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

int count(char *filepath, char option)
{
    int fd;

    if ((fd = open(filepath, O_RDONLY)) == -1)
    {
        fprintf(stderr, "Error while opening '%s' file.\n", filepath);
        exit(EXIT_FAILURE + 1);
    }

    char block[30];
    int i, r, count = 0;

    while ((r = read(fd, block, sizeof(block))))
    {
        switch (option)
        {
            case 'c':
            {
                for (i = 0; i < r; i++)
                    if ((block[i] >= 'a' && block[i] <= 'z') || (block[i] >= 'A' && block[i] <= 'Z'))
                        count ++;

                break;
            }
            case 'l':
            {
                for (i = 0; i < r; i++)
                    if (block[i] == '\n')
                        count ++;

                break;
            }
            default:
            {
                fprintf(stderr, "Invalid option.\n");
                exit(EXIT_FAILURE + 2);
            }
        }
    }

    if (close(fd) == -1)
    {
        fprintf(stderr, "Error while closing '%s' file.\n", filepath);
        exit(EXIT_FAILURE + 3);
    }

    return count;
}

void traverse(char *dirpath, char option, int fd)
{
    DIR *dir;

    if ((dir = opendir(dirpath)) == NULL)
    {
        fprintf(stderr, "Error while opening the '%s' directory.\n", dirpath);
        exit(EXIT_FAILURE + 4);
    }

    struct dirent *d;
    struct stat st;

    char path[256];

    while ((d = readdir(dir)) != NULL)
    {
        if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, ".."))
            continue;

        sprintf(path, "%s/%s", dirpath, d->d_name);

        if (lstat(path, &st) < 0)
        {
            fprintf(stderr, "Error while getting file '%s' stats.\n", path);
            exit(EXIT_FAILURE + 7);
        }

        if (S_ISREG(st.st_mode))
        {
            char buff[280];

            sprintf(buff, "F <%s> <%d>\n", path, count(path, option));
            fprintf(stdout, "%s", buff);

            write(fd, buff, strlen(buff));
        }

        if (S_ISLNK(st.st_mode))
        {
            char buff[512], link_path[256], new_path[256];

            if (readlink(path, link_path, sizeof(link_path)) == -1)
            {
                fprintf(stderr, "Error while getting links' path.\n");
                exit(EXIT_FAILURE + 8);
            }

            sprintf(new_path, "%s/%s", dirpath, link_path);
            sprintf(buff, "L <%s> <%d>\n", path, count(new_path, option));

            fprintf(stdout, "%s", buff);

            write(fd, buff, strlen(buff));
        }

        if (S_ISDIR(st.st_mode))
            traverse(path, option, fd);
    }

    if (closedir(dir) == -1)
    {
        fprintf(stderr, "Error while closing the '%s' directory.\n", dirpath);
        exit(EXIT_FAILURE + 9);
    }
}


int main(int argc, char **argv)
{
    if (argc != 3)
    {
        fprintf(stderr, "Sintaxa: %s <cale_dir> <optiune>\n", argv[0]);
        exit(EXIT_FAILURE);
    }

    if (open("log.txt", O_RDONLY) != -1)
    {
        fprintf(stderr, "File 'log.txt' does already exist.\n");
        exit(EXIT_FAILURE + 5);
    }

    int fd;

    if ((fd = open("log.txt", O_WRONLY | O_CREAT, 0666)) == -1)
    {
        fprintf(stderr, "Error while creating 'log.txt' file.\n");
        exit(EXIT_FAILURE + 6);
    }

    traverse(argv[1], argv[2][1], fd);

    if (close(fd) == -1)
    {
        fprintf(stderr, "Error while closing the 'log.txt' file.\n");
        exit(EXIT_FAILURE + 3);
    }

    return 0;
}