package com.weEat.services

import play.api.Configuration
import codes.reactive.scalatime._
import com.github.t3hnar.bcrypt._
import com.weEat.models.{User,Authorization}
import java.time.Instant
import javax.inject.{Inject,Singleton}
import scala.concurrent.{ExecutionContext,Future}
import scala.util.Success
import scalaoauth2.provider._
import org.mongodb.scala.model.Filters._
import org.mongodb.scala.bson.DefaultBsonTransformers
import org.mongodb.scala.bson.conversions.Bson
import scala.language.implicitConversions

// TOOD: Migrate to SecureSocial OAuth lib
@Singleton
class OAuth2Service @Inject()(db: MongoDBService, config: Configuration)
    extends AuthorizationHandler[User]
    with ProtectedResourceHandler[Authorization]
    with DefaultBsonTransformers {

  implicit val ec: ExecutionContext = ExecutionContext.global

  import db.withCollection

  override def createAccessToken(auth: AuthInfo[User]) = {
    println("Create token")
    val newAuth = Authorization(auth.user)
    withCollection(Authorization) {auths =>
      auths.insertOne(newAuth).head().map(_ => newAuth.toToken())
    }.flatten
  }

  val devMode = config.getOptional[Boolean](s"oauth.dev").getOrElse(false)

  override def validateClient(
    cred: Option[ClientCredential],
    requ: AuthorizationRequest
  ): Future[Boolean] = {
    val cc = cred.getOrElse(throw new UnauthorizedClient("username required"))
    requ.grantType match {
      case OAuthGrantType.PASSWORD => validateUsernamePassword(
        cc.clientId,
        cc.clientSecret.getOrElse(throw new AccessDenied("password required"))
      )
      case OAuthGrantType.REFRESH_TOKEN => validateUsernameRefresh(
        cc.clientId,
        Authorization.decodeToken(RefreshTokenRequest(requ).refreshToken)
      )
      case OAuthGrantType.AUTHORIZATION_CODE => throw new UnsupportedGrantType()
      case OAuthGrantType.CLIENT_CREDENTIALS => throw new UnsupportedGrantType()
      case OAuthGrantType.IMPLICIT => throw new UnsupportedGrantType()
    }
  }

  private def withDevModeCond(bson: Bson) =
    if (devMode) bson else and(bson, not(equal("devOnly", true)))

  private def validateUsernamePassword(
    username: String,
    pass: String
  ): Future[Boolean] = withCollection(User) {users =>
    users.find(withDevModeCond(equal("email", username)))
      .first()
      .toFutureOption()
      .map(res => res.map { x => pass.isBcryptedSafeBounded(x.password)}
        .getOrElse(Success(false))
      ).transform ({ _.flatten })
  }.flatten

  private def validateUsernameRefresh(username: String, refresh: Array[Byte]) = 
  withCollection(Authorization) {auths =>
    auths.find(and(
      equal("email", username),
      equal("refreshToken", refresh)
    )).first().toFutureOption().map { _.nonEmpty }
  }.flatten

  override def findUser(
    cred: Option[ClientCredential],
    requ: AuthorizationRequest
  ): Future[Option[User]] = withCollection(User) {users =>
    users.find(withDevModeCond(equal("email", cred.getOrElse(
      throw new UnsupportedGrantType("client_id required")
    ).clientId))).first().toFutureOption()
  }.flatten.map({x => {println(s"findUser: $x"); x}})
  
  /* 2020-07-25: Never re-issue the same authorization token. Always generate a
   * new one.
   */
  override def getStoredAccessToken(auth: AuthInfo[User]) = {
    Future.successful(None)
  }

  private def freshAccessToken(token: Array[Byte]) = and(
    gt("created", Instant.now() - Authorization.accessFreshTime),
    equal("accessToken", token)
  )

  override def findAccessToken(token: String): Future[Option[AccessToken]] = 
    withCollection(Authorization) {auths =>
      auths.find(
        freshAccessToken(Authorization.decodeToken(token))
      ).first().toFutureOption()
        .map(_.map(_.toToken()))
    }.flatten.map({x => {println(s"findAccessToken: $x"); x}})    

  override def findAuthInfoByAccessToken(token: AccessToken) =
    withCollection(Authorization) {collection =>
      collection.find(freshAccessToken(Authorization.decodeToken(token.token)))
        .first()
        .toFutureOption()
        .map(_.map(auth => AuthInfo(auth, Some(auth.email), None, None)))
    }.flatten

  implicit def optFut2FutOpt[A](
    x: Option[Future[A]]
  )(implicit ec: ExecutionContext): Future[Option[A]] = x match {
    case Some(f) => f.map(Some(_))
    case None    => Future.successful(None)
  }

  override def findAuthInfoByRefreshToken(token: String) =
    withCollection(Authorization) {auths =>
      auths.find(equal("refreshToken", Authorization.decodeToken(token)))
        .first()
        .toFutureOption()
    }.flatten
      .map(authOpt => withCollection(User) {users =>
        optFut2FutOpt(authOpt.map({ auth => users.find(
          withDevModeCond(equal("_id", auth.userId))
        ).first()
          .toFuture()
          .map({user => AuthInfo(user, Some(user.email), None, None)})
        }))
      }.flatten).flatten
    
  override def refreshAccessToken(
    auth: AuthInfo[User],
    refreshToken: String
  ): Future[AccessToken] = {
    val newAuth = Authorization(auth.user)
    withCollection(Authorization) {auths =>
      auths.replaceOne(
        and(
          equal("userId", auth.user._id),
          equal("refreshToken", Authorization.decodeToken(refreshToken))
        ),
        newAuth
      ).head().map(_ => newAuth.toToken())
    }.flatten
  }

  def revokeAccessToken(
    auth: AuthInfo[Authorization],
    user: String,
    refresh: String
  ): Future[Unit] = 
    if (user != auth.user.email)
      Future.failed(
        new InvalidClient("Invalid client or client is not authorized")
      )
    else withCollection(Authorization) {auths =>
      auths.deleteOne(and(
        equal("userId", auth.user.userId),
        equal("refreshToken", Authorization.decodeToken(refresh))
      )).head().map { _ => {} }
    }.flatten

  override def deleteAuthCode(token: String): Future[Unit] =
    throw new UnsupportedGrantType("Code grant authorizations are not supported.")

  override def findAuthInfoByCode(
    code: String
  ): Future[Option[AuthInfo[User]]] =
    throw new UnsupportedGrantType("Code grant authorizations are not supported.")
}