/* Copyright (c) 2005-2016 Dovecot authors, see the included COPYING file */

#include "lib.h"
#include "ioloop.h"
#include "str.h"
#include "dict.h"
#include "mail-user.h"
#include "mail-namespace.h"
#include "quota-private.h"


#define DICT_QUOTA_CURRENT_PATH DICT_PATH_PRIVATE"quota/"
#define DICT_QUOTA_CURRENT_BYTES_PATH DICT_QUOTA_CURRENT_PATH"storage"
#define DICT_QUOTA_CURRENT_COUNT_PATH DICT_QUOTA_CURRENT_PATH"messages"

struct dict_quota_root {
	struct quota_root root;
	struct dict *dict;
	struct timeout *to_update;
	bool disable_unset;
};

extern struct quota_backend quota_backend_dict;

static struct quota_root *dict_quota_alloc(void)
{
	struct dict_quota_root *root;

	root = i_new(struct dict_quota_root, 1);
	return &root->root;
}

static int dict_quota_init(struct quota_root *_root, const char *args,
			   const char **error_r)
{
	struct dict_quota_root *root = (struct dict_quota_root *)_root;
	struct dict_settings set;
	const char *username, *p, *error;

	p = args == NULL ? NULL : strchr(args, ':');
	if (p == NULL) {
		*error_r = "URI missing from parameters";
		return -1;
	}

	username = t_strdup_until(args, p);
	args = p+1;

	for (;;) {
		/* FIXME: pretty ugly in here. the parameters should have
		   been designed to be extensible. do it in a future version */
		if (strncmp(args, "noenforcing:", 12) == 0) {
			_root->no_enforcing = TRUE;
			args += 12;
		} else if (strncmp(args, "hidden:", 7) == 0) {
			_root->hidden = TRUE;
			args += 7;
		} else if (strncmp(args, "ignoreunlimited:", 16) == 0) {
			_root->disable_unlimited_tracking = TRUE;
			args += 16;
		} else if (strncmp(args, "no-unset:", 9) == 0) {
			root->disable_unset = TRUE;
			args += 9;
		} else if (strncmp(args, "ns=", 3) == 0) {
			p = strchr(args, ':');
			if (p == NULL)
				break;

			_root->ns_prefix = p_strdup_until(_root->pool,
							  args + 3, p);
			args = p + 1;
		} else {
			break;
		}
	}

	if (*username == '\0')
		username = _root->quota->user->username;

	if (_root->quota->set->debug) {
		i_debug("dict quota: user=%s, uri=%s, noenforcing=%d",
			username, args, _root->no_enforcing);
	}

	/* FIXME: we should use 64bit integer as datatype instead but before
	   it can actually be used don't bother */
	memset(&set, 0, sizeof(set));
	set.username = username;
	set.base_dir = _root->quota->user->set->base_dir;
	if (mail_user_get_home(_root->quota->user, &set.home_dir) <= 0)
		set.home_dir = NULL;
	if (dict_init_full(args, &set, &root->dict, &error) < 0) {
		*error_r = t_strdup_printf("dict_init(%s) failed: %s", args, error);
		return -1;
	}
	return 0;
}

static void dict_quota_deinit(struct quota_root *_root)
{
	struct dict_quota_root *root = (struct dict_quota_root *)_root;

	i_assert(root->to_update == NULL);

	if (root->dict != NULL)
		dict_deinit(&root->dict);
	i_free(root);
}

static const char *const *
dict_quota_root_get_resources(struct quota_root *root ATTR_UNUSED)
{
	static const char *resources[] = {
		QUOTA_NAME_STORAGE_KILOBYTES, QUOTA_NAME_MESSAGES, NULL
	};

	return resources;
}

static int
dict_quota_count(struct dict_quota_root *root,
		 bool want_bytes, uint64_t *value_r)
{
	struct dict_transaction_context *dt;
	uint64_t bytes, count;

	if (quota_count(&root->root, &bytes, &count) < 0)
		return -1;

