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

# Default config for:
#   curl -fsSL https://punchsky.cn/install_iot.sh | bash
#
# Fill these values before publishing this script at https://punchsky.cn/install_iot.sh.
WORK_DIR="${WORK_DIR:-/opt/app}"
CURRENT_USER="${SUDO_USER:-$(id -un)}"
SERVICE_USER="${SERVICE_USER:-$CURRENT_USER}"
SERVICE_GROUP="${SERVICE_GROUP:-$(id -gn "$SERVICE_USER")}"

# Configure programs here before publishing this script.
# Format:
#   INSTALL_<APP>=(
#     "service_name"
#     "download_url"
#     "start_command"
#     "stop_command"
#     "service_user"
#     "service_group"
#   )
#
# IOT_ENV is rendered into the systemd service file as Environment= lines,
# using the [prod] section from iot/env.file. Directory creation is driven by
# those service env values. IOT_DIR_ENV_KEYS lists env keys whose values are
# directories that must be created if they do not exist. IOT_PARENT_DIR_ENV_KEYS
# lists env keys whose values are file paths; their parent directories must be
# created if they do not exist.
#
# Use {install_dir}, {work_dir} and {service_name} in commands and directories.
# service_user and service_group are optional.

INSTALL_IOT=(
  "iot"
  "https://punchsky.cn/down/iot-0.1.0.tar.gz"
  "{install_dir}/bin/iot foreground"
  "{install_dir}/bin/iot stop"
  ""
  ""
)

IOT_ENV=(
  "IOT_API_URL=http://127.0.0.1/api/v1"
  "ENDPOINT_ROOT_DIR=/var/lib/endpoint/database/"
  "ENDPOINT_LOG_PATH=/var/lib/endpoint/endpoint_log"
  "IOT_MNESIA_DIR=/var/lib/iot/mnesia/"
  "IOT_CTRL_SOCKET_PATH=/var/lib/iot/ctl.sock"
)

IOT_DIR_ENV_KEYS=(
  "ENDPOINT_ROOT_DIR"
  "ENDPOINT_LOG_PATH"
  "IOT_MNESIA_DIR"
)

IOT_PARENT_DIR_ENV_KEYS=(
  "IOT_CTRL_SOCKET_PATH"
)

TEMP_FILES=()
INSTALLED_SERVICES=()

usage() {
  cat <<'EOF'
Usage:
  curl -fsSL https://punchsky.cn/install_iot.sh | bash

  curl -fsSL https://punchsky.cn/install_iot.sh | bash -s -- \
    -w <work_dir>

Config:
  Configure programs inside this script before publishing it.

Options:
  -w, --work-dir       Working directory used for installation.
      --user           Default service user. Default: current user.
      --group          Default service group. Default: current user's primary group.
  -h, --help           Show this help.

Array config inside script:
  INSTALL_IOT
  IOT_ENV
  IOT_DIR_ENV_KEYS
  IOT_PARENT_DIR_ENV_KEYS

Package format:
  INSTALL_<APP>=(
    "service_name"
    "download_url"
    "start_command"
    "stop_command"
    "service_user"
    "service_group"
  )

Placeholders:
  {install_dir} will be replaced with the extracted package directory.
  {work_dir} will be replaced with the root work directory.
  {service_name} will be replaced with the service name.

Example:
  curl -fsSL https://punchsky.cn/install_iot.sh | bash
EOF
}

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

cleanup() {
  local file

  set +u
  for file in "${TEMP_FILES[@]}"; do
    [[ -n "$file" ]] && rm -f "$file"
  done
  set -u
}

fail() {
  printf '[install][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
}

strip_archive_suffix() {
  local filename="$1"

  case "$filename" in
    *.tar.gz) printf '%s\n' "${filename%.tar.gz}" ;;
    *.tgz) printf '%s\n' "${filename%.tgz}" ;;
    *) fail "Unsupported archive suffix: $filename. Expected .tar.gz or .tgz" ;;
  esac
}

parse_args() {
  while [[ $# -gt 0 ]]; do
    case "$1" in
      -w|--work-dir)
        require_option_value "$1" "${2:-}"
        WORK_DIR="${2:-}"
        shift 2
        ;;
      --user)
        require_option_value "$1" "${2:-}"
        SERVICE_USER="${2:-}"
        shift 2
        ;;
      --group)
        require_option_value "$1" "${2:-}"
        SERVICE_GROUP="${2:-}"
        shift 2
        ;;
      -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"

  require_install_config INSTALL_IOT
}

prepare_work_dir() {
  log "Creating root work directory: $WORK_DIR"
  run_as_root install -d -m 0755 "$WORK_DIR"
}

render_service_file() {
  local service_name="$1"
  local service_user="$2"
  local service_group="$3"
  local install_dir="$4"
  local start_command="$5"
  local stop_command="$6"
  local env_line

  cat <<EOF
[Unit]
Description=${service_name} service
After=network-online.target
Wants=network-online.target

