Module: Hecks::Facade::Surface::AggregateDoor

Included in:
Hecks::Facade::Surface
Defined in:
lib/hecks/facade/surface/aggregate_door.rb

Overview

One aggregate's door: creating verbs as module methods returning the record in hand, CRUD delegation to the repository, the persisted_by-style binding collector a .hecksagon lands on, and the aggregate-scoped port a .hecksagon lands on beside it.

Instance Method Summary collapse

Instance Method Details

#aggregate_module(dispatcher, domain, ir) ⇒ Object 



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# File 'lib/hecks/facade/surface/aggregate_door.rb', line 16

def aggregate_module(dispatcher, domain, ir)
  fqn  = "#{domain}::#{ir.hecks_name}"
  door = Module.new

  ir.attributes.each do |attribute|
    next unless RESERVED.include?(attribute.name.to_sym)

    warn "[hecks] #{ir.hecks_name}##{attribute.name} shadows a built-in — no reader defined"
  end

  # A creating verb is a MODULE method returning the new record in hand ;
  # a verb that reaches an existing record lives on the Handle. `!` —
  # a command DOES something (mutates, may refuse), Ruby's own
  # convention for that ; `Naming.snake` alone used to leave a
  # creating command's bare name claiming the exact spelling a
  # QUERY of the SAME business name also wants (`Account`'s own
  # "Open" — the creating command AND a query listing open
  # accounts, a real same-aggregate collision this corpus already
  # has) — the suffix is what makes both nameable at all, not
  # merely a style choice.
  ir.commands.select(&:creates?).each do |command|
    door.define_singleton_method("#{Naming.snake(command.hecks_name)}!") do |**args|
      Handle.new(dispatcher: dispatcher, domain: domain, ir: ir,
                 instance: dispatcher.dispatch("#{fqn}.#{command.hecks_name}", with: args).instance)
    end
  end

  # A query is a MODULE method too — same level as a creating
  # command, since neither needs an existing record in hand — but
  # bare: a query reads and returns, nothing to warn a caller
  # about the way `!` does for a command. Answers the raw row
  # array `dispatcher.query` itself answers, the same shape
  # `runtime.query("#{fqn}.Name")` already gave.
  ir.queries.each do |query|
    door.define_singleton_method(Naming.snake(query.hecks_name)) do |**args|
      dispatcher.query("#{fqn}.#{query.hecks_name}", **args)
    end
  end

  door.define_singleton_method(:fqn)        { fqn }
  door.define_singleton_method(:ir)         { ir }

  # THE SAME VERB THE CHAPTER ANSWERS, one level down. Every
  # construct emits its own IR (Hecks::IR), so an aggregate
  # is a legitimate thing to project — `Pizzas::Order.project(
  # Projections::IR)` is this aggregate's IR, not the chapter's.
  #
  # A chapter-scoped target refuses here rather than inventing an
  # answer: `Projector.admits!` is what tells `Projections::IR`
  # (`from: :any`) apart from `Projections::Shape`
  # (`from: :chapter`), which used to return a confidently empty
  # `{"aggregates" => []}` for an aggregate.
  door.define_singleton_method(:project) do |target, out: nil, **options|
    key      = Projector.key_for(target)
    artifact = Projector.call(key, bluebook: ir, options: options)
    return artifact unless out

    Projector.write(artifact, out, as: Projector.emits_for(key))
  end
  door.define_singleton_method(:repository) { dispatcher.registry.repository(domain, ir) }
  door.define_singleton_method(:commands)   { ir.commands.map { |c| "#{Naming.snake(c.hecks_name)}!" }.sort }
  door.define_singleton_method(:queries)    { ir.queries.map { |q| Naming.snake(q.hecks_name) }.sort }
  # ONE AGGREGATE'S USAGE DOCUMENT — the same projection the chapter
  # answers with, narrowed to this head. `commands` above already
  # answers "what can I call"; this answers "and what does each one
  # want, refuse, and guarantee", which is the rest of the question.
  door.define_singleton_method(:docs) do |**options|
    Projector.call(:docs, bluebook: dispatcher.registry.bluebook(domain),
                          options:  options.merge(aggregate: ir.hecks_name))
  end
  # ONE AGGREGATE, READ BACK IN ENGLISH — the same narrowing `:docs`
  # takes, aimed at `:narrate` instead.
  door.define_singleton_method(:narrate) do |**options|
    Projector.call(:narrate, bluebook: dispatcher.registry.bluebook(domain),
                             options:  options.merge(aggregate: ir.hecks_name))
  end
  door.define_singleton_method(:count)      { dispatcher.registry.repository(domain, ir).count }
  door.define_singleton_method(:events)     { dispatcher.events.select { |event| event.aggregate == fqn } }

