/*
 * Copyright 2023, Vincent Douillet <vincent@vdouillet.fr>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * 3. Neither the name of the copyright holder nor the names of its contributors
 * may be used to endorse or promote products derived from this software without
 * specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/queue.h>

#include <dirent.h>
#include <kcgi.h>
#include <kcgihtml.h>
#include <limits.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>

#include "browse.h"
#include "cgi.h"
#include "config.h"
#include "download.h"
#include "file.h"
#include "http.h"
#include "url.h"
#include "util.h"

/*
 * a list of files
 */
SLIST_HEAD(, file) list;

/*
 * browse url = r->pname / BROWSE_URL / file->path / file->name
 */
static 	size_t
build_browse_url(struct kreq * r, struct file * file)
{
	char 	action_url[PATH_MAX];
	size_t 	action_url_len;

	if (!file->is_dir)
		return 0;

	action_url_len = url_build(action_url, PATH_MAX, r->pname, BROWSE_URL,
				   file->path, file->name, NULL);
	if (action_url_len == 0 || action_url_len >= PATH_MAX) {
		kutil_warn(r, NULL,
			   "browse: action URL overflow: %s", action_url);
		return 0;
	}
	file->action_url = v_strcpy(action_url, action_url_len);
	if (file->action_url == NULL) {
		kutil_warn(r, NULL,
			   "browse: unable to allocate file url buffer: %s",
			   action_url);
		return 0;
	}
	return action_url_len;
}

static int
build_file_list(struct kreq * r, const char *request_dir)
{
	bool 	action_url_ok;
	char   *file_name;
	DIR    *data_dir;
	struct dirent *dir;
	struct file *file;
	struct file *last_file;

	data_dir = opendir(request_dir);
	if (NULL == data_dir)
		return -1;

	SLIST_INIT(&list);
	last_file = NULL;
	while ((dir = readdir(data_dir)) != NULL) {
		/* ignore special . and .. folders */
		file_name = dir->d_name;
		if (strcmp(".", file_name) == 0 || strcmp("..", file_name) == 0)
			continue;
		/* build file */
		file = file_new(r->path, strlen(r->path), dir->d_name,
				dir->d_namlen);
		if (file == NULL) {
			kutil_warn(r, NULL,
			      "browse: unable to allocate file, skipping %s",
				   file_name);
			continue;
		}
		/* build action url */
		if (file->is_dir)
			action_url_ok = build_browse_url(r, file) > 0;
		else
			action_url_ok = build_download_url(r, file) > 0;
		if (!action_url_ok) {
			kutil_warn(r, NULL,
			   "browse: unable to build action url, skipping %s",
				   file_name);
			file_free(file);
			continue;
		}
		/* add file to list */
		if (last_file == NULL)
			SLIST_INSERT_HEAD(&list, file, files);
		else
			SLIST_INSERT_AFTER(last_file, file, files);

		last_file = file;
	}

	closedir(data_dir);
	return 0;
}

const char *const template_keys[] = {"name", "url"};

/*
 * data required in the template function
 */
struct template_data {
	struct kreq *r;
	struct file *f;
};

static int
template_callback(size_t index, void *arg)
{
	struct kreq *r;
	struct template_data *data;

	if (arg == NULL) {
		kutil_warn(NULL, NULL, "Invalid data for browse template");
		return 0;
	}
	data = arg;
	r = data->r;
	switch (index) {
	case 0:
		/* name */
		K_OK(khttp_puts(r, data->f->name), r);
		break;
	case 1:
		/* url */
		K_OK(khttp_puts(r, data->f->action_url), r);
		break;
	default:
		kutil_warnx(r, NULL, "Invalid key index for browse template: %zd", index);
		return 0;
	}

	return 1;
}

void
browse(struct kreq * r)
{
	size_t 	url_len, template_buf_len;
	char 	current_dir[PATH_MAX];
	char 	template_path[PATH_MAX];
	char   *template_buf;
	struct file *file;
	struct khtmlreq html;
	struct ktemplate template;
	struct template_data data;

	/* check that the requested URL can be safely processed */
	if (!check_request_path(r->path))
		http_exit(r, KHTTP_400, "browse: Invalid request path");

	/* list requested directory content */
	url_len = url_build(current_dir, PATH_MAX, DATA_DIR, r->path,
			    NULL);
	if (url_len == 0)
		http_exit(r, KHTTP_404, "browse: Unable to build data path");
	if (url_len >= PATH_MAX)
		http_exit(r, KHTTP_414, NULL);
	if (build_file_list(r, current_dir) < 0)
		http_exit(r, KHTTP_500, "browse: Unable to build file list");

	/* read template */
	template_path[0] = '\0';
	strlcat(template_path, TEMPLATE_DIR, PATH_MAX);
	url_len = strlcat(template_path, "/browse_file.html", PATH_MAX);
	if (url_len == 0 || url_len >= PATH_MAX)
		http_exit(r, KHTTP_404, "browse: Unable to read template");

	template_buf = NULL;
	if (read_file(template_path, &template_buf, &template_buf_len) < 0
	    || template_buf == NULL)
		http_exit(r, KHTTP_500, "browse: Unable to read template");

	/* we have all the data we need, we can start to write output page */
	http_open(r, KHTTP_200, r->mime);

	K_OK(khtml_open(&html, r, 0), r);

	K_OK(khtml_elem(&html, KELEM_DOCTYPE), r);
	K_OK(khtml_elem(&html, KELEM_HEAD), r);
	K_OK(khtml_attr(&html, KELEM_META, KATTR_CHARSET, "utf-8", KATTR__MAX),
	     r);
	K_OK(khtml_elem(&html, KELEM_HTML), r);
	K_OK(khtml_elem(&html, KELEM_BODY), r);
	K_OK(khtml_elem(&html, KELEM_P), r);
	K_OK(khtml_puts(&html, "/"), r);
	K_OK(khtml_closeelem(&html, 1), r);

	/* print file list */
	template.key = template_keys;
	template.keysz = 2;
	template.cb = template_callback;
	template.arg = &data;
	data.r = r;

	K_OK(khtml_elem(&html, KELEM_UL), r);
	SLIST_FOREACH(file, &list, files) {
		data.f = file;
		K_OK(khttp_template_buf(r, &template, template_buf,
					template_buf_len), r);
	}
	K_OK(khtml_close(&html), r);

	/* free list template and list */
	free(template_buf);
	file = NULL;
	while (!SLIST_EMPTY(&list)) {
		file = SLIST_FIRST(&list);
		SLIST_REMOVE_HEAD(&list, files);
		file_free(file);
		file = NULL;
	}
}