# encoding: utf-8
require "logstash/outputs/base"
require "logstash/namespace"
require "concurrent"
require "stud/interval"
require "java"
require "logstash-output-jdbc_jars"

class LogStash::Outputs::Jdbc < LogStash::Outputs::Base
  STRFTIME_FMT = "%Y-%m-%d %T.%L".freeze

  # Will never work, but only because it duplicates data (i.e. duplicate keys)
  # Will log a warning, but not retry.
  SQL_STATES_IGNORE = [
    ### Class: Unqualified Successful Completion
    # Success. This shouldn't get thrown, but JDBC driver quality varies, so who knows.
    0000, 
    
    ### Class: Constraint Violation 
    # Integrity constraint violation.
    23000,
    # A violation of the constraint imposed by a unique index or a unique constraint occurred.
    23505
  ]

  # Will log an error, but not retry.
  SQL_STATES_FATAL = [
    ### Class: Data Exception
    # Character data, right truncation occurred. Field too small.
    22001,
    # Numeric value out of range.
    22003,
    # A null value is not allowed.
    22004,
    # Invalid datetime format.
    22007,
    # A parameter or host variable value is invalid.
    22023,
    # Character conversion resulted in truncation.
    22524,

    ### Constraint Violation 
    # The insert or update value of a foreign key is invalid.
    23503,
    # The range of values for the identity column or sequence is exhausted.
    23522
  ]

  config_name "jdbc"

  # 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

  # [ "insert into table (message) values(?)", "%{message}" ]
  config :statement, :validate => :array, :required => true

  # If this is an unsafe statement, use event.sprintf
  # This also has potential performance penalties due to having to create a 
  # new statement for each event, rather than adding to the batch and issuing
  # multiple inserts in 1 go
  config :unsafe_statement, :validate => :boolean, :default => 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

  # We buffer a certain number of events before flushing that out to SQL.
  # This setting controls how many events will be buffered before sending a
  # batch of events.
  config :flush_size, :validate => :number, :default => 1000

  # 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

  # 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"

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

    LogStash::Logger.setup_log4j(@logger)
    load_jar_files!

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

    if (@flush_size > 1000)
      @logger.warn("JDBC - Flush size is set to > 1000")
    end

    if @statement.length < 1
      @logger.error("JDBC - No statement provided. Configuration error.")
    end

    if (!@unsafe_statement and @statement.length < 2) 
      @logger.error("JDBC - Statement has no parameters. No events will be inserted into SQL as you're not passing any event data. Likely configuration error.")
    end

    setup_and_test_pool!
  end

  def multi_receive(events)
    events.each_slice(@flush_size) do |slice|
      retrying_submit(slice)
    end
  end

  def teardown
    @pool.close()
    super
  end

  def close
    @stopping.make_true
  end

  private

  def setup_and_test_pool!  
    # Setup pool
    @pool = Java::ComZaxxerHikari::HikariDataSource.new

    @pool.setAutoCommit(@driver_auto_commit)
    @pool.setDriverClassName(@driver_class) if @driver_class

    @pool.setJdbcUrl(@connection_string)

    @pool.setUsername(@username) if @username
    @pool.setPassword(@password) if @password

    @pool.setMaximumPoolSize(@max_pool_size)
    @pool.setConnectionTimeout(@connection_timeout)

    validate_connection_timeout = (@connection_timeout / 1000) / 2

    # Test connection
    test_connection = @pool.getConnection()
    unless test_connection.isValid(validate_connection_timeout)
      @logger.error("JDBC - Connection is not valid. Please check connection string or that your JDBC endpoint is available.")
    end
    test_connection.close()
  end

  def load_jar_files!
    # Load jar from driver path
    unless @driver_jar_path.nil?
      raise Exception.new("JDBC - Could not find jar file at given path. Check config.") unless File.exists? @driver_jar_path
      require @driver_jar_path
      return
    end

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

    @logger.debug("JDBC - jarpath", path: jarpath)

    jars = Dir[jarpath]
    raise Exception.new("JDBC - No jars found in jarpath. Have you read the README?") if jars.empty?

