/*
 * Copyright (c) 2020-2022 joshua stein <jcs@jcs.org>
 *
 * Permission to use, copy, modify, and 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.
 */

#include <stdio.h>
#include <string.h>
#include "dnr.h"
#include "http.h"
#include "util.h"
#include "wikipedia.h"

struct url *
url_parse(const char *str)
{
	struct url *url = NULL;
	char *buf, *scheme, *host, *path;
	unsigned short port;
	short ret, pos;
	size_t len, schemelen, hostlen, pathlen;
	
	len = strlen(str);
	scheme = xmalloc(len + 1);
	if (scheme == NULL) {
		warn("http: Failed allocating %ld", len + 1);
		return NULL;
	}
	host = xmalloc(len + 1);
	if (host == NULL) {
		warn("http: Failed allocating %ld", len + 1);
		xfree(&scheme);
		return NULL;
	}
	path = xmalloc(len + 1);
	if (path == NULL) {
		warn("http: Failed allocating %ld", len + 1);
		xfree(&host);
		xfree(&scheme);
		return NULL;
	}

	/* scheme://host:port/path */
	ret = sscanf(str, "%[^:]://%[^:]:%d%s%n", scheme, host, &port, path,
	  &pos);
	if (ret == 4) {
		if (pos > len)
			panic("url_parse sscanf overflow");
		goto consolidate;
	}
	
	/* scheme://host/path */
	ret = sscanf(str, "%[^:]://%[^/]%s%n", scheme, host, path, &pos);
	if (ret == 3) {
		if (pos > len)
			panic("url_parse sscanf overflow");
		if (strcmp(scheme, "http") == 0)
			port = 80;
		else if (strcmp(scheme, "https") == 0)
			port = 443;
		else
			goto cleanup;
		goto consolidate;
	}
	
	goto cleanup;

consolidate:
	schemelen = strlen(scheme);
	hostlen = strlen(host);
	pathlen = strlen(path);
	
	/*
	 * Put everything in a single chunk of memory so the caller can just
	 * free(url)
	 */
	len = sizeof(struct url) + schemelen + 1 + hostlen + 1 + pathlen + 1;
	url = xmalloc(len);
	if (url == NULL) {
		warn("http: Failed allocating %ld for URL", len);
		goto cleanup;
	}
	
	url->scheme = (char *)url + sizeof(struct url);
	len = strlcpy(url->scheme, scheme, schemelen + 1);
	
	url->host = url->scheme + len + 1;
	len = strlcpy(url->host, host, hostlen + 1);

	url->path = url->host + len + 1;
	len = strlcpy(url->path, path, pathlen + 1);

	url->port = port;
	
cleanup:
	xfree(&scheme);
	xfree(&host);
	xfree(&path);

	return url;
}

char *
url_encode(unsigned char *str)
{
	char *ret = NULL;
	size_t len, n;
	bool encode = false;
	char a, b;
	
encode:
	for (n = 0, len = 0; str[n] != '\0'; n++) {
		if ((str[n] >= 'A' && str[n] <= 'Z') ||
		  (str[n] >= 'a' && str[n] <= 'z') ||
		  (str[n] >= '0' && str[n] <= '9') ||
		  (str[n] == '-' || str[n] == '_' || str[n] == '.' ||
		  str[n] == '~')) {
			if (ret)
				ret[len] = str[n];
			len++;
		} else {
			if (ret) {
				sprintf(ret + len, "%%%02X", str[n]);
			}
			len += 3;
		}
	}
	
	if (ret) {
		ret[len] = '\0';
		return ret;
	}
		
	ret = xmalloc(len + 1);
	if (ret == NULL) {
		warn("http: Failed allocating %ld", len + 1);
		return NULL;
	}
	len = 0;
	goto encode;
}

struct http_request *
http_get(const char *surl)
{
	struct url *url;
	struct http_request *req;
	size_t len, alen;
	short err;
	char ip_s[16];
	ip_addr local_ip;
	tcp_port local_port;
	
	url = url_parse(surl);
	if (url == NULL)
		return NULL;
	
	req = xmalloczero(sizeof(struct http_request));
	if (req == NULL) {
		warn("http: Failed allocating http_request");
		return NULL;
	}
	req->url = url;
	req->tcp_buf_size = (4 * 1500) + sizeof(req->chunk);
	req->tcp_buf = xmalloc(req->tcp_buf_size);
	if (req->tcp_buf == NULL) {
		warn("http: Failed allocating tcp_buf");
		xfree(&req);
		return NULL;
	}
	
	err = _TCPCreate(&req->tcp_iopb, &req->tcp_stream, (Ptr)req->tcp_buf,
	  req->tcp_buf_size, nil, nil, nil, false);
	if (err) {
		warn("TCPCreate failed: %d", err);
		goto error;
	}
	
