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

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"

resolve_repo_root() {
  local candidate
  for candidate in "${SCRIPT_DIR}/.." "${SCRIPT_DIR}/../.." "${PWD}"; do
    if [[ -f "${candidate}/credentials/.env" ]]; then
      (cd "${candidate}" && pwd)
      return 0
    fi
  done
  return 1
}

if ! REPO_ROOT="$(resolve_repo_root)"; then
  echo "Error: could not locate repository root containing credentials/.env" >&2
  exit 1
fi

ENV_FILE="${REPO_ROOT}/credentials/.env"

if [[ ! -f "${ENV_FILE}" ]]; then
  echo "Error: credentials file not found: ${ENV_FILE}" >&2
  exit 1
fi

load_env_value() {
  local key="$1"
  local line
  line="$(grep -E "^${key}=" "${ENV_FILE}" | tail -n 1 || true)"
  line="${line#*=}"
  line="${line%\"}"
  line="${line#\"}"
  line="${line%\'}"
  line="${line#\'}"
  printf '%s' "${line}"
}

SSH_HOST="$(load_env_value REMOTE_SSH_HOST)"
SSH_PORT="$(load_env_value REMOTE_SSH_PORT)"
SSH_USER="$(load_env_value REMOTE_SSH_USER)"
SSH_KEY_RAW="$(load_env_value REMOTE_SSH_KEY)"
REMOTE_MYSQL_HOST="$(load_env_value REMOTE_MYSQL_HOST)"
REMOTE_MYSQL_PORT="$(load_env_value REMOTE_MYSQL_PORT)"
LOCAL_PORT="${LOCAL_PORT:-13306}"

if [[ -z "${SSH_HOST}" || -z "${SSH_USER}" || -z "${SSH_KEY_RAW}" ]]; then
  echo "Error: missing REMOTE_SSH_* values in ${ENV_FILE}" >&2
  exit 1
fi

if [[ -z "${SSH_PORT}" ]]; then SSH_PORT=22; fi
if [[ -z "${REMOTE_MYSQL_HOST}" ]]; then REMOTE_MYSQL_HOST=127.0.0.1; fi
if [[ -z "${REMOTE_MYSQL_PORT}" ]]; then REMOTE_MYSQL_PORT=3306; fi

if [[ "${SSH_KEY_RAW}" = /* ]]; then
  SSH_KEY_PATH="${SSH_KEY_RAW}"
else
  SSH_KEY_PATH="${REPO_ROOT}/${SSH_KEY_RAW}"
fi

if [[ ! -f "${SSH_KEY_PATH}" ]]; then
  echo "Error: SSH key not found: ${SSH_KEY_PATH}" >&2
  exit 1
fi

CONTROL_SOCKET="/tmp/mailshot-mysql-tunnel-${LOCAL_PORT}.sock"
SSH_TARGET="${SSH_USER}@${SSH_HOST}"

start_tunnel() {
  if ssh -S "${CONTROL_SOCKET}" -p "${SSH_PORT}" -O check "${SSH_TARGET}" >/dev/null 2>&1; then
    echo "Tunnel already running on 127.0.0.1:${LOCAL_PORT}"
    return 0
  fi

  ssh -f -N \
    -M -S "${CONTROL_SOCKET}" \
    -o BatchMode=yes \
    -o ExitOnForwardFailure=yes \
    -o StrictHostKeyChecking=accept-new \
    -i "${SSH_KEY_PATH}" \
    -p "${SSH_PORT}" \
    -L "127.0.0.1:${LOCAL_PORT}:${REMOTE_MYSQL_HOST}:${REMOTE_MYSQL_PORT}" \
    "${SSH_TARGET}"

  echo "Tunnel started: 127.0.0.1:${LOCAL_PORT} -> ${REMOTE_MYSQL_HOST}:${REMOTE_MYSQL_PORT} via ${SSH_TARGET}:${SSH_PORT}"
  echo "Use in DBeaver: host=127.0.0.1 port=${LOCAL_PORT}"
}

stop_tunnel() {
  if ssh -S "${CONTROL_SOCKET}" -p "${SSH_PORT}" -O exit "${SSH_TARGET}" >/dev/null 2>&1; then
    rm -f "${CONTROL_SOCKET}" || true
    echo "Tunnel stopped for 127.0.0.1:${LOCAL_PORT}"
  else
    echo "No active tunnel found for 127.0.0.1:${LOCAL_PORT}"
  fi
}

status_tunnel() {
  if ssh -S "${CONTROL_SOCKET}" -p "${SSH_PORT}" -O check "${SSH_TARGET}" >/dev/null 2>&1; then
    echo "Tunnel is running on 127.0.0.1:${LOCAL_PORT}"
  else
    echo "Tunnel is not running on 127.0.0.1:${LOCAL_PORT}"
  fi
}

CMD="${1:-start}"
case "${CMD}" in
  start) start_tunnel ;;
  stop) stop_tunnel ;;
  status) status_tunnel ;;
  *)
    echo "Usage: $(basename "$0") [start|stop|status]"
    exit 1
    ;;
esac