require 'hanami/view/template'

module Hanami
  module View
    module Rendering
      # Find templates for a view
      #
      # @api private
      # @since 0.1.0
      #
      # @see View::Template
      class TemplatesFinder
        # Default format
        #
        # @api private
        # @since 0.1.0
        FORMAT    = '*'.freeze

        # Default template engines
        #
        # @api private
        # @since 0.1.0
        ENGINES   = '*'.freeze

        # Recursive pattern
        #
        # @api private
        # @since 0.2.0
        RECURSIVE = '**'.freeze

        # Initialize a finder
        #
        # @param view [Class] the view
        #
        # @api private
        # @since 0.1.0
        def initialize(view)
          @view = view
        end

        # Find all the associated templates to the view.
        # It recursively looks for templates under the root path of the view,
        # that are matching the template name
        #
        # @return [Array<Hanami::View::Template>] the templates
        #
        # @api private
        # @since 0.1.0
        #
        # @see Hanami::View::Dsl#root
        # @see Hanami::View::Dsl#template
        #
        # @example
        #   require 'hanami/view'
        #
        #   module Articles
        #     class Show
        #       include Hanami::View
        #     end
        #   end
        #
        #   Articles::Show.root     # => "/path/to/templates"
        #   Articles::Show.template # => "articles/show"
        #
        #   # This view has a template:
        #   #
        #   #   "/path/to/templates/articles/show.html.erb"
        #
        #   Hanami::View::Rendering::TemplatesFinder.new(Articles::Show).find
        #     # => [#<Hanami::View::Template:0x007f8a0a86a970 ... @file="/path/to/templates/articles/show.html.erb">]
        def find
          _find.map do |template|
            View::Template.new(template, @view.configuration.default_encoding)
          end
        end

        protected

        # @api private
        # @since 0.4.3
        #
        # Searches first for files at `../templates/articles/index.*.*`
        # If none are found, falls back to recursive search in `../templates/**/articles/index.*.*`
        #
        def _find(lookup = search_path)
          base_path = templates_path(root, template_name)
          if base_path.none?
            templates_path(root, lookup, template_name)
          else
            base_path
          end
        end

        # @api private
        # @since 0.7.0
        def templates_path(*parts)
          Dir.glob("#{ parts.join(separator) }.#{ format }.#{ engines }")
        end

        # @api private
        # @since 0.1.0
        def template_name
          @view.template
        end

        # @api private
        # @since 0.1.0
        def root
          @view.root
        end

        # @api private
        # @since 0.4.3
        def search_path
          recursive
        end

        # @api private
        # @since 0.2.0
        def recursive
          RECURSIVE
        end

        # @api private
        # @since 0.1.0
        def separator
          ::File::SEPARATOR
        end

        # @api private
        # @since 0.1.0
        def format
          FORMAT
        end

        # @api private
        # @since 0.1.0
        def engines
          ENGINES
        end
      end
    end
  end
end