	T_BEGIN {
		dt = dict_transaction_begin(root->dict);
		/* these unsets are mainly necessary for pgsql, because its
		   trigger otherwise increases quota without deleting it.
		   but some people with other databases want to store the
		   quota usage among other data in the same row, which
		   shouldn't be deleted. */
		if (!root->disable_unset) {
			dict_unset(dt, DICT_QUOTA_CURRENT_BYTES_PATH);
			dict_unset(dt, DICT_QUOTA_CURRENT_COUNT_PATH);
		}
		dict_set(dt, DICT_QUOTA_CURRENT_BYTES_PATH, dec2str(bytes));
		dict_set(dt, DICT_QUOTA_CURRENT_COUNT_PATH, dec2str(count));
	} T_END;

	dict_transaction_commit_async(&dt, NULL, NULL);
	*value_r = want_bytes ? bytes : count;
	return 1;
}

static int
dict_quota_get_resource(struct quota_root *_root,
			const char *name, uint64_t *value_r)
{
	struct dict_quota_root *root = (struct dict_quota_root *)_root;
	bool want_bytes;
	int ret;

	if (strcmp(name, QUOTA_NAME_STORAGE_BYTES) == 0)
		want_bytes = TRUE;
	else if (strcmp(name, QUOTA_NAME_MESSAGES) == 0)
		want_bytes = FALSE;
	else
		return 0;

	T_BEGIN {
		const char *value;

		ret = dict_lookup(root->dict, unsafe_data_stack_pool,
				  want_bytes ? DICT_QUOTA_CURRENT_BYTES_PATH :
				  DICT_QUOTA_CURRENT_COUNT_PATH, &value);
		if (ret < 0)
			*value_r = 0;
		else {
			intmax_t tmp;

			/* recalculate quota if it's negative or if it
			   wasn't found */
			if (ret == 0 || str_to_intmax(value, &tmp) < 0)
				tmp = -1;
			if (tmp >= 0)
				*value_r = tmp;
			else {
				ret = dict_quota_count(root, want_bytes,
						       value_r);
			}
		}
	} T_END;
	return ret;
}

static void dict_quota_recalc_timeout(struct dict_quota_root *root)
{
	uint64_t value;

	timeout_remove(&root->to_update);
	(void)dict_quota_count(root, TRUE, &value);
}

static void dict_quota_update_callback(int ret, void *context)
{
	struct dict_quota_root *root = context;

	if (ret == 0) {
		/* row doesn't exist, need to recalculate it */
		if (root->to_update == NULL)
			root->to_update = timeout_add_short(0, dict_quota_recalc_timeout, root);
	} else if (ret < 0) {
		i_error("dict quota: Quota update failed, it's now desynced");
	}
}

static int
dict_quota_update(struct quota_root *_root, 
		  struct quota_transaction_context *ctx)
{
	struct dict_quota_root *root = (struct dict_quota_root *) _root;
	struct dict_transaction_context *dt;
	uint64_t value;

	if (ctx->recalculate) {
		if (dict_quota_count(root, TRUE, &value) < 0)
			return -1;
	} else {
		dt = dict_transaction_begin(root->dict);
		if (ctx->bytes_used != 0) {
			dict_atomic_inc(dt, DICT_QUOTA_CURRENT_BYTES_PATH,
					ctx->bytes_used);
		}
		if (ctx->count_used != 0) {
			dict_atomic_inc(dt, DICT_QUOTA_CURRENT_COUNT_PATH,
					ctx->count_used);
		}
		dict_transaction_commit_async(&dt, dict_quota_update_callback,
					      root);
	}
	return 0;
}

static void dict_quota_flush(struct quota_root *_root)
{
	struct dict_quota_root *root = (struct dict_quota_root *)_root;

	(void)dict_wait(root->dict);
	if (root->to_update != NULL) {
		dict_quota_recalc_timeout(root);
		(void)dict_wait(root->dict);
	}
}

struct quota_backend quota_backend_dict = {
	"dict",

	{
		dict_quota_alloc,
		dict_quota_init,
		dict_quota_deinit,
		NULL,
		NULL,
		NULL,
		dict_quota_root_get_resources,
		dict_quota_get_resource,
		dict_quota_update,
		NULL,
		dict_quota_flush
	}
};