utilities.lua

-- utilities.lua
-- Functions shared among plugins.

function get_word(s, i) -- get the indexed word in a string

	s = s or ''
	i = i or 1

	local t = {}
	for w in s:gmatch('%g+') do
		table.insert(t, w)
	end

	return t[i] or false

end

function string:input() -- Returns the string after the first space.
	if not self:find(' ') then
		return false
	end
	return self:sub(self:find(' ')+1)
end

function string:mEscape() -- Remove the markdown.
	self = self:gsub('*', '\\*'):gsub('_', '\\_'):gsub('`', '\\`'):gsub('%]', '\\]'):gsub('%[', '\\[')
	return self
end

function string:mEscape_hard() -- Remove the markdown.
	self = self:gsub('*', ''):gsub('_', ''):gsub('`', ''):gsub('%[', ''):gsub('%]', '')
	return self
end

function is_bot_owner(msg, real_owner) --if real owner is true, the function will return true only if msg.from.id == config.admin.owner
	local id
	if msg.adder and msg.adder.id then
		id = msg.adder.id
	else
		id = msg.from.id
	end
	if real_owner then
		if id == config.admin.owner then
			return true
		end
	else
		if id and config.admin.admins[id] then
			return true
		end
	end
	return false
end

function is_bot_admin(chat_id)
	local status = api.getChatMember(chat_id, bot.id).result.status
	if not(status == 'administrator') then
		return false
	else
		return true
	end
end

function is_mod(msg)
	local res = api.getChatMember(msg.chat.id, msg.from.id)
	if not res then
		return false, false
	end
	local status = res.result.status
	if status == 'creator' or status == 'administrator' then
		return true, true
	else
		return false, true
	end
end

function is_mod2(chat_id, user_id)
	local res = api.getChatMember(chat_id, user_id)
	if not res then
		return false, false
	end
	local status = res.result.status
	if status == 'creator' or status == 'administrator' then
		return true, true
	else
		return false, true
	end
end

function is_owner(msg)
	local status = api.getChatMember(msg.chat.id, msg.from.id).result.status
	if status == 'creator' then
		return true
	else
		return false
	end
end

function is_owner2(chat_id, user_id)
	local status = api.getChatMember(chat_id, user_id).result.status
	if status == 'creator' then
		return true
	else
		return false
	end
end

function set_owner(chat_id, user_id, nick)
	db:hset('chat:'..chat_id..':mod', user_id, nick) --mod
	db:hset('chat:'..chat_id..':owner', user_id, nick) --owner
end

function is_locked(msg, cmd)
  	local hash = 'chat:'..msg.chat.id..':settings'
  	local is_adminmode_locked = db:hget(hash, 'Admin_mode')
  	if is_adminmode_locked == 'no' and (cmd == 'Rules' or cmd == 'About' or cmd == 'Modlist' or cmd == 'Extra') then
  		return true
  	end
  	local current = db:hget(hash, cmd)
  	if current == 'yes' then
  		return true
  	end
  	return false
end

function is_banned(chat_id, user_id)
	--useful only for normal groups
	local hash = 'chat:'..chat_id..':banned'
	local res = db:sismember(hash, user_id)
	if res then
		return true
	else
		return false
	end
end

function is_blocked_global(id)
	if db:sismember('bot:blocked', id) then
		return true
	else
		return false
	end
end

function mystat(cmd)
	db:hincrby('commands:stats', cmd, 1)
end	

function string:trim() -- Trims whitespace from a string.
	local s = self:gsub('^%s*(.-)%s*$', '%1')
	return s
end

function load_data(filename) -- Loads a JSON file as a table.

	local f = io.open(filename)
	if not f then
		return {}
	end
	local s = f:read('*all')
	f:close()
	local data = JSON.decode(s)

	return data

end

function save_data(filename, data) -- Saves a table to a JSON file.

