#!/usr/bin/env bash
# add-host.sh — register a new server so refresh-server-info.sh picks it up.
#
# Creates servers/<name>/ and writes servers/<name>/ssh-target with the
# given IP (or user@ip). The next `scripts/refresh-server-info.sh <name>`
# run will discover the host and pull its first system-details.txt.
#
# Usage:
#   scripts/add-host.sh <name> <ip-or-user@ip>
#   scripts/add-host.sh <name> <ip-or-user@ip> --force   # overwrite existing
#
# Example:
#   scripts/add-host.sh la-docker 10.60.50.12
#   scripts/add-host.sh edge-01   admin@203.0.113.9

set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
REPO_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
SERVERS_DIR="$REPO_ROOT/servers"

FORCE=0
POSITIONAL=()
for arg in "$@"; do
  case "$arg" in
    -f|--force) FORCE=1 ;;
    -h|--help) sed -n '2,14p' "$0"; exit 0 ;;
    -*) echo "error: unknown flag $arg" >&2; exit 2 ;;
    *)  POSITIONAL+=("$arg") ;;
  esac
done

if [ "${#POSITIONAL[@]}" -ne 2 ]; then
  echo "usage: $(basename "$0") <name> <ip-or-user@ip> [--force]" >&2
  exit 2
fi

name="${POSITIONAL[0]}"
target="${POSITIONAL[1]}"

if [[ ! "$name" =~ ^[a-zA-Z0-9][a-zA-Z0-9._-]*$ ]]; then
  echo "error: invalid host name '$name' (expected [a-zA-Z0-9._-])" >&2
  exit 2
fi

# Trivial sanity check on the target — not exhaustive, just catches typos.
if [[ -z "$target" ]] || [[ "$target" =~ [[:space:]] ]]; then
  echo "error: invalid ssh target '$target'" >&2
  exit 2
fi

host_dir="$SERVERS_DIR/$name"
ssh_target_file="$host_dir/ssh-target"

if [ -f "$ssh_target_file" ] && [ "$FORCE" -ne 1 ]; then
  existing=$(awk 'NF{print $1; exit}' "$ssh_target_file")
  if [ "$existing" = "$target" ]; then
    echo "host '$name' already registered with target '$target' — nothing to do"
    exit 0
  fi
  echo "error: $ssh_target_file already exists (currently '$existing'); pass --force to overwrite" >&2
  exit 1
fi

mkdir -p "$host_dir"
printf '%s\n' "$target" > "$ssh_target_file"

printf 'registered: %s → %s\n' "$name" "$target"
printf 'next: scripts/refresh-server-info.sh %s\n' "$name"