# frozen_string_literal: true

require_relative "device_registry"

module Lumberjack
  # Abstract base class defining the interface for logging output devices.
  # Devices are responsible for the final output of log entries to various
  # destinations such as files, streams, databases, or external services.
  #
  # This class establishes the contract that all concrete device implementations
  # must follow, with the +write+ method being the only required implementation.
  # Additional lifecycle methods (+close+, +flush+, +reopen+) and configuration
  # methods (+datetime_format+) are optional but provide standardized interfaces
  # for device management.
  #
  # The device architecture allows for flexible log output handling while
  # maintaining consistent behavior across different output destinations.
  # Devices receive formatted LogEntry objects and are responsible for their
  # final serialization and delivery.
  #
  # @abstract Subclass and implement {#write} to create a concrete device
  # @see Lumberjack::Device::Writer File-based output device
  # @see Lumberjack::Device::LoggerWrapper Ruby Logger compatibility device
  # @see Lumberjack::Device::Multi Multiple device routing
  # @see Lumberjack::Device::Null Silent device for testing
  # @see Lumberjack::Device::Test In-memory device for testing
  class Device
    require_relative "device/writer"
    require_relative "device/log_file"
    require_relative "device/logger_wrapper"
    require_relative "device/multi"
    require_relative "device/null"
    require_relative "device/test"
    require_relative "device/buffer"

    class << self
      # Open a logging device with the given options.
      #
      # @param device [nil, Symbol, String, File, IO, Array, Lumberjack::Device, ContextLogger] The device to open.
      #   The device can be:
      #   - +nil+: returns a +Device::Null+ instance that discards all log entries.
      #   - +Symbol+: looks up the device in the +DeviceRegistry+ and creates a new instance with the provided options.
      #   - +String+ or +Pathname+: treated as a file path and opens a +Device::LogFile+.
      #   - +File+: opens a +Device::LogFile+ for the given file stream.
      #   - +IO+: opens a +Device::Writer+ wrapping the given IO stream.
      #   - +Lumberjack::Device+: returns the device instance as-is.
      #   - +ContextLogger+: wraps the logger in a +Device::LoggerWrapper+.
      #   - +Array+: each element is treated as a device specification and opened recursively,
      #     returning a +Device::Multi+ that routes log entries to all specified devices. Each
      #     device can have its own options hash if passed as a two-element array +[device, options]+.
      # @param options [Hash] Options to pass to the device constructor.
      # @return [Lumberjack::Device] The opened device instance.
      #
      # @example Open a file-based device
      #   device = Lumberjack::Device.open_device("/var/log/myapp.log", shift_age: "daily")
      #
      # @example Open a stream-based device
      #   device = Lumberjack::Device.open_device($stdout)
      #
      # @example Open a device from the registry
      #   device = Lumberjack::Device.open_device(:syslog)
      #
      # @example Open multiple devices
      #   device = Lumberjack::Device.open_device([["/var/log/app.log", {shift_age: "daily"}], $stdout])
      #
      # @example Wrap another logger
      #   device = Lumberjack::Device.open_device(Lumberjack::Logger.new($stdout))
      def open_device(device, options = {})
        device = device.to_s if device.is_a?(Pathname)

        if device.nil?
          Device::Null.new
        elsif device.is_a?(Device)
          device
        elsif device.is_a?(Symbol)
          DeviceRegistry.new_device(device, options)
        elsif device.is_a?(ContextLogger) || device.is_a?(::Logger)
          Device::LoggerWrapper.new(device)
        elsif device.is_a?(Array)
          devices = device.collect do |dev, dev_options|
            dev_options = dev_options.is_a?(Hash) ? options.merge(dev_options) : options
            open_device(dev, dev_options)
          end
          Device::Multi.new(devices)
        elsif io_but_not_file_stream?(device)
          Device::Writer.new(device, options)
        else
          Device::LogFile.new(device, options)
        end
      end

      private

      def io_but_not_file_stream?(object)
        return false if object.is_a?(File)
        return false unless object.respond_to?(:write)
        return true if object.respond_to?(:tty?) && object.tty?
        return false if object.respond_to?(:path) && object.path

        true
      end
    end

    # Write a log entry to the device. This is the core method that all device
    # implementations must provide. The method receives a fully formatted
    # LogEntry object and is responsible for outputting it to the target
    # destination.
    #
    # @param entry [Lumberjack::LogEntry] The log entry to write to the device
    # @return [void]
    # @abstract Subclasses must implement this method
    # @raise [NotImplementedError] If called on the abstract base class
    def write(entry)
      raise NotImplementedError
    end

    # Close the device and release any resources. The default implementation
    # calls flush to ensure any buffered data is written before closing.
    # Subclasses should override this method if they need to perform specific
    # cleanup operations such as closing file handles or network connections.
    #
    # @return [void]
    def close
      flush
    end

    # Reopen the device, optionally with a new log destination. The default
    # implementation calls flush to ensure data consistency. This method is
    # typically used for log rotation scenarios or when changing output
    # destinations dynamically.
    #
    # @param logdev [Object, nil] Optional new log device or destination
    # @return [void]
    def reopen(logdev = nil)
      flush
    end

    # Flush any buffered data to the output destination. The default
    # implementation is a no-op since not all devices use buffering.
    # Subclasses that implement buffering should override this method
    # to ensure data is written to the final destination.
    #
    # @return [void]
    def flush
    end

    # Get the current datetime format string used for timestamp formatting.
    # The default implementation returns nil, indicating no specific format
    # is set. Subclasses may override this to provide device-specific
    # timestamp formatting.
    #
    # @return [String, nil] The datetime format string, or nil if not set
    def datetime_format
    end

    # Set the datetime format string for timestamp formatting. The default
    # implementation is a no-op. Subclasses that support configurable
    # timestamp formatting should override this method to store and apply
    # the specified format.
    #
    # @param format [String, nil] The datetime format string to use for timestamps
    # @return [void]
    def datetime_format=(format)
    end

    # Expose the underlying stream if any.
    #
    # @return [IO, Lumberjacke::Device, nil]
    # @api private
    def dev
      self
    end
  end
end