	local s = JSON.encode(data)
	local f = io.open(filename, 'w')
	f:write(s)
	f:close()

end

function vardump(value)
  print(serpent.block(value, {comment=false}))
end

function vtext(value)
  return serpent.block(value, {comment=false})
end

local function per_away(text)
	local text = tostring(text):gsub('%%', '£&£')
	return text
end

function make_text(text, par1, par2, par3, par4, par5)
	if par1 then text = text:gsub('&&&1', per_away(par1)) end
	if par2 then text = text:gsub('&&&2', per_away(par2)) end
	if par3 then text = text:gsub('&&&3', per_away(par3)) end
	if par4 then text = text:gsub('&&&4', per_away(par4)) end
	if par5 then text = text:gsub('&&&5', per_away(par5)) end
	text = text:gsub('£&£', '%%')
	return text
end

function string:build_text(par1, par2, par3, par4, par5)
	if par1 then self = self:gsub('&&&1', per_away(par1)) end
	if par2 then self = self:gsub('&&&2', per_away(par2)) end
	if par3 then self = self:gsub('&&&3', per_away(par3)) end
	if par4 then self = self:gsub('&&&4', per_away(par4)) end
	if par5 then self = self:gsub('&&&5', per_away(par5)) end
	self = self:gsub('£&£', '%%')
	return self
end

function write_file(path, text, mode)
	if not mode then
		mode = "w"
	end
	file = io.open(path, mode)
	if not file then
		create_folder('logs')
		file = io.open(path, mode)
		if not file then
			return false
		end
	end
	file:write(text)
	file:close()
	return true
end

local function create_folder(name)
	local cmd = io.popen('sudo mkdir '..name)
    cmd:read('*all')
    cmd = io.popen('sudo chmod -R 777 '..name)
    cmd:read('*all')
    cmd:close()
end

function save_log(action, arg1, arg2, arg3, arg4)
	if action == 'send_msg' then
		local text = os.date('[%A, %d %B %Y at %X]')..'\n'..arg1..'\n\n'
		local path = "./logs/msgs_errors.txt"
		local res = write_file(path, text, "a")
		if not res then
			create_folder('logs')
			write_file(path, text, "a")
		end
    elseif action == 'errors' then
    	--error, from, chat, text
    	local path = "./logs/errors.txt"
    	local text = os.date('[%A, %d %B %Y at %X]')..'\nERROR: '..arg1
    	if arg2 then
    		text = text..'\nFROM: '..arg2
    	end
 		if arg3 then
 			text = text..'\nCHAT: '..arg3
 		end
 		if arg4 then
 			text = text..'\nTEXT: '..arg4
 		end
 		text = text..'\n\n'
 		local res = write_file(path, text, "a")
    	if not res then
			create_folder('logs')
			write_file(path, text, "a")
		end
    end
end

function clone_table(t) --doing "table1 = table2" in lua = create a pointer to table2
  local new_t = {}
  local i, v = next(t, nil)
  while i do
    new_t[i] = v
    i, v = next(t, i)
  end
  return new_t
end

function remove_duplicates(t)
	if type(t) ~= 'table' then
		return false, 'Table expected, got '..type(t)
	else
		local kv_table = {}
		for i, element in pairs(t) do
			if not kv_table[element] then
				kv_table[element] = true
			end
		end
		
		local k_table = {}
		for key, boolean in pairs(kv_table) do
			k_table[#k_table + 1] = key
		end
		
		return k_table
	end
end		

function get_date(timestamp)
	if not timestamp then
		timestamp = os.time()
	end
	return os.date('%d/%m/%y')
end

function res_user(username)
	local hash = 'bot:usernames'
	local stored = db:hget(hash, username)
	if not stored then
		return false
	else
		return stored
	end
end

function res_user_group(username, chat_id)
	if not username then return false end
	username = username:lower()
	local hash = 'bot:usernames:'..chat_id
	local stored = db:hget(hash, username)
	if stored then
		return stored
	else
		hash = 'bot:usernames'
		stored = db:hget(hash, username)
		if stored then
			return stored
		else
			return false
		end
	end
end

