# See http://doc.gitlab.com/ce/development/migration_style_guide.html
# for more information on how to write migrations for GitLab.
class MovePersonalSnippetsFiles < ActiveRecord::Migration[4.2]
  include Gitlab::Database::MigrationHelpers
  disable_ddl_transaction!

  DOWNTIME = false

  def up
    return unless file_storage?

    @source_relative_location = File.join('/uploads', 'personal_snippet')
    @destination_relative_location = File.join('/uploads', '-', 'system', 'personal_snippet')

    move_personal_snippet_files
  end

  def down
    return unless file_storage?

    @source_relative_location = File.join('/uploads', '-', 'system', 'personal_snippet')
    @destination_relative_location = File.join('/uploads', 'personal_snippet')

    move_personal_snippet_files
  end

  def move_personal_snippet_files
    query = "SELECT uploads.path, uploads.model_id, snippets.description FROM uploads "\
            "INNER JOIN snippets ON snippets.id = uploads.model_id WHERE uploader = 'PersonalFileUploader'"
    select_all(query).each do |upload|
      secret = upload['path'].split('/')[0]
      file_name = upload['path'].split('/')[1]

      next unless move_file(upload['model_id'], secret, file_name)

      update_markdown(upload['model_id'], secret, file_name, upload['description'])
    end
  end

  def move_file(snippet_id, secret, file_name)
    source_dir = File.join(base_directory, @source_relative_location, snippet_id.to_s, secret)
    destination_dir = File.join(base_directory, @destination_relative_location, snippet_id.to_s, secret)

    source_file_path = File.join(source_dir, file_name)
    destination_file_path = File.join(destination_dir, file_name)

    unless File.exist?(source_file_path)
      say "Source file `#{source_file_path}` doesn't exist. Skipping."
      return
    end

    say "Moving file #{source_file_path} -> #{destination_file_path}"

    FileUtils.mkdir_p(destination_dir)
    FileUtils.move(source_file_path, destination_file_path)

    true
  end

  def update_markdown(snippet_id, secret, file_name, description)
    source_markdown_path = File.join(@source_relative_location, snippet_id.to_s, secret, file_name)
    destination_markdown_path = File.join(@destination_relative_location, snippet_id.to_s, secret, file_name)

    source_markdown = "](#{source_markdown_path})"
    destination_markdown = "](#{destination_markdown_path})"

    if description.present?
      description = description.gsub(source_markdown, destination_markdown)
      quoted_description = quote_string(description)

      execute("UPDATE snippets SET description = '#{quoted_description}', description_html = NULL "\
              "WHERE id = #{snippet_id}")
    end

    query = "SELECT id, note FROM notes WHERE noteable_id = #{snippet_id} "\
            "AND noteable_type = 'Snippet' AND note IS NOT NULL"
    select_all(query).each do |note|
      text = note['note'].gsub(source_markdown, destination_markdown)
      quoted_text = quote_string(text)

      execute("UPDATE notes SET note = '#{quoted_text}', note_html = NULL WHERE id = #{note['id']}")
    end
  end

  def base_directory
    File.join(Rails.root, 'public')
  end

  def file_storage?
    CarrierWave::Uploader::Base.storage == CarrierWave::Storage::File
  end
end