btrc-hub/backend/app/controllers/post_versions_controller.rb

class PostVersionsController < ApplicationController
  def index
    post_id = params[:post].presence
    tag_id = params[:tag].presence
    page = (params[:page].presence || 1).to_i
    limit = (params[:limit].presence || 20).to_i

    page = 1 if page < 1
    limit = 1 if limit < 1

    offset = (page - 1) * limit

    tag_name = nil
    if tag_id
      tag_name = TagName.joins(:tag).find_by(tag: { id: tag_id })
      return render json: [] unless tag_name
    end

    q = PostVersion
    q = q.where(post_id:) if post_id
    q = q.where("CONCAT(' ', tags, ' ') LIKE ?", "% #{ tag_name } %") if tag_name

    versions = q.order(created_at: :desc, id: :desc)
                .limit(limit)
                .offset(offset)

    render json: { versions:, count: q.count }
  end
end