class PodcastUploader

# File lib/podcast-to-youtube.rb, line 15
def authenticate_youtube(client_secret_file_path = 'client_secret.json')
        load_configuration client_secret_file_path

        puts "connecting to youtube account"
        Yt.configure do |config|
                config.client_id = @client_secret['installed']['client_id']
                config.client_secret = @client_secret['installed']['client_secret']
        end
        # check for refresh token in config file
        if !@client_secret['installed']['refresh_token'].nil?
                puts "using refresh token"
                authenticate_youtube_by_refresh_token
        else
                # otherwise authenticate with oauth2
                authenticate_youtube_by_access_token
                save_configuration
        end
end

# File lib/podcast-to-youtube.rb, line 34
def upload(podcast_feed_url, video_category_id, privacy = :private)
        feed = parse_feed podcast_feed_url
        feed.entries.reverse_each do |entry|
                video_title = "#{feed.title} - #{entry.title}"
                if !video_already_exists(video_title)
                        audiofile = download_asset entry.enclosure_url
                        coverart_url = entry.itunes_image
                        # if entry has no specific coverart image, use the coverart specified
                        # for the whole feed
                        if coverart_url.nil? or coverart_url == ""
                                puts "could not find episode specific coverart, using the feed default coverart."
                                coverart_url = feed.itunes_image
                        end
                        coverart = download_asset coverart_url
                        videofile = generate_videofile(audiofile, coverart)
                        video_description = generate_video_description(entry, feed)
                        tags = %w(podcast)

                        upload_video(video_title, video_description, video_category_id, privacy, tags, videofile)
                else
                        puts "video #{video_title} already exists on Youtube. Skipping."
                end
        end
end

# File lib/podcast-to-youtube.rb, line 111
def authenticate_youtube_by_access_token
        puts "authenticate youtube by access token"
        redirect_uri = 'urn:ietf:wg:oauth:2.0:oob' # special redirect uri to make the user copy the auth_code to the application
        puts "open this url in a browser"
        puts Yt::Account.new(scopes: ['youtube'], redirect_uri: redirect_uri).authentication_url
        puts "paste the authentication code here and press enter"
        auth_code = STDIN.gets.chomp
        @account = Yt::Account.new authorization_code: auth_code, redirect_uri: redirect_uri
end

# File lib/podcast-to-youtube.rb, line 100
def authenticate_youtube_by_refresh_token
        puts "reauthenticate youtube with refresh token"
        begin  
                @account = Yt::Account.new refresh_token: @client_secret['installed']['refresh_token']
        rescue
                puts "authentication with refresh token failed"
                authenticate_youtube_by_access_token
        end 
        save_configuration
end

# File lib/podcast-to-youtube.rb, line 92
def download_asset(url)
        puts "downloading asset file from #{url}"
        if !system( "wget", "-c", "#{url}" )
                raise "downloading asset from #{url} failed"
        end
        return url.split('/').last
end

# File lib/podcast-to-youtube.rb, line 142
def generate_video_description(entry, feed)
        video_description = "#{entry.itunes_summary}\n\n"
        video_description += "Mehr Infos und Links zur Episode: #{entry.url}\n"
        video_description += "Veröffentlicht: #{entry.published}\n"
        video_description += "Episode herunterladen (Audio): #{entry.url}\n\n"
        video_description += "Podcast Webseite: #{feed.url}\n"
        video_description += "Podcast Abonnieren: #{feed.url}\n"
        video_description += "Podcast Author: #{feed.itunes_author}"
        return video_description
end

# File lib/podcast-to-youtube.rb, line 78
def generate_videofile(audiofile, coverart)
        videofile = File.basename(audiofile, File.extname(audiofile)) + ".mkv"
        if !File.file?(videofile)
                puts "generating videofile #{videofile}"
                if !system( "ffmpeg", "-loop", "1", "-r", "2", "-i", "#{coverart}", "-i", "#{audiofile}", "-vf", "scale=-1:1080", "-c:v", "libx264", "-preset", "slow", "-tune", "stillimage", "-crf", "18", "-c:a", "copy", "-shortest", "-pix_fmt", "yuv420p", "-threads", "0", "#{videofile}" )
                        raise "generating videofile #{videofile} from #{audiofile} and #{coverart} failed"
                end
        else
                # file already exists
                puts "videofile #{videofile} already exists. skipping ffmpeg renderning."
        end
        return videofile
end

# File lib/podcast-to-youtube.rb, line 126
def load_configuration(file_path)
        puts "loading configuration"
        if File.file?(file_path)
                @client_secret = JSON.parse(File.read(file_path))
                @client_secret_file_path = file_path
        else 
                raise "Could not find config file at #{file_path}. This is required for the Youtube API authentication. More information can be found in the Readme."
        end
end

# File lib/podcast-to-youtube.rb, line 121
def parse_feed(podcast_feed_url)
        puts "parsing feed"
        return Feedjira::Feed.fetch_and_parse podcast_feed_url
end

# File lib/podcast-to-youtube.rb, line 61
def refresh_authentication
        if @account.authentication.expired?
                authenticate_youtube_by_refresh_token
        end
end

# File lib/podcast-to-youtube.rb, line 136
def save_configuration
        puts "saving current configuration"
        @client_secret['installed']['refresh_token'] = @account.authentication.refresh_token
        File.write(@client_secret_file_path, @client_secret.to_json)
end

# File lib/podcast-to-youtube.rb, line 67
def upload_video(video_title, video_description, video_category_id, privacy, tags, videofile)
        puts "uploading videofile to Youtube"
        refresh_authentication
        @account.upload_video(videofile, privacy_status: privacy, title: video_title, description: video_description, category_id: video_category_id, tags: tags)
end

# File lib/podcast-to-youtube.rb, line 73
def video_already_exists(video_title)
        refresh_authentication
        return @account.videos.any? {|video| video.title == video_title }
end