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

args="$(getopt -o '' --long check -- "$@")"
eval "set -- $args"
check=false
while true; do
    case "$1" in
        --check)
            check=true
            shift
            ;;
        --)
            shift
            break
            ;;
    esac
done

username="$1"
shift

homedir="$(getent passwd "$username" | cut -d: -f6)"
sshdir="$homedir/.ssh"

umask 077
workdir=$(mktemp -d)
chown "$username:$username" "$workdir"
cleanup() { ls -al "$workdir" && rm -rf "$workdir"; }
trap cleanup EXIT

umask 033

for ssh_secret_name in "$@"; do
    keydata="$(/srv/zulip-aws-tools/bin/aws --output text \
        secretsmanager get-secret-value \
        --secret-id "$ssh_secret_name" \
        --query SecretString)"
    for keyfile in $(jq -r 'keys[]' <<<"$keydata"); do
        touch "$workdir/$keyfile"
        if [[ "$keyfile" != *".pub" ]]; then
            chmod 600 "$workdir/$keyfile"
        fi
        jq -r ".[\"$keyfile\"]" <<<"$keydata" | base64 -d >"$workdir/$keyfile"
        chown "$username:$username" "$workdir/$keyfile"
    done
done

if [ "$check" = "true" ]; then
    diff -rN -x config -x authorized_keys -x known_hosts \
        "$workdir/" "$sshdir/"
    exit 0
fi

rsync -av --delete \
    --exclude config --exclude authorized_keys --exclude known_hosts \
    "$workdir/" "$sshdir/"