class Ollama::Utils::Fetcher

def self.execute(command, &block)
  Tempfile.open do |tmp|
    IO.popen(command) do |command|
      until command.eof?
        tmp.write command.read(1 << 14)
      end
      tmp.rewind
      tmp.extend(Ollama::Utils::Fetcher::HeaderExtension)
      tmp.content_type = MIME::Types['text/plain'].first
      block.(tmp)
    end
  end
rescue => e
  STDERR.puts "Cannot execute #{command.inspect} (#{e})"
  if @debug && !e.is_a?(RuntimeError)
    STDERR.puts "#{e.backtrace * ?\n}"
  end
  yield HeaderExtension.failed
end

def self.get(url, **options, &block)
  cache = options.delete(:cache) and
    cache = Ollama::Utils::CacheFetcher.new(cache)
  if result = cache&.get(url, &block)
    infobar.puts "Getting #{url.to_s.inspect} from cache."
    return result
  else
    new(**options).send(:get, url) do |tmp|
      result = block.(tmp)
      if cache && !tmp.is_a?(StringIO)
        tmp.rewind
        cache.put(url, tmp)
      end
      result
    end
  end
end

def self.normalize_url(url)
  url = url.to_s
  url = URI.decode_uri_component(url)
  url = url.sub(/#.*/, '')
  URI::Parser.new.escape(url).to_s
end

def self.read(filename, &block)
  if File.exist?(filename)
    File.open(filename) do |file|
      file.extend(Ollama::Utils::Fetcher::HeaderExtension)
      file.content_type = MIME::Types.type_for(filename).first
      block.(file)
    end
  else
    STDERR.puts "File #{filename.to_s.inspect} doesn't exist."
  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(HeaderExtension)
  if content_type = MIME::Types[response.headers['content-type']].first
    tmp.content_type = content_type
  end
  if cache_control = response.headers['cache-control'] and
      cache_control !~ /no-store|no-cache/ and
      ex = cache_control[/s-maxage\s*=\s*(\d+)/, 1] || cache_control[/max-age\s*=\s*(\d+)/, 1]
  then
    tmp.ex = ex.to_i
  end
end

def excon(url, **options)
  url = self.class.normalize_url(url)
  Excon.new(url, options.merge(@http_options))
end

def get(url, &block)
  response = nil
  Tempfile.open do |tmp|
    infobar.label = 'Getting'
    if @streaming
      response = excon(url, headers:, response_block: callback(tmp)).request(method: :get)
      response.status != 200 || !@started and raise RetryWithoutStreaming
      decorate_io(tmp, response)
      infobar.finish
      block.(tmp)
    else
      response = excon(url, headers:, middlewares:).request(method: :get)
      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 || 'n/a'}"
  if @debug && !e.is_a?(RuntimeError)
    STDERR.puts "#{e.backtrace * ?\n}"
  end
  yield HeaderExtension.failed
end

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

def initialize(debug: false, http_options: {})
  @debug        = debug
  @started      = false
  @streaming    = true
  @http_options = http_options
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