local json = require "util.json";

local sql = require "util.sql";

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

local uuid = require "util.uuid";

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

local stanza_mt = require"util.stanza".stanza_mt;

local getmetatable = getmetatable;

local t_concat = table.concat;

local function is_stanza(x) return getmetatable(x) == stanza_mt; end

local noop = function() end

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 function serialize(value)

	local t = type(value);

	if t == "string" or t == "boolean" or t == "number" then

		return t, tostring(value);

	elseif is_stanza(value) then

		return "xml", tostring(value);

	elseif t == "table" then

		local value,err = json.encode(value);

		if value then return "json", value; end

		return nil, err;

	end

	return nil, "Unhandled value type: "..t;

end

local function deserialize(t, value)

	if t == "string" then return value;

	elseif t == "boolean" then

		if value == "true" then return true;

		elseif value == "false" then return false; end

	elseif t == "number" then return tonumber(value);

	elseif t == "json" then

		return json.decode(value);

	elseif t == "xml" then

		return xml_parse(value);

	end

end

local host = module.host;

local user, store;

local function keyval_store_get()

	local haveany;

	local result = {};

	for row in engine:select("SELECT `key`,`type`,`value` FROM `prosody` WHERE `host`=? AND `user`=? AND `store`=?", host, user or "", store) do

		haveany = true;

		local k = row[1];

		local v = deserialize(row[2], row[3]);

		if k and v then

			if k ~= "" then result[k] = v; elseif type(v) == "table" then

				for a,b in pairs(v) do

					result[a] = b;

				end

			end

		end

	end

	if haveany then

		return result;

	end

end

local function keyval_store_set(data)

	engine:delete("DELETE FROM `prosody` WHERE `host`=? AND `user`=? AND `store`=?", host, user or "", store);

	if data and next(data) ~= nil then

		local extradata = {};

		for key, value in pairs(data) do

			if type(key) == "string" and key ~= "" then

				local t, value = serialize(value);

				assert(t, value);

				engine:insert("INSERT INTO `prosody` (`host`,`user`,`store`,`key`,`type`,`value`) VALUES (?,?,?,?,?,?)", host, user or "", store, key, t, value);

			else

				extradata[key] = value;

			end

		end

		if next(extradata) ~= nil then

			local t, extradata = serialize(extradata);

			assert(t, extradata);

			engine:insert("INSERT INTO `prosody` (`host`,`user`,`store`,`key`,`type`,`value`) VALUES (?,?,?,?,?,?)", host, user or "", store, "", t, extradata);

		end

	end

	return true;

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:set(username, data)

	user,store = username,self.store;

	return engine:transaction(function()

		return keyval_store_set(data);

	end);

end

function keyval_store:users()

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

		return engine:select("SELECT DISTINCT `user` FROM `prosody` WHERE `host`=? AND `store`=?", host, self.store);

	end);

	if not ok then return ok, result end

	return iterator(result);

end

--- Archive store API

local map_store = {};

map_store.__index = map_store;

function map_store:get(username, key)

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

		if type(key) == "string" and key ~= "" then

			for row in engine:select("SELECT `type`, `value` FROM `prosody` WHERE `host`=? AND `user`=? AND `store`=? AND `key`=?", host, username or "", self.store, key) do

				return deserialize(row[1], row[2]);

			end

		else

			error("TODO: non-string keys");

		end

	end);

	if not ok then return nil, result; end

	return result;

end

function map_store:set(username, key, data)

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

		if type(key) == "string" and key ~= "" then

			engine:delete("DELETE FROM `prosody` WHERE `host`=? AND `user`=? AND `store`=? AND `key`=?",

				host, username or "", self.store, key);

			if data ~= nil then

				local t, value = assert(serialize(data));

				engine:insert("INSERT INTO `prosody` (`host`,`user`,`store`,`key`,`type`,`value`) VALUES (?,?,?,?,?,?)", host, username or "", self.store, key, t, value);

			end

		else

			error("TODO: non-string keys");

		end

		return true;

	end);

	if not ok then return nil, result; end

	return result;

end

local archive_store = {}

archive_store.caps = {

	total = true;

};

archive_store.__index = archive_store

function archive_store:append(username, key, value, when, with)

	if type(when) ~= "number" then

		when, with, value = value, when, with;

	end

	local user,store = username,self.store;

	return engine:transaction(function()

		if key then

			engine:delete("DELETE FROM `prosodyarchive` WHERE `host`=? AND `user`=? AND `store`=? AND `key`=?", host, user or "", store, key);

		else

			key = uuid.generate();

		end

		local t, value = serialize(value);

		engine:insert("INSERT INTO `prosodyarchive` (`host`, `user`, `store`, `when`, `with`, `key`, `type`, `value`) VALUES (?,?,?,?,?,?,?,?)", host, user or "", store, when, with, key, t, value);

		return key;

	end);

end

-- Helpers for building the WHERE clause

local function archive_where(query, args, where)

	-- Time range, inclusive

	if query.start then

		args[#args+1] = query.start

		where[#where+1] = "`when` >= ?"

