#
# Author:: Nuo Yan <nuo@chef.io>
# Author:: Bryan McLellan <btm@loftninjas.org>
# Author:: Seth Chisamore <schisamo@chef.io>
# Copyright:: Copyright 2010-2017, Chef Software Inc.
# License:: Apache License, Version 2.0
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

require "chef/provider/service/simple"
if RUBY_PLATFORM =~ /mswin|mingw32|windows/
  require "chef/win32/error"
  require "win32/service"
end

class Chef::Provider::Service::Windows < Chef::Provider::Service
  provides :service, os: "windows"
  provides :windows_service, os: "windows"

  include Chef::Mixin::ShellOut
  include Chef::ReservedNames::Win32::API::Error rescue LoadError

  #Win32::Service.get_start_type
  AUTO_START = "auto start"
  MANUAL = "demand start"
  DISABLED = "disabled"

  #Win32::Service.get_current_state
  RUNNING = "running"
  STOPPED = "stopped"
  CONTINUE_PENDING = "continue pending"
  PAUSE_PENDING = "pause pending"
  PAUSED = "paused"
  START_PENDING = "start pending"
  STOP_PENDING  = "stop pending"

  TIMEOUT = 60

  SERVICE_RIGHT = "SeServiceLogonRight"

  def load_current_resource
    @current_resource = Chef::Resource::WindowsService.new(@new_resource.name)
    @current_resource.service_name(@new_resource.service_name)
    @current_resource.running(current_state == RUNNING)
    Chef::Log.debug "#{@new_resource} running: #{@current_resource.running}"
    case current_start_type
    when AUTO_START
      @current_resource.enabled(true)
    when DISABLED
      @current_resource.enabled(false)
    end
    Chef::Log.debug "#{@new_resource} enabled: #{@current_resource.enabled}"
    @current_resource
  end

  def start_service
    if Win32::Service.exists?(@new_resource.service_name)
      # reconfiguration is idempotent, so just do it.
      new_config = {
        service_name: @new_resource.service_name,
        service_start_name: @new_resource.run_as_user,
        password: @new_resource.run_as_password,
      }.reject { |k, v| v.nil? || v.length == 0 }

      Win32::Service.configure(new_config)
      Chef::Log.info "#{@new_resource} configured."

      if new_config.has_key?(:service_start_name)
        unless Chef::ReservedNames::Win32::Security.get_account_right(canonicalize_username(new_config[:service_start_name])).include?(SERVICE_RIGHT)
          grant_service_logon(new_config[:service_start_name])
        end
      end

      state = current_state
      if state == RUNNING
        Chef::Log.debug "#{@new_resource} already started - nothing to do"
      elsif state == START_PENDING
        Chef::Log.debug "#{@new_resource} already sent start signal - waiting for start"
        wait_for_state(RUNNING)
      elsif state == STOPPED
        if @new_resource.start_command
          Chef::Log.debug "#{@new_resource} starting service using the given start_command"
          shell_out!(@new_resource.start_command)
        else
          spawn_command_thread do
            begin
              Win32::Service.start(@new_resource.service_name)
            rescue SystemCallError => ex
              if ex.errno == ERROR_SERVICE_LOGON_FAILED
                Chef::Log.error ex.message
                raise Chef::Exceptions::Service,
                "Service #{@new_resource} did not start due to a logon failure (error #{ERROR_SERVICE_LOGON_FAILED}): possibly the specified user '#{@new_resource.run_as_user}' does not have the 'log on as a service' privilege, or the password is incorrect."
              else
                raise ex
              end
            end
          end
          wait_for_state(RUNNING)
        end
        @new_resource.updated_by_last_action(true)
      else
        raise Chef::Exceptions::Service, "Service #{@new_resource} can't be started from state [#{state}]"
      end
    else
      Chef::Log.debug "#{@new_resource} does not exist - nothing to do"
    end
  end

  def stop_service
    if Win32::Service.exists?(@new_resource.service_name)
      state = current_state
      if state == RUNNING
        if @new_resource.stop_command
          Chef::Log.debug "#{@new_resource} stopping service using the given stop_command"
          shell_out!(@new_resource.stop_command)
        else
          spawn_command_thread do
            Win32::Service.stop(@new_resource.service_name)
          end
          wait_for_state(STOPPED)
        end
        @new_resource.updated_by_last_action(true)
      elsif state == STOPPED
        Chef::Log.debug "#{@new_resource} already stopped - nothing to do"
      elsif state == STOP_PENDING
        Chef::Log.debug "#{@new_resource} already sent stop signal - waiting for stop"
        wait_for_state(STOPPED)
      else
        raise Chef::Exceptions::Service, "Service #{@new_resource} can't be stopped from state [#{state}]"
      end
    else
      Chef::Log.debug "#{@new_resource} does not exist - nothing to do"
    end
  end

