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

BASE_DIR="${PANEL_BASE_DIR:-/var/lib/containers}"
STACKS_DIR="${BASE_DIR}/stacks"
VOLUMES_DIR="${BASE_DIR}/volumes"
ROUTES_DIR="${BASE_DIR}/routes"
STATE_DIR="${BASE_DIR}/state"
APPS_DIR="${STATE_DIR}/apps"

FORWARD_AUTH_BLOCK='  forward_auth 127.0.0.1:9091 {
    uri /api/authz/forward-auth
    copy_headers Remote-User Remote-Groups Remote-Email Remote-Name
  }
'

usage() {
  cat <<'EOF'
panelctl - minimal app panel helper

Usage:
  panelctl init <name> <domain> <port> [auth]
  panelctl render-route <name>
  panelctl deploy <name>
  panelctl stop <name>
  panelctl remove <name> [--keep-volumes]
  panelctl list
  panelctl show <name>

Examples:
  panelctl init whoami whoami.srazka.com 18080 true
  panelctl deploy whoami
EOF
}

fail() {
  echo "error: $*" >&2
  exit 1
}

ensure_base_dirs() {
  mkdir -p "${STACKS_DIR}" "${VOLUMES_DIR}" "${ROUTES_DIR}" "${APPS_DIR}"
}

validate_name() {
  local name="$1"
  [[ "${name}" =~ ^[a-z0-9]([a-z0-9-]*[a-z0-9])?$ ]] || fail "invalid name '${name}' (use lowercase slug)"
}

validate_domain() {
  local domain="$1"
  [[ "${domain}" =~ ^[A-Za-z0-9.-]+$ ]] || fail "invalid domain '${domain}'"
  [[ "${domain}" == *.* ]] || fail "domain must include a dot"
}

validate_port() {
  local port="$1"
  [[ "${port}" =~ ^[0-9]+$ ]] || fail "port must be numeric"
  (( port >= 1024 && port <= 65535 )) || fail "port must be in range 1024-65535"
}

app_manifest() {
  local name="$1"
  echo "${APPS_DIR}/${name}.env"
}

app_stack_dir() {
  local name="$1"
  echo "${STACKS_DIR}/${name}"
}

app_volume_dir() {
  local name="$1"
  echo "${VOLUMES_DIR}/${name}"
}

app_route_file() {
  local name="$1"
  echo "${ROUTES_DIR}/routes.caddy"
}

load_app() {
  local name="$1"
  local manifest
  manifest="$(app_manifest "${name}")"
  [[ -f "${manifest}" ]] || fail "app '${name}' does not exist"
  # shellcheck disable=SC1090
  source "${manifest}"
}

compose_command() {
  local podman_bin=""
  local podman_compose_bin=""

  if command -v podman >/dev/null 2>&1; then
    podman_bin="$(command -v podman)"
  elif [[ -x /run/current-system/sw/bin/podman ]]; then
    podman_bin="/run/current-system/sw/bin/podman"
  fi

  if command -v podman-compose >/dev/null 2>&1; then
    podman_compose_bin="$(command -v podman-compose)"
  elif [[ -x /run/current-system/sw/bin/podman-compose ]]; then
    podman_compose_bin="/run/current-system/sw/bin/podman-compose"
  fi

  if [[ -n "${podman_bin}" ]] && "${podman_bin}" compose version >/dev/null 2>&1; then
    echo "${podman_bin} compose"
    return
  fi

  if [[ -n "${podman_compose_bin}" ]]; then
    echo "${podman_compose_bin}"
    return
  fi

  fail "no compose command available (need 'podman compose' or 'podman-compose')"
}

ensure_podman_runtime_env() {
  local uid
  uid="$(id -u)"

  if [[ -z "${HOME:-}" ]]; then
    HOME="$(getent passwd "${uid}" | cut -d: -f6 || true)"
    export HOME
  fi

  if [[ -z "${XDG_RUNTIME_DIR:-}" ]]; then
    XDG_RUNTIME_DIR="/run/user/${uid}"
    export XDG_RUNTIME_DIR
  fi

  if [[ ! -d "${XDG_RUNTIME_DIR}" ]]; then
    fail "XDG_RUNTIME_DIR '${XDG_RUNTIME_DIR}' does not exist for uid ${uid}. Ensure user runtime is available (e.g. loginctl enable-linger $(id -un))."
  fi

  if [[ -z "${DBUS_SESSION_BUS_ADDRESS:-}" && -S "${XDG_RUNTIME_DIR}/bus" ]]; then
    DBUS_SESSION_BUS_ADDRESS="unix:path=${XDG_RUNTIME_DIR}/bus"
    export DBUS_SESSION_BUS_ADDRESS
  fi

