#include <lib/string.h>

#include <stddef.h>

static int is_delim(char c, const char* delim) {
    while (*delim) {
        if (c == *delim) {
            return 1;
        }
        delim++;
    }
    return 0;
}

char* strtok_r(char* str, const char* delim, char** saveptr) {
    if (saveptr == NULL) {
        return NULL;
    }

    char* next_token = (str != NULL) ? str : *saveptr;

    if (next_token == NULL || *next_token == '\0') {
        *saveptr = NULL;
        return NULL;
    }

    while (*next_token && is_delim(*next_token, delim)) {
        next_token++;
    }

    if (*next_token == '\0') {
        *saveptr = next_token;
        return NULL;
    }

    char* token_start = next_token;

    while (*next_token) {
        if (is_delim(*next_token, delim)) {
            *next_token = '\0';        // Destructively null-terminate the token
            *saveptr = next_token + 1; // Save the position right after the null-terminator
            return token_start;
        }
        next_token++;
    }

    *saveptr = next_token;
    return token_start;
}