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

class MaterialsController < ApplicationController
  def index
    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_id = params[:tag_id].presence
    parent_id = params[:parent_id].presence

    q = Material.includes(:tag, :created_by_user).with_attached_file
    q = q.where(tag_id:) if tag_id
    q = q.where(parent_id:) if parent_id

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

    render json: { materials: materials.map { |m| material_json(m) }, count: count }
  end

  def show
    material =
        Material
        .includes(:tag)
        .with_attached_file
        .find_by(id: params[:id])
    return head :not_found unless material

    render json: material.as_json(methods: [:content_type]).merge(
        file: if material.file.attached?
                rails_storage_proxy_url(material.file, only_path: false)
              end,
        tag: TagRepr.base(material.tag))
  end

  def create
    return head :unauthorized unless current_user

    tag_name_raw = params[:tag].to_s.strip
    file = params[:file]
    url = params[:url].to_s.strip.presence
    return head :bad_request if tag_name_raw.blank? || (file.blank? && url.blank?)

    tag_name = TagName.find_undiscard_or_create_by!(name: tag_name_raw)
    tag = tag_name.tag
    tag = Tag.create!(tag_name:, category: :material) unless tag

    material = Material.new(tag:, url:,
                            created_by_user: current_user,
                            updated_by_user: current_user)
    material.file.attach(file)

    if material.save
      render json: material_json(material), status: :created
    else
      render json: { errors: material.errors.full_messages }, status: :unprocessable_entity
    end
  end

  def update
    return head :unauthorized unless current_user
    return head :forbidden unless current_user.gte_member?

    material = Material.with_attached_file.find_by(id: params[:id])
    return head :not_found unless material

    tag_name_raw = params[:tag].to_s.strip
    file = params[:file]
    url = params[:url].to_s.strip.presence
    return head :bad_request if tag_name_raw.blank? || (file.blank? && url.blank?)

    tag_name = TagName.find_undiscard_or_create_by!(name: tag_name_raw)
    tag = tag_name.tag
    tag = Tag.create!(tag_name:, category: :material) unless tag

    material.update!(tag:, url:, updated_by_user: current_user)
    if file
      material.file.attach(file)
    else
      material.file.purge(file)
    end

    if material.save
      render json: material.as_json(methods: [:content_type]).merge(
          file: if material.file.attached?
                  rails_storage_proxy_url(material.file, only_path: false)
                end,
          tag: TagRepr.base(material.tag))
    else
      render json: { errors: material.errors.full_messages }, status: :unprocessable_entity
    end
  end

  def destroy
    return head :unauthorized unless current_user
    return head :forbidden unless current_user.gte_member?

    material = Material.find_by(id: params[:id])
    return head :not_found unless material

    material.discard
    head :no_content
  end

  private

  def material_json(material)
    MaterialRepr.base(material).merge(
      'filename' => material.file.attached? ? material.file.filename.to_s : nil,
      'byte_size' => material.file.attached? ? material.file.byte_size : nil,
      'content_type' => material.file.attached? ? material.file.content_type : nil,
      'url' => material.file.attached? ? url_for(material.file) : nil
    )
  end
end