#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <pthread.h>
#include <netdb.h>
#include <unistd.h>
#include <ctype.h>
#include <string.h>

#include <httputils.h>

#ifdef DMALLOC
#include <dmalloc.h>
#endif

int http_getpage(const char *url, char *databuf, int max_len) {
	
	/* Split domain name */
	
	if (memcmp(url, "http://", 7) != 0) {
		fprintf(stderr, "Invalid url %s\n", url);
		return HTTP_INVALIDURL;
	}
	
	int domainlen;
	domainlen = strstr(url + 7, "/") - (url + 7);
	
	if (domainlen < 0)
		domainlen = strlen(url + 7);
	
	struct hostent *host;
	char *domain = malloc(domainlen + 1);
	
	memcpy(domain, url + 7, domainlen);
	domain[domainlen] = '\0';
	
	/* Check if port included */
	
	int port = 80;
	char *portpos = strstr(domain, ":");
	if (portpos != NULL) {
		port = atoi(portpos + 1);
		*portpos = '\0';
	}
	
	/* Get host address */
	
	host = gethostbyname(domain);
	
	if (host == NULL) {
		fprintf(stderr, "Domain not found %s\n", domain);
		free(domain);
		return HTTP_DOMAINNOTFOUND;
	}
	
	free(domain);
	
	/* Connect to server */
	
	struct sockaddr_in serv_addr;
	int s = socket(AF_INET, SOCK_STREAM, 0);
	FILE *sfile = fdopen(s, "w+");
	
	memset(&serv_addr, 0, sizeof(serv_addr));
	
	serv_addr.sin_family = AF_INET;
	memcpy(&serv_addr.sin_addr.s_addr, host->h_addr, sizeof(serv_addr.sin_addr.s_addr));
	serv_addr.sin_port = htons(port);
	
	if (connect(s, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0) {
		fprintf(stderr, "Connect to %s failed", domain);
		perror("");
		return HTTP_CONNECTFAILED;
	}

	/* Send request */
	
	fprintf(sfile, "GET %s HTTP/1.0\r\n\r\n", url);
	
	/* Get response */
	
	
	char linebuf[256];
	
	if (fgets(linebuf, 256, sfile) == NULL) {
		fprintf(stderr, "Read failed\n");
		return HTTP_CONNECTFAILED;
	}
	
	/* Get response code */
	
	char *codestart = strstr(linebuf, " ");
	
	if (memcmp(linebuf, "HTTP", 4) != 0 || codestart == NULL) {
		fprintf(stderr, "Protocol error, data %s\n", linebuf);
		return HTTP_CONNECTFAILED;
	}
	
	int rcode = atoi(codestart);
	
	if (rcode != 200) {
		fprintf(stderr, "Response code %d\n", rcode);
		return HTTP_STATUSFAIL;
	}
	
	/* Wait for blank line */
	
	int empty = 0;
	
	while (fgets(linebuf, 256, sfile)) {
		int i;
		empty = 1;
		
		for (i = 0; i < strlen(linebuf); i++) {
			if (!isspace(linebuf[i])) {
				empty = 0;
				break;
			}
		}
		
		if (empty)
			break;
	}
	
	if (!empty) {
		fprintf(stderr, "No blank line found\n");
		return HTTP_CONNECTFAILED;
	}
	
	int count = fread(databuf, 1, max_len, sfile);
	fclose(sfile);
	return count;
}

/* Asynchronous downloading */

struct dlthread {
	struct dlthread *next;
	
	char *url;
	char *databuf;
	int max_len;
	int complete;
	int returnval;
	int timestamp;
	
	pthread_t thread;
};

static struct dlthread *dlstack = NULL;

struct dlthread *dlstack_add(const char *url, int max_len) {
	struct dlthread *newitem = malloc(sizeof(struct dlthread));
	
	newitem->next = dlstack;
	dlstack = newitem;
	
	newitem->url = malloc(strlen(url) + 1);
	strcpy(newitem->url, url);
	
	newitem->databuf = malloc(max_len);
	newitem->max_len = max_len;
	
	newitem->complete = 0;
	newitem->returnval = 0;
	newitem->timestamp = time(NULL);
	
	return newitem;
}

void dlstack_remove(struct dlthread *item) {
	free(item->url);
	free(item->databuf);
	
	struct dlthread *parent = dlstack;
	
	if (dlstack == item) {
		dlstack = item->next;
	} else {
		while (parent->next != item)
			parent = parent->next;
		parent->next = item->next;
	}
	
	free(item);
}

struct dlthread *dlstack_find(const char *url) {
	struct dlthread *p = dlstack;
	
	while (p != NULL && strcmp(p->url, url) != 0)
		p = p->next;
	
	return p;
}

void *dlthread_getpage(void *arg) {
	struct dlthread *item = (struct dlthread *) arg;
	item->returnval = http_getpage(item->url, item->databuf, item->max_len);
	
	if (item->returnval < 0)
		item->databuf[0] = '\0';
	
	item->complete = 1;
	
	pthread_exit(NULL);
}

int http_getpage_async(const char *url, char *databuf, int max_len, int *timestamp) {
	static int bytes_in_hour = 0, last_hour = 0;
	const int max_bytes_in_hour = 400000;
	
	struct dlthread *p;
	const int timeout = 20;
	
	int len;
	
	if (last_hour + 3600 < time(NULL)) {
		last_hour = time(NULL);
		bytes_in_hour = 0;
	}
	
	p = dlstack_find(url);
	
	if (p && !p->complete && p->timestamp + timeout < time(NULL)) {
		// Timeouted request
		fprintf(stderr, "Timeouted async http request at 0x%x\n", (unsigned int) p);
		p = NULL;
	}
	
	if (p) {
		if (!p->complete)
			return HTTP_ASYNCWAIT;
		
		if (p->max_len < max_len)
			max_len = p->max_len;
		
		len = strlen(p->databuf);
		bytes_in_hour += len;
		
		strncpy(databuf, p->databuf, max_len);
		*timestamp = p->timestamp;
		
		int r = p->returnval;
		dlstack_remove(p);
		return r;
	}
	
	/* Not found, add */
	
	if (bytes_in_hour > max_bytes_in_hour) {
		fprintf(stderr, "Transfer limit exceeded, %d bytes (%d bytes max)\n",
			bytes_in_hour, max_bytes_in_hour);
		return HTTP_RATELIMIT;
	}
	
	struct dlthread *item;
	
	item = dlstack_add(url, max_len);
	
	if (pthread_create(&item->thread, NULL, &dlthread_getpage, item) != 0)
		fprintf(stderr, "Error in pthread_create\n");

	return HTTP_ASYNCWAIT;
}