Working on take-offer logic

src/adapters/wallet.js

@@ -178,63 +178,19 @@ class WalletAdapter {
     }
   }
 
-// Burn enough PSF to generate a valide proof-of-burn for writing to the P2WDB.
-// async burnPsf () {
-//   try {
-//     // TODO: Throw error if this.bchWallet has not been instantiated.
-//
-//     // console.log('walletData: ', walletData)
-//     // console.log(
-//     //   `walletData.utxos.utxoStore.slpUtxos: ${JSON.stringify(
-//     //     walletData.utxos.utxoStore.slpUtxos,
-//     //     null,
-//     //     2,
-//     //   )}`,
-//     // )
-//
-//     // Get token UTXOs held by the wallet.
-//     const tokenUtxos = this.bchWallet.utxos.utxoStore.slpUtxos.type1.tokens
-//     // console.log(`tokenUtxos: ${JSON.stringify(tokenUtxos, null, 2)}`)
-//
-//     // Find a token UTXO that contains PSF with a quantity higher than needed
-//     // to generate a proof-of-burn.
-//     let tokenUtxo = {}
-//     for (let i = 0; i < tokenUtxos.length; i++) {
-//       const thisUtxo = tokenUtxos[i]
-//
-//       // If token ID matches.
-//       if (thisUtxo.tokenId === P2WDB_TOKEN_ID) {
-//         if (parseFloat(thisUtxo.qtyStr) >= PROOF_OF_BURN_QTY) {
-//           tokenUtxo = thisUtxo
-//           break
-//         }
-//       }
-//     }
-//
-//     if (tokenUtxo.tokenId !== P2WDB_TOKEN_ID) {
-//       throw new Error(
-//         `Token UTXO of with ID of ${P2WDB_TOKEN_ID} and quantity greater than ${PROOF_OF_BURN_QTY} could not be found in wallet.`
-//       )
-//     }
-//     // console.log(`tokenUtxo: ${JSON.stringify(tokenUtxo, null, 2)}`)
-//
-//     const result = await this.bchWallet.burnTokens(
-//       PROOF_OF_BURN_QTY,
-//       P2WDB_TOKEN_ID
-//     )
-//     // console.log('walletData.burnTokens() result: ', result)
-//
-//     return result
-//
-//     // return {
-//     //   success: true,
-//     //   txid: 'fakeTxid',
-//     // }
-//   } catch (err) {
-//     console.error('Error in burnPsf(): ', err)
-//     throw err
-//   }
-// }
+  // Generate a partial transcation to *take* a 'sell' order.
+  async generatePartialTx (orderInfo) {
+    // try {
+    //   // const bchjs = this.bchWallet.bchjs
+    //
+    //   return true
+    // } catch (err) {
+    //   console.error('Error in wallet.js/generatePartialTx()')
+    //   throw err
+    // }
+
+    return true
+  }
 }
 
 module.exports = WalletAdapter

src/controllers/rest-api/order/controller.js

@@ -61,6 +61,27 @@ class OrderRESTControllerLib {
     }
   }
 
+  // Currently only supports 'sell' orders, and will only buy the 'numTokens'
+  // listed in the order.
+  async takeOrder (ctx) {
+    try {
+      console.log('body: ', ctx.request.body)
+
+      const orderCid = ctx.request.body.orderCid
+
+      // Find the Order.
+      // const orderEntity = await _this.useCases.order.findOrder(orderId)
+
+      // 'Take' the Order.
+      const hash = await _this.useCases.order.takeOrder(orderCid)
+
+      ctx.body = { hash }
+    } catch (err) {
+      console.log('Error in takeOrder REST API handler.')
+      _this.handleError(ctx, err)
+    }
+  }
+
   // DRY error handler
   handleError (ctx, err) {
     console.log('err', err.message)

src/controllers/rest-api/order/index.js

@@ -51,6 +51,7 @@ class OrderRouter {
     // Define the routes and attach the controller.
     this.router.post('/', _this.orderRESTController.createOrder)
     this.router.get('/list', _this.orderRESTController.listOrders)
+    this.router.post('/take', _this.orderRESTController.takeOrder)
 
     // Attach the Controller routes to the Koa app.
     app.use(_this.router.routes())

src/use-cases/offer.js

@@ -90,7 +90,7 @@ class OfferLib {
 
       const utxoInfo = {
         txid,
-        vout: 0,
+        vout: 1,
         hdIndex: keyPair.hdIndex
       }
 

