# frozen_string_literal: true

require "string_doc"

require "pakyow/support/class_state"
require "pakyow/support/deep_dup"
require "pakyow/support/core_refinements/string/normalization"

require "pakyow/presenter/errors"

module Pakyow
  module Presenter
    module Composers
      # @api private
      class View
        extend Support::ClassState
        class_state :__cache, default: {}

        using Support::DeepDup
        using Support::Refinements::String::Normalization

        attr_reader :view_path

        UNRETAINED_SIGNIFICANCE = %i(container partial template).freeze

        def initialize(view_path, app:)
          @view_path = String.normalize_path(view_path)
          @app = app
        end

        def key
          @view_path
        end

        def view(return_cached: false)
          cache_key = :"#{@app.config.name}__#{@view_path}"

          unless view = View.__cache[cache_key]
            unless info = @app.view_info_for_path(@view_path)
              error = UnknownPage.new("No view at path `#{@view_path}'")
              error.context = @view_path
              raise error
            end

            info = info.deep_dup
            view = info[:layout].build(info[:page]).tap { |view_without_partials|
              view_without_partials.mixin(info[:partials])
            }

            # We collapse built views down to significance that is considered "renderable". This is
            # mostly an optimization, since it lets us collapse some nodes into single strings and
            # reduce the number of operations needed for a render.
            #
            # FIXME: This breaks when a collapsed string doc is transformed. Once that's fixed, we
            # can enable this code again. It's pretty low-priority and not worth fixing right now.
            #
            # view.object.collapse(
            #   *(StringDoc.significant_types.keys - UNRETAINED_SIGNIFICANCE)
            # )

            # Empty nodes are removed as another render-time optimization leading to fewer operations.
            #
            view.object.remove_empty_nodes

            View.__cache[cache_key] = view
          end

          if return_cached
            view
          else
            view.dup
          end
        end
      end
    end
  end
end