#!/usr/bin/env bash

# Generate Ed25519 SSH keys for the given service names.

set -euo pipefail

if [[ "${1:-}" == "-h" || "${1:-}" == "--help" ]]; then
    awk '/^#!/ {next} /^[^#]/ {exit} {sub(/^# ?/, ""); print}' "$0"
    exit 0
fi

if (( $# == 0 )); then
    echo "[+] No services specified; nothing to do."
    exit 0
fi

mkdir -p ~/.ssh
chmod 700 ~/.ssh

host_short="$(hostname -s)"

for service in "$@"; do
    file="$HOME/.ssh/id_$service"
    if [[ -f "$file" ]]; then
        echo "[+] skipping: $file already exists"
        continue
    fi
    echo "[+] generating: $file"
    ssh-keygen -t ed25519 -f "$file" -N "" -C "$service@$host_short"
done