src/use-cases/order/index.js

@@ -68,6 +68,112 @@ class OrderUseCases {
       throw error
     }
   }
+
+  // Generate phase 2 of 3 - take the other side of an Order.
+  // Based on this example:
+  // https://github.com/Permissionless-Software-Foundation/bch-js-examples/blob/master/bch/applications/collaborate/sell-slp/e2e-exchange/step2-purchase-tx.js
+  async takeOrder (orderCid) {
+    try {
+      console.log('orderCid: ', orderCid)
+
+      // Get the Order information
+      const orderInfo = await this.findOrderByHash(orderCid)
+      console.log(`orderInfo: ${JSON.stringify(orderInfo, null, 2)}`)
+
+      // Ensure the order is in a 'posted' state and not already 'taken'
+      if (orderInfo.orderStatus && orderInfo.orderStatus !== 'posted') {
+        throw new Error('order already taken')
+      }
+
+      // Verify that UTXO for sale is unspent. Abort if it's been spent.
+      const txid = orderInfo.utxoTxid
+      const vout = orderInfo.utxoVout
+      const utxoStatus = await this.adapters.bchjs.Blockchain.getTxOut(
+        txid,
+        vout
+      )
+      console.log('utxoStatus: ', utxoStatus)
+      if (utxoStatus === null) {
+        console.log(`utxo txid: ${txid}, vout: ${vout}`)
+        throw new Error('UTXO does not exist. Aborting.')
+      }
+
+      // Ensure the app has enough funds to complete the trade.
+      await this.ensureFunds(orderInfo)
+
+      // Get UTXOs.
+      const utxos = this.adapters.wallet.bchWallet.utxos.utxoStore
+      console.log(`utxos: ${JSON.stringify(utxos, null, 2)}`)
+
+      // Create a partially signed transaction.
+      // https://github.com/Permissionless-Software-Foundation/bch-js-examples/blob/master/bch/applications/collaborate/sell-slp/e2e-exchange/step2-purchase-tx.js#L59
+      // const partialTxHex = await this.adapaters.wallet.generatePartialTx(orderInfo)
+
+      // return partialTxHex
+
+      return true
+    } catch (err) {
+      console.error('Error in use-cases/order/takeOrder()')
+      throw err
+    }
+  }
+
+  // Ensure that the wallet has enough BCH and tokens to complete the requested
+  // trade. Will return true if it does. Will throw an error if it doesn't.
+  async ensureFunds (orderEntity) {
+    try {
+      // console.log('this.adapters.wallet: ', this.adapters.wallet.bchWallet)
+      // console.log(`walletInfo: ${JSON.stringify(this.adapters.wallet.bchWallet.walletInfo, null, 2)}`)
+
+      // Ensure the app wallet has enough funds to write to the P2WDB.
+      const wif = this.adapters.wallet.bchWallet.walletInfo.privateKey
+      const canWriteToP2WDB = await this.adapters.p2wdb.checkForSufficientFunds(wif)
+      if (!canWriteToP2WDB) throw new Error('App wallet does not have funds for writing to the P2WDB.')
+
+      if (orderEntity.buyOrSell.includes('sell')) {
+        // Sell Offer
+
+        // Ensure the app wallet controlls enough BCH to pay for the tokens.
+        const satsNeeded = orderEntity.numTokens * parseInt(orderEntity.rateInSats)
+        const balance = await this.adapters.wallet.bchWallet.getBalance()
+        console.log(`wallet balance: ${balance}, sats needed: ${satsNeeded}`)
+        const SATS_MARGIN = 5000
+        if (satsNeeded + SATS_MARGIN > balance) { throw new Error('App wallet does not control enough BCH to purchase the tokens.') }
+
+      //
+      } else {
+        // Buy Offer
+        throw new Error('Buy orders are not supported yet.')
+      }
+
+      return true
+    } catch (err) {
+      console.error('Error in ensureFunds()')
+      throw err
+    }
+  }
+
+  async findOrderByHash (p2wdbHash) {
+    try {
+      if (typeof p2wdbHash !== 'string' || !p2wdbHash) {
+        throw new Error('p2wdbHash must be a string')
+      }
+
+      const order = await this.OrderModel.findOne({ p2wdbHash })
+
+      if (!order) {
+        throw new Error('order not found')
+      }
+
+      const orderObject = order.toObject()
+      // return this.orderEntity.validateFromModel(orderObject)
+
+      return orderObject
+    } catch (err) {
+      console.error('Error in findOrder(): ', err)
+      throw err
+    }
+  }
 }
 
 module.exports = OrderUseCases

test/e2e/manual/02-take-order.js

@@ -0,0 +1,25 @@
+/*
+  Part 2 of 3: Take an order
+*/
+
+const axios = require('axios')
+
+const LOCALHOST = 'http://localhost:5700'
+
+async function start () {
+  try {
+    const options = {
+      method: 'post',
+      url: `${LOCALHOST}/order/take`,
+      data: {
+        orderCid: 'zdpuAkp98gTuivaNzGP31jTQi3ADXrFA6uANrceQcrQkTXy2j'
+      }
+    }
+
+    const result = await axios(options)
+    console.log('result.data: ', result.data)
+  } catch (err) {
+    console.log(err)
+  }
+}
+start()