/*
 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
 *
 * SPDX-License-Identifier: MPL-2.0
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0.  If a copy of the MPL was not distributed with this
 * file, you can obtain one at https://mozilla.org/MPL/2.0/.
 *
 * See the COPYRIGHT file distributed with this work for additional
 * information regarding copyright ownership.
 */

#include <stdbool.h>
#include <stdlib.h>

#include <isc/commandline.h>
#include <isc/mem.h>
#include <isc/print.h>
#include <isc/string.h>
#include <isc/util.h>

#include <dns/fixedname.h>
#include <dns/rbt.h>
#include <dns/result.h>

const char *progname;
isc_mem_t *mctx;

#define DNSNAMELEN 255

static dns_name_t *
create_name(char *s) {
	int length;
	isc_result_t result;
	isc_buffer_t source, target;
	static dns_name_t *name;

	if (s == NULL || *s == '\0') {
		printf("missing name argument\n");
		return (NULL);
	}

	length = strlen(s);

	isc_buffer_init(&source, s, length);
	isc_buffer_add(&source, length);

	/*
	 * It isn't really necessary in this program to create individual
	 * memory spaces for each name structure and its associated character
	 * string.  It is done here to provide a relatively easy way to test
	 * the callback from dns_rbt_deletename that is supposed to free the
	 * data associated with a node.
	 *
	 * The buffer for the actual name will immediately follow the
	 * name structure.
	 */
	name = isc_mem_get(mctx, sizeof(*name) + DNSNAMELEN);

	dns_name_init(name, NULL);
	isc_buffer_init(&target, name + 1, DNSNAMELEN);

	result = dns_name_fromtext(name, &source, dns_rootname, 0, &target);

	if (result != ISC_R_SUCCESS) {
		printf("dns_name_fromtext(%s) failed: %s\n", s,
		       dns_result_totext(result));
		return (NULL);
	}

	return (name);
}

static void
delete_name(void *data, void *arg) {
	dns_name_t *name;

	UNUSED(arg);
	name = data;
	isc_mem_put(mctx, name, sizeof(*name) + DNSNAMELEN);
}

static void
print_name(dns_name_t *name) {
	isc_buffer_t target;
	char buffer[1024];

	isc_buffer_init(&target, buffer, sizeof(buffer));

	/*
	 * false means absolute names have the final dot added.
	 */
	dns_name_totext(name, false, &target);

	printf("%.*s", (int)target.used, (char *)target.base);
}

static void
detail(dns_rbt_t *rbt, dns_name_t *name) {
	dns_name_t *foundname, *origin, *fullname;
	dns_fixedname_t fixedfoundname, fixedorigin, fixedfullname;
	dns_rbtnode_t *node1, *node2;
	dns_rbtnodechain_t chain;
	isc_result_t result;
	bool nodes_should_match = false;

	dns_rbtnodechain_init(&chain);

	origin = dns_fixedname_initname(&fixedorigin);
	fullname = dns_fixedname_initname(&fixedfullname);
	foundname = dns_fixedname_initname(&fixedfoundname);

	node1 = node2 = NULL;

	printf("checking chain information for ");
	print_name(name);
	printf("\n");

	result = dns_rbt_findnode(rbt, name, foundname, &node1, &chain,
				  DNS_RBTFIND_EMPTYDATA, NULL, NULL);

	switch (result) {
	case ISC_R_SUCCESS:
		printf("  found exact.");
		nodes_should_match = true;
		break;
	case DNS_R_PARTIALMATCH:
		printf("  found parent.");
		break;
	case ISC_R_NOTFOUND:
		printf("  name not found.");
		break;
	default:
		printf("  unexpected result: %s\n", dns_result_totext(result));
		return;
	}

	if (node1 != NULL && node1->data != NULL) {
		printf("  data at node: ");
		print_name(node1->data);
	} else {
		printf("  no data at node.");
	}

