#!/usr/bin/env bash
# ╔══════════════════════════════════════════════════════════════════╗
# ║  arch-dev roaming :: add_new_machine                            ║
# ║  Onboard a new host into the roaming fleet:                     ║
# ║    1. push your SSH key (ssh-copy-id)                           ║
# ║    2. register it in ~/.config/roaming/hosts                    ║
# ║    3. optionally test the connection + mount                    ║
# ╚══════════════════════════════════════════════════════════════════╝
set -euo pipefail

ROAMING_DIR="${ROAMING_DIR:-$HOME/.config/roaming}"
ROAMING_HOSTS="${ROAMING_HOSTS:-$ROAMING_DIR/hosts}"
ROAMING_DEFAULT_USER="${ROAMING_DEFAULT_USER:-$USER}"

usage() {
    cat <<EOF
Usage: add_new_machine.sh <name> <fqdn> [user] [mount]

  name    short alias for the host (e.g. mail)
  fqdn    reachable hostname (e.g. mail.tailnet.ts)
  user    ssh user (default: $ROAMING_DEFAULT_USER)
  mount   remote path to expose via sshfs (optional, e.g. / or /srv)

Examples:
  add_new_machine.sh mail mail.tailnet.ts root /
  add_new_machine.sh proxy proxy.tailnet.ts admin /etc/caddy
  add_new_machine.sh dev dev-server.tailnet.ts wayne
EOF
    exit 1
}

[[ $# -lt 2 ]] && usage

NAME="$1"
FQDN="$2"
USER_ARG="${3:-$ROAMING_DEFAULT_USER}"
MOUNT="${4:-}"

mkdir -p "$ROAMING_DIR"
touch "$ROAMING_HOSTS"

# ── Guard: already registered? ────────────────────────────────────────────────
if grep -qE "^\s*${NAME}\s" "$ROAMING_HOSTS" 2>/dev/null; then
    echo "✗ '$NAME' is already in $ROAMING_HOSTS"
    echo "  edit the file directly to change it"
    exit 1
fi

# ── Step 1: SSH key ───────────────────────────────────────────────────────────
echo "── Step 1: pushing SSH key to ${USER_ARG}@${FQDN} ──"
echo "  (you'll be prompted for the remote password once)"
if ssh-copy-id "${USER_ARG}@${FQDN}"; then
    echo "  ✓ key installed"
else
    echo "  ✗ ssh-copy-id failed — aborting, nothing registered"
    exit 1
fi

# ── Step 2: register ──────────────────────────────────────────────────────────
echo "── Step 2: registering in $ROAMING_HOSTS ──"
printf "%-10s %-26s %-8s %s\n" "$NAME" "$FQDN" "$USER_ARG" "$MOUNT" >> "$ROAMING_HOSTS"
echo "  ✓ registered"

# ── Step 3: verify ────────────────────────────────────────────────────────────
echo "── Step 3: verifying connection ──"
if ssh -o BatchMode=yes -o ConnectTimeout=8 "${USER_ARG}@${FQDN}" 'echo ok' >/dev/null 2>&1; then
    echo "  ✓ key-based SSH works"
else
    echo "  ⚠ key-based SSH test failed (host may still be fine — check manually)"
fi

echo ""
echo "✓ Done. In a new shell (or after 'roaming-reload'):"
echo "    $NAME                       # interactive shell"
echo "    $NAME sudo systemctl status # run a command"
[[ -n "$MOUNT" ]] && echo "    mount_host $NAME            # sshfs ${MOUNT} → /workspace/$NAME"