[Service]
Type=simple
User=${service_user}
Group=${service_group}
WorkingDirectory=${install_dir}
EOF

  while IFS= read -r env_line; do
    [[ -n "$env_line" ]] || continue
    validate_environment_line "$env_line"
    printf 'Environment="%s"\n' "$env_line"
  done < <(service_env_lines "$service_name")

  printf 'ExecStart=%s\n' "$start_command"

  if [[ -n "$stop_command" ]]; then
    printf 'ExecStop=%s\n' "$stop_command"
  fi

  cat <<'EOF'
Restart=on-failure
RestartSec=5

[Install]
WantedBy=multi-user.target
EOF
}

write_service_file() {
  local service_file="$1"
  local service_name="$2"
  local service_user="$3"
  local service_group="$4"
  local install_dir="$5"
  local start_command="$6"
  local stop_command="$7"

  if [[ -f "$service_file" ]]; then
    local backup_file="${service_file}.bak.$(date +%Y%m%d%H%M%S)"
    log "Backing up existing service file: $backup_file"
    run_as_root cp "$service_file" "$backup_file"
  fi

  log "Writing systemd service file: $service_file"
  render_service_file "$service_name" "$service_user" "$service_group" "$install_dir" "$start_command" "$stop_command" | run_as_root tee "$service_file" >/dev/null
}

validate_install_item() {
  local service_name="$1"
  local download_url="$2"
  local start_command="$3"

  [[ -n "$service_name" ]] || fail "Invalid package config: service name is empty"
  [[ -n "$download_url" ]] || fail "Invalid package config for $service_name: download URL is empty"
  [[ -n "$start_command" ]] || fail "Invalid package config for $service_name: start command is empty"
  [[ "$service_name" =~ ^[a-zA-Z0-9_.@-]+$ ]] || fail "Invalid service name: $service_name"
}

require_install_config() {
  local config_name="$1"
  local config_count
  local service_name
  local download_url
  local start_command

  eval "config_count=\${#${config_name}[@]}"
  eval "service_name=\"\${${config_name}[0]:-}\""
  eval "download_url=\"\${${config_name}[1]:-}\""
  eval "start_command=\"\${${config_name}[2]:-}\""

  [[ "$config_count" -ge 4 ]] || fail "Invalid $config_name config. Expected service name, URL and commands"
  [[ -n "$service_name" ]] || fail "Invalid $config_name config: service name is empty"
  [[ -n "$download_url" ]] || fail "Invalid $config_name config: download URL is empty"
  [[ -n "$start_command" ]] || fail "Invalid $config_name config: start command is empty"
}

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"
}

validate_environment_line() {
  local env_line="$1"
  local env_key="${env_line%%=*}"

  [[ "$env_line" == *=* ]] || fail "Invalid environment line: $env_line"
  [[ "$env_key" =~ ^[a-zA-Z_][a-zA-Z0-9_]*$ ]] || fail "Invalid environment key: $env_key"
}

service_env_lines() {
  local service_name="$1"
  local env_array_name=""
  local env_count
  local index
  local env_line

  case "$service_name" in
    iot)
      env_array_name="IOT_ENV"
      ;;
    *)
      return 0
      ;;
  esac

  eval "env_count=\${#${env_array_name}[@]}"
  for ((index=0; index<env_count; index++)); do
    eval "env_line=\"\${${env_array_name}[$index]}\""
    printf '%s\n' "$env_line"
  done
}

service_dir_env_keys() {
  local service_name="$1"
  local dir_keys_array_name=""
  local dir_keys_count
  local index
  local env_key

  case "$service_name" in
    iot)
      dir_keys_array_name="IOT_DIR_ENV_KEYS"
      ;;
    *)
      return 0
      ;;
  esac

  eval "dir_keys_count=\${#${dir_keys_array_name}[@]}"
  for ((index=0; index<dir_keys_count; index++)); do
    eval "env_key=\"\${${dir_keys_array_name}[$index]}\""
    printf '%s\n' "$env_key"
  done
}

service_parent_dir_env_keys() {
  local service_name="$1"
  local parent_dir_keys_array_name=""
  local parent_dir_keys_count
  local index
  local env_key

  case "$service_name" in
    iot)
      parent_dir_keys_array_name="IOT_PARENT_DIR_ENV_KEYS"
      ;;
    *)
      return 0
      ;;
  esac

  eval "parent_dir_keys_count=\${#${parent_dir_keys_array_name}[@]}"
  for ((index=0; index<parent_dir_keys_count; index++)); do
    eval "env_key=\"\${${parent_dir_keys_array_name}[$index]}\""
    printf '%s\n' "$env_key"
  done
}

env_value_for_key() {
  local service_name="$1"
  local env_key="$2"
  local env_line
  local value

  while IFS= read -r env_line; do
    [[ "$env_line" == "${env_key}="* ]] || continue
    value="${env_line#*=}"
    printf '%s\n' "$value"
    return 0
  done < <(service_env_lines "$service_name")

  fail "Missing env key $env_key for $service_name"
}

create_dependency_dirs_from_env() {
  local service_name="$1"
  local install_dir="$2"
  local service_user="$3"
  local service_group="$4"
  local env_key
  local dependency_dir

  while IFS= read -r env_key; do
    [[ -n "$env_key" ]] || continue
    dependency_dir="$(env_value_for_key "$service_name" "$env_key")"
    dependency_dir="$(replace_placeholders "$dependency_dir" "$install_dir" "$service_name")"