	if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH) {
		printf("\n  name from dns_rbt_findnode: ");
		print_name(foundname);
	}

	result = dns_rbtnodechain_current(&chain, foundname, origin, &node2);

	if (result == ISC_R_SUCCESS) {
		printf("\n  name from dns_rbtnodechain_current: ");

		result = dns_name_concatenate(foundname, origin, fullname,
					      NULL);
		if (result == ISC_R_SUCCESS) {
			print_name(fullname);
		} else {
			printf("%s\n", dns_result_totext(result));
		}
		printf("\n      (foundname = ");
		print_name(foundname);
		printf(", origin = ");
		print_name(origin);
		printf(")\n");
		if (nodes_should_match && node1 != node2) {
			printf("  nodes returned from each function "
			       "DO NOT match!\n");
		}
	} else {
		printf("\n  result from dns_rbtnodechain_current: %s\n",
		       dns_result_totext(result));
	}

	printf("  level_matches = %u, level_count = %u\n", chain.level_matches,
	       chain.level_count);
}

static void
iterate(dns_rbt_t *rbt, bool forward) {
	dns_name_t foundname, *origin;
	dns_rbtnodechain_t chain;
	dns_fixedname_t fixedorigin;
	isc_result_t result;
	isc_result_t (*move)(dns_rbtnodechain_t *chain, dns_name_t *name,
			     dns_name_t *origin);

	dns_rbtnodechain_init(&chain);

	dns_name_init(&foundname, NULL);
	origin = dns_fixedname_initname(&fixedorigin);

	if (forward) {
		printf("iterating forward\n");
		move = dns_rbtnodechain_next;

		result = dns_rbtnodechain_first(&chain, rbt, &foundname,
						origin);
	} else {
		printf("iterating backward\n");
		move = dns_rbtnodechain_prev;

		result = dns_rbtnodechain_last(&chain, rbt, &foundname, origin);
	}

	if (result != ISC_R_SUCCESS && result != DNS_R_NEWORIGIN) {
		printf("start not found!\n");
	} else {
		for (;;) {
			if (result == DNS_R_NEWORIGIN) {
				printf("  new origin: ");
				print_name(origin);
				printf("\n");
			}

			if (result == ISC_R_SUCCESS ||
			    result == DNS_R_NEWORIGIN)
			{
				print_name(&foundname);
				printf("\n");
			} else {
				if (result != ISC_R_NOMORE) {
					printf("UNEXPECTED ITERATION ERROR: %s",
					       dns_result_totext(result));
				}
				break;
			}

			result = move(&chain, &foundname, origin);
		}
	}
}

#define CMDCHECK(s) (strncasecmp(command, (s), length) == 0)
#define PRINTERR(r)             \
	if (r != ISC_R_SUCCESS) \
		printf("... %s\n", dns_result_totext(r));

int
main(int argc, char **argv) {
	char *command, *arg, buffer[1024];
	const char *whitespace;
	dns_name_t *name, *foundname;
	dns_fixedname_t fixedname;
	dns_rbt_t *rbt = NULL;
	int length, ch;
	bool show_final_mem = false;
	isc_result_t result;
	void *data;

	progname = strrchr(*argv, '/');
	if (progname != NULL) {
		progname++;
	} else {
		progname = *argv;
	}

	while ((ch = isc_commandline_parse(argc, argv, "m")) != -1) {
		switch (ch) {
		case 'm':
			show_final_mem = true;
			break;
		}
	}

	argc -= isc_commandline_index;
	argv += isc_commandline_index;
	POST(argv);

	if (argc > 1) {
		printf("Usage: %s [-m]\n", progname);
		exit(1);
	}

	setbuf(stdout, NULL);