function is_lang_supported(code)
	for i=1,#config.available_languages do
		if code:lower() == config.available_languages[i] then
			return true
		end
	end
	return false
end

function get_media_type(msg)
	if msg.photo then
		return 'image'
	elseif msg.video then
		return 'video'
	elseif msg.audio then
		return 'audio'
	elseif msg.voice then
		return 'voice'
	elseif msg.document then
		if msg.document.mime_type == 'video/mp4' then
			return 'gif'
		else
			return 'file'
		end
	elseif msg.sticker then
		return 'sticker'
	elseif msg.contact then
		return 'contact'
	end
	return false
end

function get_media_id(msg)
	if msg.photo then
		if msg.photo[3] then
			return msg.photo[3].file_id, 'photo'
		else
			if msg.photo[2] then
				return msg.photo[2].file_id, 'photo'
			else
				if msg.photo[1] then
					return msg.photo[1].file_id, 'photo'
				else
					return msg.photo.file_id, 'photo'
				end
			end
		end
	elseif msg.document then
		return msg.document.file_id
	elseif msg.video then
		return msg.video.file_id, 'video'
	elseif msg.audio then
		return msg.audio.file_id
	elseif msg.voice then
		return msg.voice.file_id, 'voice'
	elseif msg.sticker then
		return msg.sticker.file_id
	else
		return false, 'The message has not a media file_id'
	end
end

voice_updated = 0
voice_succ = 0

function give_result(res)
	--doesn't handle a nil "res"
	if res == 1 then
		voice_succ = voice_succ + 1
		return ' done (res: 1)'
	else
		voice_updated = voice_updated + 1
		return ' updated (res: 0)'
	end
end

function migrate_chat_info(old, new, on_request)
	if not old or not new then
		print('A group id is missing')
		return false
	end
	
	local about = db:get('chat:'..old..':about')
	if about then
		db:set('chat:'..new..':about', about)
	end
	
	local rules = db:get('chat:'..old..':rules')
	if rules then
		db:set('chat:'..new..':rules', rules)
	end
	
	for set, default in pairs(config.chat_settings) do
		local old_t = db:hgetall('chat:'..old..':'..set)
		for field, val in pairs(old_t) do
			db:hset('chat:'..new..':'..set, field, val)
		end
	end
	
	local extra = db:hgetall('chat:'..old..':extra')
	for trigger, response in pairs(extra) do
		db:hset('chat:'..new..':extra', trigger, response)
	end
	
	if on_request then
		api.sendReply(msg, 'Should be done')
	end
end

function div()
	print('XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX')
	print('XXXXXXXXXXXXXXXXXX BREAK XXXXXXXXXXXXXXXXXXX')
	print('XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX')
end

function to_supergroup(msg)
	local old = msg.chat.id
	local new = msg.migrate_to_chat_id
	migrate_chat_info(old, new, false)
	cross.remGroup(old, true)
	api.sendMessage(new, '(_service notification: migration of the group executed_)', true)
end

function getname(msg)
    local name = msg.from.first_name
	if msg.from.username then name = name..' (@'..msg.from.username..')' end
    return name
end

function getname_id(msg)
    return msg.from.first_name..' ('..msg.from.id..')'
end

function bash(str)
	local cmd = io.popen(str)
    local result = cmd:read('*all')
    cmd:close()
    return result
end

function download_to_file(url, file_path)--https://github.com/yagop/telegram-bot/blob/master/bot/utils.lua
  --print("url to download: "..url)

  local respbody = {}
  local options = {
    url = url,
    sink = ltn12.sink.table(respbody),
    redirect = true
  }
  -- nil, code, headers, status
  local response = nil
    options.redirect = false
    response = {HTTPS.request(options)}
  local code = response[2]
  local headers = response[3]
  local status = response[4]
  if code ~= 200 then return false, code end

  print("Saved to: "..file_path)

  file = io.open(file_path, "w+")
  file:write(table.concat(respbody))
  file:close()
  return file_path, code
end

function telegram_file_link(res)
	--res = table returned by getFile()
	return "https://api.telegram.org/file/bot"..config.bot_api_key.."/"..res.result.file_path
end

