/*
 * Copyright 2024, 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/types.h>
#include <sys/stat.h>
#include <fts.h>
#include <kcgi.h>
#include <kcgihtml.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "browse.h"
#include "cgi.h"
#include "delete.h"
#include "http.h"
#include "str.h"
#include "template.h"
#include "url.h"

/*
 * delete url = r->pname / DELETE_URL / file->path
 */
size_t
build_delete_url(const struct kreq * r, struct file * file)
{
	char 	action_url[PATH_MAX];
	size_t 	action_url_len;

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

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

static const char *const header_template_keys[] = {"path", "submit_url"};

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

	if (arg == NULL) {
		kutil_warn(NULL, NULL,
			   "Invalid data for delete header template");
		return 0;
	}
	data = arg;
	r = data->r;
	html = data->html;

	switch (index) {
	case 0:
		/* path */
		K_OK(khtml_puts(html, data->f->path), r);
		break;
	case 1:
		/* submit_url */
		K_OK(khtml_puts(html, data->f->action_url), r);
		break;
	default:
		kutil_warnx(r, NULL,
			 "Invalid key index for delete header template: %zd",
			    index);
		return 0;
	}

	return 1;
}

/*
 * GET request, we print delete form
 */
void
delete_get(struct kreq * r, struct file * file)
{
	struct khtmlreq html;
	struct ktemplate template;
	struct page_template *tmpl;
	struct template_data data;

	tmpl = NULL;

	/* action url is form submit url */
	if (build_delete_url(r, file) == 0) {
		http_exit(r, KHTTP_500, "delete: Can't build delete url");
		goto end;
	}
	/* read template */
	tmpl = page_template_new(DELETE_URL);
	if (tmpl == NULL) {
		http_exit(r, KHTTP_500, "delete: Unable to read template");
		goto end;
	}
	/* print delete form */
	http_open(r, KHTTP_200, KMIME_TEXT_HTML);

	K_OK(khttp_puts(r, tmpl->header), r);
	K_OK(khtml_open(&html, r, 0), r);

	template.key = header_template_keys;
	template.keysz = 2;
	template.cb = header_template_callback;
	template.arg = &data;
	data.r = r;
	data.html = &html;
	data.f = file;
	K_OK(khttp_template_buf(r, &template, tmpl->page_header,
				strlen(tmpl->page_header)), r);

	K_OK(khttp_puts(r, tmpl->page_footer), r);
	K_OK(khttp_puts(r, tmpl->footer), r);

	K_OK(khtml_close(&html), r);

end:
	page_template_free(tmpl);
}

/*
 * POST request, we handle delete form
 */
void
delete_post(struct kreq * r, struct file * f)
{
	char 	path[PATH_MAX];
	char   *paths[2];
	FTS    *fts;
	FTSENT *ftsent;
	int 	fts_opts;
	struct file *parent;
	unsigned short fi;

	fts = NULL;
	ftsent = NULL;

	/* prepare action url for return redirection in case of success */
	parent = file_get_parent(f);
	if (parent == NULL || build_browse_url(r, parent) == 0) {
		http_exit(r, KHTTP_500, "delete: can't build return url");
		goto end;
	}
	/* build file path on disk */
	if (file_get_data_path(f, path, sizeof(path), NULL) <= 0) {
		http_exit(r, KHTTP_500, "delete: can't build file data path");
		goto end;
	}
	if (f->is_dir) {
		/* don't follow symlinks */
		fts_opts = 0x0 | FTS_PHYSICAL;
		paths[0] = path;
		paths[1] = NULL;
		if ((fts = fts_open(paths, fts_opts, NULL)) == NULL) {
			http_exit(r, KHTTP_500,
				  "delete: can't open file hierarchy");
			goto end;
		}
		/* file and directory delete loop */
		while ((ftsent = fts_read(fts)) != NULL) {
			fi = ftsent->fts_info;

			/* halt on fts errors */
			if (fi == FTS_DNR || fi == FTS_ERR || fi == FTS_NS) {
				http_exit(r, KHTTP_500,
					  "delete: fts_read error");
				goto end;
			}
			/* delete regular files and empty folders */
			else if ((fi == FTS_DP || fi == FTS_F) &&
				 remove(ftsent->fts_path) < 0) {
				http_exit(r, KHTTP_500,
					  "delete: failed to delete file");
				goto end;
			}
		}
	} else {
		if (remove(path) < 0) {
			http_exit(r, KHTTP_500,
				  "delete: failed to delete file");
			goto end;
		}
	}

	/* on success, redirect to the parent directory of deleted files */
	khttp_head(r, kresps[KRESP_LOCATION], "%s", parent->action_url);
	http_open(r, KHTTP_303, r->mime);

end:
	if (parent != NULL)
		file_free(parent);
	if (fts != NULL)
		fts_close(fts);
}

void
del(struct kreq * r)
{
	char   *path;
	size_t 	suffix_len;
	struct file *file;

	file = NULL;

	/* build file corresponding to request (ie. delete) path */
	suffix_len = strlen(r->suffix);
	if (suffix_len > 0) {
		if (str_concat(&path, r->path, ".", r->suffix, NULL) <= 0) {
			http_exit(r, KHTTP_404,
				  "delete: Unable to build file path");
			goto end;
		}
	} else {
		path = r->path;
	}

	file = file_new(path);
	if (file == NULL) {
		http_exit(r, KHTTP_404, "delete: Unable to build data file");
		goto end;
	}
	/* print form or handle submission according to HTTP method */
	if (r->method == KMETHOD_POST)
		delete_post(r, file);
	else
		delete_get(r, file);

end:
	if (suffix_len > 0)
		free(path);
	file_free(file);
}