package com.xsn.explorer.services

import com.alexitc.playsonify.core.FutureOr.Implicits.{FutureOps, OrOps}
import com.alexitc.playsonify.core.{ApplicationResult, FutureApplicationResult}
import com.alexitc.playsonify.models.ApplicationError
import com.xsn.explorer.config.{ExplorerConfig, RPCConfig}
import com.xsn.explorer.errors._
import com.xsn.explorer.executors.ExternalServiceExecutionContext
import com.xsn.explorer.models._
import com.xsn.explorer.models.values._
import javax.inject.Inject
import org.scalactic.{Bad, Good}
import org.slf4j.LoggerFactory
import play.api.libs.json.{JsNull, JsValue, Reads}
import play.api.libs.ws.{WSAuthScheme, WSClient, WSResponse}

import scala.util.Try

trait XSNService {

  def getTransaction(txid: TransactionId): FutureApplicationResult[rpc.Transaction[rpc.TransactionVIN]]

  def getRawTransaction(txid: TransactionId): FutureApplicationResult[JsValue]

  def getAddressBalance(address: Address): FutureApplicationResult[rpc.AddressBalance]

  def getTransactions(address: Address): FutureApplicationResult[List[TransactionId]]

  def getBlock(blockhash: Blockhash): FutureApplicationResult[rpc.Block]

  def getRawBlock(blockhash: Blockhash): FutureApplicationResult[JsValue]

  def getBlockhash(height: Height): FutureApplicationResult[Blockhash]

  def getLatestBlock(): FutureApplicationResult[rpc.Block]

  def getServerStatistics(): FutureApplicationResult[rpc.ServerStatistics]

  def getMasternodeCount(): FutureApplicationResult[Int]

  def getDifficulty(): FutureApplicationResult[BigDecimal]

  def getMasternodes(): FutureApplicationResult[List[rpc.Masternode]]

  def getMasternode(ipAddress: IPAddress): FutureApplicationResult[rpc.Masternode]

  def getUnspentOutputs(address: Address): FutureApplicationResult[JsValue]

  def sendRawTransaction(hex: HexString): FutureApplicationResult[String]

  def cleanGenesisBlock(block: rpc.Block): rpc.Block = {
    Option(block)
      .filter(_.hash == genesisBlockhash)
      .map(_.copy(transactions = List.empty))
      .getOrElse(block)
  }

  def genesisBlockhash: Blockhash

}

class XSNServiceRPCImpl @Inject() (
    ws: WSClient,
    rpcConfig: RPCConfig,
    explorerConfig: ExplorerConfig)(
    implicit ec: ExternalServiceExecutionContext)
    extends XSNService {

  private val logger = LoggerFactory.getLogger(this.getClass)

  private val server = ws.url(rpcConfig.host.string)
      .withAuth(rpcConfig.username.string, rpcConfig.password.string, WSAuthScheme.BASIC)
      .withHttpHeaders("Content-Type" -> "text/plain")


  override def getTransaction(txid: TransactionId): FutureApplicationResult[rpc.Transaction[rpc.TransactionVIN]] = {
    val errorCodeMapper = Map(-5 -> TransactionNotFoundError)

    server
        .post(s"""{ "jsonrpc": "1.0", "method": "getrawtransaction", "params": ["${txid.string}", 1] }""")
        .map { response =>

          val maybe = getResult[rpc.Transaction[rpc.TransactionVIN]](response, errorCodeMapper)
          maybe.getOrElse {
            logger.warn(s"Unexpected response from XSN Server, txid = ${txid.string}, status = ${response.status}, response = ${response.body}")

            Bad(XSNUnexpectedResponseError).accumulating
          }
        }
  }

  override def getRawTransaction(txid: TransactionId): FutureApplicationResult[JsValue] = {
    val errorCodeMapper = Map(-5 -> TransactionNotFoundError)

    server
        .post(s"""{ "jsonrpc": "1.0", "method": "getrawtransaction", "params": ["${txid.string}", 1] }""")
        .map { response =>

          val maybe = getResult[JsValue](response, errorCodeMapper)
          maybe.getOrElse {
            logger.warn(s"Unexpected response from XSN Server, txid = ${txid.string}, status = ${response.status}, response = ${response.body}")

