BEGIN {FS="["}
Ff != gensub("^([^,]+).*","\\1","g",$0) { Ff = gensub("^([^,]+).*","\\1","g",$0) ; Lf = $NF ; if (length(Ml) > 0) { print Ml } }  
Ff == gensub("^([^,]+).*","\\1","g",$0) { if (length($NF) > length(Lf)) { Lf=$NF ; Ml=$0 } }   
END {if (length(Ml) > 0) { print Ml }}