Merge pull request #3 from christroutner/unstable

generateBurnOpReturn
christroutner · Jan 1, 2020 · 2e2e695 · 2e2e695
2 parents 086e43e + d6733c4
commit 2e2e695
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diff --git a/src/slp/tokentype1.js b/src/slp/tokentype1.js
@@ -42,6 +42,7 @@ class TokenType1 {
         totalTokens += tokenUtxos[i].tokenQty
 
       const change = totalTokens - sendQty
+      // console.log(`change: ${change}`)
 
       let script
       let outputs = 1
@@ -104,6 +105,56 @@ class TokenType1 {
     }
   }
 
+  /**
+   * @api SLP.TokenType1.generateBurnOpReturn() generateBurnOpReturn() - OP_RETURN code for SLP Send tx
+   * @apiName generateBurnOpReturn
+   * @apiGroup SLP
+   * @apiDescription Generate the OP_RETURN value needed to create an SLP Send transaction that burns tokens.
+   * This is a slight variation of generateSendOpReturn(). It generates an SLP
+   * SEND transaction designed to burn a select quantity of tokens.
+   *
+   * It's assumed all elements in the tokenUtxos array belong to the same token.
+   * Returns an object with two properties:
+   *  - script: an array of Bufers that is ready to fed into bchjs.Script.encode() to be turned into a transaction output.
+   *  - outputs: an integer with a value of 1. There is no token change to be sent with this transaction.
+   */
+  generateBurnOpReturn(tokenUtxos, burnQty) {
+    try {
+      const tokenId = tokenUtxos[0].tokenId
+      const decimals = tokenUtxos[0].decimals
+
+      // Calculate the total amount of tokens owned by the wallet.
+      let totalTokens = 0
+      for (let i = 0; i < tokenUtxos.length; i++)
+        totalTokens += tokenUtxos[i].tokenQty
+
+      const remainder = totalTokens - burnQty
+
+      let baseQty = new BigNumber(remainder).times(10 ** decimals)
+      baseQty = baseQty.absoluteValue()
+      baseQty = Math.floor(baseQty)
+      let baseQtyHex = baseQty.toString(16)
+      baseQtyHex = baseQtyHex.padStart(16, "0")
+
+      // console.log(`baseQty: ${baseQty.toString()}`)
+
+      const script = [
+        this.Script.opcodes.OP_RETURN,
+        Buffer.from("534c5000", "hex"),
+        //BITBOX.Script.opcodes.OP_1,
+        Buffer.from("01", "hex"),
+        Buffer.from(`SEND`),
+        Buffer.from(tokenId, "hex"),
+        Buffer.from(baseQtyHex, "hex")
+      ]
+
+      return script
+    } catch (err) {
+      console.log(`Error in generateSendOpReturn()`)
+      throw err
+    }
+  }
+
   /**
    * @api SLP.TokenType1.generateGenesisOpReturn() generateGenesisOpReturn() - OP_RETURN code for SLP Genesis tx
    * @apiName generateGenesisOpReturn

diff --git a/test/unit/slp-tokentype1.js b/test/unit/slp-tokentype1.js
@@ -70,6 +70,75 @@ describe("#SLP TokenType1", () => {
       assert.hasAllKeys(result, ["script", "outputs"])
       assert.isNumber(result.outputs)
     })
+
+    //   it("should handle problematic configuration", async () => {
+    //     // Mock UTXO.
+    //     const tokenUtxos = [
+    //       {
+    //         txid:
+    //           "0bd6b874246202b4cbc2f501419a5ce6f9b01e8ba9521298afd15c7e8eac5951",
+    //         vout: 2,
+    //         value: "546",
+    //         confirmations: 0,
+    //         satoshis: 546,
+    //         utxoType: "token",
+    //         transactionType: "send",
+    //         tokenId:
+    //           "155784a206873c98acc09e8dabcccf6abf13c4c14d8662190534138a16bb93ce",
+    //         tokenTicker: "PSF",
+    //         tokenName: "PSF Testnet Token",
+    //         tokenDocumentUrl: "",
+    //         tokenDocumentHash: "",
+    //         decimals: 8,
+    //         tokenQty: 18004.71169917
+    //       }
+    //     ]
+    //
+    //     const result = await bchjs.SLP.TokenType1.generateSendOpReturn(
+    //       tokenUtxos,
+    //       5000
+    //     )
+    //     console.log(`result: ${JSON.stringify(result, null, 2)}`)
+    //
+    //     // console.log(`decoded: ${result.script[6].toString("ascii")}`)
+    //     // const msg = Buffer.from(result.script[6], "hex").toString("ascii")
+    //     const msg = result.script[6].toString("ascii")
+    //     console.log(`msg: ${msg}`)
+    //   })
+  })
+
+  describe("#generateBurnOpReturn", () => {
+    it("should generate burn OP_RETURN code", async () => {
+      // Mock UTXO.
+      const tokenUtxos = [
+        {
+          txid:
+            "a8eb788b8ddda6faea00e6e2756624b8feb97655363d0400dd66839ea619d36e",
+          vout: 2,
+          value: "546",
+          confirmations: 0,
+          satoshis: 546,
+          utxoType: "token",
+          transactionType: "send",
+          tokenId:
+            "497291b8a1dfe69c8daea50677a3d31a5ef0e9484d8bebb610dac64bbc202fb7",
+          tokenTicker: "TOK-CH",
+          tokenName: "TokyoCash",
+          tokenDocumentUrl: "",
+          tokenDocumentHash: "",
+          decimals: 8,
+          tokenQty: 7
+        }
+      ]
+
+      const result = await bchjs.SLP.TokenType1.generateBurnOpReturn(
+        tokenUtxos,
+        1
+      )
+      // console.log(`result: ${JSON.stringify(result, null, 2)}`)
+
+      assert.isArray(result)
+    })
   })
 
   describe("#generateGenesisOpReturn", () => {