/* Copyright (c) 2005-2018 Dovecot authors, see the included COPYING file */

#include "lib.h"
#include "array.h"
#include "settings-parser.h"
#include "master-service-settings.h"
#include "config-parser.h"
#include "config-filter.h"
#include "dns-util.h"

struct config_filter_context {
	pool_t pool;
	struct config_filter_parser *const *parsers;
};

static bool config_filter_match_service(const struct config_filter *mask,
					const struct config_filter *filter)
{
	if (mask->service != NULL) {
		if (filter->service == NULL)
			return FALSE;
		if (mask->service[0] == '!') {
			/* not service */
			if (strcmp(filter->service, mask->service + 1) == 0)
				return FALSE;
		} else {
			if (strcmp(filter->service, mask->service) != 0)
				return FALSE;
		}
	}
	return TRUE;
}

static bool
config_filter_match_local_name(const struct config_filter *mask,
			       const char *filter_local_name)
{
	/* Handle multiple names separated by spaces in local_name
	   * Ex: local_name "mail.domain.tld domain.tld mx.domain.tld" { ... } */
	const char *ptr, *local_name = mask->local_name;
	while((ptr = strchr(local_name, ' ')) != NULL) {
		if (dns_match_wildcard(filter_local_name,
		    t_strdup_until(local_name, ptr)) == 0)
			return TRUE;
		local_name = ptr+1;
	}
	return dns_match_wildcard(filter_local_name, local_name) == 0;
}

static bool config_filter_match_rest(const struct config_filter *mask,
				     const struct config_filter *filter)
{
	bool matched;

	if (mask->local_name != NULL) {
		if (filter->local_name == NULL)
			return FALSE;
		T_BEGIN {
			matched = config_filter_match_local_name(mask, filter->local_name);
		} T_END;
		if (!matched)
			return FALSE;
	}
	/* FIXME: it's not comparing full masks */
	if (mask->remote_bits != 0) {
		if (filter->remote_bits == 0)
			return FALSE;
		if (!net_is_in_network(&filter->remote_net, &mask->remote_net,
				       mask->remote_bits))
			return FALSE;
	}
	if (mask->local_bits != 0) {
		if (filter->local_bits == 0)
			return FALSE;
		if (!net_is_in_network(&filter->local_net, &mask->local_net,
				       mask->local_bits))
			return FALSE;
	}
	return TRUE;
}

bool config_filter_match(const struct config_filter *mask,
			 const struct config_filter *filter)
{
	if (!config_filter_match_service(mask, filter))
		return FALSE;

	return config_filter_match_rest(mask, filter);
}

bool config_filters_equal(const struct config_filter *f1,
			  const struct config_filter *f2)
{
	if (null_strcmp(f1->service, f2->service) != 0)
		return FALSE;

	if (f1->remote_bits != f2->remote_bits)
		return FALSE;
	if (!net_ip_compare(&f1->remote_net, &f2->remote_net))
		return FALSE;

	if (f1->local_bits != f2->local_bits)
		return FALSE;
	if (!net_ip_compare(&f1->local_net, &f2->local_net))
		return FALSE;

	if (null_strcasecmp(f1->local_name, f2->local_name) != 0)
		return FALSE;

	return TRUE;
}

struct config_filter_context *config_filter_init(pool_t pool)
{
	struct config_filter_context *ctx;

	ctx = p_new(pool, struct config_filter_context, 1);
	ctx->pool = pool;
	return ctx;
}

void config_filter_deinit(struct config_filter_context **_ctx)
{
	struct config_filter_context *ctx = *_ctx;
	unsigned int i;

	*_ctx = NULL;

	for (i = 0; ctx->parsers[i] != NULL; i++)
		config_filter_parsers_free(ctx->parsers[i]->parsers);
	pool_unref(&ctx->pool);
}

void config_filter_add_all(struct config_filter_context *ctx,
			   struct config_filter_parser *const *parsers)
{
	ctx->parsers = parsers;
}

static int
config_filter_parser_cmp(struct config_filter_parser *const *p1,
			 struct config_filter_parser *const *p2)
{
	const struct config_filter *f1 = &(*p1)->filter, *f2 = &(*p2)->filter;

