module Dbcp
  class EnvironmentNotFound < StandardError; end
  class ExecutionError      < StandardError; end

  class Environment
    ENVIRONMENT_PROVIDERS = [
      DatabaseYamlEnvironmentProvider.new('config/database.yml'),
      UriEnvironmentProvider.new,
      (Capistrano3EnvironmentProvider.new if defined?(Capistrano3EnvironmentProvider.new))
    ].compact

    class << self
      def find(environment_name)
        ENVIRONMENT_PROVIDERS.each do |provider|
          environment = provider.find environment_name
          return environment if environment
        end

        raise EnvironmentNotFound.new "Could not locate '#{environment_name}' environment"
      end
    end

    # coersion causes issues when assigning rspec doubles
    include Virtus.value_object(coerce: false)
    values do
      attribute :environment_name, String
      attribute :database,         Database
      attribute :execution_host,   ExecutionHost
    end

    def export
      DatabaseSnapshotFile.new(self).tap do |snapshot_file|
        execution_host.execute database.export_command(snapshot_file)
      end
    end

    def import(snapshot_file)
      execution_host.execute database.import_command(snapshot_file)
    end
  end
end