/*
 * Generic HTTP routines
 *
 * Copyright (C) 2015, Broadcom Corporation. All Rights Reserved.
 * 
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 * $Id: http.c 435851 2013-11-12 10:17:29Z $
 */

#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <ctype.h>
#include <string.h>
#include <signal.h>
#include <time.h>
#include <unistd.h>
#include <errno.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include <shutils.h>

static char *
base64enc(const char *p, char *buf, int len)
{
	char al[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
		"0123456789+/";
	char *s = buf;

	while (*p) {
		if (s >= buf+len-4)
			break;
		*(s++) = al[(*p >> 2) & 0x3F];
		*(s++) = al[((*p << 4) & 0x30) | ((*(p+1) >> 4) & 0x0F)];
		*s = *(s+1) = '=';
		*(s+2) = 0;
		if (! *(++p)) break;
		*(s++) = al[((*p << 2) & 0x3C) | ((*(p+1) >> 6) & 0x03)];
		if (! *(++p)) break;
		*(s++) = al[*(p++) & 0x3F];
	}

	return buf;
}

enum {
	METHOD_GET,
	METHOD_POST
};

static int
wget(int method, const char *server, char *buf, size_t count, off_t offset)
{
	char url[PATH_MAX] = { 0 }, *s;
	char *host = url, *path = "", auth[128] = { 0 }, line[512];
	unsigned short port = 80;
	int fd;
	FILE *fp;
	struct sockaddr_in sin;
	int chunked = 0, len = 0;

	if (server == NULL || !strcmp(server, "")) {
		dprintf("wget: null server input\n");
		return (0);
	}

	if (strlen(server) >= sizeof(url)) {
		dprintf("wget: server url is too long\n");
		return 0;
	}
	strcpy(url, server);

	/* Parse URL */
	if (!strncmp(url, "http://", 7)) {
		port = 80;
		host = url + 7;
	}
	if ((s = strchr(host, '/'))) {
		*s++ = '\0';
		path = s;
	}
	if ((s = strchr(host, '@'))) {
		*s++ = '\0';
		base64enc(host, auth, sizeof(auth));
		host = s;
	}
	if ((s = strchr(host, ':'))) {
		*s++ = '\0';
		port = atoi(s);
	}

	/* Open socket */
	if (!inet_aton(host, &sin.sin_addr))
		return 0;
	sin.sin_family = AF_INET;
	sin.sin_port = htons(port);

	dprintf("Connecting to %s:%u...\n", host, port);
	if ((fd = socket(AF_INET, SOCK_STREAM, 0)) < 0 ||
	    connect(fd, (struct sockaddr *) &sin, sizeof(sin)) < 0 ||
	    !(fp = fdopen(fd, "r+"))) {
		perror(host);
		if (fd >= 0)
			close(fd);
		return 0;
	}
	dprintf("connected!\n");

	/* Send HTTP request */
	fprintf(fp, "%s /%s HTTP/1.1\r\n", method == METHOD_POST ? "POST" : "GET", path);
	fprintf(fp, "Host: %s\r\n", host);
	fprintf(fp, "User-Agent: wget\r\n");
	if (strlen(auth))
		fprintf(fp, "Authorization: Basic %s\r\n", auth);
	if (offset)
		fprintf(fp, "Range: bytes=%ld-\r\n", offset);
	if (method == METHOD_POST) {
		fprintf(fp, "Content-Type: application/x-www-form-urlencoded\r\n");
		fprintf(fp, "Content-Length: %d\r\n\r\n", (int) strlen(buf));
		fputs(buf, fp);
	} else
		fprintf(fp, "Connection: close\r\n\r\n");

	/* Check HTTP response */
	dprintf("HTTP request sent, awaiting response...\n");
	if (fgets(line, sizeof(line), fp)) {
		dprintf("%s", line);
		for (s = line; *s && !isspace((int)*s); s++);
		for (; isspace((int)*s); s++);
		switch (atoi(s)) {
		case 200: if (offset) goto done; else break;
		case 206: if (offset) break; else goto done;
		default: goto done;
		}
	}

	/* Parse headers */
	while (fgets(line, sizeof(line), fp)) {
		dprintf("%s", line);
		for (s = line; *s == '\r'; s++);
		if (*s == '\n')
			break;
		if (!strncasecmp(s, "Content-Length:", 15)) {
			for (s += 15; isblank(*s); s++);
			chomp(s);
			len = atoi(s);
		}
		else if (!strncasecmp(s, "Transfer-Encoding:", 18)) {
			for (s += 18; isblank(*s); s++);
			chomp(s);
			if (!strncasecmp(s, "chunked", 7))
				chunked = 1;
		}
	}

	if (chunked && fgets(line, sizeof(line), fp))
		len = strtol(line, NULL, 16);

	len = (len > count) ? count : len;
	len = fread(buf, 1, len, fp);

done:
	/* Close socket */
	fflush(fp);
	fclose(fp);
	return len;
}

int
http_get(const char *server, char *buf, size_t count, off_t offset)
{
	return wget(METHOD_GET, server, buf, count, offset);
}

int
http_post(const char *server, char *buf, size_t count)
{
	/* No continuation generally possible with POST */
	return wget(METHOD_POST, server, buf, count, 0);
}