-- Prosody IM

-- Copyright (C) 2008-2010 Matthew Wild

-- Copyright (C) 2008-2010 Waqas Hussain

-- 

-- This project is MIT/X11 licensed. Please see the

-- COPYING file in the source package for more information.

--

local format = string.format;

local setmetatable, type = setmetatable, type;

local pairs, ipairs = pairs, ipairs;

local char = string.char;

local loadfile, setfenv, pcall = loadfile, setfenv, pcall;

local log = require "util.logger".init("datamanager");

local io_open = io.open;

local os_remove = os.remove;

local tostring, tonumber = tostring, tonumber;

local error = error;

local next = next;

local t_insert = table.insert;

local append = require "util.serialization".append;

local path_separator = "/"; if os.getenv("WINDIR") then path_separator = "\\" end

local lfs = require "lfs";

local raw_mkdir;

if prosody.platform == "posix" then

	raw_mkdir = require "util.pposix".mkdir; -- Doesn't trample on umask

else

	raw_mkdir = lfs.mkdir;

end

module "datamanager"

---- utils -----

local encode, decode;

do

	local urlcodes = setmetatable({}, { __index = function (t, k) t[k] = char(tonumber("0x"..k)); return t[k]; end });

	decode = function (s)

		return s and (s:gsub("+", " "):gsub("%%([a-fA-F0-9][a-fA-F0-9])", urlcodes));

	end

	encode = function (s)

		return s and (s:gsub("%W", function (c) return format("%%%02x", c:byte()); end));

	end

end

local _mkdir = {};

local function mkdir(path)

	path = path:gsub("/", path_separator); -- TODO as an optimization, do this during path creation rather than here

	if not _mkdir[path] then

		raw_mkdir(path);

		_mkdir[path] = true;

	end

	return path;

end

local data_path = "data";

local callbacks = {};

------- API -------------

function set_data_path(path)

	log("debug", "Setting data path to: %s", path);

	data_path = path;

end

local function callback(username, host, datastore, data)

	for _, f in ipairs(callbacks) do

		username, host, datastore, data = f(username, host, datastore, data);

		if username == false then break; end

	end

	return username, host, datastore, data;

end

function add_callback(func)

	if not callbacks[func] then -- Would you really want to set the same callback more than once?

		callbacks[func] = true;

		callbacks[#callbacks+1] = func;

		return true;

	end

end

function remove_callback(func)

	if callbacks[func] then

		for i, f in ipairs(callbacks) do

			if f == func then

				callbacks[i] = nil;

				callbacks[f] = nil;

				return true;

			end

		end

	end

end

function getpath(username, host, datastore, ext, create)

	ext = ext or "dat";

	host = (host and encode(host)) or "_global";

	username = username and encode(username);

	if username then

		if create then mkdir(mkdir(mkdir(data_path).."/"..host).."/"..datastore); end

		return format("%s/%s/%s/%s.%s", data_path, host, datastore, username, ext);

	elseif host then

		if create then mkdir(mkdir(data_path).."/"..host); end

		return format("%s/%s/%s.%s", data_path, host, datastore, ext);

	else

		if create then mkdir(data_path); end

		return format("%s/%s.%s", data_path, datastore, ext);

	end

end

function load(username, host, datastore)

	local data, ret = loadfile(getpath(username, host, datastore));

	if not data then

		local mode = lfs.attributes(getpath(username, host, datastore), "mode");

		if not mode then

			log("debug", "Failed to load "..datastore.." storage ('"..ret.."') for user: "..(username or "nil").."@"..(host or "nil"));

			return nil;

		else -- file exists, but can't be read

			-- TODO more detailed error checking and logging?

			log("error", "Failed to load "..datastore.." storage ('"..ret.."') for user: "..(username or "nil").."@"..(host or "nil"));

			return nil, "Error reading storage";

		end

	end

	setfenv(data, {});

	local success, ret = pcall(data);

	if not success then

		log("error", "Unable to load "..datastore.." storage ('"..ret.."') for user: "..(username or "nil").."@"..(host or "nil"));

		return nil, "Error reading storage";

	end

	return ret;

end

function store(username, host, datastore, data)

	if not data then

		data = {};

	end

	username, host, datastore, data = callback(username, host, datastore, data);

	if username == false then

		return true; -- Don't save this data at all

	end

	-- save the datastore

	local f, msg = io_open(getpath(username, host, datastore, nil, true), "w+");

	if not f then

		log("error", "Unable to write to "..datastore.." storage ('"..msg.."') for user: "..(username or "nil").."@"..(host or "nil"));

		return nil, "Error saving to storage";

	end

	f:write("return ");

	append(f, data);

	f:close();

	if next(data) == nil then -- try to delete empty datastore

		log("debug", "Removing empty %s datastore for user %s@%s", datastore, username or "nil", host or "nil");

		os_remove(getpath(username, host, datastore));

	end

	-- we write data even when we are deleting because lua doesn't have a

	-- platform independent way of checking for non-exisitng files

	return true;

end

function list_append(username, host, datastore, data)

	if not data then return; end

	if callback(username, host, datastore) == false then return true; end

	-- save the datastore

	local f, msg = io_open(getpath(username, host, datastore, "list", true), "a+");

	if not f then

		log("error", "Unable to write to "..datastore.." storage ('"..msg.."') for user: "..(username or "nil").."@"..(host or "nil"));

		return;

	end

	f:write("item(");

	append(f, data);

	f:write(");\n");

	f:close();

	return true;

end

function list_store(username, host, datastore, data)

	if not data then

		data = {};

	end

	if callback(username, host, datastore) == false then return true; end

	-- save the datastore

	local f, msg = io_open(getpath(username, host, datastore, "list", true), "w+");

	if not f then

		log("error", "Unable to write to "..datastore.." storage ('"..msg.."') for user: "..(username or "nil").."@"..(host or "nil"));

		return;

	end

	for _, d in ipairs(data) do

		f:write("item(");

		append(f, d);

		f:write(");\n");

	end

	f:close();

	if next(data) == nil then -- try to delete empty datastore

		log("debug", "Removing empty %s datastore for user %s@%s", datastore, username or "nil", host or "nil");

		os_remove(getpath(username, host, datastore, "list"));

	end

	-- we write data even when we are deleting because lua doesn't have a

	-- platform independent way of checking for non-exisitng files

	return true;

end

function list_load(username, host, datastore)

	local data, ret = loadfile(getpath(username, host, datastore, "list"));

	if not data then

	end

	local items = {};

	setfenv(data, {item = function(i) t_insert(items, i); end});

	local success, ret = pcall(data);

	if not success then

		log("error", "Unable to load "..datastore.." storage ('"..ret.."') for user: "..(username or "nil").."@"..(host or "nil"));

		return nil;

	end

	return items;

end

return _M;