    jars.each do |jar|
      @logger.debug("JDBC - Loaded jar", :jar => jar)
      require jar
    end
  end
      
  def submit(events)
    connection = nil
    statement = nil
    events_to_retry = []
    
    begin
      connection = @pool.getConnection()
    rescue => e
      log_jdbc_exception(e)
      return events
    end

    events.each do |event|
      begin
        if @unsafe_statement == true
          statement = connection.prepareStatement(event.sprintf(@statement[0]))
        else
          statement = connection.prepareStatement(@statement[0])
        end
        
        statement = add_statement_event_params(statement, event) if @statement.length > 1

        statement.execute()
      rescue java.sql.SQLException => e
        if SQL_STATES_IGNORE.include? e.getSQLState()
          @logger.warn('JDBC - Dropping event. Ignore-able exception (duplicate key most likely)', exception: e, event: event)
        elsif SQL_STATES_FATAL.include? e.getSQLState()
          @logger.error('JDBC - Fatal SQL exception. Can never succeed. Dropping event.', exception: e, event: event)
        else
          log_jdbc_exception(e)
          events_to_retry.push(event)
        end
      rescue => e
        # Something else happened.
        log_jdbc_exception(e)        
        events_to_retry.push(event)
      ensure
        statement.close() unless statement.nil?
      end
    end
    
    connection.close() unless connection.nil?

    return events_to_retry
  end

  def retrying_submit(actions)
    # Initially we submit the full list of actions
    submit_actions = actions

    attempts = 0

    sleep_interval = @retry_initial_interval
    while submit_actions && submit_actions.length > 0
      return if !submit_actions || submit_actions.empty? # If everything's a success we move along
      # We retry whatever didn't succeed
      submit_actions = submit(submit_actions)

      # Everything was a success!
      break if !submit_actions || submit_actions.empty?

      if @max_flush_exceptions > 0
        attempts += 1

        if attempts > @max_flush_exceptions
          @logger.error("JDBC - max_flush_exceptions has been reached. #{submit_actions.length} events have been unable to be sent to SQL and are being dropped. See previously logged exceptions for details.")
          break
        end
      end

      # If we're retrying the action sleep for the recommended interval
      # Double the interval for the next time through to achieve exponential backoff
      Stud.stoppable_sleep(sleep_interval) { @stopping.true? }
      sleep_interval = next_sleep_interval(sleep_interval)
    end
  end

  def add_statement_event_params(statement, event)
    @statement[1..-1].each_with_index do |i, idx|
      case event.get(i)
      when Time
        # See LogStash::Timestamp, below, for the why behind strftime.
        statement.setString(idx + 1, event.get(i).strftime(STRFTIME_FMT))
      when LogStash::Timestamp
        # XXX: Using setString as opposed to setTimestamp, because setTimestamp 
        # doesn't behave correctly in some drivers (Known: sqlite)
        #
        # Additionally this does not use `to_iso8601`, since some SQL databases 
        # choke on the 'T' in the string (Known: Derby).
        #
        # strftime appears to be the most reliable across drivers.
        statement.setString(idx + 1, event.get(i).time.strftime(STRFTIME_FMT))
      when Fixnum, Integer
        statement.setInt(idx + 1, event.get(i))
      when Float
        statement.setFloat(idx + 1, event.get(i))
      when String
        statement.setString(idx + 1, event.get(i))
      when true
        statement.setBoolean(idx + 1, true)
      when false
        statement.setBoolean(idx + 1, false)
      else
        if event.get(i).nil? and i =~ /%\{/
          statement.setString(idx + 1, event.sprintf(i))
        else
          statement.setString(idx + 1, nil)
        end
      end
    end

    statement
  end

  def log_jdbc_exception(exception)
    current_exception = exception
    loop do
      @logger.warn("JDBC Exception encountered: Will automatically retry.", :exception => current_exception)
      current_exception = current_exception.getNextException()
      break if current_exception == nil
    end
  end

  def next_sleep_interval(current_interval)
    doubled = current_interval * 2
    doubled > @retry_max_interval ? @retry_max_interval : doubled
  end
end # class LogStash::Outputs::jdbc