#include <string.h>
#include <stdlib.h>
#include <stdio.h>

#define DEFAULT_PATH "/"

char* url_to_proto(char* url) {
        size_t length = strlen(url);
	int sentinel = 0;
	char* to_return = malloc(sizeof(char) * 10);
	for (int i=0;i<length;i++) {
		if (*(url + (sizeof(char) * i)) == ':') { /* If the character is ':' ...*/
			sentinel = i; /* ...Then we stop scanning the string */
		}
	}
	strncpy(to_return,url,sentinel);
	return to_return;
}

char* url_to_hostname(char* url) {
	/* This function relies on a hack-y assumption: that, given a string
	that represents a URL (e.g. https://www.example.com/index.html), the length of the host portion 
	of the address is the distance between the second slash (:/'/') and the third ('/'index.html),
	or the second slash and the end of the string, if the path isn't present. */

	size_t length = strlen(url);
	char* protocol = url_to_proto(url);

        char* temp_substring = malloc(sizeof(char) * 256);
	char* to_return = malloc(sizeof(char) * 256);

	/* This is a very roundabout way of saying that, starting from a certain point in the
	URL (length of protocol string + 3 (':','/','/'), we are copying the rest of the string into another
	substring. */

	strncpy(temp_substring,url+(strlen(protocol) + 3),(length - (strlen(protocol) + 3)));

	/* Now we need to substring _this_ substring, by returning only the part before the next slash. */
	int sentinel = 0;
	for (int i=0;i<strlen(temp_substring);i++) {
		if (*(temp_substring+(sizeof(char) * i)) == '/') {
			sentinel = i;
		}
	}


	if (sentinel == 0) { /* If there are no more slashes */
		return temp_substring;
	}
	strncpy(to_return,temp_substring,sentinel);
	free(temp_substring);
	return to_return;
}

char* url_to_path(char* url) {
	/* Assumption: The path starts from the third slash to the end of the string. */
	int str_len = strlen(url);
	int sentinel = 0;
	int num_slashes = 0;
	char* to_return = malloc(sizeof(char) * 512);
	for (int i=0;i<strlen(url);i++) {
		if (*(url + (sizeof(char) * i)) == '/') {
			num_slashes++;
			sentinel = i;
		}
		if (num_slashes == 3) {
			break;
		}
	}

	if (num_slashes < 3 || sentinel == str_len) { 	/* If we don't find the requisite number of slashes after 
							parsing the string OR the third slash is at the end of the string
							("e.g. www.example.com/")... */

		strcpy(to_return,DEFAULT_PATH); /* ...Then return the default path - "/" */
		return to_return;
	}

	/* Copy all bytes of the string, starting from the third slash */
	strncpy(to_return, url+(sizeof(char) * sentinel), strlen(url)-(sizeof(char) * sentinel));
	return to_return;

}