            Bad(XSNUnexpectedResponseError).accumulating
          }
        }
  }

  override def getAddressBalance(address: Address): FutureApplicationResult[rpc.AddressBalance] = {
    val body = s"""
         |{
         |  "jsonrpc": "1.0",
         |  "method": "getaddressbalance",
         |  "params": [
         |    { "addresses": ["${address.string}"] }
         |  ]
         |}
         |""".stripMargin

    // the network returns 0 for valid addresses
    val errorCodeMapper = Map(-5 -> AddressFormatError)

    server
        .post(body)
        .map { response =>

          val maybe = getResult[rpc.AddressBalance](response, errorCodeMapper)
          maybe.getOrElse {
            logger.warn(s"Unexpected response from XSN Server, status = ${response.status}, address = ${address.string}, response = ${response.body}")

            Bad(XSNUnexpectedResponseError).accumulating
          }
        }
  }

  override def getTransactions(address: Address): FutureApplicationResult[List[TransactionId]] = {
    val body = s"""
                  |{
                  |  "jsonrpc": "1.0",
                  |  "method": "getaddresstxids",
                  |  "params": [
                  |    { "addresses": ["${address.string}"] }
                  |  ]
                  |}
                  |""".stripMargin

    // the network returns 0 for valid addresses
    val errorCodeMapper = Map(-5 -> AddressFormatError)

    server
        .post(body)
        .map { response =>

          val maybe = getResult[List[TransactionId]](response, errorCodeMapper)
          maybe.getOrElse {
            logger.warn(s"Unexpected response from XSN Server, status = ${response.status}, address = ${address.string}, response = ${response.body}")

            Bad(XSNUnexpectedResponseError).accumulating
          }
        }
  }

  override def getBlock(blockhash: Blockhash): FutureApplicationResult[rpc.Block] = {
    val errorCodeMapper = Map(-5 -> BlockNotFoundError)
    val body = s"""{ "jsonrpc": "1.0", "method": "getblock", "params": ["${blockhash.string}"] }"""

    server
        .post(body)
        .map { response =>

          val maybe = getResult[rpc.Block](response, errorCodeMapper)
          maybe
              .map {
                case Good(block) => Good(cleanGenesisBlock(block))
                case x => x
              }
              .getOrElse {
            logger.warn(s"Unexpected response from XSN Server, blockhash = ${blockhash.string}, status = ${response.status}, response = ${response.body}")

            Bad(XSNUnexpectedResponseError).accumulating
          }
        }
  }

  override def getRawBlock(blockhash: Blockhash): FutureApplicationResult[JsValue] = {
    val errorCodeMapper = Map(-5 -> BlockNotFoundError)
    val body = s"""{ "jsonrpc": "1.0", "method": "getblock", "params": ["${blockhash.string}"] }"""

    server
        .post(body)
        .map { response =>

          val maybe = getResult[JsValue](response, errorCodeMapper)
          maybe.getOrElse {
            logger.warn(s"Unexpected response from XSN Server, blockhash = ${blockhash.string}, status = ${response.status}, response = ${response.body}")

            Bad(XSNUnexpectedResponseError).accumulating
          }
        }
  }

  override def getBlockhash(height: Height): FutureApplicationResult[Blockhash] = {
    val errorCodeMapper = Map(-8 -> BlockNotFoundError)
    val body = s"""{ "jsonrpc": "1.0", "method": "getblockhash", "params": [${height.int}] }"""

    server
        .post(body)
        .map { response =>

          val maybe = getResult[Blockhash](response, errorCodeMapper)
          maybe.getOrElse {
            logger.warn(s"Unexpected response from XSN Server, blockhash = ${height.int}, status = ${response.status}, response = ${response.body}")

