/*
 * Copyright 2024 Vsevolod Stakhov
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "config.h"
#include "rspamadm.h"
#include "cryptobox.h"
#include "printf.h"
#include "ucl.h"
#include "libcryptobox/keypair.h"
#include "libutil/str_util.h"
#include "libutil/util.h"
#include "unix-std.h"
#ifdef HAVE_SYS_WAIT_H
#include <sys/wait.h>
#endif

static gboolean verify = FALSE;
static gboolean quiet = FALSE;
static char *suffix = NULL;
static char *pubkey_file = NULL;
static char *pubkey = NULL;
static char *pubout = NULL;
static char *keypair_file = NULL;
static char *editor = NULL;
static gboolean edit = FALSE;

static void rspamadm_signtool(int argc, char **argv,
							  const struct rspamadm_command *cmd);
static const char *rspamadm_signtool_help(gboolean full_help,
										  const struct rspamadm_command *cmd);

struct rspamadm_command signtool_command = {
	.name = "signtool",
	.flags = 0,
	.help = rspamadm_signtool_help,
	.run = rspamadm_signtool,
	.lua_subrs = NULL,
};

static GOptionEntry entries[] = {
	{"verify", 'v', 0, G_OPTION_ARG_NONE, &verify,
	 "Verify signatures and not sign", NULL},
	{"suffix", 'S', 0, G_OPTION_ARG_STRING, &suffix,
	 "Save signatures in file<suffix> files", NULL},
	{"pubkey", 'p', 0, G_OPTION_ARG_STRING, &pubkey,
	 "Base32 encoded pubkey to verify", NULL},
	{"pubout", '\0', 0, G_OPTION_ARG_FILENAME, &pubout,
	 "Output public key to the specified file", NULL},
	{"pubfile", 'P', 0, G_OPTION_ARG_FILENAME, &pubkey_file,
	 "Load base32 encoded pubkey to verify from the file", NULL},
	{"keypair", 'k', 0, G_OPTION_ARG_STRING, &keypair_file,
	 "UCL with keypair to load for signing", NULL},
	{"quiet", 'q', 0, G_OPTION_ARG_NONE, &quiet,
	 "Be quiet", NULL},
	{"edit", 'e', 0, G_OPTION_ARG_NONE, &edit,
	 "Run editor and sign the edited file", NULL},
	{"editor", '\0', 0, G_OPTION_ARG_STRING, &editor,
	 "Use the specified editor instead of $EDITOR environment var", NULL},
	{NULL, 0, 0, G_OPTION_ARG_NONE, NULL, NULL, NULL}};

static const char *
rspamadm_signtool_help(gboolean full_help,
					   const struct rspamadm_command *cmd)
{
	const char *help_str;

	if (full_help) {
		help_str = "Manage digital signatures\n\n"
				   "Usage: rspamadm signtool [-o] -k <keypair_file> [-v -p <pubkey> | -P <pubkey_file>] [-S <suffix>] file1 ...\n"
				   "Where options are:\n\n"
				   "-v: verify against pubkey instead of \n"
				   "-o: use ECDSA instead of EdDSA\n"
				   "-p: load pubkey as base32 string\n"
				   "-P: load pubkey paced in file\n"
				   "-k: load signing keypair from ucl file\n"
				   "-S: append suffix for signatures and store them in files\n"
				   "-q: be quiet\n"
				   "-e: opens file for editing and sign the result\n"
				   "--editor: use the specified editor instead of $EDITOR environment var\n"
				   "--help: shows available options and commands";
	}
	else {
		help_str = "Sign and verify files tool";
	}

	return help_str;
}

static int
rspamadm_edit_file(const char *fname)
{
	char tmppath[PATH_MAX], run_cmdline[PATH_MAX];
	unsigned char *map;
	gsize len = 0;
	int fd_out, retcode, child_argc;
	GPid child_pid;
	char *tmpdir, **child_argv = NULL;
	struct stat st;
	GError *err = NULL;

	if (editor == NULL) {
		editor = getenv("EDITOR");
	}

	if (editor == NULL) {
		rspamd_fprintf(stderr, "cannot find editor: specify $EDITOR "
							   "environment variable or pass --editor argument\n");
		exit(EXIT_FAILURE);
	}

	tmpdir = getenv("TMPDIR");
	if (tmpdir == NULL) {
		tmpdir = "/tmp";
	}

	if (stat(fname, &st) == -1 || st.st_size == 0) {
		/* The source does not exist, but that shouldn't be a problem */
		len = 0;
		map = NULL;

