@type collect_context() :: %{dependencies: map(), app_params: term()}

@type collect_fun() :: (collect_context() -> collect_result())

@type collect_result() :: [{Solve.Collection.id(), collected_item_opts()}]

@type collected_item_opts() :: keyword()

@type collection_binding() :: {:solve_collection_binding, atom(), nil | function()}

@type dependency_binding() :: %{
  key: atom(),
  source: atom(),
  kind: :single | :collection,
  filter: nil | (Solve.Collection.id(), map() -> boolean())
}

@type dependency_spec() :: atom() | {atom(), atom() | collection_binding()}

@type name() :: atom()

@type t() :: %Solve.ControllerSpec{
  callbacks: map(),
  collect: collect_fun() | nil,
  dependencies: [name()],
  dependency_bindings: [dependency_binding()],
  module: module(),
  name: name(),
  params: term(),
  variant: variant()
}

@type variant() :: :singleton | :collection