require 'adapter'
require 'forwardable'
require 'cassanity'

module Adapter
  module Cassanity
    extend Forwardable

    # Public
    def read(key, options = nil)
      operation_options = {where: where(key)}
      adapter_options = @options[:read]
      arguments = update_arguments(operation_options, adapter_options, options)

      rows = @client.select(arguments)
      rows.empty? ? nil : rows.first
    end

    # Public
    def write(key, attributes, options = nil)
      operation, operation_options = prepare_operation(options, :update, set: attributes, where: where(key))
      adapter_options = @options[:write]
      arguments = update_arguments(operation_options, adapter_options, options)

      @client.send(operation, arguments)
    end

    # Public
    def delete(key, options = nil)
      operation_options = {where: where(key)}
      adapter_options = @options[:delete]
      arguments = update_arguments(operation_options, adapter_options, options)

      @client.delete(arguments)
    end

    # Public
    def clear(options = nil)
      @client.truncate
    end

    # Private
    def where(key)
      primary_key = @options.fetch(:primary_key)
      {primary_key => key}
    end

    # Private.
    def prepare_operation(options, operation, operation_options)
      if options && (modifications = options[:modifications]) && modifications.any?
        operation_options = {modifications: [ [operation, operation_options], *modifications ]}
        operation = :batch
      end
      [ operation, operation_options ]
    end

    # Private
    def update_arguments(operation_options, adapter_options, method_options)
      keys = operation_options.keys

      if !adapter_options.nil? && !adapter_options.empty?
        filtered_options = adapter_options.reject { |key| keys.include?(key) }
        operation_options.update(filtered_options)
      end

      if !method_options.nil? && !method_options.empty?
        filtered_options = method_options.reject { |key| keys.include?(key) }
        operation_options.update(filtered_options)
      end

      operation_options
    end
  end
end

Adapter.define(:cassanity, Adapter::Cassanity)