// UNIX cp copy
// Wrote for Computer Networks and Systems lab classes
// AUTHOR : Sergiusz Warga

#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>

#define BUFFER_SIZE 8 // TODO: Think about it.

enum ERROR{NO_ARGUMENTS, WRONG_ARGUMENT, DUNNO};

int print_error_message(enum ERROR error_type) {
    if (error_type == NO_ARGUMENTS) {
        fprintf(stderr,"cp: missing file operand\n"); // TODO: Maybe replace "cp" with argv[0]?
        fprintf(stderr,"Try cp --help for more information.\n");
        return 0;
    } else if (error_type == WRONG_ARGUMENT) {
        fprintf(stderr, "cp: unrecognized option\n");
        fprintf(stderr,"Try cp --help for more information.\n");
    } else if (error_type == DUNNO) {
        fprintf(stderr, "Something went wrong!\n");
    }
    return 0;
}

int print_help() {
    printf("HELP\n");
    return 0;
}

int is_dir(const char *name) {
    struct stat path;
    stat(name, &path);
    return S_ISDIR(path.st_mode);
}

int cp(char *old_name, char *new_name) {
// int cp(char *old_argv, char *new_argv) {
    // char *old_name, *new_name;
    // strncpy(old_name, old_argv, sizeof(old_argv));
    // strncpy(new_name, new_argv, sizeof(new_argv));
    int old, new;
    if (is_dir(new_name)) {
        printf("%s\n", new_name);
        strncat(new_name, "/", 1);
        printf("%s\n", new_name);
        strncat(new_name, old_name, sizeof(old_name));
        printf("%s\n", new_name);
    }
    printf("Moving %s to %s\n", old_name, new_name);
    old = open(old_name, O_RDONLY);
    new = open(new_name, O_CREAT | O_WRONLY);
    char buffer[BUFFER_SIZE];
    int read_bytes;

    while ((read_bytes = read(old, buffer, sizeof(buffer))) > 0) {
        write(new, buffer, read_bytes);
    }

    printf("%s moved to %s\n", old_name, new_name);

    close(old);
    close(new);

    return 0;
}

int copy_mod_bits(char *old_name, char *new_name) {
    struct stat mod_bits;

    stat(old_name, &mod_bits);
    chmod(new_name, mod_bits.st_mode);

    return 0;
}

int main(int argc, char *argv[]) {
    if (argc == 1) {
        print_error_message(NO_ARGUMENTS);
        return 1;
    }
    if (argc == 2) {
        if (strcmp(argv[1], "--help") == 0) {
            print_help();
            return 0;
        } else {
            print_error_message(WRONG_ARGUMENT);
            return 2;
        }
    }
    if (argc == 3) {
        if (cp(argv[1], argv[2]) > 0) return 1;
        copy_mod_bits(argv[1], argv[2]);
    }
    if (argc > 3) {
        int no_of_old_files = argc - 2;
        for (int i = 1; i <= no_of_old_files; ++i) {
            printf("TOOO %s\n", argv[argc-1]);
            if (cp(argv[i], argv[argc-1]) > 0) return 1;
            copy_mod_bits(argv[i], argv[argc-1]);
        }
    }

    return 0;
}