class PostImportRunner
  def initialize actor:, rows:
    @actor = actor
    @rows = rows
  end

  def run
    normalised_rows = PostImportRowNormaliser.normalise!(@rows)
    previews = PostImportPreviewer.new.preview_rows(rows: normalised_rows,
                                                    fetch_metadata: false)
    preview_map = previews.index_by { _1[:source_row] }

    results = normalised_rows.map do |row|
      run_row(row, preview_map.fetch(row['source_row']))
    end

    { created: results.count { _1[:status] == 'created' },
      skipped: results.count { _1[:status] == 'skipped' },
      failed: results.count { _1[:status] == 'failed' },
      rows: results }
  end

  private

  def run_row row, preview
    attributes = row.fetch('attributes', { }).transform_keys { _1.to_s.underscore }
    return { source_row: row['source_row'],
             status: 'failed',
             errors: preview[:validation_errors],
             recoverable: true } if preview[:validation_errors].present?
    if preview[:skip_reason] == 'existing'
      return { source_row: row['source_row'],
               status: 'skipped',
               existing_post_id: preview[:existing_post_id] }
    end

    attributes['tags'] = preview[:attributes]['tags']
    attributes['url'] = row['url']
    creator = PostCreator.new(actor: @actor, attributes:)
    post = creator.create!
    result = { source_row: row['source_row'], status: 'created', post: PostRepr.base(post) }
    if creator.field_warnings.present?
      result[:field_warnings] = creator.field_warnings
    end
    result
  rescue ActiveRecord::RecordInvalid => e
    existing_post = existing_post_for_race(row, e.record)
    if existing_post
      return { source_row: row['source_row'],
               status: 'skipped',
               existing_post_id: existing_post.id }
    end

    { source_row: row['source_row'],
      status: 'failed',
      errors: e.record.errors.to_hash,
      recoverable: true }
  rescue ActiveRecord::RecordNotUnique => e
    raise unless url_record_not_unique?(e)

    existing_post = existing_post_for_race(row)
    raise unless existing_post

    { source_row: row['source_row'],
      status: 'skipped',
      existing_post_id: existing_post.id }
  rescue Tag::NicoTagNormalisationError
    { source_row: row['source_row'],
      status: 'failed',
      errors: { tags: ['ニコニコ・タグは直接指定できません．'] },
      recoverable: true }
  rescue Tag::DeprecatedTagNormalisationError
    { source_row: row['source_row'],
      status: 'failed',
      errors: { tags: ['廃止済みタグは付与できません．'] },
      recoverable: true }
  rescue PostCreator::VideoMsParseError
    { source_row: row['source_row'],
      status: 'failed',
      errors: { duration: ['動画時間の記法が不正です．'] },
      recoverable: true }
  rescue ArgumentError
    { source_row: row['source_row'],
      status: 'failed',
      errors: { base: ['入力値が不正です．'] },
      recoverable: true }
  rescue StandardError => e
    Rails.logger.error("post_import_runner_failure #{ { error: e.class.name,
                                                        message: e.message }.to_json }")
    { source_row: row['source_row'],
      status: 'failed',
      errors: { base: ['登録中にエラーが発生しました．'] } }
  end

  def existing_post_for_race row, record = nil
    if record && !(record.errors.of_kind?(:url, :taken))
      return nil
    end

    normal_url = PostUrlNormaliser.normalise(row['url'])
    return nil if normal_url.blank?

    Post.find_by(url: normal_url)
  end

  def url_record_not_unique? error
    error.message.include?('index_posts_on_url')
  end
end