@startuml

start
note left
    Do this for each item in the list.
    An item has a name, a sell in value and a quality value
end note

if (not "Aged Brie") then (yes)
    if (quality > 0) then (yes)
        if (not "Sulfuras, Hand of Ragnaros") then (yes)
            -lower quality with 1
        else (no)
        endif
    else (no)
    endif
else (no)
    if (quality < 50) then (yes)
        -increase quality with 1
    else (no)
    endif
endif

if (not "Sulfuras, Hand of Ragnaros") then (yes)
    -lower sell in with 1
else (no)
endif

if (sell in < 0) then (yes)
    if (not "Aged Brie") then (yes)
        if (quality > 0) then (yes)
            if (not "Sulfuras, Hand of Ragnaros") then (yes)
                -lower quality with 1
            else (no)
            endif
        else (no)
        endif
    else (no)
        if (quality < 50) then (yes)
            -increase quality with 1
        else (no)
        endif
    endif
else (no)
endif

stop

@enduml