  # Avoid inherited docker/podman remote host env from external callers.
  unset DOCKER_HOST
  unset CONTAINER_HOST
}

run_compose() {
  local compose
  compose="$(compose_command)"

  ensure_podman_runtime_env

  if [[ "${compose}" == *" compose" ]]; then
    local podman_bin="${compose% compose}"
    "${podman_bin}" compose "$@"
    return
  fi

  "${compose}" "$@"
}

write_default_compose() {
  local name="$1"
  local port="$2"
  local stack_dir
  local volume_dir
  stack_dir="$(app_stack_dir "${name}")"
  volume_dir="$(app_volume_dir "${name}")"

  cat >"${stack_dir}/compose.yaml" <<EOF
services:
  app:
    image: docker.io/traefik/whoami:latest
    restart: unless-stopped
    ports:
      - "127.0.0.1:${port}:80"
    volumes:
      - ${volume_dir}/data:/data
EOF
}

write_manifest() {
  local name="$1"
  local domain="$2"
  local port="$3"
  local auth="$4"
  local manifest
  local stack_dir
  local volume_dir
  local route_file

  manifest="$(app_manifest "${name}")"
  stack_dir="$(app_stack_dir "${name}")"
  volume_dir="$(app_volume_dir "${name}")"
  route_file="$(app_route_file "${name}")"

  cat >"${manifest}" <<EOF
APP_NAME="${name}"
APP_DOMAIN="${domain}"
APP_PORT="${port}"
APP_UPSTREAM="127.0.0.1:${port}"
APP_AUTH_PROTECTED="${auth}"
APP_STACK_DIR="${stack_dir}"
APP_COMPOSE_FILE="${stack_dir}/compose.yaml"
APP_VOLUME_DIR="${volume_dir}"
APP_ROUTE_FILE="${route_file}"
EOF
}

cmd_init() {
  local name="$1"
  local domain="$2"
  local port="$3"
  local auth="${4:-true}"

  validate_name "${name}"
  validate_domain "${domain}"
  validate_port "${port}"
  [[ "${auth}" == "true" || "${auth}" == "false" ]] || fail "auth must be true or false"

  ensure_base_dirs

  local manifest
  local stack_dir
  local volume_dir
  manifest="$(app_manifest "${name}")"
  stack_dir="$(app_stack_dir "${name}")"
  volume_dir="$(app_volume_dir "${name}")"

  [[ ! -f "${manifest}" ]] || fail "app '${name}' already exists"

  mkdir -p "${stack_dir}" "${volume_dir}/data"
  write_default_compose "${name}" "${port}"
  write_manifest "${name}" "${domain}" "${port}" "${auth}"
  cmd_render_route "${name}"

  echo "initialized app '${name}'"
}

cmd_render_route() {
  local name="$1"
  validate_name "${name}"
  load_app "${name}"

  local auth_block=""
  if [[ "${APP_AUTH_PROTECTED}" == "true" ]]; then
    auth_block="${FORWARD_AUTH_BLOCK}"
  fi

  # Append to aggregate routes file (idempotent: remove stale block first).
  local tmp
  tmp="$(mktemp)"

  # Strip any existing block for this app from the aggregate file.
  if [[ -f "${APP_ROUTE_FILE}" ]]; then
    # Use sed to remove the block between # route:name:start and # route:name:end
    sed "/^# route:${name}:start$/,/^# route:${name}:end$/d" "${APP_ROUTE_FILE}" >"${tmp}" || true
  else
    printf "" >"${tmp}"
  fi

  {
    printf "# route:%s:start\n" "${name}"
    printf "%s {\n" "${APP_DOMAIN}"
    if [[ -n "${auth_block}" ]]; then
      printf "%s\n" "${auth_block}"
    fi
    printf "  reverse_proxy %s\n" "${APP_UPSTREAM}"
    printf "}\n"
    printf "# route:%s:end\n" "${name}"
  } >>"${tmp}"

  mv "${tmp}" "${APP_ROUTE_FILE}"
  echo "rendered route ${APP_ROUTE_FILE}"
}

maybe_reload_caddy() {
  if [[ -x /run/current-system/sw/bin/caddy && -f /etc/caddy/Caddyfile ]]; then
    /run/current-system/sw/bin/caddy validate --config /etc/caddy/Caddyfile --adapter caddyfile || echo "warning: caddy validation failed" >&2
  fi