		/* Try to touch source anyway */
		fd_out = rspamd_file_xopen(fname, O_WRONLY | O_CREAT | O_EXCL, 00644,
								   0);

		if (fd_out == -1) {
			rspamd_fprintf(stderr, "cannot open %s: %s\n", fname,
						   strerror(errno));
			exit(EXIT_FAILURE);
		}

		close(fd_out);
	}
	else {
		map = rspamd_file_xmap(fname, PROT_READ, &len, TRUE);

		if (map == NULL) {
			rspamd_fprintf(stderr, "cannot open %s: %s\n", fname,
						   strerror(errno));
			exit(EXIT_FAILURE);
		}
	}

	rspamd_snprintf(tmppath, sizeof(tmppath),
					"%s/rspamd_sign-XXXXXXXXXX", tmpdir);
	mode_t cur_umask = umask(S_IRWXO | S_IRWXG);
	fd_out = mkstemp(tmppath);
	(void) umask(cur_umask);

	if (fd_out == -1) {
		rspamd_fprintf(stderr, "cannot open tempfile %s: %s\n", tmppath,
					   strerror(errno));
		exit(EXIT_FAILURE);
	}

	if (len > 0 && write(fd_out, map, len) == -1) {
		rspamd_fprintf(stderr, "cannot write to tempfile %s: %s\n", tmppath,
					   strerror(errno));
		unlink(tmppath);
		munmap(map, len);
		close(fd_out);
		exit(EXIT_FAILURE);
	}

	if (len > 0) {
		munmap(map, len);
	}

	fsync(fd_out);
	close(fd_out);

	/* Now we spawn editor with the filename as argument */
	rspamd_snprintf(run_cmdline, sizeof(run_cmdline), "%s %s", editor, tmppath);
	if (!g_shell_parse_argv(run_cmdline, &child_argc,
							&child_argv, &err)) {
		rspamd_fprintf(stderr, "cannot exec %s: %e\n", editor,
					   err);
		unlink(tmppath);
		exit(EXIT_FAILURE);
	}

	if (!g_spawn_async(NULL, child_argv, NULL,
					   G_SPAWN_CHILD_INHERITS_STDIN | G_SPAWN_SEARCH_PATH | G_SPAWN_DO_NOT_REAP_CHILD,
					   NULL, NULL, &child_pid, &err)) {
		rspamd_fprintf(stderr, "cannot exec %s: %e\n", editor,
					   err);
		unlink(tmppath);
		exit(EXIT_FAILURE);
	}

	g_strfreev(child_argv);

	for (;;) {
		if (waitpid((pid_t) child_pid, &retcode, 0) != -1) {
			break;
		}

		if (errno != EINTR) {
			rspamd_fprintf(stderr, "failed to wait for %s: %s\n", editor,
						   strerror(errno));
			unlink(tmppath);
			exit(EXIT_FAILURE);
		}
	}

#if GLIB_MAJOR_VERSION >= 2 && GLIB_MINOR_VERSION >= 34
#if GLIB_MINOR_VERSION >= 70
	if (!g_spawn_check_wait_status(retcode, &err)) {
#else
	if (!g_spawn_check_exit_status(retcode, &err)) {
#endif
		unlink(tmppath);
		rspamd_fprintf(stderr, "%s returned error code: %d - %e\n", editor,
					   retcode, err);
		exit(EXIT_FAILURE);
	}
#else
	if (retcode != 0) {
		unlink(tmppath);
		rspamd_fprintf(stderr, "%s returned error code: %d\n", editor,
					   retcode);
		exit(retcode);
	}
#endif

