# plugins/discourse-legacy_links/plugin.rb

# frozen_string_literal: true

# name: discourse-legacy_links
# about: A plugin to handle legacy Gossamer Forums URLs
# version: 0.2
# authors: saint@federated.computer
# url: https://gitea.federated.computer/saint/discourse-legacy_links.git

# require 'digest'

# enabled_site_setting :discourse_legacy_routing_enabled

# after_initialize do
after_initialize do
  module ::DiscourseCustomRouting
    class Engine < ::Rails::Engine
      engine_name "discourse_custom_routing"
      isolate_namespace DiscourseCustomRouting
    end

    # Define the custom controller
    class CustomPostController < ::ApplicationController
      # Match URLs that include a post_id at the end or query parameter
      def index
        post_id = extract_post_id_from_request

        if post_id
          post = find_post_by_custom_field(post_id)
          
          if post
            # Redirect to the post URL if found
            redirect_to post_url(post)
          else
            # Return 404 if the post is not found
            render plain: 'Post not found', status: 404
          end
        else
          # Handle cases where the post_id cannot be extracted
          render plain: 'Invalid URL', status: 400
        end
      end

      private

      def extract_post_id_from_request
        # Extract post_id from various URL formats
        if params[:post_id]
          params[:post_id].to_i
        elsif request.path.match(%r{/forum/[^/]+/P(\d+)/})
          $1.to_i
        elsif request.query_string.match(/post=(\d+)/)
          $1.to_i
        elsif request.query_string.match(/parent_post_id=(\d+)/)
          $1.to_i
        else
          nil
        end
      end

      def find_post_by_custom_field(post_id)
        # Find the post with the specified custom field
        Post.joins(:topic_custom_fields)
            .where(topic_custom_fields: { name: 'original_gossamer_id', value: post_id.to_s })
            .first
      end
    end

    # Register custom routes
    Discourse::Application.routes.append do
      get '/forum/*path' => 'custom_post#index'
    end
  end
end