    [[ "$dependency_dir" = /* ]] || fail "Dependency directory must be an absolute path: $dependency_dir"

    log "Creating dependency directory from $env_key: $dependency_dir"
    run_as_root install -d -m 0755 "$dependency_dir"
    run_as_root chown -R "${service_user}:${service_group}" "$dependency_dir"
  done < <(service_dir_env_keys "$service_name")
}

create_parent_dependency_dirs_from_env() {
  local service_name="$1"
  local install_dir="$2"
  local service_user="$3"
  local service_group="$4"
  local env_key
  local dependency_path
  local dependency_dir

  while IFS= read -r env_key; do
    [[ -n "$env_key" ]] || continue
    dependency_path="$(env_value_for_key "$service_name" "$env_key")"
    dependency_path="$(replace_placeholders "$dependency_path" "$install_dir" "$service_name")"

    [[ "$dependency_path" = /* ]] || fail "Dependency path must be an absolute path: $dependency_path"

    dependency_dir="$(dirname "$dependency_path")"
    [[ -n "$dependency_dir" && "$dependency_dir" != "." ]] || fail "Cannot parse parent directory from path: $dependency_path"

    log "Creating parent dependency directory from $env_key: $dependency_dir"
    run_as_root install -d -m 0755 "$dependency_dir"
    run_as_root chown -R "${service_user}:${service_group}" "$dependency_dir"
  done < <(service_parent_dir_env_keys "$service_name")
}

install_program() {
  local service_name="$1"
  local download_url="$2"
  local start_command="$3"
  local stop_command="$4"
  local service_user="$5"
  local service_group="$6"
  local clean_url="$download_url"
  local archive_name

  validate_install_item "$service_name" "$download_url" "$start_command"

  clean_url="${clean_url%%\?*}"
  clean_url="${clean_url%%#*}"
  archive_name="$(basename "$clean_url")"
  [[ -n "$archive_name" ]] || fail "Cannot parse archive filename from URL: $download_url"

  local app_dir_name
  app_dir_name="$(strip_archive_suffix "$archive_name")"

  local archive_path="${WORK_DIR}/${archive_name}"
  local install_dir="${WORK_DIR}/${app_dir_name}"
  local service_file="/etc/systemd/system/${service_name}.service"
  local temp_archive
  temp_archive="$(mktemp)"
  TEMP_FILES+=("$temp_archive")

  service_user="${service_user:-$SERVICE_USER}"
  service_group="${service_group:-$SERVICE_GROUP}"
  start_command="$(replace_placeholders "$start_command" "$install_dir" "$service_name")"
  stop_command="$(replace_placeholders "$stop_command" "$install_dir" "$service_name")"

  log "Downloading $download_url"
  wget --tries=3 --timeout=20 -O "$temp_archive" "$download_url"
  run_as_root install -m 0644 "$temp_archive" "$archive_path"

  log "Creating install directory: $install_dir"
  run_as_root install -d -m 0755 "$install_dir"

  log "Extracting archive to $install_dir"
  run_as_root tar -zxvf "$archive_path" -C "$install_dir"

  log "Setting owner for install directory: ${service_user}:${service_group}"
  run_as_root chown -R "${service_user}:${service_group}" "$install_dir"

  create_dependency_dirs_from_env "$service_name" "$install_dir" "$service_user" "$service_group"
  create_parent_dependency_dirs_from_env "$service_name" "$install_dir" "$service_user" "$service_group"

  write_service_file "$service_file" "$service_name" "$service_user" "$service_group" "$install_dir" "$start_command" "$stop_command"
  INSTALLED_SERVICES+=("$service_name")
}

install_program_from_config() {
  local config_name="$1"
  local service_name
  local download_url
  local start_command
  local stop_command
  local service_user
  local service_group

  eval "service_name=\"\${${config_name}[0]:-}\""
  eval "download_url=\"\${${config_name}[1]:-}\""
  eval "start_command=\"\${${config_name}[2]:-}\""
  eval "stop_command=\"\${${config_name}[3]:-}\""
  eval "service_user=\"\${${config_name}[4]:-}\""
  eval "service_group=\"\${${config_name}[5]:-}\""

  install_program \
    "$service_name" \
    "$download_url" \
    "$start_command" \
    "$stop_command" \
    "$service_user" \
    "$service_group"
}

install_programs() {
  install_program_from_config INSTALL_IOT
}

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

enable_installed_services() {
  local service_name

  set +u
  for service_name in "${INSTALLED_SERVICES[@]}"; do
    set -u
    log "Enabling service on boot: ${service_name}.service"
    run_as_root systemctl enable "${service_name}.service"
    set +u
  done
  set -u
}

main() {
  trap cleanup EXIT

  parse_args "$@"
  validate_args

  require_command wget
  require_root_runner
  require_command dirname
  require_command tar
  require_command systemctl

  prepare_work_dir
  install_programs
  reload_systemd
  enable_installed_services

  log "IOT installation completed"
}

main "$@"