----------------------- specific cross-plugins functions---------------------

local function getAbout(chat_id, ln)
	local hash = 'chat:'..chat_id..':about'
	local about = db:get(hash)
    if not about then
        return lang[ln].setabout.no_bio
    else
       	return about
    end
end

local function getRules(chat_id, ln)
	local hash = 'chat:'..chat_id..':rules'
	local rules = db:get(hash)
    if not rules then
        return lang[ln].setrules.no_rules
    else
       	return rules
    end
end

local function getModlist(chat_id, no_usernames)
	local list, code = api.getChatAdministrators(chat_id)
	if not list then
		if code == 107 then
			return false, code
		else
			return false, false
		end
	end
	local creator = ''
	local adminlist = ''
	local count = 1
	for i,admin in pairs(list.result) do
		local name
		if admin.status == 'administrator' then
			name = admin.user.first_name
			if not no_usernames then
				if admin.user.username then name = name..' (@'..admin.user.username..')' end
			end
			adminlist = adminlist..'*'..count..'* - '..name:mEscape()..'\n'
			count = count + 1
		elseif admin.status == 'creator' then
			creator = admin.user.first_name
			if not no_usernames then
				if admin.user.username then creator = creator..' (@'..admin.user.username..')' end
			end
			creator = creator:mEscape()
		end
	end
	if adminlist == '' then adminlist = '-' end
	if creator == '' then creator = '-' end
	return creator, adminlist
end

local function getExtraList(chat_id, ln)
	local hash = 'chat:'..chat_id..':extra'
	local commands = db:hkeys(hash)
	local text = ''
	if commands[1] == nil then
		return make_text(lang[ln].extra.no_commands)
	else
	    for k,v in pairs(commands) do
	    	text = text..v..'\n'
	    end
	    return make_text(lang[ln].extra.commands_list, text)
	end
end

local function getSettings(chat_id, ln)
	--get settings from redis
    local hash = 'chat:'..chat_id..':settings'
    local settings = db:hgetall(hash)
    if not next(settings) then
    	return lang[ln].settings.broken_group, false
    end
        
    local message = make_text(lang[ln].bonus.settings_header, ln)
        
    --build the message
    for key,val in pairs(settings) do
        
        local yes_icon, no_icon = '🚫', '✅'
        if cross.is_info_message_key(key) then
        	yes_icon, no_icon = '👤', '👥'
        end
        
        local text
        if val == 'yes' then
            text = '`'..lang[ln].settings[key]..'`: '..yes_icon..'\n'
        else
            text = '`'..lang[ln].settings[key]..'`: '..no_icon..'\n'
        end
        message = message..text --concatenete the text
    end
    
    --build the "welcome" line
    hash = 'chat:'..chat_id..':welcome'
    local type = db:hget(hash, 'type')
    if type == 'composed' then
    	local wel = db:hget(hash, 'content')
    	if wel == 'a' then
    	    message = message..lang[ln].settings.resume.w_a
    	elseif wel == 'r' then
    	    message = message..lang[ln].settings.resume.w_r
    	elseif wel == 'm' then
    	    message = message..lang[ln].settings.resume.w_m
    	elseif wel == 'ra' then
    	    message = message..lang[ln].settings.resume.w_ra
    	elseif wel == 'rm' then
    	    message = message..lang[ln].settings.resume.w_rm
    	elseif wel == 'am' then
    	    message = message..lang[ln].settings.resume.w_am
    	elseif wel == 'ram' then
    	    message = message..lang[ln].settings.resume.w_ram
    	elseif wel == 'no' then
    	    message = message..lang[ln].settings.resume.w_no
    	end
	elseif type == 'media' then
		message = message..lang[ln].settings.resume.w_media
	elseif type == 'custom' then
		message = message..lang[ln].settings.resume.w_custom
	end
    
