# OgreDupe ELO system

# New rating = Old rating + K * (Result - Expected result)
# Expected result = 1 / (1 + 10^((Opponent's rating - Player's rating) / 400))
# Result is the actual result of the game (1 for a win, 0.5 for a draw, and 0 for a loss).
# K = how quickly a player's rating will change based on their performance. (We use 20)

on load:
	set {K} to 30

on first join:
	set {-ELO::%player's uuid%} to 800
on join:
	if {-ELO::%player's uuid%} is not set:
		set {-ELO::%player's uuid%} to 800

function EloUpdate(P: uuid, O: uuid, R: integer):
	set {_ExpectedResult} to 1 / (1 + 10^(({-ELO::%{_O}%} - {-ELO::%{_P}%}) / 400))
	# This next equation wasnt working so I had to spread it out, if you are able to fix it please pull request your code.
	set {_RDIF} to {_R} - {_ExpectedResult}
	set {_CHANGE} to {_RDIF} * {K}
	set {-ELO::%{_P}%} to {-ELO::%{_P}%} + {_CHANGE}
	set {_ExpectedResult} to {_ExpectedResult} * 100
	send "&9ELO> &7We expected a %{_ExpectedResult}% Precent chance of you winning" to {_P}
	if {_R} is 1:
		send "&9ELO> &7And You Won" to {_P}
	else if {_R} is less than 1:
		send "&9ELO> &7And you lost" to {_P}
	send "&9ELO> &7So your ELO is now %{-ELO::%{_P}%}%" to {_P}
	send "&9ELO> &7Which makes your oponents ELO %{-ELO::%{_O}%}%" to {_P}

command /elo <player>:
	trigger:
		send "&9ELO> &7%arg-1's uuid%'s ELO is %{-ELO::%arg-1's uuid%}%"

on death:    
	if victim is player:
		if attacker is player:
			EloUpdate(victim's uuid, attacker's uuid, 0)
			EloUpdate(attacker's uuid, victim's uuid, 1)