	/* remote and locals are first, although it doesn't really
	   matter which one comes first */
	if (f1->local_name != NULL && f2->local_name == NULL)
		return -1;
	if (f1->local_name == NULL && f2->local_name != NULL)
		return 1;

	if (f1->local_bits > f2->local_bits)
		return -1;
	if (f1->local_bits < f2->local_bits)
		return 1;

	if (f1->remote_bits > f2->remote_bits)
		return -1;
	if (f1->remote_bits < f2->remote_bits)
		return 1;

	if (f1->service != NULL && f2->service == NULL)
		return -1;
	if (f1->service == NULL && f2->service != NULL)
		return 1;
	return 0;
}

static int
config_filter_parser_cmp_rev(struct config_filter_parser *const *p1,
			     struct config_filter_parser *const *p2)
{
	return -config_filter_parser_cmp(p1, p2);
}

static bool str_array_contains(ARRAY_TYPE(const_string) *arr, const char *str)
{
	const char *p;

	array_foreach_elem(arr, p) {
		if (strcmp(p, str) == 0)
			return TRUE;
	}
	return FALSE;
}

static bool have_changed_settings(const struct config_filter_parser *parser,
				  const char *const *modules)
{
	const unsigned char *changes;
	unsigned int i, j, size;

	for (i = 0; parser->parsers[i].root != NULL; i++) {
		if (!config_module_want_parser(config_module_parsers,
					       modules, parser->parsers[i].root))
			continue;

		changes = settings_parser_get_changes(parser->parsers[i].parser);
		size = parser->parsers[i].root->struct_size;
		for (j = 0; j < size; j++) {
			if (changes[j] != 0)
				return TRUE;
		}
	}
	return FALSE;
}

static struct config_filter_parser *const *
config_filter_find_all(struct config_filter_context *ctx, pool_t pool,
		       const char *const *modules,
		       const struct config_filter *filter,
		       struct master_service_settings_output *output_r)
{
	ARRAY_TYPE(config_filter_parsers) matches;
	ARRAY_TYPE(const_string) service_names;
	unsigned int i;

	i_zero(output_r);

	p_array_init(&matches, pool, 8);
	p_array_init(&service_names, pool, 8);
	for (i = 0; ctx->parsers[i] != NULL; i++) {
		const struct config_filter *mask = &ctx->parsers[i]->filter;

		if (!config_filter_match_service(mask, filter)) {
			if (!str_array_contains(&service_names, mask->service) &&
			    have_changed_settings(ctx->parsers[i], modules))
				array_push_back(&service_names,
						&mask->service);
			continue;
		}

		if (mask->local_bits > 0 || mask->local_name != NULL)
			output_r->service_uses_local = TRUE;
		if (mask->remote_bits > 0)
			output_r->service_uses_remote = TRUE;
		if (config_filter_match_rest(mask, filter)) {
			if (mask->local_bits > 0 || mask->local_name != NULL)
				output_r->used_local = TRUE;
			if (mask->remote_bits > 0)
				output_r->used_remote = TRUE;
			array_push_back(&matches, &ctx->parsers[i]);
		}
	}
	if (filter->service == NULL) {
		array_append_zero(&service_names);
		output_r->specific_services = array_front(&service_names);
	}

	array_sort(&matches, config_filter_parser_cmp);
	array_append_zero(&matches);
	return array_front(&matches);
}

struct config_filter_parser *const *
config_filter_get_all(struct config_filter_context *ctx)
{
	ARRAY_TYPE(config_filter_parsers) filters;
	unsigned int i;

	t_array_init(&filters, 8);
	for (i = 0; ctx->parsers[i] != NULL; i++) {
		array_push_back(&filters, &ctx->parsers[i]);
	}
	array_sort(&filters, config_filter_parser_cmp_rev);
	array_append_zero(&filters);
	return array_front(&filters);
}

struct config_filter_parser *const *
config_filter_find_subset(struct config_filter_context *ctx,
			  const struct config_filter *filter)
{
	ARRAY_TYPE(config_filter_parsers) matches;
	struct config_filter tmp_mask;
	unsigned int i;