	map = rspamd_file_xmap(tmppath, PROT_READ, &len, TRUE);

	if (map == NULL) {
		rspamd_fprintf(stderr, "cannot map %s: %s\n", tmppath,
					   strerror(errno));
		unlink(tmppath);
		exit(EXIT_FAILURE);
	}

	rspamd_snprintf(run_cmdline, sizeof(run_cmdline), "%s.new", fname);
	fd_out = rspamd_file_xopen(run_cmdline, O_RDWR | O_CREAT | O_TRUNC, 00600,
							   0);

	if (fd_out == -1) {
		rspamd_fprintf(stderr, "cannot open new file %s: %s\n", run_cmdline,
					   strerror(errno));
		unlink(tmppath);
		munmap(map, len);
		exit(EXIT_FAILURE);
	}

	if (write(fd_out, map, len) == -1) {
		rspamd_fprintf(stderr, "cannot write new file %s: %s\n", run_cmdline,
					   strerror(errno));
		unlink(tmppath);
		unlink(run_cmdline);
		close(fd_out);
		munmap(map, len);
		exit(EXIT_FAILURE);
	}

	unlink(tmppath);
	(void) lseek(fd_out, 0, SEEK_SET);
	munmap(map, len);

	return fd_out;
}

static bool
rspamadm_sign_file(const char *fname, struct rspamd_cryptobox_keypair *kp)
{
	int fd_sig, fd_input;
	unsigned char sig[rspamd_cryptobox_MAX_SIGBYTES], *map;
	char sigpath[PATH_MAX];
	FILE *pub_fp;
	struct stat st;
	const unsigned char *sk;

	if (suffix == NULL) {
		suffix = ".sig";
	}

	if (edit) {
		/* We need to open editor and then sign the temporary file */
		fd_input = rspamadm_edit_file(fname);
	}
	else {
		fd_input = rspamd_file_xopen(fname, O_RDONLY, 0, TRUE);
	}

	if (fd_input == -1) {
		rspamd_fprintf(stderr, "cannot open %s: %s\n", fname,
					   strerror(errno));
		exit(EXIT_FAILURE);
	}

	g_assert(fstat(fd_input, &st) != -1);

	rspamd_snprintf(sigpath, sizeof(sigpath), "%s%s", fname, suffix);
	fd_sig = rspamd_file_xopen(sigpath, O_WRONLY | O_CREAT | O_TRUNC, 00644, 0);

	if (fd_sig == -1) {
		close(fd_input);
		rspamd_fprintf(stderr, "cannot open %s: %s\n", sigpath,
					   strerror(errno));
		exit(EXIT_FAILURE);
	}

	map = mmap(NULL, st.st_size, PROT_READ, MAP_SHARED, fd_input, 0);
	close(fd_input);

	if (map == MAP_FAILED) {
		close(fd_sig);
		rspamd_fprintf(stderr, "cannot map %s: %s\n", fname,
					   strerror(errno));
		exit(EXIT_FAILURE);
	}

	sk = rspamd_keypair_component(kp, RSPAMD_KEYPAIR_COMPONENT_SK, NULL);
	rspamd_cryptobox_sign(sig, NULL, map, st.st_size, sk);

	if (edit) {
		/* We also need to rename .new file */
		rspamd_snprintf(sigpath, sizeof(sigpath), "%s.new", fname);

		if (rename(sigpath, fname) == -1) {
			rspamd_fprintf(stderr, "cannot rename %s to %s: %s\n", sigpath, fname,
						   strerror(errno));
			exit(EXIT_FAILURE);
		}

		unlink(sigpath);
	}

	rspamd_snprintf(sigpath, sizeof(sigpath), "%s%s", fname, suffix);

	if (write(fd_sig, sig, crypto_sign_bytes()) == -1) {
		rspamd_fprintf(stderr, "cannot write signature to %s: %s\n", sigpath,
					   strerror(errno));
		exit(EXIT_FAILURE);
	}

	close(fd_sig);
	munmap(map, st.st_size);

