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

WORK_DIR="${WORK_DIR:-/opt/app}"
PURGE_DATA="${PURGE_DATA:-0}"

# Keep this list in sync with install_iot.sh and install_efka.sh.
# Format:
#   "service_name|download_url|start_command|stop_command|dependency_dirs|service_user|service_group"
INSTALL_ITEMS=(
  "iot|https://punchsky.cn/down/iot-0.1.0.tar.gz|{install_dir}/bin/iot foreground|{install_dir}/bin/iot stop|/var/lib/iot/mnesia,/var/lib/endpoint/database,/var/lib/endpoint/endpoint_log"
  "efka|https://punchsky.cn/down/efka-0.1.0.tar.gz|{install_dir}/bin/efka foreground|{install_dir}/bin/efka stop|/var/lib/efka/mnesia,/var/lib/efka/dets,/var/lib/efka/docker"
)

usage() {
  cat <<'EOF'
Usage:
  sudo ./uninstall_service.sh [options]

Options:
  -w, --work-dir       Working directory used during installation. Default: /opt/app.
      --purge-data     Also remove dependency/data directories from INSTALL_ITEMS.
  -h, --help           Show this help.

Default behavior:
  - Stop services in reverse INSTALL_ITEMS order.
  - Disable services from boot.
  - Remove /etc/systemd/system/<service>.service and service backups.
  - Run systemctl daemon-reload and reset-failed.
  - Remove downloaded archives and service-name program directories under WORK_DIR.
  - Remove /usr/local/bin/iot_ctrl.
  - Keep dependency/data directories unless --purge-data is passed.
EOF
}

log() {
  printf '[uninstall] %s\n' "$*"
}

fail() {
  printf '[uninstall][error] %s\n' "$*" >&2
  exit 1
}

require_command() {
  command -v "$1" >/dev/null 2>&1 || fail "Missing required command: $1"
}

require_option_value() {
  local option="$1"
  local value="${2:-}"

  [[ -n "$value" ]] || fail "$option requires a value"
}

require_root_runner() {
  if [[ "${EUID}" -ne 0 ]]; then
    require_command sudo
  fi
}

run_as_root() {
  if [[ "${EUID}" -eq 0 ]]; then
    "$@"
  else
    sudo "$@"
  fi
}

parse_args() {
  while [[ $# -gt 0 ]]; do
    case "$1" in
      -w|--work-dir)
        require_option_value "$1" "${2:-}"
        WORK_DIR="${2:-}"
        shift 2
        ;;
      --purge-data)
        PURGE_DATA=1
        shift
        ;;
      -h|--help)
        usage
        exit 0
        ;;
      *)
        fail "Unknown argument: $1"
        ;;
    esac
  done
}

validate_args() {
  [[ -n "$WORK_DIR" ]] || fail "--work-dir is required"
  [[ "$WORK_DIR" = /* ]] || fail "--work-dir must be an absolute path"

  set +u
  local item_count="${#INSTALL_ITEMS[@]}"
  set -u

  [[ "$item_count" -gt 0 ]] || fail "No programs configured. Fill INSTALL_ITEMS inside this script"
}

archive_name_from_url() {
  local download_url="$1"
  local clean_url="$download_url"

  clean_url="${clean_url%%\?*}"
  clean_url="${clean_url%%#*}"
  basename "$clean_url"
}

replace_placeholders() {
  local value="$1"
  local install_dir="$2"
  local service_name="$3"

  value="${value//\{install_dir\}/$install_dir}"
  value="${value//\{work_dir\}/$WORK_DIR}"
  value="${value//\{service_name\}/$service_name}"

  printf '%s\n' "$value"
}

service_name_from_item() {
  local item="$1"
  local service_name

  IFS='|' read -r service_name _ <<< "$item"
  printf '%s\n' "$service_name"
}

stop_and_disable_services() {
  local index
  local service_name

  set +u
  for ((index=${#INSTALL_ITEMS[@]} - 1; index >= 0; index--)); do
    set -u
    service_name="$(service_name_from_item "${INSTALL_ITEMS[$index]}")"
    [[ -n "$service_name" ]] || continue

    log "Stopping service: ${service_name}.service"
    run_as_root systemctl stop "${service_name}.service" || log "Service not running or not found: ${service_name}.service"

    log "Disabling service on boot: ${service_name}.service"
    run_as_root systemctl disable "${service_name}.service" || log "Service not enabled or not found: ${service_name}.service"
    set +u
  done
  set -u
}

remove_service_files() {
  local item
  local service_name
  local service_file

  set +u
  for item in "${INSTALL_ITEMS[@]}"; do
    set -u
    service_name="$(service_name_from_item "$item")"
    [[ -n "$service_name" ]] || continue

    service_file="/etc/systemd/system/${service_name}.service"
    log "Removing systemd service file: $service_file"
    run_as_root rm -f "$service_file"

    log "Removing systemd service backups: ${service_file}.bak.*"
    run_as_root sh -c 'rm -f "$1".bak.*' sh "$service_file"
    set +u
  done
  set -u
}

remove_program_files() {
  local item
  local service_name
  local download_url
  local start_command
  local stop_command
  local dependency_dirs
  local service_user
  local service_group
  local archive_name
  local archive_path
  local install_dir

  set +u
  for item in "${INSTALL_ITEMS[@]}"; do
    set -u
    IFS='|' read -r service_name download_url start_command stop_command dependency_dirs service_user service_group <<< "$item"
    [[ -n "$service_name" ]] || continue
    [[ -n "$download_url" ]] || fail "Invalid package config for $service_name: download URL is empty"

    archive_name="$(archive_name_from_url "$download_url")"
    [[ -n "$archive_name" ]] || fail "Cannot parse archive filename from URL: $download_url"

    archive_path="${WORK_DIR}/${archive_name}"
    install_dir="${WORK_DIR}/${service_name}"

    log "Removing downloaded archive: $archive_path"
    run_as_root rm -f "$archive_path"

    log "Removing installed program directory: $install_dir"
    run_as_root rm -rf "$install_dir"

    if [[ "$PURGE_DATA" = "1" ]]; then
      remove_dependency_dirs "$dependency_dirs" "$install_dir" "$service_name"
    fi
    set +u
  done
  set -u
}

remove_global_links() {
  local link_path="/usr/local/bin/iot_ctrl"

  log "Removing global command link: $link_path"
  run_as_root rm -f "$link_path"
}

remove_dependency_dirs() {
  local dependency_dirs="$1"
  local install_dir="$2"
  local service_name="$3"
  local dependency_dir
  local dependency_dir_list
  local -a dependency_dir_array

  [[ -n "$dependency_dirs" ]] || return 0

  dependency_dir_list="$(replace_placeholders "$dependency_dirs" "$install_dir" "$service_name")"

  IFS=',' read -ra dependency_dir_array <<< "$dependency_dir_list"
  for dependency_dir in "${dependency_dir_array[@]}"; do
    [[ -n "$dependency_dir" ]] || continue
    [[ "$dependency_dir" = /* ]] || fail "Dependency directory must be an absolute path: $dependency_dir"

    log "Removing dependency/data directory: $dependency_dir"
    run_as_root rm -rf "$dependency_dir"
  done
}

reload_systemd() {
  log "Reloading systemd"
  run_as_root systemctl daemon-reload

  log "Resetting failed systemd state"
  run_as_root systemctl reset-failed || true
}

main() {
  parse_args "$@"
  validate_args

  require_root_runner
  require_command systemctl

  stop_and_disable_services
  remove_service_files
  reload_systemd
  remove_global_links
  remove_program_files

  log "Uninstall completed"
}

main "$@"