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

int fd, fd2, digits = 0, low = 0, up = 0, n, occurences=0;

int process_file(char *path, char *ch, char *output){
    //int fd, fd2;
    char buf[256];
    char character = *ch;
    if((fd = open(path, O_RDONLY)) < 0) {
        printf("Error opening input file\n");
        exit(3);
    }
    if((fd2 = open(output, O_WRONLY | O_EXCL, S_IRWXU)) < 0) {
        printf("Error at opening output file.");
        exit(4);
    }
    while((n = read(fd, buf, 256)) > 0) {
        for(int i=0; i<n; i++) {
            if(isdigit(buf[i])) digits++;
            else {
                if(buf[i]>='a' && buf[i]<='z') low++;
                else if(buf[i]>='A' && buf[i]<='Z') up++;
            }
            if(buf[i]==character) occurences++;
        }
    }
    if(n<0) {
        printf("Error reading input file\n");
        exit(4);
    }

    /*Write file*/
    char str[256];
    sprintf(str, "Number of digits: %d\nNumber of lowercase: %d\nNumber of uppercase: %d\nNumber occurences: %d\n", digits, low, up, occurences);
    write(fd2,str, strlen(str));
    close(fd);
    close(fd2);


}

int parse(char *ch, char *dirName, char *fileName) {
    DIR *dir;

    if ((dir = opendir(dirName)) == NULL) {
        printf("Error at opendir().");
        exit(1);
    }

    struct dirent *d;
    struct stat st;
    char path[50];

    while ((d = readdir(dir))) {
        if ((strcmp(d->d_name, ".") == 0) || (strcmp(d->d_name, "..") == 0))
            continue;
        snprintf(path, 50, "%s/%s", dirName, d->d_name);
        printf("%s\n", path);
        if (lstat(path, &st) == -1) {
            printf("Error at lstat().");
            exit(2);
        }
        if (S_ISDIR(st.st_mode)) {
            parse(ch, path, fileName);
        }
        if (S_ISREG(st.st_mode)) {
            process_file(path, ch, fileName);
        }
    }
    closedir(dir);
    return 0;
}

int main (int argc, char *argv[]) {
    if (argc != 4) {
        printf("Usage: Program <%s> char directory file", argv[0]);
        exit(0);
    }
    parse(argv[1], argv[2], argv[3]);
    return 0;
}