# encoding: utf-8
require 'logstash/outputs/base'
require 'logstash/namespace'
require 'concurrent'
require 'stud/interval'
require 'java'
require 'logstash-output-charrington_jars'
require 'json'
require 'bigdecimal'
require 'pry'
require File.join(File.dirname(__FILE__), "charrington/process")
require File.join(File.dirname(__FILE__), "charrington/transform")
require File.join(File.dirname(__FILE__), "charrington/insert")

# Write events to a SQL engine, using JDBC.
# It is upto the user of the plugin to correctly configure the plugin.

# This class is responsible for setting things up, creating the connection,
# and handling retries. Charrington::Insert is where the insert
# is attempted. If that fails, it will try to either
# create a table via Charrington::CreateTable
# or alter an existing one via Charrington::AlterTable

class LogStash::Outputs::Charrington < LogStash::Outputs::Base
  concurrency :shared

  STRFTIME_FMT = '%Y-%m-%d %T.%L'.freeze

  # RETRYABLE_SQLSTATE_CLASSES = [
  #   # Classes of retryable SQLSTATE codes
  #   # Not all in the class will be retryable. However, this is the best that
  #   # we've got right now.
  #   # If a custom state code is required, set it in retry_sql_states.
  #   '08', # Connection Exception
  #   '24', # Invalid Cursor State (Maybe retry-able in some circumstances)
  #   '25', # Invalid Transaction State
  #   '40', # Transaction Rollback
  #   '53', # Insufficient Resources
  #   '54', # Program Limit Exceeded (MAYBE)
  #   '55', # Object Not In Prerequisite State
  #   '57', # Operator Intervention
  #   '58', # System Error
  # ].freeze

  config_name 'charrington'

  # Driver class - Reintroduced for https://github.com/theangryangel/logstash-output-jdbc/issues/26
  config :driver_class, validate: :string

  # Does the JDBC driver support autocommit?
  config :driver_auto_commit, validate: :boolean, default: true, required: true

  # Where to find the jar
  # Defaults to not required, and to the original behaviour
  config :driver_jar_path, validate: :string, required: false

  # jdbc connection string
  config :connection_string, validate: :string, required: true

  # jdbc username - optional, maybe in the connection string
  config :username, validate: :string, required: false

  # jdbc password - optional, maybe in the connection string
  config :password, validate: :string, required: false

  # Number of connections in the pool to maintain
  config :max_pool_size, validate: :number, default: 5

  # Connection timeout
  config :connection_timeout, validate: :number, default: 10000

  # Set initial interval in seconds between retries. Doubled on each retry up to `retry_max_interval`
  config :retry_initial_interval, validate: :number, default: 2

  # Maximum time between retries, in seconds
  config :retry_max_interval, validate: :number, default: 128

  # Any additional custom, retryable SQL state codes.
  # Suitable for configuring retryable custom JDBC SQL state codes.
  config :retry_sql_states, validate: :array, default: []

  # Run a connection test on start.
  config :connection_test, validate: :boolean, default: true

  config :connection_test_query, validate: :string, required: false

  # Maximum number of sequential failed attempts, before we stop retrying.
  # If set to < 1, then it will infinitely retry.
  # At the default values this is a little over 10 minutes
  config :max_flush_exceptions, validate: :number, default: 10

  config :max_repeat_exceptions, obsolete: 'This has been replaced by max_flush_exceptions - which behaves slightly differently. Please check the documentation.'
  config :max_repeat_exceptions_time, obsolete: 'This is no longer required'
  config :idle_flush_time, obsolete: 'No longer necessary under Logstash v5'

  # Allows the whole event to be converted to JSON
  config :enable_event_as_json_keyword, validate: :boolean, default: false

  # The magic key used to convert the whole event to JSON. If you need this, and you have the default in your events, you can use this to change your magic keyword.
  config :event_as_json_keyword, validate: :string, default: '@event'

  # The database schema
  config :schema, validate: :string, default: ''

  def register
    @logger.info('JDBC - Starting up')

    load_jar_files!
    @stopping = Concurrent::AtomicBoolean.new(false)

    setup_and_test_pool!
  end

  def multi_receive(events)
    events.each do |event|
      connection = get_connection
      break unless connection

      opts = { connection: connection,
               schema: @schema,
               max_retries: @max_flush_exceptions,
               retry_initial_interval: @retry_initial_interval }

      Charrington::Process.call(connection, event, opts)
      connection.close unless connection.nil?
    end
  end

  def close
    @stopping.make_true
    @pool.close
    super
  end

  private

  def setup_and_test_pool!
    @pool = Java::ComZaxxerHikari::HikariDataSource.new
    @pool.setDriverClassName(@driver_class) if @driver_class
    @pool.setUsername(@username) if @username
    @pool.setPassword(@password) if @password
    @pool.setMaximumPoolSize(@max_pool_size)
    @pool.setConnectionTimeout(@connection_timeout)
    @pool.setAutoCommit(@driver_auto_commit)
    @pool.setJdbcUrl(@connection_string)

    validate_connection_timeout = (@connection_timeout / 1000) / 2

    if !@connection_test_query.nil? and @connection_test_query.length > 1
      @pool.setConnectionTestQuery(@connection_test_query)
      @pool.setConnectionInitSql(@connection_test_query)
    end

    return unless @connection_test

    # Test connection
    test_connection = @pool.getConnection
    unless test_connection.isValid(validate_connection_timeout)
      @logger.warn('JDBC - Connection is not reporting as validate. Either connection is invalid, or driver is not getting the appropriate response.')
    end
    test_connection.close
  end

  # Load jar from driver path
  def load_jar_files!
    unless @driver_jar_path.nil?
      raise LogStash::ConfigurationError, 'JDBC - Could not find jar file at given path. Check config.' unless File.exist? @driver_jar_path
      require @driver_jar_path
      return
    end

    # Revert original behaviour of loading from vendor directory if no path given
    jarpath = if ENV['LOGSTASH_HOME']
                File.join(ENV['LOGSTASH_HOME'], '/vendor/jar/jdbc/*.jar')
              else
                File.join(File.dirname(__FILE__), '../../../vendor/jar/jdbc/*.jar')
              end

    @logger.trace('JDBC - jarpath', path: jarpath)

    jars = Dir[jarpath]
    raise LogStash::ConfigurationError, 'JDBC - No jars found. Have you read the README?' if jars.empty?

    jars.each do |jar|
      @logger.trace('JDBC - Loaded jar', jar: jar)
      require jar
    end
  end

  def get_connection
    connection = @pool.getConnection
  rescue => e
    log_jdbc_exception(e, true, nil)
    false
  end

  def log_jdbc_exception(exception, retrying, event)
    current_exception = exception
    log_text = 'JDBC - Exception. ' + (retrying ? 'Retrying' : 'Not retrying')

    log_method = (retrying ? 'warn' : 'error')

    loop do
      # TODO reformat event output so that it only shows the fields necessary.

      @logger.send(log_method, log_text, :exception => current_exception, :event => event)

      if current_exception.respond_to? 'getNextException'
        current_exception = current_exception.getNextException()
      else
        current_exception = nil
      end

      break if current_exception == nil
    end
  end
end