#!/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"

online_ssh_host="${SHZ_ONLINE_SSH_HOST:-root@39.98.44.136}"
online_ssh_port="${SHZ_ONLINE_SSH_PORT:-6022}"
online_remote_log_dir="${SHZ_ONLINE_LOG_DIR:-/opt/service/project/shz-backend/logs}"

test_ssh_host="${SHZ_TEST_SSH_HOST:-root@47.111.103.66}"
test_ssh_port="${SHZ_TEST_SSH_PORT:-22}"
test_remote_log_dir="${SHZ_TEST_LOG_DIR:-/data/code/shz-backend/logs}"

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

Examples:
  view.sh local 200
  view.sh local 100 --follow
  view.sh online backend 200
  view.sh test error 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_remote() {
  local target="$1"
  local kind="${2:-backend}"
  local lines="${3:-200}"
  local follow="${4:-}"
  local ssh_host ssh_port remote_log_dir remote_file

  case "${target}" in
    online|production)
      ssh_host="${online_ssh_host}"
      ssh_port="${online_ssh_port}"
      remote_log_dir="${online_remote_log_dir}"
      ;;
    test)
      ssh_host="${test_ssh_host}"
      ssh_port="${test_ssh_port}"
      remote_log_dir="${test_remote_log_dir}"
      ;;
    *)
      echo "Unknown remote environment: ${target}" >&2
      usage >&2
      exit 2
      ;;
  esac

  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 log type: ${kind}" >&2
      usage >&2
      exit 2
      ;;
  esac

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

  local -a ssh_args=(-o BatchMode=yes -o ConnectTimeout=10)
  if [[ -n "${ssh_port}" ]]; then
    ssh_args+=(-p "${ssh_port}")
  fi

  if [[ "${follow}" == "--follow" ]]; then
    ssh "${ssh_args[@]}" "${ssh_host}" \
      tail -n "${lines}" -F -- "${remote_file}"
  else
    ssh "${ssh_args[@]}" "${ssh_host}" \
      tail -n "${lines}" -- "${remote_file}"
  fi
}

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