	if (!quiet) {
		rspamd_fprintf(stdout, "signed %s; stored hash in %s\n",
					   fname, sigpath);
	}

	if (pubout) {
		GString *b32_pk;

		pub_fp = fopen(pubout, "w");

		if (pub_fp == NULL) {
			rspamd_fprintf(stderr, "cannot write pubkey to %s: %s",
						   pubout, strerror(errno));
		}
		else {
			b32_pk = rspamd_keypair_print(kp,
										  RSPAMD_KEYPAIR_ENCODING_DEFAULT,
										  RSPAMD_KEYPAIR_PUBKEY);

			if (b32_pk) {
				rspamd_fprintf(pub_fp, "%v", b32_pk);
				g_string_free(b32_pk, TRUE);
			}

			fclose(pub_fp);
		}
		if (!quiet) {
			rspamd_fprintf(stdout, "stored pubkey in %s\n",
						   pubout);
		}
	}

	return true;
}

static bool
rspamadm_verify_file(const char *fname, const unsigned char *pk)
{
	int fd_sig, fd_input;
	unsigned char *map, *map_sig;
	char sigpath[PATH_MAX];
	struct stat st, st_sig;
	bool ret;

	if (suffix == NULL) {
		suffix = ".sig";
	}

	fd_input = rspamd_file_xopen(fname, O_RDONLY, 0, TRUE);

	if (fd_input == -1) {
		rspamd_fprintf(stderr, "cannot open %s: %s\n", fname,
					   strerror(errno));
		exit(EXIT_FAILURE);
	}

	g_assert(fstat(fd_input, &st) != -1);

	rspamd_snprintf(sigpath, sizeof(sigpath), "%s%s", fname, suffix);
	fd_sig = rspamd_file_xopen(sigpath, O_RDONLY, 0, TRUE);

	if (fd_sig == -1) {
		close(fd_input);
		rspamd_fprintf(stderr, "cannot open %s: %s\n", sigpath,
					   strerror(errno));
		exit(EXIT_FAILURE);
	}

	map = mmap(NULL, st.st_size, PROT_READ, MAP_SHARED, fd_input, 0);
	close(fd_input);

	if (map == MAP_FAILED) {
		close(fd_sig);
		rspamd_fprintf(stderr, "cannot open %s: %s\n", sigpath,
					   strerror(errno));
		exit(EXIT_FAILURE);
	}

	g_assert(fstat(fd_sig, &st_sig) != -1);

	if (st_sig.st_size != crypto_sign_bytes()) {
		close(fd_sig);
		rspamd_fprintf(stderr, "invalid signature size %s: %ud\n", fname,
					   (unsigned int) st_sig.st_size);
		munmap(map, st.st_size);
		exit(EXIT_FAILURE);
	}

	map_sig = mmap(NULL, st_sig.st_size, PROT_READ, MAP_SHARED, fd_sig, 0);
	close(fd_sig);

	if (map_sig == MAP_FAILED) {
		munmap(map, st.st_size);
		rspamd_fprintf(stderr, "cannot map %s: %s\n", sigpath,
					   strerror(errno));
		exit(EXIT_FAILURE);
	}

	ret = rspamd_cryptobox_verify(map_sig, st_sig.st_size,
								  map, st.st_size, pk);
	munmap(map, st.st_size);
	munmap(map_sig, st_sig.st_size);

	if (!ret) {
		rspamd_fprintf(stderr, "cannot verify %s using %s: invalid signature\n",
					   fname, sigpath);
	}
	else if (!quiet) {
		rspamd_fprintf(stdout, "verified %s using %s\n",
					   fname, sigpath);
	}

	return ret;
}


static void
rspamadm_signtool(int argc, char **argv, const struct rspamadm_command *cmd)
{
	GOptionContext *context;
	GError *error = NULL;
	struct ucl_parser *parser;
	ucl_object_t *top;
	struct rspamd_cryptobox_pubkey *pk;
	struct rspamd_cryptobox_keypair *kp;
	gsize fsize, flen;
	int i;

