#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <sys/ioctl.h>
#include <linux/fs.h>

#define BLKSZ (100 * 1024 * 1024) // 100MB buffer
#define PATTERN_SIZE 7 // 7-byte repeating pattern
#define BAR_WIDTH 50   // Progress bar width

// Function to get total size of block device
size_t get_device_size(int fd) {
    size_t size = 0;
    if (ioctl(fd, BLKGETSIZE64, &size) < 0) {
        perror("Failed to get device size");
        exit(EXIT_FAILURE);
    }
    return size;
}

// Function to print progress bar
void print_progress(size_t total_written, size_t total_size) {
    float percent = (float)total_written / total_size;
    if (percent > 1.0) percent = 1.0;

    int filled = (int)(percent * BAR_WIDTH);
    printf("\r[");
    for (int i = 0; i < BAR_WIDTH; i++) {
        printf(i < filled ? "#" : " ");
    }
    printf("] %lu MB / %lu MB", total_written / (1024 * 1024), total_size / (1024 * 1024));
    fflush(stdout);
}

void fill_device(const char *device) {
    int fd = open(device, O_WRONLY);
    if (fd < 0) {
        perror("Failed to open device");
        exit(EXIT_FAILURE);
    }

    // Get total device size
    size_t total_size = get_device_size(fd);

    // Allocate 100MB buffer
    unsigned char *buffer = (unsigned char *)malloc(BLKSZ);
    if (!buffer) {
        perror("Failed to allocate buffer");
        close(fd);
        exit(EXIT_FAILURE);
    }

    // Define the 7-byte repeating pattern
    unsigned char pattern[PATTERN_SIZE] = {0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07};

    // Fill the buffer with the repeating pattern
    for (size_t i = 0; i < BLKSZ; i++) {
        buffer[i] = pattern[i % PATTERN_SIZE];
    }

    printf("Writing to %s with a 7-byte repeating pattern in 100MB chunks...\n", device);
    printf("Total device size: %lu MB\n", total_size / (1024 * 1024));

    size_t total_written = 0;
    while (total_written < total_size) {
        ssize_t written = write(fd, buffer, BLKSZ);
        if (written < 0) {
            perror("\nWrite failed");
            break;
        }
        total_written += written;
        print_progress(total_written, total_size);
    }

    printf("\nCompleted. Total written: %lu MB\n", total_written / (1024 * 1024));

    free(buffer);
    close(fd);
}

int main(int argc, char *argv[]) {
    if (argc != 2) {
        fprintf(stderr, "Usage: %s <device>\n", argv[0]);
        return EXIT_FAILURE;
    }

    fill_device(argv[1]);
    return EXIT_SUCCESS;
}