Remove unneeded dependencies from Cygwin

In Cygwin when I install a new package it automatically installs any dependencies needed for that package.

Later if I choose to remove that package, how can I remove the dependencies it installed with it, which are no longer needed?

Well, here is my current solution I came up with. Using my (very) limited knowledge of bash and Google.

#!/bin/bash
# Print a list of packages that no other package depends on

PackageCount=0
PackageIter=0

# Populate package array
declare -A Packages
PackageList=$(cygcheck.exe -c | cut -d' ' -f1 | tail -n +3)
for P in $PackageList; do
    Packages[${P,,}]=0
    ((PackageCount++))
done

# Determine the last mirror used
LastMirror=$(sed -n '/last-mirror/{n;p}' /etc/setup/setup.rc | tr -d '\t')
echo "[DEBUG] LastMirror = $LastMirror"

# Download the setup.ini file from the mirror server
echo "[DEBUG] Downloading setup.ini from mirror"
if which bzcat &>/dev/null; then
    wget --quiet "${LastMirror}$(uname -m)/setup.bz2" -O - | bzcat > setup.ini
else
    wget --quiet "${LastMirror}$(uname -m)/setup.ini" -O setup.ini
fi

for P in $PackageList; do
    ((PackageIter++))
    echo -ne "[DEBUG] Processing packages $((PackageIter * 100 / PackageCount))%\r"

    deps=$(sed -n "/^@ $P$/,/^requires/p" setup.ini | grep -i '^requires' | cut -d' ' -f2-)

    for dep in $deps; do
        if [[ ${Packages[${dep,,}]} ]]; then
            Packages[${dep,,}]=$((Packages[${dep,,}]+1))
        fi
    done
done

echo -e "\n== Packages =="

for P in $PackageList; do
    if [[ ${Packages[${P,,}]} == 0 ]]; then
        echo $P
    fi
done

rm setup.ini

I'd love to see if anyone has a better solution, or any tips to improve my script.