	t_array_init(&matches, 8);
	for (i = 0; ctx->parsers[i] != NULL; i++) {
		const struct config_filter *mask = &ctx->parsers[i]->filter;

		if (filter->service != NULL) {
			if (!config_filter_match_service(mask, filter))
				continue;
		}

		tmp_mask = *mask;
		if (filter->local_name == NULL)
			tmp_mask.local_name = NULL;
		if (filter->local_bits == 0)
			tmp_mask.local_bits = 0;
		if (filter->remote_bits == 0)
			tmp_mask.remote_bits = 0;

		if (config_filter_match_rest(&tmp_mask, filter))
			array_push_back(&matches, &ctx->parsers[i]);
	}
	array_sort(&matches, config_filter_parser_cmp_rev);
	array_append_zero(&matches);
	return array_front(&matches);
}

static bool
config_filter_is_superset(const struct config_filter *sup,
			  const struct config_filter *filter)
{
	/* assume that both of the filters match the same subset, so we don't
	   need to compare IPs and service name. */
	if (sup->local_bits > filter->local_bits)
		return FALSE;
	if (sup->remote_bits > filter->remote_bits)
		return FALSE;
	if (sup->local_name != NULL && filter->local_name == NULL) {
		i_warning("%s", sup->local_name);
		return FALSE;
	}
	if (sup->service != NULL && filter->service == NULL)
		return FALSE;
	return TRUE;
}

static int
config_module_parser_apply_changes(struct config_module_parser *dest,
				   const struct config_filter_parser *src,
				   pool_t pool, const char **error_r)
{
	const char *conflict_key;
	unsigned int i;

	for (i = 0; dest[i].root != NULL; i++) {
		if (settings_parser_apply_changes(dest[i].parser,
						  src->parsers[i].parser, pool,
						  error_r == NULL ? NULL :
						  &conflict_key) < 0) {
			i_assert(error_r != NULL);
			*error_r = t_strdup_printf("Conflict in setting %s "
				"found from filter at %s", conflict_key,
				src->file_and_line);
			return -1;
		}
	}
	return 0;
}

int config_filter_parsers_get(struct config_filter_context *ctx, pool_t pool,
			      const char *const *modules,
			      const struct config_filter *filter,
			      struct config_module_parser **parsers_r,
			      struct master_service_settings_output *output_r,
			      const char **error_r)
{
	struct config_filter_parser *const *src;
	struct config_module_parser *dest;
	const char *error = NULL, **error_p;
	unsigned int i, count;

	/* get the matching filters. the most specific ones are handled first,
	   so that if more generic filters try to override settings we'll fail
	   with an error. Merging SET_STRLIST types requires
	   settings_parser_apply_changes() to work a bit unintuitively by
	   letting the destination settings override the source settings. */
	src = config_filter_find_all(ctx, pool, modules, filter, output_r);

	/* all of them should have the same number of parsers.
	   duplicate our initial parsers from the first match */
	for (count = 0; src[0]->parsers[count].root != NULL; count++) ;
	dest = p_new(pool, struct config_module_parser, count + 1);
	for (i = 0; i < count; i++) {
		dest[i] = src[0]->parsers[i];
		dest[i].parser =
			settings_parser_dup(src[0]->parsers[i].parser, pool);
	}

	/* apply the changes from rest of the matches */
	for (i = 1; src[i] != NULL; i++) {
		if (config_filter_is_superset(&src[i]->filter,
					      &src[i-1]->filter))
			error_p = NULL;
		else
			error_p = &error;

		if (config_module_parser_apply_changes(dest, src[i], pool,
						       error_p) < 0) {
			i_assert(error != NULL);
			config_filter_parsers_free(dest);
			*error_r = error;
			return -1;
		}
	}
	*parsers_r = dest;
	return 0;
}

void config_filter_parsers_free(struct config_module_parser *parsers)
{
	unsigned int i;

	for (i = 0; parsers[i].root != NULL; i++)
		settings_parser_deinit(&parsers[i].parser);
}