// crawl.c ... build a graph of a part of the web
// Uses the cURL library and functions by Vincent Sanders
// <vince@kyllikki.org>

#include <ctype.h>
#include <curl/curl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#include "Graph.h"
#include "html.h"
#include "Set.h"
#include "Stack.h"
#include "Queue.h"
#include "url_file.h"

#define BUFSIZE 1024

static void setFirstURL(char *, char *);

int main(int argc, char *argv[]) {
	URL_FILE *handle;
	char buffer[BUFSIZE];
	char baseURL[BUFSIZE];
	char firstURL[BUFSIZE];
	char next[BUFSIZE];
	int maxURLs;

	if (argc > 2) {
		strcpy(baseURL, argv[1]);
		setFirstURL(baseURL, firstURL);
		maxURLs = atoi(argv[2]);
		if (maxURLs < 40) {
			maxURLs = 40;
		}
	} else {
		fprintf(stderr, "Usage: %s BaseURL MaxURLs\n", argv[0]);
		exit(EXIT_FAILURE);
	}

	// You need to modify the code below to implement:
	//
	// add firstURL to the ToDo list
	// initialise a Graph to hold up to maxURLs
	// initialise a set of Seen URLs
	// while (ToDo list not empty and Graph not filled) {
	//     grab Next URL from ToDo list
	//     if (not allowed) continue
	//     foreach line in the opened URL {
	//         foreach URL on that line {
	//             if (Graph not filled or both URLs in Graph)
	//                 add an edge from Next to this URL
	//             if (this URL not Seen already) {
	//                 add it to the Seen set
	//                 add it to the ToDo list
	//             }
	//         }
	//     }
	//     close the opened URL
	//     sleep(1)
	// }
	
	if (!(handle = url_fopen(firstURL, "r"))) {
		fprintf(stderr, "Couldn't open %s\n", next);
		exit(EXIT_FAILURE);
	}
	
	while (!url_feof(handle)) {
		url_fgets(buffer, sizeof(buffer), handle);
		// fputs(buffer, stdout);
		int pos = 0;
		char result[BUFSIZE];
		memset(result, 0, BUFSIZE);
		while ((pos = GetNextURL(buffer, firstURL, result, pos)) > 0) {
			printf("Found: '%s'\n", result);
			memset(result, 0, BUFSIZE);
		}
	}
	
	url_fclose(handle);
	sleep(1);
}

// - sets a "normalised" version of Base as First
// - modifies Base to a "normalised" version of itself
static void setFirstURL(char *base, char *first) {
	char *c;
	if ((c = strstr(base, "/index.html")) != NULL) {
		strcpy(first, base);
		*c = '\0';
	} else if (base[strlen(base) - 1] == '/') {
		strcpy(first, base);
		strcat(first, "index.html");
		base[strlen(base) - 1] = '\0';
	} else {
		strcpy(first, base);
		strcat(first, "/index.html");
	}
}