require 'faraday'
require File.expand_path('../version', __FILE__)

module Exchanges
  module Configuration
    VALID_OPTIONS_KEYS = [
      :adapter,
      :client_id,
      :client_secret,
      :token,
      :endpoint,
      :format,
      :user_agent,
      :cache,
      :cache_prefix
    ].freeze

    VALID_FORMATS = [:json].freeze

    # The adapter that will be used to connect if none is set
    #
    # @note The default faraday adapter is Net::HTTP.
    DEFAULT_ADAPTER = Faraday.default_adapter

    # By default, don't set an application ID
    DEFAULT_CLIENT_ID = nil

    # By default, don't set an application secret
    DEFAULT_CLIENT_SECRET = nil

    # By default, don't set an application redirect uri
    DEFAULT_REDIRECT_URI = nil

    # By default, don't set a user access token
    DEFAULT_TOKEN = nil

    # cache object (must respond to #[], #[]=, and #keys)
    DEFAULT_CACHE = nil

    DEFAULT_CACHE_PREFIX = 'exchanges_cache:'

    # The endpoint that will be used to connect if none is set
    #
    # @note There is no reason to use any other endpoint at this time
    DEFAULT_ENDPOINT = 'https://exchang.es/api/v1/'.freeze

    # The response format appended to the path and sent in the 'Accept' header if none is set
    #
    # @note JSON is the only available format at this time
    DEFAULT_FORMAT = :json

    # The user agent that will be sent to the API endpoint if none is set
    DEFAULT_USER_AGENT = "Exchanges Ruby Gem #{Exchanges::VERSION}".freeze

    attr_accessor *VALID_OPTIONS_KEYS

    # When this module is extended, set all configuration options to their default values
    def self.extended(base)
      base.reset
    end

    # Convenience method to allow configuration options to be set in a block
    def configure
      yield self
    end

    # Create a hash of options and their values
    def options
      VALID_OPTIONS_KEYS.inject({}) do |option, key|
        option.merge!(key => send(key))
      end
    end

    # Reset all configuration options to defaults
    def reset
      self.adapter        = DEFAULT_ADAPTER
      self.client_id      = DEFAULT_CLIENT_ID
      self.client_secret  = DEFAULT_CLIENT_SECRET
      self.token          = DEFAULT_TOKEN
      self.endpoint       = DEFAULT_ENDPOINT
      self.format         = DEFAULT_FORMAT
      self.user_agent     = DEFAULT_USER_AGENT
      self.cache          = DEFAULT_CACHE
      self.cache_prefix   = DEFAULT_CACHE_PREFIX
    end
  end
end
