-- luacheck: ignore 212/self

local sql = require "util.sql";

local xml_parse = require "util.xml".parse;

local resolve_relative_path = require "util.paths".resolve_relative_path;

local stanza_preserialize = require "util.stanza".preserialize;

local unpack = unpack

local function iterator(result)

	return function(result_)

		local row = result_();

		if row ~= nil then

			return unpack(row);

		end

	end, result, nil;

end

local default_params = { driver = "SQLite3" };

local engine;

local host = module.host;

local user, store;

local function keyval_store_get()

	if store == "accounts" then

		--for row in engine:select("SELECT `password`,`created_at` FROM `users` WHERE `username`=?", user or "") do

		local result;

		for row in engine:select("SELECT `password` FROM `users` WHERE `username`=? LIMIT 1", user or "") do result = row end

		local password = result[1];

		--local created_at = result[2];

		return { password = password };

	elseif store == "roster" then

		local roster = {};

		local pending = nil;

		--for row in engine:select("SELECT `jid`,`nick`,`subscription`,`ask`,`askmessage`,`server`,`subscribe`,`type`,`created_at` FROM `rosterusers` WHERE `username`=?", user or "") do

		for row in engine:select("SELECT `jid`,`nick`,`subscription`,`ask` FROM `rosterusers` WHERE `username`=?", user or "") do

			local contact = row[1];

			local name = row[2];

			if name == "" then name = nil; end

			local subscription = row[3];

			if subscription == "N" then

				subscription = "none"

			elseif subscription == "B" then

				subscription = "both"

			elseif subscription == "F" then

				subscription = "from"

			elseif subscription == "T" then

				subscription = "to"

			else error("Unknown subscription type: "..subscription) end;

			local ask = row[4];

			if ask == "N" then

				ask = nil;

			elseif ask == "O" then

				ask = "subscribe";

			elseif ask == "I" then

				if pending == nil then pending = {} end;

				pending[contact] = true;

				ask = nil;

			elseif ask == "B" then

				if pending == nil then pending = {} end;

				pending[contact] = true;

				ask = "subscribe";

			else error("Unknown ask type: "..ask); end

			--local askmessage = row[5];

			--local server = row[6];

			--local subscribe = row[7];

			--local type = row[8];

			--local created_at = row[9];

			local groups = {};

			for row in engine:select("SELECT `grp` FROM `rostergroups` WHERE `username`=? AND `jid`=?", user or "", contact) do

				local group = row[1];

				groups[group] = true;

			end

			roster[contact] = { name = name, ask = ask, subscription = subscription, groups = groups };

		end

		return roster;

	elseif store == "vcard" then

		local result = nil;

		for row in engine:select("SELECT `vcard` FROM `vcard` WHERE `username`=? LIMIT 1", user or "") do result = row end

		if not result then

			return nil;

		end

		local data, err = xml_parse(result[1]);

		if data then

			return stanza_preserialize(data);

		end

	elseif store == "private" then

		local private = nil;

		local result;

		for row in engine:select("SELECT `namespace`,`data` FROM `private_storage` WHERE `username`=?", user or "") do

			if private == nil then private = {} end;

			local namespace = row[1];

			local data, err = xml_parse(row[2]);

			if data then

				assert(namespace == data.attr.xmlns, "Wrong namespace in private data!");

				local key = data.name..":"..data.attr.xmlns;

				private[key] = stanza_preserialize(data);

			end

		end

		return private;

	end

end

--- Key/value store API (default store type)

local keyval_store = {};

keyval_store.__index = keyval_store;

function keyval_store:get(username)

	user, store = username, self.store;

	local ok, result = engine:transaction(keyval_store_get);

	if not ok then

		module:log("error", "Unable to read from database %s store for %s: %s", store, username or "<host>", result);

		return nil, result;

	end

	return result;

end

function keyval_store:users()

	local ok, result = engine:transaction(function()

		return engine:select("SELECT `username` FROM `users`");

	end);

	if not ok then return ok, result end

	return iterator(result);

end

local stores = {

	keyval = keyval_store;

};

--- Implement storage driver API

-- FIXME: Some of these operations need to operate on the archive store(s) too

local driver = {};

function driver:open(store, typ)

	local store_mt = stores[typ or "keyval"];

	if store_mt then

		return setmetatable({ store = store }, store_mt);

	end

	return nil, "unsupported-store";

end

function driver:stores(username)

	local query = "SELECT 'accounts', 'roster', 'vcard', 'private'";

	if username == true or not username then

		username = "";

	end

	local ok, result = engine:transaction(function()

		return engine:select(query, host, username);

	end);

	if not ok then return ok, result end

	return iterator(result);

end

--- Initialization

local function normalize_params(params)

	if params.driver == "SQLite3" then

		if params.database ~= ":memory:" then

			params.database = resolve_relative_path(prosody.paths.data or ".", params.database or "prosody.sqlite");

		end

	end

	assert(params.driver and params.database, "Configuration error: Both the SQL driver and the database need to be specified");

	return params;

end

function module.load()

	if prosody.prosodyctl then return; end

	local engines = module:shared("/*/sql/connections");

	local params = normalize_params(module:get_option("sql", default_params));

	engine = engines[sql.db2uri(params)];

	if not engine then

		module:log("debug", "Creating new engine");

		engine = sql:create_engine(params);

		engines[sql.db2uri(params)] = engine;

	end

	module:provides("storage", driver);

end