  def restart_service
    if Win32::Service.exists?(@new_resource.service_name)
      if @new_resource.restart_command
        Chef::Log.debug "#{@new_resource} restarting service using the given restart_command"
        shell_out!(@new_resource.restart_command)
      else
        stop_service
        start_service
      end
      @new_resource.updated_by_last_action(true)
    else
      Chef::Log.debug "#{@new_resource} does not exist - nothing to do"
    end
  end

  def enable_service
    if Win32::Service.exists?(@new_resource.service_name)
      set_startup_type(:automatic)
    else
      Chef::Log.debug "#{@new_resource} does not exist - nothing to do"
    end
  end

  def disable_service
    if Win32::Service.exists?(@new_resource.service_name)
      set_startup_type(:disabled)
    else
      Chef::Log.debug "#{@new_resource} does not exist - nothing to do"
    end
  end

  def action_enable
    if current_start_type != AUTO_START
      converge_by("enable service #{@new_resource}") do
        enable_service
        Chef::Log.info("#{@new_resource} enabled")
      end
    else
      Chef::Log.debug("#{@new_resource} already enabled - nothing to do")
    end
    load_new_resource_state
    @new_resource.enabled(true)
  end

  def action_disable
    if current_start_type != DISABLED
      converge_by("disable service #{@new_resource}") do
        disable_service
        Chef::Log.info("#{@new_resource} disabled")
      end
    else
      Chef::Log.debug("#{@new_resource} already disabled - nothing to do")
    end
    load_new_resource_state
    @new_resource.enabled(false)
  end

  def action_configure_startup
    case @new_resource.startup_type
    when :automatic
      if current_start_type != AUTO_START
        converge_by("set service #{@new_resource} startup type to automatic") do
          set_startup_type(:automatic)
        end
      else
        Chef::Log.debug("#{@new_resource} startup_type already automatic - nothing to do")
      end
    when :manual
      if current_start_type != MANUAL
        converge_by("set service #{@new_resource} startup type to manual") do
          set_startup_type(:manual)
        end
      else
        Chef::Log.debug("#{@new_resource} startup_type already manual - nothing to do")
      end
    when :disabled
      if current_start_type != DISABLED
        converge_by("set service #{@new_resource} startup type to disabled") do
          set_startup_type(:disabled)
        end
      else
        Chef::Log.debug("#{@new_resource} startup_type already disabled - nothing to do")
      end
    end

    # Avoid changing enabled from true/false for now
    @new_resource.enabled(nil)
  end

  private

  def grant_service_logon(username)
    begin
      Chef::ReservedNames::Win32::Security.add_account_right(canonicalize_username(username), SERVICE_RIGHT)
    rescue Chef::Exceptions::Win32APIError => err
      Chef::Log.fatal "Logon-as-service grant failed with output: #{err}"
      raise Chef::Exceptions::Service, "Logon-as-service grant failed for #{username}: #{err}"
    end

    Chef::Log.info "Grant logon-as-service to user '#{username}' successful."
    true
  end

  # remove characters that make for broken or wonky filenames.
  def clean_username_for_path(username)
    username.gsub(/[\/\\. ]+/, "_")
  end

  def canonicalize_username(username)
    username.sub(/^\.?\\+/, "")
  end

  def current_state
    Win32::Service.status(@new_resource.service_name).current_state
  end

  def current_start_type
    Win32::Service.config_info(@new_resource.service_name).start_type
  end

  # Helper method that waits for a status to change its state since state
  # changes aren't usually instantaneous.
  def wait_for_state(desired_state)
    retries = 0
    loop do
      break if current_state == desired_state
      raise Timeout::Error if ( retries += 1 ) > resource_timeout
      sleep 1
    end
  end

  def resource_timeout
    @resource_timeout ||= @new_resource.timeout || TIMEOUT
  end

  def spawn_command_thread
    worker = Thread.new do
      yield
    end

    Timeout.timeout(resource_timeout) do
      worker.join
    end
  end

  # Takes Win32::Service start_types
  def set_startup_type(type)
    # Set-Service Startup Type => Win32::Service Constant
    allowed_types = { :automatic => Win32::Service::AUTO_START,
                      :manual    => Win32::Service::DEMAND_START,
                      :disabled  => Win32::Service::DISABLED }
    unless allowed_types.keys.include?(type)
      raise Chef::Exceptions::ConfigurationError, "#{@new_resource.name}: Startup type '#{type}' is not supported"
    end

    Chef::Log.debug "#{@new_resource.name} setting start_type to #{type}"
    Win32::Service.configure(
      :service_name => @new_resource.service_name,
      :start_type => allowed_types[type]
    )
    @new_resource.updated_by_last_action(true)
  end
end