require 'stringio'
require 'time'  # for Time#httpdate
require 'rack/deflater'
require 'rack/lint'
require 'rack/mock'
require 'zlib'

describe Rack::Deflater do
  def deflater(app)
    Rack::Lint.new Rack::Deflater.new(app)
  end

  def build_response(status, body, accept_encoding, headers = {})
    body = [body]  if body.respond_to? :to_str
    app = lambda do |env|
      res = [status, {}, body]
      res[1]["Content-Type"] = "text/plain" unless res[0] == 304
      res
    end
    request = Rack::MockRequest.env_for("", headers.merge("HTTP_ACCEPT_ENCODING" => accept_encoding))
    response = deflater(app).call(request)

    return response
  end

  def inflate(buf)
    inflater = Zlib::Inflate.new(-Zlib::MAX_WBITS)
    inflater.inflate(buf) << inflater.finish
  end

  should "be able to deflate bodies that respond to each" do
    body = Object.new
    class << body; def each; yield("foo"); yield("bar"); end; end

    response = build_response(200, body, "deflate")

    response[0].should.equal(200)
    response[1].should.equal({
      "Content-Encoding" => "deflate",
      "Vary" => "Accept-Encoding",
      "Content-Type" => "text/plain"
    })
    buf = ''
    response[2].each { |part| buf << part }
    inflate(buf).should.equal("foobar")
  end

  should "flush deflated chunks to the client as they become ready" do
    body = Object.new
    class << body; def each; yield("foo"); yield("bar"); end; end

    response = build_response(200, body, "deflate")

    response[0].should.equal(200)
    response[1].should.equal({
      "Content-Encoding" => "deflate",
      "Vary" => "Accept-Encoding",
      "Content-Type" => "text/plain"
    })
    buf = []
    inflater = Zlib::Inflate.new(-Zlib::MAX_WBITS)
    response[2].each { |part| buf << inflater.inflate(part) }
    buf << inflater.finish
    buf.delete_if { |part| part.empty? }
    buf.join.should.equal("foobar")
  end

  # TODO: This is really just a special case of the above...
  should "be able to deflate String bodies" do
    response = build_response(200, "Hello world!", "deflate")

    response[0].should.equal(200)
    response[1].should.equal({
      "Content-Encoding" => "deflate",
      "Vary" => "Accept-Encoding",
      "Content-Type" => "text/plain"
    })
    buf = ''
    response[2].each { |part| buf << part }
    inflate(buf).should.equal("Hello world!")
  end

  should "be able to gzip bodies that respond to each" do
    body = Object.new
    class << body; def each; yield("foo"); yield("bar"); end; end

    response = build_response(200, body, "gzip")

    response[0].should.equal(200)
    response[1].should.equal({
      "Content-Encoding" => "gzip",
      "Vary" => "Accept-Encoding",
      "Content-Type" => "text/plain"
    })

    buf = ''
    response[2].each { |part| buf << part }
    io = StringIO.new(buf)
    gz = Zlib::GzipReader.new(io)
    gz.read.should.equal("foobar")
    gz.close
  end

  should "flush gzipped chunks to the client as they become ready" do
    body = Object.new
    class << body; def each; yield("foo"); yield("bar"); end; end

    response = build_response(200, body, "gzip")

    response[0].should.equal(200)
    response[1].should.equal({
      "Content-Encoding" => "gzip",
      "Vary" => "Accept-Encoding",
      "Content-Type" => "text/plain"
    })
    buf = []
    inflater = Zlib::Inflate.new(Zlib::MAX_WBITS + 32)
    response[2].each { |part| buf << inflater.inflate(part) }
    buf << inflater.finish
    buf.delete_if { |part| part.empty? }
    buf.join.should.equal("foobar")
  end

  should "be able to fallback to no deflation" do
    response = build_response(200, "Hello world!", "superzip")

    response[0].should.equal(200)
    response[1].should.equal({ "Vary" => "Accept-Encoding", "Content-Type" => "text/plain" })
    response[2].to_enum.to_a.should.equal(["Hello world!"])
  end

  should "be able to skip when there is no response entity body" do
    response = build_response(304, [], "gzip")

    response[0].should.equal(304)
    response[1].should.equal({})
    response[2].to_enum.to_a.should.equal([])
  end

  should "handle the lack of an acceptable encoding" do
    response1 = build_response(200, "Hello world!", "identity;q=0", "PATH_INFO" => "/")
    response1[0].should.equal(406)
    response1[1].should.equal({"Content-Type" => "text/plain", "Content-Length" => "71"})
    response1[2].to_enum.to_a.should.equal(["An acceptable encoding for the requested resource / could not be found."])

    response2 = build_response(200, "Hello world!", "identity;q=0", "SCRIPT_NAME" => "/foo", "PATH_INFO" => "/bar")
    response2[0].should.equal(406)
    response2[1].should.equal({"Content-Type" => "text/plain", "Content-Length" => "78"})
    response2[2].to_enum.to_a.should.equal(["An acceptable encoding for the requested resource /foo/bar could not be found."])
  end

  should "handle gzip response with Last-Modified header" do
    last_modified = Time.now.httpdate

    app = lambda { |env| [200, { "Content-Type" => "text/plain", "Last-Modified" => last_modified }, ["Hello World!"]] }
    request = Rack::MockRequest.env_for("", "HTTP_ACCEPT_ENCODING" => "gzip")
    response = deflater(app).call(request)

    response[0].should.equal(200)
    response[1].should.equal({
      "Content-Encoding" => "gzip",
      "Vary" => "Accept-Encoding",
      "Last-Modified" => last_modified,
      "Content-Type" => "text/plain"
    })

    buf = ''
    response[2].each { |part| buf << part }
    io = StringIO.new(buf)
    gz = Zlib::GzipReader.new(io)
    gz.read.should.equal("Hello World!")
    gz.close
  end

  should "do nothing when no-transform Cache-Control directive present" do
    app = lambda { |env| [200, {'Content-Type' => 'text/plain', 'Cache-Control' => 'no-transform'}, ['Hello World!']] }
    request = Rack::MockRequest.env_for("", "HTTP_ACCEPT_ENCODING" => "gzip")
    response = deflater(app).call(request)

    response[0].should.equal(200)
    response[1].should.not.include "Content-Encoding"
    response[2].to_enum.to_a.join.should.equal("Hello World!")
  end

  should "do nothing when Content-Encoding already present" do
    app = lambda { |env| [200, {'Content-Type' => 'text/plain', 'Content-Encoding' => 'gzip'}, ['Hello World!']] }
    request = Rack::MockRequest.env_for("", "HTTP_ACCEPT_ENCODING" => "gzip")
    response = deflater(app).call(request)

    response[0].should.equal(200)
    response[2].to_enum.to_a.join.should.equal("Hello World!")
  end

  should "deflate when Content-Encoding is identity" do
    app = lambda { |env| [200, {'Content-Type' => 'text/plain', 'Content-Encoding' => 'identity'}, ['Hello World!']] }
    request = Rack::MockRequest.env_for("", "HTTP_ACCEPT_ENCODING" => "deflate")
    response = deflater(app).call(request)

    response[0].should.equal(200)
    buf = ''
    response[2].each { |part| buf << part }
    inflate(buf).should.equal("Hello World!")
  end
end