package controllers

import javax.inject.*
import play.api.*
import play.api.mvc.*
import authentication.{AuthenticatedAction, AuthenticatedRequest}
import caching.{Etagable, checkFresh}
import models.User
import play.api.libs.json.Json

import java.nio.ByteBuffer
import java.nio.charset.StandardCharsets.UTF_8
import java.security.MessageDigest
import java.util.Base64

/**
 * This controller creates an `Action` to handle HTTP requests to the
 * application's home page.
 */
@Singleton
class HomeController @Inject()(val controllerComponents: ControllerComponents,
                               authenticatedAction: AuthenticatedAction)
  extends BaseController with Logging {

  /**
   * Create an Action to render an HTML page.
   *
   * The configuration in the `routes` file means that this method
   * will be called when the application receives a `GET` request with
   * a path of `/`.
   */
  def index() = Action { implicit request: Request[AnyContent] =>
    Ok(views.html.index())
  }

  def userData = authenticatedAction { implicit request: AuthenticatedRequest[AnyContent] =>
    val user = request.user
    request.checkFresh(user) {
      // TODO: put the max-age somewhere into config
      Ok(Json.toJson(user)).withHeaders("Etag" -> user.etag, "Cache-Control" -> "private, max-age=15, must-revalidate")
    }
  }

  private given Etagable[models.User] with {
    private val base64 = Base64.getUrlEncoder

    extension (a: User)
      override def etag: String = {
        val md = MessageDigest.getInstance("SHA-1")
        md.update(ByteBuffer.allocate(8).putLong(a.id.getOrElse(0)))
        md.update(a.gid.getBytes(UTF_8))
        md.update(a.username.getBytes(UTF_8))

        base64.encodeToString(md.digest())
      }
  }
}