    local warnmax_std = (db:get('chat:'..chat_id..':max')) or 3
    local warnmax_media = (db:get('chat:'..chat_id..':mediamax')) or 2
    
    message = message..'`Warn (standard)`: *'..warnmax_std..'*\n`Warn (media)`: *'..warnmax_media..'*\n\n'..lang[ln].settings.resume.legenda
    
    return message
end

local function enableSetting(chat_id, field, ln)
	local hash = 'chat:'..chat_id..':settings'
    local field_lower = field:lower()
    local now = db:hget(hash, field)
    if now == 'no' then
        return lang[ln].settings.enable[field_lower..'_already']
    else
        db:hset(hash, field, 'no')
        return lang[ln].settings.enable[field_lower..'_unlocked']
    end
end

local function disableSetting(chat_id, field, ln)
	local hash = 'chat:'..chat_id..':settings'
    local field_lower = field:lower()
    local now = db:hget(hash, field)
    if now == 'yes' then
        return lang[ln].settings.disable[field_lower..'_already']
    else
        db:hset(hash, field, 'yes')
        return lang[ln].settings.disable[field_lower..'_locked']
    end
end

local function changeSettingStatus(chat_id, field, ln)
	local hash = 'chat:'..chat_id..':settings'
	local field_lower = field:lower()
	local now = db:hget(hash, field)
	if now == 'no' then
		db:hset(hash, field, 'yes')
		return lang[ln].settings.disable[field_lower..'_locked']
	else
		db:hset(hash, field, 'no')
		return lang[ln].settings.enable[field_lower..'_unlocked']
	end
end

local function changeFloodSettings(chat_id, screm, ln)
	local hash = 'chat:'..chat_id..':flood'
	if type(screm) == 'string' then
		if screm == 'kick' then
			db:hset(hash, 'ActionFlood', 'ban')
        	return lang[ln].floodmanager.ban
        elseif screm == 'ban' then
        	db:hset(hash, 'ActionFlood', 'kick')
        	return lang[ln].floodmanager.kick
        end
    elseif type(screm) == 'number' then
    	local old = tonumber(db:hget(hash, 'MaxFlood')) or 5
    	local new
    	if screm > 0 then
    		new = db:hincrby(hash, 'MaxFlood', 1)
    		if new > 25 then
    			db:hincrby(hash, 'MaxFlood', -1)
    			return make_text(lang[ln].floodmanager.number_invalid, new)
    		end
    	elseif screm < 0 then
    		new = db:hincrby(hash, 'MaxFlood', -1)
    		if new < 4 then
    			db:hincrby(hash, 'MaxFlood', 1)
    			return make_text(lang[ln].floodmanager.number_invalid, new)
    		end
    	end
    	return make_text(lang[ln].floodmanager.changed_cross, old, new)
    end 	
end

local function changeMediaStatus(chat_id, media, new_status, ln)
	local old_status = db:hget('chat:'..chat_id..':media', media)
	if new_status == 'next' then
		if not old_status then
			new_status = 'kick'
		elseif old_status == 'kick' then
			new_status = 'ban'
		elseif old_status == 'ban' then
			new_status = 'allowed'
		elseif old_status == 'allowed' then
			new_status = 'kick'
		end
	end
	if new_status == 'allow' then
		new_status = 'allowed'
	end
	if old_status == new_status then
		return make_text(lang[ln].mediasettings.already, media, new_status), false
	else
		db:hset('chat:'..chat_id..':media', media, new_status)
		return make_text(lang[ln].mediasettings.changed, media, new_status), true
	end
end

local function sendStartMe(msg, ln)
    local keyboard = {}
    keyboard.inline_keyboard = {
    	{
    		{text = 'Start me', url = 'https://telegram.me/'..bot.username}
	    }
    }
	api.sendKeyboard(msg.chat.id, lang[ln].help.group_not_success, keyboard, true)
end

local function initGroup(chat_id)
	
	for set, setting in pairs(config.chat_settings) do
		local hash = 'chat:'..chat_id..':'..set
		for field, value in pairs(setting) do
			db:hset(hash, field, value)
		end
	end
	
