datamapper/dm-mapper

# encoding: utf-8

module ROM

  # The environment configures repositories and loads schema with relations
  #
  class Environment
    include Concord.new(:repositories, :registry)

    # Build an environment instance from a repository config hash
    #
    # @example
    #
    #   config = { 'test' => 'memory://test' }
    #   env    = ROM::Environment.setup(config)
    #
    # @param [Environment, Hash<#to_sym, String>] config
    #   an environment or a hash of adapter uri strings,
    #   keyed by repository name
    #
    # @return [Environment]
    #
    # @api public
    def self.setup(config)
      return config if config.kind_of?(self)

      repositories = config.each_with_object({}) { |(name, uri), hash|
        hash[name.to_sym] = Repository.build(name, Addressable::URI.parse(uri))
      }

      build(repositories)
    end

    # Build a new environment
    #
    # @param [Hash] repositories
    #
    # @param [Hash] registry for relations
    #
    # @return [Environment]
    #
    # @api private
    def self.build(repositories, registry = {})
      new(repositories, registry)
    end

    # Build a relation schema for this environment
    #
    # @example
    #   env = Environment.coerce(test: 'memory://test')
    #
    #   env.schema do
    #     base_relation :users do
    #       repository :test
    #
    #       attribute :id, Integer
    #       attribute :name, String
    #     end
    #   end
    #
    # @return [Schema]
    #
    # @api public
    def schema(&block)
      @schema ||= Schema.build(repositories)
      @schema.call(&block) if block
      @schema
    end

    # Define mapping for relations
    #
    # @example
    #
    #   env.schema do
    #     base_relation :users do
    #       repository :test
    #
    #       attribute :id,        Integer
    #       attribtue :user_name, String
    #     end
    #   end
    #
    #   env.mapping do
    #     users do
    #       model User
    #
    #       map :id
    #       map :user_name, :to => :name
    #     end
    #   end
    #
    # @return [Mapping]
    #
    # @api public
    def mapping(&block)
      Mapping.build(self, schema, &block)
    end

    # Return registered relation
    #
    # @example
    #
    #   env[:users]
    #
    # @param [Symbol] relation name
    #
    # @return [Relation]
    #
    # @api public
    def [](name)
      registry[name]
    end

    # Register a rom relation
    #
    # @return [Environment]
    #
    # @api private
    def []=(name, relation)
      registry[name] = relation
    end

    # The repository with the given +name+
    #
    # @return [Repository]
    #
    # @api public
    def repository(name)
      repositories[name]
    end

  end # Environment
end # ROM