  if [[ "${EUID}" -eq 0 ]]; then
    systemctl reload caddy
    echo "reloaded caddy"
    return
  fi

  if command -v sudo >/dev/null 2>&1 && sudo -n true >/dev/null 2>&1; then
    sudo -n /run/current-system/sw/bin/systemctl reload caddy
    echo "reloaded caddy via sudo"
    return
  fi

  echo "caddy reload requires root; run: sudo systemctl reload caddy"
}

cmd_deploy() {
  local name="$1"
  validate_name "${name}"
  load_app "${name}"

  echo "Starting deployment for app '${name}'" | systemd-cat -t panelctl -p info

  cmd_render_route "${name}"
  
  if ! run_compose -f "${APP_COMPOSE_FILE}" up -d 2>&1 | systemd-cat -t panelctl -p info; then
    echo "Deployment failed for app '${name}'" | systemd-cat -t panelctl -p err
    fail "compose up failed"
  fi
  
  maybe_reload_caddy

  echo "Successfully deployed app '${name}'" | systemd-cat -t panelctl -p info
  echo "deployed app '${name}'"
}

cmd_stop() {
  local name="$1"
  validate_name "${name}"
  load_app "${name}"

  run_compose -f "${APP_COMPOSE_FILE}" down || fail "compose down failed"
  echo "stopped app '${name}'"
}

cmd_remove() {
  local name="$1"
  local keep_volumes="${2:-}"
  validate_name "${name}"
  load_app "${name}"

  run_compose -f "${APP_COMPOSE_FILE}" down 2>/dev/null || true

  # Remove this app's block from the aggregate routes file.
  if [[ -f "${APP_ROUTE_FILE}" ]]; then
    local tmp
    tmp="$(mktemp)"
    sed "/^# route:${name}:start$/,/^# route:${name}:end$/d" "${APP_ROUTE_FILE}" >"${tmp}" || true
    mv "${tmp}" "${APP_ROUTE_FILE}"
  fi

  rm -f "$(app_manifest "${name}")"
  rm -rf "${APP_STACK_DIR}"

  if [[ "${keep_volumes}" != "--keep-volumes" ]]; then
    rm -rf "${APP_VOLUME_DIR}"
  fi

  maybe_reload_caddy
  echo "removed app '${name}'"
}

cmd_list() {
  ensure_base_dirs
  local found=0
  for mf in "${APPS_DIR}"/*.env; do
    [[ -e "${mf}" ]] || continue
    found=1
    # shellcheck disable=SC1090
    source "${mf}"
    echo "${APP_NAME} ${APP_DOMAIN} ${APP_UPSTREAM} auth=${APP_AUTH_PROTECTED}"
  done

  if [[ "${found}" -eq 0 ]]; then
    echo "no apps found"
  fi
}

cmd_show() {
  local name="$1"
  validate_name "${name}"
  local mf
  mf="$(app_manifest "${name}")"
  [[ -f "${mf}" ]] || fail "app '${name}' does not exist"
  cat "${mf}"
}

main() {
  local cmd="${1:-}"

  case "${cmd}" in
    init)
      [[ $# -ge 4 ]] || fail "usage: panelctl init <name> <domain> <port> [auth]"
      cmd_init "$2" "$3" "$4" "${5:-true}"
      ;;
    render-route)
      [[ $# -eq 2 ]] || fail "usage: panelctl render-route <name>"
      cmd_render_route "$2"
      ;;
    deploy)
      [[ $# -eq 2 ]] || fail "usage: panelctl deploy <name>"
      cmd_deploy "$2"
      ;;
    stop)
      [[ $# -eq 2 ]] || fail "usage: panelctl stop <name>"
      cmd_stop "$2"
      ;;
    remove)
      [[ $# -ge 2 ]] || fail "usage: panelctl remove <name> [--keep-volumes]"
      cmd_remove "$2" "${3:-}"
      ;;
    list)
      [[ $# -eq 1 ]] || fail "usage: panelctl list"
      cmd_list
      ;;
    show)
      [[ $# -eq 2 ]] || fail "usage: panelctl show <name>"
      cmd_show "$2"
      ;;
    ""|-h|--help|help)
      usage
      ;;
    *)
      fail "unknown command '${cmd}'"
      ;;
  esac
}

main "$@"