Derive gas price estimate from previous transactions

Return the 50th percentile lowest gas price of the previous 20 blocks.

1 files changed, 20 insertions, 1 deletions

diff --git a/app/scripts/metamask-controller.js b/app/scripts/metamask-controller.js
index 23f2a1598..7ffa653e4 100644
--- a/app/scripts/metamask-controller.js
+++ b/app/scripts/metamask-controller.js
@@ -35,13 +35,15 @@ const accountImporter = require('./account-import-strategies')
 const getBuyEthUrl = require('./lib/buy-eth-url')
 const Mutex = require('await-semaphore').Mutex
 const version = require('../manifest.json').version
+const BN = require('ethereumjs-util').BN
+const GWEI_BN = new BN('1000000000')
+const percentile = require('percentile')
 
 module.exports = class MetamaskController extends EventEmitter {
 
   constructor (opts) {
     super()
 
-
     this.sendUpdate = debounce(this.privateSendUpdate.bind(this), 200)
 
     this.opts = opts
@@ -139,6 +141,7 @@ module.exports = class MetamaskController extends EventEmitter {
       provider: this.provider,
       blockTracker: this.blockTracker,
       ethQuery: this.ethQuery,
+      getGasPrice: this.getGasPrice.bind(this),
     })
     this.txController.on('newUnapprovedTx', opts.showUnapprovedTx.bind(opts))
 
@@ -484,6 +487,22 @@ module.exports = class MetamaskController extends EventEmitter {
     this.emit('update', this.getState())
   }
 
+  getGasPrice () {
+    const { recentBlocksController } = this
+    console.dir(recentBlocksController)
+    const { recentBlocks } = recentBlocksController.store.getState()
+    console.dir(recentBlocks)
+    const lowestPrices = recentBlocks.map((block) => {
+      return block.transactions
+      .sort((a, b) => {
+        return a.gt(b) ? 1 : -1
+      })[0]
+    })
+    .map(number => number.div(GWEI_BN).toNumber())
+    console.dir({ lowestPrices })
+    return percentile(50, lowestPrices)
+  }
+
   //
   // Vault Management
   //