	err = DNSResolveName(&req->url->host, &req->host_ip, NULL);
	if (err) {
		warn("Couldn't resolve host %s (%d)", req->url->host, err);
		goto error;
	}
	
	long2ip(req->host_ip, (char *)&ip_s);

	err = _TCPActiveOpen(&req->tcp_iopb, req->tcp_stream, req->host_ip,
	  req->url->port, &local_ip, &local_port, nil, nil, false);
	if (err) {
		warn("Failed connecting to %s (%s) port %d: %d",
		  req->url->host, ip_s, req->url->port, err);
		goto error;
	}

	alen = 256 + strlen(req->url->host) + strlen(req->url->path);
	req->message = xmalloc(alen);
	if (req->message == NULL) {
		warn("http: Failed allocating message");
		goto error;
	}
	len = snprintf(req->message, alen,
	  "GET %s HTTP/1.0\r\n"
	  "Host: %s\r\n"
	  "User-Agent: %s\r\n"
	  "Accept: */*\r\n"
	  "\r\n", req->url->path, req->url->host, PROGRAM_NAME);
	if (len > alen)
		panic("snprintf overflow");
	
	memset(&req->tcp_wds, 0, sizeof(req->tcp_wds));
	req->tcp_wds[0].ptr = req->message;
	req->tcp_wds[0].length = len;

	err = _TCPSend(&req->tcp_iopb, req->tcp_stream, req->tcp_wds, nil, nil,
	  false);
	if (err) {
		warn("TCPSend to %s (%s) failed: %d", req->url->host, ip_s, err);
		goto error;
	}
	
	return req;

error:
	http_req_free(&req);
	return NULL;
}

ssize_t
http_req_read(struct http_request *req, char *data, size_t len)
{
	short err;
	unsigned short rlen;
	
	if (!req)
		return -1;
	
	err = _TCPStatus(&req->tcp_iopb, req->tcp_stream, &req->tcp_status_pb,
	  nil, nil, false);
	if (err)
		return -1;
		
	if (req->tcp_status_pb.amtUnreadData == 0)
		return 0;
	
	rlen = MIN(req->tcp_status_pb.amtUnreadData, len);

	err = _TCPRcv(&req->tcp_iopb, req->tcp_stream, data, &rlen, nil, nil,
	  false);
	if (err)
		return -1;
	
	return rlen;
}

bool
http_req_skip_header(struct http_request *req)
{
	size_t len, n;
	bool last_nl = false;
	
	for (;;) {
		if (req->chunk_len == sizeof(req->chunk))
			/* this sure is a long header... */
			req->chunk_len = 0;
			
		len = http_req_read(req, req->chunk + req->chunk_len,
		  sizeof(req->chunk) - req->chunk_len);
		if (len < 0)
			return false;
		if (len == 0)
			continue;
		req->chunk_len += len;
		
		for (n = 1; n < req->chunk_len; n++) {
			if (req->chunk[n - 1] != '\r' || req->chunk[n] != '\n') {
				last_nl = false;
				continue;
			}
				
			/* newline, shift chunk back */
			if (strncmp(req->chunk, "Content-Length: ", 16) == 0) {
				if (sscanf(req->chunk, "Content-Length: %ld", &len) == 1)
					req->content_len = len;
			}
			req->chunk_len -= n + 1;
			memmove(req->chunk, req->chunk + n + 1, req->chunk_len);
			req->chunk_off = 0;
			
			if (last_nl)
				return true;
				
			last_nl = true;
			n = 0; /* start at 1 on next iteration */
		}
	}
	
	return false;
}

short
http_req_chunk_peek(void *cookie)
{
	struct http_request *req = (struct http_request *)cookie;

	if (req->chunk_len == 0 || (req->chunk_off + 1 > req->chunk_len)) {
		req->chunk_len = http_req_read(req, req->chunk, sizeof(req->chunk));
		req->chunk_off = 0;
	}
	
	if (req->chunk_len == 0 || (req->chunk_off + 1 > req->chunk_len))
		return EOF;
	
	return req->chunk[req->chunk_off];
}

short
http_req_chunk_read(void *cookie)
{
	struct http_request *req = (struct http_request *)cookie;
	short c;
	
	c = http_req_chunk_peek(req);
	if (c == EOF)
		return c;

	req->chunk_off++;
	
	return c;
}

void
http_req_free(void *reqptr)
{
	unsigned long *addr = (unsigned long *)reqptr;
	void *ptr = (void *)*addr;
	struct http_request *req = (struct http_request *)ptr;

	if (req == NULL)
		return;
		
	_TCPRelease(&req->tcp_iopb, req->tcp_stream, nil, nil, false);

	if (req->message != NULL)
		xfree(&req->message);
	xfree(&req->tcp_buf);
	xfree(&req->url);
	xfree(&req);
	
	*addr = 0L;
}