#!/usr/bin/env bash
set -euxo pipefail

# prepare workspace just in case
mkdir -p /nix/var/nix/gcroots/albatros
cd /nix/var/nix/gcroots/albatros

# remove any symlink that is older than 7 days
NOW=$(date +%s)
EXPIRE=$((60*60*24*7)) # 7 days in seconds

for f in $(ls); do
  CR=$(stat $f -c %W)
  DIFF=$((NOW-CR))
  if [[ $DIFF -gt $EXPIRE ]]; then 
    echo "deleting $f"
    rm -f $f
  else 
    echo "keeping $f"; 
  fi
done

# we don't want to slow down the build too much, so
# we limit to 1GB of deletion
nix store gc --verbose --max 1G