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

usage() {
  cat <<'USAGE'
Copy files via scp with consistent options.

Usage:
  ssh_copy.sh [options] push HOST LOCAL_PATH REMOTE_PATH
  ssh_copy.sh [options] pull HOST REMOTE_PATH LOCAL_PATH

Options:
  -u, --user USER     Override SSH user (or set REMOTE_USER)
  -p, --port PORT     SSH port (default: REMOTE_PORT or 22)
  -i, --key PATH      Identity file (default: REMOTE_KEY)
  -r, --recursive     Copy directories recursively
      --accept-new    Set StrictHostKeyChecking=accept-new
      --dry-run       Print the scp command that would run
  -h, --help          Show help

Environment defaults:
  REMOTE_USER, REMOTE_PORT, REMOTE_KEY

Examples:
  ssh_copy.sh push my-server ./app.tar.gz /tmp/app.tar.gz
  ssh_copy.sh --user ubuntu pull 10.0.0.1 /var/log/syslog ./syslog
USAGE
}

port="${REMOTE_PORT:-22}"
user="${REMOTE_USER:-}"
key="${REMOTE_KEY:-}"

recursive=false
accept_new=false
dry_run=false

while [[ $# -gt 0 ]]; do
  case "$1" in
    -u|--user)
      user="${2:-}"
      shift 2
      ;;
    -p|--port)
      port="${2:-}"
      shift 2
      ;;
    -i|--key)
      key="${2:-}"
      shift 2
      ;;
    -r|--recursive)
      recursive=true
      shift
      ;;
    --accept-new)
      accept_new=true
      shift
      ;;
    --dry-run)
      dry_run=true
      shift
      ;;
    -h|--help)
      usage
      exit 0
      ;;
    -*)
      echo "Unknown option: $1" >&2
      usage >&2
      exit 2
      ;;
    *)
      break
      ;;
  esac
done

if [[ $# -lt 4 ]]; then
  usage >&2
  exit 2
fi

direction="$1"
shift

host="$1"
shift

dest_host="$host"
if [[ -n "$user" ]]; then
  host_no_user="${host#*@}"
  dest_host="${user}@${host_no_user}"
fi

scp_opts=(-P "$port" -p)
if [[ -n "$key" ]]; then
  scp_opts+=(-i "$key" -o "IdentitiesOnly=yes")
fi
if $recursive; then
  scp_opts+=(-r)
fi
if $accept_new; then
  scp_opts+=(-o "StrictHostKeyChecking=accept-new")
fi

case "$direction" in
  push)
    local_path="$1"
    remote_path="$2"
    full_cmd=(scp "${scp_opts[@]}" "$local_path" "${dest_host}:${remote_path}")
    ;;
  pull)
    remote_path="$1"
    local_path="$2"
    full_cmd=(scp "${scp_opts[@]}" "${dest_host}:${remote_path}" "$local_path")
    ;;
  *)
    echo "Unknown direction: $direction (expected: push|pull)" >&2
    usage >&2
    exit 2
    ;;
esac

if $dry_run; then
  printf '%q ' "${full_cmd[@]}"
  printf '\n'
  exit 0
fi

"${full_cmd[@]}"