  door.define_singleton_method(:find) do |id|
    found = dispatcher.registry.repository(domain, ir).find(id)
    found && Handle.new(dispatcher: dispatcher, domain: domain, ir: ir, instance: found)
  end

  door.define_singleton_method(:all) do |**opts|
    dispatcher.registry.repository(domain, ir).all(**opts).map do |instance|
      Handle.new(dispatcher: dispatcher, domain: domain, ir: ir, instance: instance)
    end
  end

  # THE SAME REASON `method_missing` BELOW EXISTS AT ALL — a facade
  # left over from a PREVIOUS boot in this process shadows the fresh
  # `BindingProxy` a `.hecksagon` would otherwise reach through
  # `ConstShim`/`const_missing`, so `Pizzas::Pizza.port(...)` lands
  # HERE instead once any boot has run before.
  #
  # RE-RESOLVED, NOT THE CLOSED-OVER `ir` — this door can be a STALE
  # one, built by a boot from earlier in this same process, sitting
  # on the `Pizzas`/`Pizza` constants only because nothing has
  # re-installed them since. Attaching to this door's OWN `ir` would
  # attach the port to a discarded aggregate from that old boot,
  # invisible to the CURRENT one actually being loaded — silently,
  # the exact way `method_missing` below already has to avoid it for
  # a plain bind, via `HecksagonBuilder.collector` rather than
  # anything this door closes over. `Hecks.current_registry` is
  # the same "whichever boot is actually in progress" indirection,
  # and `BindingProxy#port` already re-resolves through it the same
  # way — this is that door's fallback twin, not a shortcut past it.
  door.define_singleton_method(:port) do |name, &block|
    current = Hecks.current_registry&.bluebook(domain)&.aggregate(ir.hecks_name) or
      raise Bluebook::DSL::Malformed, "#{fqn}.port(#{name.inspect}) called outside a boot"

    domain_port = Bluebook::DSL::ConstShim.with(->(const) { const }) do
      Bluebook::DSL::DomainPortBuilder.build(name, owner: current.hecks_name, &block)
    end
    domain_port.operations.each do |operation|
      operation.attributes.select(&:reference?).each { |attribute| attribute.type.declared_in = current }
    end
    current.add_port(domain_port)
    self
  end

  door.define_singleton_method(:method_missing) do |verb, *args, **kwargs, &block|
    collector = Bluebook::DSL::HecksagonBuilder.collector
    return super(verb, *args, **kwargs, &block) unless collector

    collector << Bluebook::Bind.new(
      aggregate: fqn,
      verb:      verb.to_s,
      adapter:   args.first.to_s,
      role:      kwargs[:role]&.to_s
    )
    block&.call
    self
  end

  door.define_singleton_method(:respond_to_missing?) do |name, include_private = false|
    !Bluebook::DSL::HecksagonBuilder.collector.nil? || super(name, include_private)
  end

  # THE SAME STALE-FACADE HAZARD `method_missing`/`port` ABOVE ALREADY
  # DOCUMENT, one door lower — `Surface.install` installs an aggregate's
  # OWN name as a bare TOP-LEVEL constant too (`Namespace.install(Object,
  # aggregate.hecks_name, ...)`, surface.rb's own `install`), not only
  # nested under its chapter. So once ANY domain has booted once in this
  # process, `Account::Debit` written while declaring some OTHER
  # bluebook — same domain or a different one — reaches THIS door's
  # const_missing directly, never `Object.const_missing`/`ConstShim::
  # Hook` at all: real modules resolve without ever calling that.
  #
  # `ir.hecks_name`, NOT the qualified `fqn` — a scoped reference has to
  # read the SAME either way, whether or not a stale door happens to be
  # sitting on this process from an earlier boot; qualifying it here
  # would make `Account::Debit`'s own meaning depend on incidental
  # process history, which is the exact instability S0b exists to
  # remove (docs/dsl-work-slices.md — "two domains in one registry" is
  # this file's own reason for being owned by that slice).
  door.define_singleton_method(:const_missing) do |name|
    resolver = Bluebook::DSL::ConstShim.resolver
    return resolver.call("#{ir.hecks_name}::#{name}") if resolver

    super(name)
  end

  door
end