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

skill_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
project_dir="$(cd "${skill_dir}/../../.." && pwd)"
local_log="${project_dir}/.local/logs/backend.log"

ssh_host="root@39.98.44.136"
ssh_port="6022"
remote_log_dir="/opt/service/project/shz-backend/logs"

usage() {
  cat <<'EOF'
Usage:
  view.sh local [lines] [--follow]
  view.sh online [backend|error|info|user] [lines] [--follow]

Examples:
  view.sh local 200
  view.sh local 100 --follow
  view.sh online backend 200
  view.sh online error 500 --follow
EOF
}

validate_lines() {
  local lines="$1"
  if [[ ! "${lines}" =~ ^[0-9]+$ ]] || (( lines < 1 || lines > 5000 )); then
    echo "Lines must be an integer between 1 and 5000: ${lines}" >&2
    exit 2
  fi
}

validate_follow() {
  local follow="${1:-}"
  if [[ -n "${follow}" && "${follow}" != "--follow" ]]; then
    echo "Unknown option: ${follow}" >&2
    usage >&2
    exit 2
  fi
}

view_local() {
  local lines="${1:-200}"
  local follow="${2:-}"
  validate_lines "${lines}"
  validate_follow "${follow}"

  if [[ ! -f "${local_log}" ]]; then
    echo "Local log does not exist: ${local_log}" >&2
    echo "Start the project first with: ./local.sh start" >&2
    exit 1
  fi

  if [[ "${follow}" == "--follow" ]]; then
    tail -n "${lines}" -F -- "${local_log}"
  else
    tail -n "${lines}" -- "${local_log}"
  fi
}

view_online() {
  local kind="${1:-backend}"
  local lines="${2:-200}"
  local follow="${3:-}"
  local remote_file

  case "${kind}" in
    backend) remote_file="${remote_log_dir}/backend.log" ;;
    error) remote_file="${remote_log_dir}/sys-error.log" ;;
    info) remote_file="${remote_log_dir}/sys-info.log" ;;
    user) remote_file="${remote_log_dir}/sys-user.log" ;;
    *)
      echo "Unknown online log type: ${kind}" >&2
      usage >&2
      exit 2
      ;;
  esac

  validate_lines "${lines}"
  validate_follow "${follow}"

  if [[ "${follow}" == "--follow" ]]; then
    ssh -p "${ssh_port}" -o BatchMode=yes -o ConnectTimeout=10 "${ssh_host}" \
      tail -n "${lines}" -F -- "${remote_file}"
  else
    ssh -p "${ssh_port}" -o BatchMode=yes -o ConnectTimeout=10 "${ssh_host}" \
      tail -n "${lines}" -- "${remote_file}"
  fi
}

target="${1:-}"
case "${target}" in
  local)
    [[ $# -le 3 ]] || { usage >&2; exit 2; }
    view_local "${2:-200}" "${3:-}"
    ;;
  online)
    [[ $# -le 4 ]] || { usage >&2; exit 2; }
    view_online "${2:-backend}" "${3:-200}" "${4:-}"
    ;;
  help|-h|--help)
    usage
    ;;
  *)
    usage >&2
    exit 2
    ;;
esac