            Bad(XSNUnexpectedResponseError).accumulating
          }
        }
  }

  override def getLatestBlock(): FutureApplicationResult[rpc.Block] = {
    val body = s"""
                  |{
                  |  "jsonrpc": "1.0",
                  |  "method": "getbestblockhash",
                  |  "params": []
                  |}
                  |""".stripMargin

    server
        .post(body)
        .flatMap { response =>

          val result = for {
            blockhash <- getResult[Blockhash](response)
                .orElse {
                  logger.warn(s"Unexpected response from XSN Server, status = ${response.status}, response = ${response.body}")
                  None
                }
                .getOrElse(Bad(XSNUnexpectedResponseError).accumulating)
                .toFutureOr

            block <- getBlock(blockhash).
                map {
                  case Good(block) => Good(cleanGenesisBlock(block))
                  case x => x
                }
                .toFutureOr
          } yield block

          result.toFuture
        }
  }

  override def getServerStatistics(): FutureApplicationResult[rpc.ServerStatistics] = {
    val body = s"""
                  |{
                  |  "jsonrpc": "1.0",
                  |  "method": "gettxoutsetinfo",
                  |  "params": []
                  |}
                  |""".stripMargin

    server
        .post(body)
        .map { response =>
          val maybe = getResult[rpc.ServerStatistics](response)
          maybe.getOrElse {
            logger.warn(s"Unexpected response from XSN Server, status = ${response.status}, response = ${response.body}")

            Bad(XSNUnexpectedResponseError).accumulating
          }
        }
  }

  override def getMasternodeCount(): FutureApplicationResult[Int] = {
    val body = s"""
                  |{
                  |  "jsonrpc": "1.0",
                  |  "method": "masternode",
                  |  "params": ["count"]
                  |}
                  |""".stripMargin

    server
        .post(body)
        .map { response =>
          val maybe = getResult[Int](response)
          maybe.getOrElse {
            logger.warn(s"Unexpected response from XSN Server, status = ${response.status}, response = ${response.body}")

            Bad(XSNUnexpectedResponseError).accumulating
          }
        }
  }

  override def getDifficulty(): FutureApplicationResult[BigDecimal] = {
    val body = s"""
                  |{
                  |  "jsonrpc": "1.0",
                  |  "method": "getdifficulty",
                  |  "params": []
                  |}
                  |""".stripMargin

    server
      .post(body)
      .map { response =>
        val maybe = getResult[BigDecimal](response)
        maybe.getOrElse {
          logger.warn(s"Unexpected response from XSN Server, status = ${response.status}, response = ${response.body}")

          Bad(XSNUnexpectedResponseError).accumulating
        }
      }
  }


  override def getMasternodes(): FutureApplicationResult[List[rpc.Masternode]] = {
    val body = s"""
                  |{
                  |  "jsonrpc": "1.0",
                  |  "method": "masternode",
                  |  "params": ["list", "full"]
                  |}
                  |""".stripMargin

    server
        .post(body)
        .map { response =>
          val maybe = getResult[Map[String, String]](response)
              .map {
                case Good(map) => Good(rpc.Masternode.fromMap(map))
                case Bad(errors) => Bad(errors)
              }

          maybe.getOrElse {
            logger.warn(s"Unexpected response from XSN Server, status = ${response.status}, response = ${response.body}")

            Bad(XSNUnexpectedResponseError).accumulating
          }
        }
  }

  override def getMasternode(ipAddress: IPAddress): FutureApplicationResult[rpc.Masternode] = {
    val body = s"""
                  |{
                  |  "jsonrpc": "1.0",
                  |  "method": "masternode",
                  |  "params": ["list", "full", "${ipAddress.string}"]
                  |}
                  |""".stripMargin

    server
        .post(body)
        .map { response =>
          val maybe = getResult[Map[String, String]](response)
              .map {
                case Good(map) =>
                  rpc.Masternode
                      .fromMap(map)
                      .headOption
                      .map(Good(_))
                      .getOrElse(Bad(MasternodeNotFoundError).accumulating)

                case Bad(errors) => Bad(errors)
              }

          maybe.getOrElse {
            logger.warn(s"Unexpected response from XSN Server, status = ${response.status}, response = ${response.body}")

