class Ollama::Utils::Fetcher

def self.get(url, &block)
  new.get(url, &block)
end

def self.read(filename, &block)
  if File.exist?(filename)
    File.open(filename) do |file|
      file.extend(Ollama::Utils::Fetcher::ContentType)
      file.content_type = MIME::Types.type_for(filename).first
      block.(file)
    end
  end
end

def callback(tmp)
  -> chunk, remaining_bytes, total_bytes do
    total   = total_bytes or next
    current = total_bytes - remaining_bytes
    if @started
      infobar.counter.progress(by: total - current)
    else
      @started = true
      infobar.counter.reset(total:, current:)
    end
    infobar.update(message: message(current, total), force: true)
    tmp.print(chunk)
  end
end

def decorate_io(tmp, response)
  tmp.rewind
  tmp.extend(ContentType)
  if content_type = MIME::Types[response.headers['content-type']].first
    tmp.content_type = content_type
  end
end

def get(url, &block)
  response = nil
  Tempfile.open do |tmp|
    infobar.label = 'Getting'
    if @streaming
      response = Excon.get(url, headers:, response_block: callback(tmp))
      response.status != 200 || !@started and raise RetryWithoutStreaming
      decorate_io(tmp, response)
      infobar.finish
      block.(tmp)
    else
      response = Excon.get(url, headers:, middlewares:)
      if response.status != 200
        raise "invalid response status code"
      end
      body = response.body
      tmp.print body
      infobar.update(message: message(body.size, body.size), force: true)
      decorate_io(tmp, response)
      infobar.finish
      block.(tmp)
    end
  end
rescue RetryWithoutStreaming
  @streaming = false
  retry
rescue => e
  STDERR.puts "Cannot get #{url.to_s.inspect} (#{e}): #{response&.status_line}"
  unless e.is_a?(RuntimeError)
    STDERR.puts "#{e.backtrace * ?\n}"
  end
  yield nil
end

def headers
  {
    'User-Agent' => Ollama::Client.user_agent,
  }
end

def initialize
  @started   = false
  @streaming = true
end

def message(current, total)
  progress = '%s/%s' % [ current, total ].map {
    Tins::Unit.format(_1, format: '%.2f %U')
  }
  '%l ' + progress + ' in %te, ETA %e @%E'
end

def middlewares
  (Excon.defaults[:middlewares] + [ Excon::Middleware::RedirectFollower ]).uniq
end