	end

	if query["end"] then

		args[#args+1] = query["end"];

		if query.start then

			where[#where] = "`when` BETWEEN ? AND ?" -- is this inclusive?

		else

			where[#where+1] = "`when` <= ?"

		end

	end

	-- Related name

	if query.with then

		where[#where+1] = "`with` = ?";

		args[#args+1] = query.with

	end

	-- Unique id

	if query.key then

		where[#where+1] = "`key` = ?";

		args[#args+1] = query.key

	end

end

local function archive_where_id_range(query, args, where)

	local args_len = #args

	-- Before or after specific item, exclusive

	if query.after then  -- keys better be unique!

		where[#where+1] = "`sort_id` > (SELECT `sort_id` FROM `prosodyarchive` WHERE `key` = ? AND `host` = ? AND `user` = ? AND `store` = ? LIMIT 1)"

		args[args_len+1], args[args_len+2], args[args_len+3], args[args_len+4] = query.after, args[1], args[2], args[3];

		args_len = args_len + 4

	end

	if query.before then

		where[#where+1] = "`sort_id` < (SELECT `sort_id` FROM `prosodyarchive` WHERE `key` = ? AND `host` = ? AND `user` = ? AND `store` = ? LIMIT 1)"

		args[args_len+1], args[args_len+2], args[args_len+3], args[args_len+4] = query.before, args[1], args[2], args[3];

	end

end

function archive_store:find(username, query)

	query = query or {};

	local user,store = username,self.store;

	local total;

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

		local sql_query = "SELECT `key`, `type`, `value`, `when`, `with` FROM `prosodyarchive` WHERE %s ORDER BY `sort_id` %s%s;";

		local args = { host, user or "", store, };

		local where = { "`host` = ?", "`user` = ?", "`store` = ?", };

		archive_where(query, args, where);

		-- Total matching

		if query.total then

			local stats = engine:select("SELECT COUNT(*) FROM `prosodyarchive` WHERE " .. t_concat(where, " AND "), unpack(args));

			if stats then

				local _total = stats()

				total = _total and _total[1];

			end

			if query.limit == 0 then -- Skip the real query

				return noop, total;

			end

		end

		archive_where_id_range(query, args, where);

		if query.limit then

			args[#args+1] = query.limit;

		end

		sql_query = sql_query:format(t_concat(where, " AND "), query.reverse and "DESC" or "ASC", query.limit and " LIMIT ?" or "");

		module:log("debug", sql_query);

		return engine:select(sql_query, unpack(args));

	end);

	if not ok then return ok, result end

	return function()

		local row = result();

		if row ~= nil then

			return row[1], deserialize(row[2], row[3]), row[4], row[5];

		end

	end, total;

end

function archive_store:delete(username, query)

	query = query or {};

	local user,store = username,self.store;

	return engine:transaction(function()

		local sql_query = "DELETE FROM `prosodyarchive` WHERE %s;";

		local args = { host, user or "", store, };

		local where = { "`host` = ?", "`user` = ?", "`store` = ?", };

		if user == true then

			table.remove(args, 2);

			table.remove(where, 2);

		end

		archive_where(query, args, where);

		archive_where_id_range(query, args, where);

		sql_query = sql_query:format(t_concat(where, " AND "));

		module:log("debug", sql_query);

		return engine:delete(sql_query, unpack(args));

	end);

end

local stores = {

	keyval = keyval_store;

	map = map_store;

	archive = archive_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 DISTINCT `store` FROM `prosody` WHERE `host`=? AND `user`" ..

		(username == true and "!=?" or "=?");

	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

function driver:purge(username)

	return engine:transaction(function()

		local stmt,err = engine:delete("DELETE FROM `prosody` WHERE `host`=? AND `user`=?", host, username);

		return true, err;

	end);

end

--- Initialization

local function create_table(name)

	local Table, Column, Index = sql.Table, sql.Column, sql.Index;

	local ProsodyTable = Table {

		name= name or "prosody";

		Column { name="host", type="TEXT", nullable=false };

		Column { name="user", type="TEXT", nullable=false };

		Column { name="store", type="TEXT", nullable=false };

		Column { name="key", type="TEXT", nullable=false };

		Column { name="type", type="TEXT", nullable=false };

		Column { name="value", type="MEDIUMTEXT", nullable=false };

		Index { name="prosody_index", "host", "user", "store", "key" };

	};

	engine:transaction(function()

		ProsodyTable:create(engine);

	end);

	local ProsodyArchiveTable = Table {

		name="prosodyarchive";

		Column { name="sort_id", type="INTEGER", primary_key=true, auto_increment=true };

		Column { name="host", type="TEXT", nullable=false };

		Column { name="user", type="TEXT", nullable=false };

		Column { name="store", type="TEXT", nullable=false };

		Column { name="key", type="TEXT", nullable=false }; -- item id

		Column { name="when", type="INTEGER", nullable=false }; -- timestamp

		Column { name="with", type="TEXT", nullable=false }; -- related id

		Column { name="type", type="TEXT", nullable=false };

		Column { name="value", type="MEDIUMTEXT", nullable=false };