# frozen_string_literal: true

module Bridgetown
  module Resource
    class PermalinkProcessor
      # @return [Bridgetown::Resource::Base]
      attr_accessor :resource

      attr_accessor :slugify_mode

      def self.placeholder_processors
        @placeholder_processors || {}
      end

      def self.register_placeholder(key, block)
        @placeholder_processors ||= {}
        @placeholder_processors[key] = block
      end

      def initialize(resource)
        @resource = resource
        @slugify_mode = @resource.site.config.slugify_mode
      end

      def final_ext
        resource.method(:destination).arity == 1 ? resource.extname : resource.destination.final_ext
      end

      def transform
        permalink = resource.data.permalink ||
          permalink_for_permalink_style(resource.collection.default_permalink)

        # Strip out file extension and process each segment of a URL to swap out
        # placeholders such as :categories or :title
        url_segments = Bridgetown::Filters::URLFilters.strip_extname(permalink).split("/")
        new_url = url_segments.map do |segment|
          segment.starts_with?(":") ? process_segment(segment.sub(%r{^:}, "")) : segment
        end.select(&:present?).join("/")
        # No relative URLs should ever end in /index.html
        new_url.sub!(%r{/index$}, "") if final_ext == ".html"

        ensure_base_path finalize_permalink(new_url, permalink)
      end

      def process_segment(segment)
        segment = segment.to_sym
        if self.class.placeholder_processors[segment]
          segment_value = self.class.placeholder_processors[segment].(resource)
          case segment_value
          when Hash
            segment_value[:raw_value]
          when Array
            segment_value.map do |subsegment|
              Utils.slugify(subsegment, mode: slugify_mode)
            end.join("/")
          else
            Utils.slugify(segment_value, mode: slugify_mode)
          end
        else
          segment
        end
      end

      def permalink_for_permalink_style(permalink_style)
        collection_prefix = ("/:collection" unless resource.collection.builtin?)

        case permalink_style.to_sym
        when :pretty
          "/:locale/#{collection_prefix}/:categories/:year/:month/:day/:slug/"
        when :pretty_ext, :date
          "/:locale/#{collection_prefix}/:categories/:year/:month/:day/:slug.*"
        when :simple
          "/:locale/#{collection_prefix}/:categories/:slug/"
        when :simple_ext
          "/:locale/#{collection_prefix}/:categories/:slug.*"
        else
          permalink_style.to_s
        end
      end

      # @param new_url [String]
      # @param permalink [String]
      def finalize_permalink(new_url, permalink)
        # Handle .* style permalinks or files not ending in .html
        if permalink.ends_with?(".*") || !%r{\.html?$}.match?(final_ext)
          "/#{new_url}#{final_ext}"
        # If permalink includes the file extension, add it back in to the URL
        elsif permalink =~ %r{\.[^/]*$}
          "/#{new_url}#{Regexp.last_match[0]}"
        # Ensure index-style URLs get output correctly
        elsif permalink.ends_with?("/")
          "/#{new_url}/".sub(%r{^/index/$}, "/")
        # We good :)
        else
          "/#{new_url}"
        end
      end

      def ensure_base_path(permalink)
        if resource.site.base_path.present?
          return "#{resource.site.base_path(strip_slash_only: true)}#{permalink}"
        end

        permalink
      end

      ### Default Placeholders Processors

      # @param resource [Bridgetown::Resource::Base]
      register_placeholder :path, ->(resource) do
        {
          raw_value: resource.relative_path_basename_without_prefix.tap do |path|
            if resource.site.config["collections_dir"].present?
              path.delete_prefix! "#{resource.site.config["collections_dir"]}/"
            end
            if resource.data.locale && path.ends_with?(".#{resource.data.locale}")
              path.chomp!(".#{resource.data.locale}")
            end
          end,
        }
      end

      # @param resource [Bridgetown::Resource::Base]
      register_placeholder :name, ->(resource) do
        resource.basename_without_ext
      end

      # @param resource [Bridgetown::Resource::Base]
      register_placeholder :slug, ->(resource) do
        resource.data.slug || placeholder_processors[:name].(resource)
      end

      # @param resource [Bridgetown::Resource::Base]
      register_placeholder :title, ->(resource) do
        resource.data.title || placeholder_processors[:slug].(resource)
      end

      # @param resource [Bridgetown::Resource::Base]
      register_placeholder :locale, ->(resource) do
        next nil if resource.data.locale&.to_sym == resource.site.config.default_locale

        locale_data = resource.data.locale&.to_sym
        resource.site.config.available_locales.include?(locale_data) ? locale_data.to_s : nil
      end
      register_placeholder :lang, placeholder_processors[:locale]

      # @param resource [Bridgetown::Resource::Base]
      register_placeholder :collection, ->(resource) do
        resource.collection.label
      end

      # @param resource [Bridgetown::Resource::Base]
      register_placeholder :categories, ->(resource) do
        resource.taxonomies.category&.terms&.map(&:label)&.uniq
      end

      # YYYY
      # @param resource [Bridgetown::Resource::Base]
      register_placeholder :year, ->(resource) do
        resource.date.strftime("%Y")
      end

      # MM: 01..12
      # @param resource [Bridgetown::Resource::Base]
      register_placeholder :month, ->(resource) do
        resource.date.strftime("%m")
      end

      # DD: 01..31
      # @param resource [Bridgetown::Resource::Base]
      register_placeholder :day, ->(resource) do
        resource.date.strftime("%d")
      end

      # D: 1..31
      # @param resource [Bridgetown::Resource::Base]
      register_placeholder :i_day, ->(resource) do
        resource.date.strftime("%-d")
      end

      # M: 1..12
      # @param resource [Bridgetown::Resource::Base]
      register_placeholder :i_month, ->(resource) do
        resource.date.strftime("%-m")
      end

      # YY: 00..99
      # @param resource [Bridgetown::Resource::Base]
      register_placeholder :short_year, ->(resource) do
        resource.date.strftime("%y")
      end
    end
  end
end