	--save group id
	db:sadd('bot:groupsid', chat_id)
	--remove the group id from the list of dead groups
	db:srem('bot:groupsid:removed', chat_id)
	
	--save stats
	hash = 'bot:general'
    local num = db:hincrby(hash, 'groups', 1)
    print('Stats saved', 'Groups: '..num)
end

local function remGroup(chat_id, full)
	--remove group id
	db:srem('bot:groupsid', chat_id)
	--add to the removed groups list
	db:sadd('bot:groupsid:removed', chat_id)
	
	for set,field in pairs(config.chat_settings) do
		db:del('chat:'..chat_id..':'..set)
	end
	
	if full then
		for i, set in pairs(config.chat_custom_texts) do
			db:del('chat:'..chat_id..':'..set)
		end
	end
end

local function addBanList(chat_id, user_id, nick, why)
    local hash = 'chat:'..chat_id..':bannedlist'
    local res, is_id_added = rdb.set(hash, user_id, 'nick', nick)
    if why and not(why == '') then
        rdb.set(hash, user_id, 'why', why)
    end
    return is_id_added
end

local function remBanList(chat_id, user_id)
	if not chat_id or not user_id then return false end
    local hash = 'chat:'..chat_id..':bannedlist'
    local res, des = rdb.rem(hash, user_id)
    return res
end

local function getUserStatus(chat_id, user_id)
	local res = api.getChatMember(chat_id, user_id)
	if res then
		return res.result.status
	else
		return false
	end
end

local function saveBan(user_id, motivation)
	local hash = 'ban:'..user_id
	return db:hincrby(hash, motivation, 1)
end

local function is_info_message_key(key)
    if key == 'Modlist' or key == 'Rules' or key == 'About' or key == 'Extra' then
        return true
    else
        return false
    end
end

local function table2keyboard(t)
	local keyboard = {inline_keyboard = {}}
    for i, line in pairs(t) do
        if type(line) ~= 'table' then return false, 'Wrong structure (each line need to be a table, not a single value)' end
        local new_line ={}
        for k,v in pairs(line) do
            if type(k) ~= 'string' then return false, 'Wrong structure (table of arrays)' end
            local button = {}
            button.text = k
            button.callback_data = v
            table.insert(new_line, button)
        end
        table.insert(keyboard.inline_keyboard, new_line)
    end
    
    return keyboard
end

-----------------------redis shorcuts---------------------------------------

--[[

------------|---------------------------|
IDS SET     | SUB-HASH WITH SUB-KEY/VAL |
------------|---------------------------|
hash        | hash:id[n]                |
------------|---------------------------|
------------|---------------------------|
            |             |
id[1] ----->| key1 = val1 |
            | key2 = val2 |
            | key3 = val3 |
            | key4 = val4 |
------------|-------------|
id[2] ----->| key1 = val1 |
            | key2 = val2 |
            | key3 = val3 |
            | key4 = val4 |
            | key5 = val5 |
------------|-------------|

extSet(hash, id, key, val)
extGet(hash{, id{, key}})
extSetTable(hash, table)
extRem(hash{, id{, key}})
]]

local function extSet(hash, id, key, val)
    
    --returns false if an argument is missing
    --else, returns true, true if the id has been added to the ids set or false if it hasn't, 0 the sub-key/val has been setted or 1 if only updated, 
    
    if not val then
        return false, 'Missing field(s)'
    else
        local res_sadd = db:sadd(hash, id)
		if res_sadd > 0 then res_sadd = false else res_sadd = true end
        local res_hset = db:hset(hash..':'..id, key, val)
        if res_hset then --or res_set == 1
            return true, res_sadd, 1
        else
            return true, res_sadd, 0
        end
    end
end

local function extGet(hash, id, key)
    
