on join:
    {coins.%player%} is not set
    set {coins.%player%} to 0

command /wymiana [<text>]:
    trigger:
        set {_gui} to chest inventory with 3 rows named "&8&lWymiana EXP -> Coin"
        set slot 11 of {_gui} to exp bottle named "&a&l1LVL &8&m&l->&r &6&l10 Coinów"
        set slot 13 of {_gui} to exp bottle named "&a&l5LVL &8&m&l->&r &6&l50 Coinów"
        set slot 15 of {_gui} to exp bottle named "&a&l10LVL &8&m&l->&r &6&l100 Coinów"
        open {_gui} to player
        
on inventory click:
    name of event-inventory is "&8&lWymiana EXP -> Coin"
    cancel event
    event-inventory is not player's inventory
    if index of event-slot is 11:
        if player's level < 1:
            send "&cMasz zbyt niski poziom!"
            close player's inventory
            stop
        reduce player's level by 1
        add 10 to {coins.%player%}
        send "&aPomyślnie wymieniono 1 poziom!"
    if index of event-slot is 13:
        if player's level < 5:
            send "&cMasz zbyt niski poziom!"
            close player's inventory
            stop
        reduce player's level by 5
        add 50 to {coins.%player%}
        send "&aPomyślnie wymieniono 5 poziomów!"
    if index of event-slot is 15:
        if player's level < 10:
            send "&cMasz zbyt niski poziom!"
            close player's inventory
            stop
        reduce player's level by 10
        add 100 to {coins.%player%}
        send "&aPomyślnie wymieniono 10 poziomów!"
        
command /coins [<text>]:
    trigger:
        send "&6Stan konta: &f%{coins.%player%} coinów"