_flowcontrol(port, SP_FLOWCONTROL_NONE) != SP_OK) {
        serial_error("Failed to open port");
        return 1;
    }

    usleep(100000LL);
    sp_flush(port, SP_BUF_BOTH);

    fputs("Waiting for device... ", stdout);
    fflush(stdout);
    for (;;) {
        char c = 0;
        sp_blocking_write(port, &c, 1, 0);
        if (sp_blocking_read(port, &c, 1, 1000) == 1) {
            if (c == 0) {
                puts("ROM OK!");
            } else {
                puts("ROM ERROR");
            }
            break;
        }
    }

    char command = 1;
    uint32_t address = 0x147;
    uint32_t size = 3;
    sp_blocking_write(port, &command, 1, 0);
    sp_blocking_write(port, &address, 4, 0);
    sp_blocking_write(port, &size, 4, 0);

    sp_blocking_read(port, &command, 1, 0);
    if (command != 0) {
        puts("An error has occurred");
        return 1;
    }

    char cart_type = 0;
    sp_blocking_read(port, &cart_type, 1, 0);
    printf("Cart type: %02X\n", cart_type);

    char rom_size = 0;
    sp_blocking_read(port, &rom_size, 1, 0);
    printf("Rom size: %02X\n", rom_size);

    char ram_size = 0;
    sp_blocking_read(port, &ram_size, 1, 0);
    printf("Ram size: %02X\n", ram_size);

    command = save ? 3 : 2;
    address = 0;
    if (!save) {
        size = 0x8000 << rom_size;
    } else {
        size = save;
    }
    sp_blocking_write(port, &command, 1, 0);
    sp_blocking_write(port, &address, 4, 0);
    sp_blocking_write(port, &size, 4, 0);
    sp_blocking_read(port, &command, 1, 0);
    if (command != 0) {
        puts("An error has occurred");
        return 1;
    }

    struct timeval begin, end;
    gettimeofday(&begin, NULL);

    FILE *file = fopen("out.bin", "w");
    for (unsigned x = 0; x < size; x += 0x200) {
        char c[0x200];
        sp_blocking_read(port, &c, 0x200, 0);
        if (!save) {
            printf("\r%02X:%04X", x / 0x4000, x % 0x4000);
        } else {
            printf("\r%02X:%04X", x / 0x2000, x % 0x2000);
        }
        fflush(stdout);
        fwrite(&c, 0x200, 1, file);
    }
    putchar('\n');
    fclose(file);

    gettimeofday(&end, NULL);
    double dt = (double)end.tv_sec - begin.tv_sec + ((double)end.tv_usec - begin.tv_usec) / 1000000;
    printf("Average speed: %f KB/s\n", size / 1000 / dt);
}