    --returns false when the hash/id is not found or when the sub-hash/the ids set is empty, plus the descritption
    --returns nil when the key passed does not exists
    --else, returns the table/value
    
    local res = {}
    local hash_exists = db:exists(hash)
    if not hash_exists then
        return false, 'hash does not exists'
    else
        if key then
            return db:hegt(hahs..':'..id, key)
        else
            if id then
                local hgetall_res = db:hgetall(hash..':'..id)
                if not next(hgetall_res) then
                    return false, 'empty sub-hash'
                else
                    return hgetall_res
                end
            else
                local ids = db:smembers(hash)
                if not next(ids) then
                    return false, 'empty ids set'
                else
                    for i=1,#ids do
                        local hgetall_res = db:hgetall(hash..':'..ids[i])
                        if next(hgetall_res) then
                            res[ids[i]] = hgetall_res
                        end
                    end
                    return res
                end
            end
        end
    end
end

local function extSetTable(hash, table)
    
    --returns false if "table" argument is not a table, and the descriprion of the error
    --else, returns true, the number of ids setted in the ids set, and the number of key/vals setted
    
    if not(type(table) == 'table') then
        return false, 'the second argument is not a table'
    else
        local reset_res = rdb.rem(hash)
        local id_setted = 0
        local kv_setted = 0
        for id,sub_table in pairs(table) do
            id_setted = id_setted + 1
            db:sadd(hash, id)
            for key,val in pairs(sub_table) do
                db:hset(hash..':'..id, key, val)
                kv_setted = kv_setted + 1
            end
        end
        return true, id_setted, kv_setted
    end
end

local function extRem(hash, id, key)
    
    --if the hash/id/key is not found, returns false and a description of the error
    --if the key/id/hash has been successfully removed, returns true with the number of sub-keys removed
    
    local hash_exists = db:exists(hash)
    if not hash_exists then
        return false, 'hash does not exists'
    else
        local ids = db:smembers(hash)
        if next(ids) then --if the set is not empty
            if not id then --if id and key are not provided, delete the whole hash
                local subhash_removed = 0
                for i,id in pairs(ids) do --delete each sub-hash, before delete the ids set
                    db:del(hash..':'..id) --remove directly the entire sub-hash
                    subhash_removed = subhash_removed + 1
                end
                db:del(hash) --remove the set of ids
                return true, subhash_removed
            else --else, if id is provided then
                local id_exists = db:sismember(hash, id)
                if not id_exists then
                    return false, 'id does not exists'
                else
                    if key then --if the key is provided, then delete only the key
                        local res_key = db:hdel(hash..':'..id, key)
                        if res_key == 0 then --if the key does not exists then
                            return false, 'key does not exists'
                        else
                            return true
                        end
                    else --if the key is not provided, then delete only id provided from the ids set, and the associated sub-hash
                        db:del(hash..':'..id) --delete the whole sub-hash
                        db:srem(hash, id) --remove the id from the set of ids
                        return true, 1
                    end
                end
            end
        else
            return false, 'id set is empty'
        end
    end
end

local cross = {
	getAbout = getAbout,
	getRules = getRules,
	getModlist = getModlist,
	getExtraList = getExtraList,
	getSettings = getSettings,
	enableSetting = enableSetting,
	disableSetting = disableSetting,
	changeSettingStatus = changeSettingStatus,
	changeFloodSettings = changeFloodSettings,
	changeMediaStatus = changeMediaStatus,
	sendStartMe = sendStartMe,
	initGroup = initGroup,
	remGroup = remGroup,
	addBanList= addBanList,
	remBanList = remBanList,
	getUserStatus = getUserStatus,
	saveBan = saveBan,
	is_info_message_key = is_info_message_key
}

local rdb = {
	set = extSet,
	get = extGet,
	rem = extRem,
	setTable = extSetTable,
}

return cross, rdb