btrc-hub/backend/app/services/discovery/youtube_video_discoverer.rb

class Discovery::YoutubeVideoDiscoverer
  def initialize(client: Youtube::SearchClient.new)
    @client = client
  end

  def call discovery_query:, published_after:, published_before:
    body = @client.search_videos(
        query: discovery_query.query,
        published_after: published_after,
        published_before: published_before)

    body.fetch('items', []).each do |item|
      next unless item.dig('id', 'kind') == 'youtube#video'

      upsert_candidate!(discovery_query, item)
    end
  end

  private

  def upsert_candidate! discovery_query, item
    snippet = item.fetch('snippet')
    code = item.fetch('id').fetch('videoId')

    candidate = VideoCandidate.find_or_initialize_by(provider: 'youtube', code:)

    candidate.title = snippet['title'].to_s
    candidate.description = snippet['description'].to_s
    candidate.channel_code = snippet['channelId']
    candidate.channel_title = snippet['channelTitle']
    candidate.published_at = Time.zone.parse(snippet['publishedAt'])
    candidate.thumbnail_url = snippet.dig('thumbnails', 'high', 'url')
    candidate.raw_data = item
    candidate.last_discovered_at = Time.current
    candidate.save!

    VideoCandidateHit.find_or_create_by!(
      video_candidate: candidate,
      discovery_query: discovery_query
    ) do |hit|
      hit.matched_field = 'youtube_search'
      hit.score = 0
      hit.searched_at = Time.current
    end
  end
end