CSVars.lua

--[[
	~ CSVars ~
	Copyright (c) 2011 Lexi Robinson

	This module is free software: you can redistribute it and/or modify it under
	the terms of the GNU Lesser General Public License as published by the Free
	Software Foundation, either version 3 of the License, or (at your option)
	any later version.

	This module is distributed in the hope that it will be useful, but WITHOUT
	ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
	for more details.

	You should have received a copy of the GNU Lesser General Public License
	along with this module. If not, see <https://www.gnu.org/licenses/>.
--]]

-- Server functions
local umsg, pairs, error, SERVER, tostring = umsg, pairs, error, SERVER, tostring
-- Client functions
local ErrorNoHalt, pcall, usermessage      = ErrorNoHalt, pcall, usermessage


-- Enums
CLASS_STRING = 1
CLASS_LONG   = 2
CLASS_SHORT  = 3
CLASS_BOOL   = 4
CLASS_VECTOR = 5
CLASS_ENTITY = 6
CLASS_ANGLE  = 7
CLASS_CHAR   = 8
CLASS_FLOAT  = 9
-- locals
local c_str  = CLASS_STRING
local c_lng  = CLASS_LONG
local c_srt  = CLASS_SHORT
local c_bln  = CLASS_BOOL
local c_vec  = CLASS_VECTOR
local c_ent  = CLASS_ENTITY
local c_ang  = CLASS_ANGLE
local c_chr  = CLASS_CHAR
local c_flt  = CLASS_FLOAT


---
-- Provides a method of automagically setting variables on a client's player object.
-- @version 0.1 Pre-release beta
local CSVars = {}

local inverted = {
	[c_str] = "String",
	[c_lng] = "Long",
	[c_srt] = "Short",
	[c_bln] = "Bool",
	[c_vec] = "Vector",
	[c_ent] = "Entity",
	[c_ang] = "Angle",
	[c_chr] = "Char",
	[c_flt] = "Float",
}


if SERVER then
	local function handle(ply, class, key, value)
		umsg.Start("CSVar", ply)
		umsg.Char(class)
		umsg.String(key)
		local name = inverted[class]
		if not name then
			error("Unknown class '" .. tostring(class) .. "' for CSVar '" .. key .. "'='" .. tostring(value) .. "'!", 3)
		end
		umsg[name](value)
		umsg.End()
	end

	---
	-- Sets a variable clientside on the player. Will not send the value if a player already has it
	-- @param ply The player to set the var on
	-- @param class One of the CLASS_ enums indicating the kind of variable
	-- @param key The name of the variable to set on the client
	-- @param value The value to set
	function CSVars.SetPlayer(ply, class, key, value)
		if ply.CSVars[key] == nil or ply.CSVars[key] ~= value then
			ply.CSVars[key] = value
			handle(ply, class, key, value)
		end
	end

	---
	-- Sets a variable clientside on all players. *Will* send the value even if a client already has it.
	-- @param class One of the CLASS_ enums indicating the kind of variable
	-- @param key The name of the variable to set on the client
	-- @param value The value to set
	function CSVars.SetGlobal(class, key, value)
		handle(nil, class, key, value)
		for _, ply in pairs(player.GetAll()) do
			ply.CSVars[key] = value
		end
	end
else
	CSVars.vars = {}
	local hooks = {}
	local lpl = NULL
	---
	-- Adds a hook to be called every time a CSVar is updated
	-- @param key The name of the CSVar to hook on
	-- @param name The unique name of the hook
	-- @param func (value, class) the hook callback
	function CSVars.Hook(key, name, func)
		hooks[key] = hooks[key] or {}
		hooks[key][name] = func
	end

	---
	-- Removes a perviously active hook
	-- @param key The name of the CSVar the hook was on on
	-- @param name The unique name of the hook
	function CSVars.UnHook(key, name)
		if hooks[key] and hooks[key][name] then
			hooks[key][name] = nil
		end
	end

	local function singleVar(msg)
		local class = msg:ReadChar()
		local key = msg:ReadString()

		local name = inverted[class]
		if not name then
			ErrorNoHalt("Unknown class sent for CSVar '", key, "': ", class, "!")
			return
		end
		local var = msg["Read" .. name](msg)
		CSVars.vars[key] = var
		if hooks[key] then
			for _, func in pairs(hooks[key]) do
				local res, err = pcall(func, var, class)
				if not res then
					ErrorNoHalt("Error in CSVar hook '", name, "' for '", key, "': ", err)
				end
			end
		end
		-- Check if the local player is a valid entity.
		if lpl ~= NULL then
			lpl[key] = var
		end
	end
	local function massVars(msg)
		local num = msg:ReadChar()
		for i = 1, num do
			singleVar(msg)
		end
	end
	usermessage.Hook("CSVar", singleVar)
	usermessage.Hook("MassCSVars", massVars)

	---
	-- Called when the player's object is created and assigned to the global lpl
	function CSVars.PlayerInitialized(ply)
		lpl = ply
		for k, v in pairs(CSVars.vars) do
			lpl[k] = v
		end
	end

	hook.Add("LocalPlayerCreated", "CSVars Startup", function(ply)
		CSVars.PlayerInitialized(ply)
	end)
end

return CSVars