	/*
	 * So isc_mem_stats() can report any allocation leaks.
	 */
	isc_mem_debugging = ISC_MEM_DEBUGRECORD;

	isc_mem_create(&mctx);

	result = dns_rbt_create(mctx, delete_name, NULL, &rbt);
	if (result != ISC_R_SUCCESS) {
		printf("dns_rbt_create: %s: exiting\n",
		       dns_result_totext(result));
		exit(1);
	}

	whitespace = " \t";

	while (fgets(buffer, sizeof(buffer), stdin) != NULL) {
		length = strlen(buffer);

		if (buffer[length - 1] != '\n') {
			printf("line to long (%lu max), ignored\n",
			       (unsigned long)sizeof(buffer) - 2);
			continue;
		}

		buffer[length - 1] = '\0';

		command = buffer + strspn(buffer, whitespace);

		if (*command == '#') {
			continue;
		}

		arg = strpbrk(command, whitespace);
		if (arg != NULL) {
			*arg++ = '\0';
			arg += strspn(arg, whitespace);
		}

		length = strlen(command);
		if (*command != '\0') {
			if (CMDCHECK("add")) {
				name = create_name(arg);
				if (name != NULL) {
					printf("adding name %s\n", arg);
					result = dns_rbt_addname(rbt, name,
								 name);
					PRINTERR(result);
				}
			} else if (CMDCHECK("delete")) {
				name = create_name(arg);
				if (name != NULL) {
					printf("deleting name %s\n", arg);
					result = dns_rbt_deletename(rbt, name,
								    false);
					PRINTERR(result);
					delete_name(name, NULL);
				}
			} else if (CMDCHECK("nuke")) {
				name = create_name(arg);
				if (name != NULL) {
					printf("nuking name %s "
					       "and its descendants\n",
					       arg);
					result = dns_rbt_deletename(rbt, name,
								    true);
					PRINTERR(result);
					delete_name(name, NULL);
				}
			} else if (CMDCHECK("search")) {
				name = create_name(arg);
				if (name != NULL) {
					printf("searching for name %s ... ",
					       arg);

					foundname = dns_fixedname_initname(
						&fixedname);
					data = NULL;

					result = dns_rbt_findname(
						rbt, name, 0, foundname, &data);
					switch (result) {
					case ISC_R_SUCCESS:
						printf("found exact: ");
						print_name(data);
						putchar('\n');
						break;
					case DNS_R_PARTIALMATCH:
						printf("found parent: ");
						print_name(data);
						printf("\n\t(foundname: ");
						print_name(foundname);
						printf(")\n");
						break;
					case ISC_R_NOTFOUND:
						printf("NOT FOUND!\n");
						break;
					case ISC_R_NOMEMORY:
						printf("OUT OF MEMORY!\n");
						break;
					default:
						printf("UNEXPECTED RESULT\n");
					}

					delete_name(name, NULL);
				}
			} else if (CMDCHECK("check")) {
				/*
				 * Or "chain".  I know, I know.  Lame name.
				 * I was having a hard time thinking of a
				 * name (especially one that did not have
				 * a conflicting first letter with another
				 * command) that would differentiate this
				 * from the search command.
				 *
				 * But it is just a test program, eh?
				 */
				name = create_name(arg);
				if (name != NULL) {
					detail(rbt, name);

					delete_name(name, NULL);
				}
			} else if (CMDCHECK("forward")) {
				iterate(rbt, true);
			} else if (CMDCHECK("backward")) {
				iterate(rbt, false);
			} else if (CMDCHECK("print")) {
				if (arg == NULL || *arg == '\0') {
					dns_rbt_printtext(rbt, NULL, stdout);
				} else {
					printf("usage: print\n");
				}
			} else if (CMDCHECK("quit")) {
				if (arg == NULL || *arg == '\0') {
					break;
				} else {
					printf("usage: quit\n");
				}
			} else {
				printf("a(dd) NAME, d(elete) NAME, "
				       "s(earch) NAME, p(rint), or q(uit)\n");
			}
		}
	}

	dns_rbt_destroy(&rbt);

	if (show_final_mem) {
		isc_mem_stats(mctx, stderr);
	}

	return (0);
}