require "logger"

module LaunchDarkly
  #
  # This class exposes advanced configuration options for the LaunchDarkly
  # client library. Most users will not need to use a custom configuration--
  # the default configuration sets sane defaults for most use cases.
  #
  #
  class Config
    #
    # Constructor for creating custom LaunchDarkly configurations.
    #
    # @param opts [Hash] the configuration options
    # @option opts [Logger] :logger A logger to use for messages from the
    #   LaunchDarkly client. Defaults to the Rails logger in a Rails
    #   environment, or stdout otherwise.
    # @option opts [String] :base_uri ("https://app.launchdarkly.com") The base
    #   URL for the LaunchDarkly server. Most users should use the default value.
    # @option opts [Integer] :capacity (10000) The capacity of the events
    #   buffer. The client buffers up to this many events in memory before
    #   flushing. If the capacity is exceeded before the buffer is flushed,
    #   events will be discarded.
    # @option opts [Float] :flush_interval (30) The number of seconds between
    #   flushes of the event buffer.
    # @option opts [Float] :read_timeout (10) The read timeout for network
    #   connections in seconds.
    # @option opts [Float] :connect_timeout (2) The connect timeout for network
    #   connections in seconds.
    # @option opts [Object] :store A cache store for the Faraday HTTP caching
    #   library. Defaults to the Rails cache in a Rails environment, or a
    #   thread-safe in-memory store otherwise.
    #
    # @return [type] [description]
    def initialize(opts = {})
      @base_uri = (opts[:base_uri] || Config.default_base_uri).chomp("/")
      @stream_uri = (opts[:stream_uri] || Config.default_stream_uri).chomp("/")
      @capacity = opts[:capacity] || Config.default_capacity
      @logger = opts[:logger] || Config.default_logger
      @store = opts[:store] || Config.default_store
      @flush_interval = opts[:flush_interval] || Config.default_flush_interval
      @connect_timeout = opts[:connect_timeout] || Config.default_connect_timeout
      @read_timeout = opts[:read_timeout] || Config.default_read_timeout
      @feature_store = opts[:feature_store] || Config.default_feature_store
      @stream = opts.has_key?(:stream) ? opts[:stream] : Config.default_stream
      @log_timings = opts.has_key?(:log_timings) ? opts[:log_timings] : Config.default_log_timings
      @debug_stream = opts.has_key?(:debug_stream) ? opts[:debug_stream] : Config.default_debug_stream
    end

    #
    # The base URL for the LaunchDarkly server.
    #
    # @return [String] The configured base URL for the LaunchDarkly server.
    attr_reader :base_uri

    #
    # The base URL for the LaunchDarkly streaming server.
    #
    # @return [String] The configured base URL for the LaunchDarkly streaming server.
    attr_reader :stream_uri

    #
    # Whether streaming mode should be enabled. Streaming mode asynchronously updates
    # feature flags in real-time using server-sent events.
    #
    # @return [Boolean] True if streaming mode should be enabled
    def stream?
      @stream
    end

    #
    # Whether we should debug streaming mode. If set, the client will fetch features via polling
    # and compare the retrieved feature with the value in the feature store
    #
    # @return [Boolean] True if we should debug streaming mode
    def debug_stream?
      @debug_stream
    end

    #
    # The number of seconds between flushes of the event buffer. Decreasing the flush interval means
    # that the event buffer is less likely to reach capacity.
    #
    # @return [Float] The configured number of seconds between flushes of the event buffer.
    attr_reader :flush_interval

    #
    # The configured logger for the LaunchDarkly client. The client library uses the log to
    # print warning and error messages.
    #
    # @return [Logger] The configured logger
    attr_reader :logger

    #
    # The capacity of the events buffer. The client buffers up to this many
    # events in memory before flushing. If the capacity is exceeded before
    # the buffer is flushed, events will be discarded.
    # Increasing the capacity means that events are less likely to be discarded,
    # at the cost of consuming more memory.
    #
    # @return [Integer] The configured capacity of the event buffer
    attr_reader :capacity

    #
    # The store for the Faraday HTTP caching library. Stores should respond to
    # 'read' and 'write' requests.
    #
    # @return [Object] The configured store for the Faraday HTTP caching library.
    attr_reader :store

    #
    # The read timeout for network connections in seconds.
    #
    # @return [Float] The read timeout in seconds.
    attr_reader :read_timeout

    #
    # The connect timeout for network connections in seconds.
    #
    # @return [Float] The connect timeout in seconds.
    attr_reader :connect_timeout

    #
    # Whether timing information should be logged. If it is logged, it will be logged to the DEBUG
    # level on the configured logger.  This can be very verbose.
    #
    # @return [Boolean] True if timing information should be logged.
    def log_timings?
      @log_timings
    end

    #
    # TODO docs
    #
    attr_reader :feature_store

    #
    # The default LaunchDarkly client configuration. This configuration sets
    # reasonable defaults for most users.
    #
    # @return [Config] The default LaunchDarkly configuration.
    def self.default
      Config.new
    end

    def self.default_capacity
      10000
    end

    def self.default_base_uri
      "https://app.launchdarkly.com"
    end

    def self.default_stream_uri
      "https://stream.launchdarkly.com"
    end

    def self.default_store
      defined?(Rails) && Rails.respond_to?(:cache) ? Rails.cache : ThreadSafeMemoryStore.new
    end

    def self.default_flush_interval
      10
    end

    def self.default_read_timeout
      10
    end

    def self.default_connect_timeout
      2
    end

    def self.default_logger
      defined?(Rails) && Rails.respond_to?(:logger) ? Rails.logger : ::Logger.new($stdout)
    end

    def self.default_log_timings
      false
    end

    def self.default_stream
      true
    end

    def self.default_feature_store
      nil
    end

    def self.default_debug_stream
      false
    end
  end
end