	context = g_option_context_new(
		"keypair - create encryption keys");
	g_option_context_set_summary(context,
								 "Summary:\n  Rspamd administration utility version " RVERSION
								 "\n  Release id: " RID);
	g_option_context_add_main_entries(context, entries, NULL);

	if (!g_option_context_parse(context, &argc, &argv, &error)) {
		rspamd_fprintf(stderr, "option parsing failed: %s\n", error->message);
		g_error_free(error);
		g_option_context_free(context);
		exit(EXIT_FAILURE);
	}

	g_option_context_free(context);

	if (verify && (!pubkey && !pubkey_file)) {
		rspamd_fprintf(stderr, "no pubkey for verification\n");
		exit(EXIT_FAILURE);
	}
	else if (!verify && (!keypair_file)) {
		rspamd_fprintf(stderr, "no keypair for signing\n");
		exit(EXIT_FAILURE);
	}

	if (verify) {
		g_assert(pubkey || pubkey_file);

		if (pubkey_file) {
			int fd;
			char *map;
			struct stat st;

			fd = open(pubkey_file, O_RDONLY);

			if (fd == -1) {
				rspamd_fprintf(stderr, "cannot open %s: %s\n", pubkey_file,
							   strerror(errno));
				exit(EXIT_FAILURE);
			}

			g_assert(fstat(fd, &st) != -1);
			fsize = st.st_size;
			flen = fsize;
			map = mmap(NULL, fsize, PROT_READ, MAP_SHARED, fd, 0);
			close(fd);

			if (map == MAP_FAILED) {
				rspamd_fprintf(stderr, "cannot read %s: %s\n", pubkey_file,
							   strerror(errno));
				exit(EXIT_FAILURE);
			}

			/* XXX: assume base32 pubkey now */
			while (flen > 0 && g_ascii_isspace(map[flen - 1])) {
				flen--;
			}

			pk = rspamd_pubkey_from_base32(map, flen, RSPAMD_KEYPAIR_SIGN);

			if (pk == NULL) {
				rspamd_fprintf(stderr, "bad size %s: %ud, %ud expected\n",
							   pubkey_file,
							   (unsigned int) flen,
							   crypto_sign_publickeybytes());
				exit(EXIT_FAILURE);
			}

			munmap(map, fsize);
		}
		else {
			pk = rspamd_pubkey_from_base32(pubkey, strlen(pubkey),
										   RSPAMD_KEYPAIR_SIGN);

			if (pk == NULL) {
				rspamd_fprintf(stderr, "bad size %s: %ud, %ud expected\n",
							   pubkey_file,
							   (unsigned int) strlen(pubkey),
							   crypto_sign_publickeybytes());
				exit(EXIT_FAILURE);
			}
		}

		for (i = 1; i < argc; i++) {
			/* XXX: support cmd line signature */
			if (!rspamadm_verify_file(argv[i], rspamd_pubkey_get_pk(pk, NULL))) {
				exit(EXIT_FAILURE);
			}
		}

		g_free(pk);
	}
	else {
		g_assert(keypair_file != NULL);

		parser = ucl_parser_new(0);

		if (!ucl_parser_add_file(parser, keypair_file) ||
			(top = ucl_parser_get_object(parser)) == NULL) {
			rspamd_fprintf(stderr, "cannot load keypair: %s\n",
						   ucl_parser_get_error(parser));
			exit(EXIT_FAILURE);
		}

		ucl_parser_free(parser);

		kp = rspamd_keypair_from_ucl(top);

		if (kp == NULL) {
			rspamd_fprintf(stderr, "invalid signing key\n");
			exit(EXIT_FAILURE);
		}

		if (rspamd_keypair_type(kp) != RSPAMD_KEYPAIR_SIGN) {
			rspamd_fprintf(stderr, "unsuitable for signing key\n");
			exit(EXIT_FAILURE);
		}

		for (i = 1; i < argc; i++) {
			/* XXX: support cmd line signature */
			if (!rspamadm_sign_file(argv[i], kp)) {
				rspamd_keypair_unref(kp);
				exit(EXIT_FAILURE);
			}
		}

		rspamd_keypair_unref(kp);
	}
}