#99

backend/app/controllers/materials_controller.rb

@@ -0,0 +1,94 @@
+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, :created_by_user).with_attached_file.find_by(id: params[:id])
+    return head :not_found unless material
+
+    render json: material_json(material)
+  end
+
+  def create
+    return head :unauthorized unless current_user
+    return head :forbidden unless current_user.gte_member?
+
+    file = params[:file]
+    return head :bad_request if file.blank?
+
+    material = Material.new(
+        url: params[:url].presence,
+        parent_id: params[:parent_id].presence,
+        tag_id: params[:tag_id].presence,
+        created_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
+
+    material.assign_attributes(
+      url: params[:url].presence,
+      parent_id: params[:parent_id].presence,
+      tag_id: params[:tag_id].presence
+    )
+    material.file.attach(params[:file]) if params[:file].present?
+
+    if material.save
+      render json: material_json(material)
+    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

backend/app/models/material.rb

@@ -0,0 +1,31 @@
+class Material < ApplicationRecord
+  include MyDiscard
+
+  default_scope -> { kept }
+
+  belongs_to :parent, class_name: 'Material', optional: true
+  has_many :children, class_name: 'Material', foreign_key: :parent_id, dependent: :nullify
+
+  belongs_to :tag, optional: true
+  belongs_to :created_by_user, class_name: 'User', optional: true
+  belongs_to :updated_by_user, class_name: 'User', optional: true
+
+  has_one_attached :file, dependent: :purge
+
+  validate :file_must_be_attached
+  validate :tag_must_be_material_category
+
+  private
+
+  def file_must_be_attached
+    return if url.present? || file.attached?
+
+    errors.add(:url, 'URL かファイルのどちらかは必須です．')
+  end
+
+  def tag_must_be_material_category
+    return if tag.blank? || tag.material?
+
+    errors.add(:tag, '素材カテゴリのタグを指定してください．')
+  end
+end

backend/app/representations/material_repr.rb

@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+
+module MaterialRepr
+  BASE = { only: [:id, :url, :parent_id, :created_at, :updated_at],
+           include: { created_by_user: UserRepr::BASE, tag: TagRepr::BASE } }.freeze
+
+  module_function
+
+  def base(material)
+    material.as_json(BASE)
+  end
+
+  def many(materials)
+    materials.map { |m| base(m) }
+  end
+end