From c6800a1fc77879874a500f5384ebe2ff3b61b1fe Mon Sep 17 00:00:00 2001
From: Alexis Hernandez <alexis22229@gmail.com>
Date: Sat, 30 Mar 2019 11:49:31 -0700
Subject: [PATCH] server: Add the TPoSContract model

---
 .../xsn/explorer/models/TPoSContract.scala    | 68 +++++++++++++++++++
 .../explorer/models/TPoSContractSpec.scala    | 50 ++++++++++++++
 2 files changed, 118 insertions(+)
 create mode 100644 server/app/com/xsn/explorer/models/TPoSContract.scala
 create mode 100644 server/test/com/xsn/explorer/models/TPoSContractSpec.scala

diff --git a/server/app/com/xsn/explorer/models/TPoSContract.scala b/server/app/com/xsn/explorer/models/TPoSContract.scala
new file mode 100644
index 0000000..ae8f002
--- /dev/null
+++ b/server/app/com/xsn/explorer/models/TPoSContract.scala
@@ -0,0 +1,68 @@
+package com.xsn.explorer.models
+
+import com.xsn.explorer.models.values.{Address, TransactionId}
+import enumeratum._
+
+import scala.util.Try
+
+case class TPoSContract(
+    id: TPoSContract.Id,
+    details: TPoSContract.Details,
+    time: Long,
+    state: TPoSContract.State) {
+
+  val txid: TransactionId = id.txid
+}
+
+object TPoSContract {
+
+  case class Id(txid: TransactionId, index: Int)
+  class Commission private (val int: Int) extends AnyVal
+  object Commission {
+
+    val range = 1 until 100
+
+    def from(int: Int): Option[Commission] = {
+      if (range contains int) Some(new Commission(int))
+      else None
+    }
+  }
+
+  case class Details(owner: Address, merchant: Address, merchantCommission: Commission)
+  object Details {
+
+    /**
+     * Try to get the contract details from the output script ASM.
+     *
+     * expected format:
+     * - "OP_RETURN [hex_encoded_owner_address] [hex_encoded_merchant_address] [owner_commission] [signature]
+     *
+     * example:
+     * - "OP_RETURN 5869337351664d51737932437a4d5a54726e4b573648464770315671465468644c77 58794a4338786e664672484e634d696e68366778755052595939484361593944416f 99"
+     */
+    def fromOutputScriptASM(asm: String): Option[Details] = {
+      val parts = asm.split(" ").toList
+
+      parts match {
+        case op :: owner :: merchant :: commission :: signature :: Nil if op == "OP_RETURN" =>
+          for {
+            ownerAddress <- Address.fromHex(owner)
+            merchantAddress <- Address.fromHex(merchant)
+            ownerCommission <- Try(commission.toInt).toOption
+            merchantCommission <- TPoSContract.Commission.from(100 - ownerCommission)
+          } yield Details(owner = ownerAddress, merchant = merchantAddress, merchantCommission = merchantCommission)
+
+        case _ => None
+      }
+    }
+  }
+
+  sealed abstract class State(override val entryName: String) extends EnumEntry
+  object State extends Enum[State] {
+
+    val values = findValues
+
+    final case object Active extends State("ACTIVE")
+    final case object Closed extends State("CLOSED")
+  }
+}
diff --git a/server/test/com/xsn/explorer/models/TPoSContractSpec.scala b/server/test/com/xsn/explorer/models/TPoSContractSpec.scala
new file mode 100644
index 0000000..9cd9f9c
--- /dev/null
+++ b/server/test/com/xsn/explorer/models/TPoSContractSpec.scala
@@ -0,0 +1,50 @@
+package com.xsn.explorer.models
+
+import com.xsn.explorer.models.values.Address
+import javax.xml.bind.DatatypeConverter
+import org.scalatest.MustMatchers._
+import org.scalatest.OptionValues._
+import org.scalatest.WordSpec
+
+class TPoSContractSpec extends WordSpec {
+
+  val address1 = Address.from("Xi3sQfMQsy2CzMZTrnKW6HFGp1VqFThdLw").get
+  val address2 = Address.from("XyJC8xnfFrHNcMinh6gxuPRYY9HCaY9DAo").get
+  val address1Hex = DatatypeConverter.printHexBinary(address1.string.getBytes())
+  val address2Hex = DatatypeConverter.printHexBinary(address2.string.getBytes())
+  val commission = "99"
+  val signature = "1f60a6a385a4e5163ffef65dd873f17452bb0d9f89da701ffcc5a0f72287273c0571485c29123fef880d2d8169cfdb884bf95a18a0b36461517acda390ce4cf441"
+
+  val failureCases = Map(
+    "fail when the signature is missing" -> s"OP_RETURN $address1Hex $address2Hex $commission",
+    "fail when there is an extra field" -> s"OP_RETURN $address1Hex $address2Hex $commission $signature $signature",
+    "fail if OP_RETURN is not present" -> s"OP_RTURN $address1Hex $address2Hex $commission $signature",
+    "fail if the commission is missing" -> s"OP_RETURN $address1Hex $address2Hex  $signature",
+    "fail if the commission is corrupted" -> s"OP_RETURN $address1Hex $address2Hex $commission$commission $signature",
+    "fail if the commission is 0" -> s"OP_RETURN $address1Hex $address2Hex 0 $signature",
+    "fail if the commission is 100" -> s"OP_RETURN $address1Hex $address2Hex 100 $signature",
+    "fail if the owner address is malformed" -> s"OP_RETURN x$address1Hex $address2Hex $commission $signature",
+    "fail if the merchant address is malformed" -> s"OP_RETURN x$address1Hex $address2Hex $commission $signature"
+  )
+
+  "parsing details" should {
+    "succeed on a valid contract" in {
+      val asm = s"OP_RETURN $address1Hex $address2Hex $commission $signature"
+
+      val expected = TPoSContract.Details(
+        owner = address1,
+        merchant = address2,
+        merchantCommission = TPoSContract.Commission.from(100 - commission.toInt).get)
+
+      val result = TPoSContract.Details.fromOutputScriptASM(asm)
+      result.value must be(expected)
+    }
+
+    failureCases.foreach { case (test, input) =>
+      test in {
+        val result = TPoSContract.Details.fromOutputScriptASM(input)
+        result must be(empty)
+      }
+    }
+  }
+}