search for files and create conditions using gnuplot

Tell me please how to make a script using gnuplot:

have folder:

d:/data/

in which there are files in the format

[text1][delta=text2][text3][mac=text4].csv

need to create the script for all the files in the folder:

for [file] of [files]
{
    if [file] content text1 == 'packets' and text4 == 'all'
    {
        set xlabel "amount" font "Calibri, 10"
    }
    else
    {
        set xlabel "size" font "Calibri, 10"
    }

    set output "d:/images/out_[file].png"
    plot [file] using ...
}

more simple code without conditions I could create

files = system("ls -1 d:/data/*.csv")
plot for [data in files] data using 1:3 with line ls 2 notitle

but how can I make a more complex code with the terms I can not understand :(