Add getTimeEstimate to GasFee controller

src/gas/GasFee.controller.ts

@@ -12,8 +12,16 @@ import type {
 import {
   fetchGasEstimates as defaultFetchGasEstimates,
   fetchLegacyGasPriceEstimate as defaultFetchLegacyGasPriceEstimate,
+  calculateTimeEstimate,
 } from './gas-util';
 
+export type unknownString = 'unknown';
+
+export interface EstimatedGasFeeTimeBounds {
+  lowerTimeBound: number | null;
+  upperTimeBound: number | unknownString;
+}
+
 /**
  * @type LegacyGasPriceEstimate
  *
@@ -44,6 +52,16 @@ interface Eip1559GasFee {
   suggestedMaxFeePerGas: string; // a GWEI hex number
 }
 
+function isEIP1559GasFeee(object: any): object is Eip1559GasFee {
+  return (
+    'minWaitTimeEstimate' in object &&
+    'maxWaitTimeEstimate' in object &&
+    'suggestedMaxPriorityFeePerGas' in object &&
+    'suggestedMaxFeePerGas' in object &&
+    Object.keys(object).length === 4
+  );
+}
+
 /**
  * @type GasFeeEstimates
  *
@@ -62,6 +80,18 @@ export interface GasFeeEstimates {
   estimatedBaseFee: string;
 }
 
+function isEIP1559Estimate(object: any): object is GasFeeEstimates {
+  return (
+    'low' in object &&
+    isEIP1559GasFeee(object.low) &&
+    'medium' in object &&
+    isEIP1559GasFeee(object.medium) &&
+    'high' in object &&
+    isEIP1559GasFeee(object.high) &&
+    'estimatedBaseFee' in object
+  );
+}
+
 const metadata = {
   gasFeeEstimates: { persist: true, anonymous: false },
 };
@@ -276,6 +306,23 @@ export class GasFeeController extends BaseController<typeof name, GasFeeState> {
       currentNetworkIsEIP1559Compatible && currentAccountIsEIP1559Compatible
     );
   }
+
+  getTimeEstimate(
+    maxPriorityFeePerGas: string,
+    maxFeePerGas: string,
+  ): EstimatedGasFeeTimeBounds | undefined {
+    if (
+      !this.state.gasFeeEstimates ||
+      !isEIP1559Estimate(this.state.gasFeeEstimates)
+    ) {
+      return undefined;
+    }
+    return calculateTimeEstimate(
+      maxPriorityFeePerGas,
+      maxFeePerGas,
+      this.state.gasFeeEstimates,
+    );
+  }
 }
 
 export default GasFeeController;

src/gas/gas-util.ts

@@ -1,5 +1,11 @@
+import { BN } from 'ethereumjs-util';
 import { query } from '../util';
-import { GasFeeEstimates, LegacyGasPriceEstimate } from './GasFee.controller';
+import {
+  GasFeeEstimates,
+  LegacyGasPriceEstimate,
+  EstimatedGasFeeTimeBounds,
+  unknownString,
+} from './GasFee.controller';
 
 // import { handleFetch } from '../util';
 
@@ -150,3 +156,66 @@ export async function fetchLegacyGasPriceEstimate(
 ): Promise<LegacyGasPriceEstimate> {
   return await query(ethQuery, 'gasPrice');
 }
+
+function gweiHexToWEIBN(n: any) {
+  const BN_1000 = new BN(1000, 10);
+  return new BN(n, 16).mul(BN_1000);
+}
+
+export function calculateTimeEstimate(
+  maxPriorityFeePerGas: string,
+  maxFeePerGas: string,
+  gasFeeEstimates: GasFeeEstimates,
+): EstimatedGasFeeTimeBounds {
+  const { low, medium, high, estimatedBaseFee } = gasFeeEstimates;
+
+  const maxPriorityFeePerGasInWEI = gweiHexToWEIBN(maxPriorityFeePerGas);
+  const maxFeePerGasInWEI = gweiHexToWEIBN(maxFeePerGas);
+  const estimatedBaseFeeInWEI = gweiHexToWEIBN(estimatedBaseFee);
+
+  const effectiveMaxPriorityFee = BN.min(
+    maxPriorityFeePerGasInWEI,
+    maxFeePerGasInWEI.sub(estimatedBaseFeeInWEI),
+  );
+
+  const lowMaxPriorityFeeInWEI = gweiHexToWEIBN(
+    low.suggestedMaxPriorityFeePerGas,
+  );
+  const mediumMaxPriorityFeeInWEI = gweiHexToWEIBN(
+    medium.suggestedMaxPriorityFeePerGas,
+  );
+  const highMaxPriorityFeeInWEI = gweiHexToWEIBN(
+    high.suggestedMaxPriorityFeePerGas,
+  );
+
+  let lowerTimeBound;
+  let upperTimeBound;
+
+  if (effectiveMaxPriorityFee.lt(lowMaxPriorityFeeInWEI)) {
+    lowerTimeBound = null;
+    upperTimeBound = 'unknown' as unknownString;
+  } else if (
+    effectiveMaxPriorityFee.gte(lowMaxPriorityFeeInWEI) &&
+    effectiveMaxPriorityFee.lt(mediumMaxPriorityFeeInWEI)
+  ) {
+    lowerTimeBound = low.minWaitTimeEstimate;
+    upperTimeBound = low.maxWaitTimeEstimate;
+  } else if (
+    effectiveMaxPriorityFee.gte(mediumMaxPriorityFeeInWEI) &&
+    effectiveMaxPriorityFee.lt(highMaxPriorityFeeInWEI)
+  ) {
+    lowerTimeBound = medium.minWaitTimeEstimate;
+    upperTimeBound = medium.maxWaitTimeEstimate;
+  } else if (effectiveMaxPriorityFee.eq(highMaxPriorityFeeInWEI)) {
+    lowerTimeBound = high.minWaitTimeEstimate;
+    upperTimeBound = high.maxWaitTimeEstimate;
+  } else {
+    lowerTimeBound = 0;
+    upperTimeBound = high.maxWaitTimeEstimate;
+  }
+
+  return {
+    lowerTimeBound,
+    upperTimeBound,
+  };
+}