            Bad(XSNUnexpectedResponseError).accumulating
          }
        }
  }

  override def getUnspentOutputs(address: Address): FutureApplicationResult[JsValue] = {
    val body = s"""
                  |{
                  |  "jsonrpc": "1.0",
                  |  "method": "getaddressutxos",
                  |  "params": [
                  |    { "addresses": ["${address.string}"] }
                  |  ]
                  |}
                  |""".stripMargin

    server
        .post(body)
        .map { response =>
          val maybe = getResult[JsValue](response)
          maybe.getOrElse {
            logger.warn(s"Unexpected response from XSN Server, status = ${response.status}, response = ${response.body}")

            Bad(XSNUnexpectedResponseError).accumulating
          }
        }
  }

  override def sendRawTransaction(hex: HexString): FutureApplicationResult[String] = {
    val errorCodeMapper = Map(
      -26 -> InvalidRawTransactionError,
      -22 -> InvalidRawTransactionError,
      -27 -> RawTransactionAlreadyExistsError)

    val body = s"""
                  |{
                  |  "jsonrpc": "1.0",
                  |  "method": "sendrawtransaction",
                  |  "params": ["${hex.string}"]
                  |}
                  |""".stripMargin

    server
        .post(body)
        .map { response =>
          val maybe = getResult[String](response, errorCodeMapper).map { _.map(_.toString()) }

          maybe.getOrElse {
            logger.warn(s"Unexpected response from XSN Server, status = ${response.status}, response = ${response.body}")

            Bad(XSNUnexpectedResponseError).accumulating
          }
        }
  }

  private def mapError(json: JsValue, errorCodeMapper: Map[Int, ApplicationError]): Option[ApplicationError] = {
    val jsonErrorMaybe = (json \ "error")
        .asOpt[JsValue]
        .filter(_ != JsNull)

    val errorMaybe = jsonErrorMaybe
        .flatMap { jsonError =>
          // from error code if possible
          (jsonError \ "code")
              .asOpt[Int]
              .flatMap(errorCodeMapper.get)
              .orElse {
                // from message
                (jsonError \ "message")
                    .asOpt[String]
                    .filter(_.nonEmpty)
                    .map(XSNMessageError.apply)
              }
        }

    errorMaybe
        .collect {
          case XSNMessageError("Work queue depth exceeded") => XSNWorkQueueDepthExceeded
        }
        .orElse(errorMaybe)
  }

  private def getResult[A](
      response: WSResponse,
      errorCodeMapper: Map[Int, ApplicationError] = Map.empty)(
      implicit reads: Reads[A]): Option[ApplicationResult[A]] = {

    val maybe = Option(response)
        .filter(_.status == 200)
        .flatMap { r => Try(r.json).toOption }
        .flatMap { json =>
          if (logger.isDebugEnabled) {
            val x = (json \ "result").validate[A]
            x.asEither.left.foreach { errors =>
              val msg = errors
                  .map { case (path, error) => path.toJsonString -> error.toString() }
                  .mkString(", ")
              logger.debug(s"Failed to decode result, errors = ${msg}")
            }
          }
          (json \ "result")
              .asOpt[A]
              .map { Good(_) }
              .orElse {
                mapError(json, errorCodeMapper)
                    .map(Bad.apply)
                    .map(_.accumulating)
              }
        }

    maybe
        .orElse {
          // if there is no result nor error, it is probably that the server returned non 200 status
          Try(response.json)
              .toOption
              .flatMap { json => mapError(json, errorCodeMapper) }
              .map { e => Bad(e).accumulating }
        }
        .orElse {
          // if still there is no error, the response might not be a json
          Try(response.body)
              .collect {
                case "Work queue depth exceeded" => Bad(XSNWorkQueueDepthExceeded).accumulating
              }
              .toOption
        }
  }

  override val genesisBlockhash: Blockhash = explorerConfig.genesisBlock

}