From 19f7af84a5c8f3df70f0d0e0c67ddb07103f3423 Mon Sep 17 00:00:00 2001
From: Willian Mitsuda <wmitsuda@gmail.com>
Date: Sat, 30 Oct 2021 21:06:11 -0300
Subject: [PATCH] Extract resolver api

---
 .../CompositeAddressResolver.ts               | 26 +++++++++++++++
 .../address-resolver/ENSAddressResolver.ts    | 15 +++++++++
 src/api/address-resolver/address-resolver.ts  |  8 +++++
 src/api/address-resolver/index.ts             | 33 +++++++++++++++++++
 src/types.ts                                  |  4 +--
 src/useReverseCache.ts                        | 16 ++-------
 6 files changed, 85 insertions(+), 17 deletions(-)
 create mode 100644 src/api/address-resolver/CompositeAddressResolver.ts
 create mode 100644 src/api/address-resolver/ENSAddressResolver.ts
 create mode 100644 src/api/address-resolver/address-resolver.ts
 create mode 100644 src/api/address-resolver/index.ts

diff --git a/src/api/address-resolver/CompositeAddressResolver.ts b/src/api/address-resolver/CompositeAddressResolver.ts
new file mode 100644
index 0000000..bee73da
--- /dev/null
+++ b/src/api/address-resolver/CompositeAddressResolver.ts
@@ -0,0 +1,26 @@
+import { BaseProvider } from "@ethersproject/providers";
+import { IAddressResolver } from "./address-resolver";
+
+export class CompositeAddressResolver implements IAddressResolver {
+  private resolvers: IAddressResolver[] = [];
+
+  addResolver(resolver: IAddressResolver) {
+    this.resolvers.push(resolver);
+  }
+
+  async resolveAddress(
+    provider: BaseProvider,
+    address: string
+  ): Promise<string | undefined> {
+    for (const r of this.resolvers) {
+      const name = r.resolveAddress(provider, address);
+      if (name !== undefined) {
+        return name;
+      }
+    }
+
+    return undefined;
+    // TODO: fallback to address itself
+    // return address;
+  }
+}
diff --git a/src/api/address-resolver/ENSAddressResolver.ts b/src/api/address-resolver/ENSAddressResolver.ts
new file mode 100644
index 0000000..ef45a64
--- /dev/null
+++ b/src/api/address-resolver/ENSAddressResolver.ts
@@ -0,0 +1,15 @@
+import { BaseProvider } from "@ethersproject/providers";
+import { IAddressResolver } from "./address-resolver";
+
+export class ENSAddressResolver implements IAddressResolver {
+  async resolveAddress(
+    provider: BaseProvider,
+    address: string
+  ): Promise<string | undefined> {
+    const name = await provider.lookupAddress(address);
+    if (name === null) {
+      return undefined;
+    }
+    return name;
+  }
+}
diff --git a/src/api/address-resolver/address-resolver.ts b/src/api/address-resolver/address-resolver.ts
new file mode 100644
index 0000000..246db34
--- /dev/null
+++ b/src/api/address-resolver/address-resolver.ts
@@ -0,0 +1,8 @@
+import { BaseProvider } from "@ethersproject/providers";
+
+export interface IAddressResolver {
+  resolveAddress(
+    provider: BaseProvider,
+    address: string
+  ): Promise<string | undefined>;
+}
diff --git a/src/api/address-resolver/index.ts b/src/api/address-resolver/index.ts
new file mode 100644
index 0000000..a9b4ff6
--- /dev/null
+++ b/src/api/address-resolver/index.ts
@@ -0,0 +1,33 @@
+import { BaseProvider } from "@ethersproject/providers";
+import { ENSReverseCache } from "../../types";
+import { IAddressResolver } from "./address-resolver";
+import { CompositeAddressResolver } from "./CompositeAddressResolver";
+import { ENSAddressResolver } from "./ENSAddressResolver";
+
+// Create and configure the main resolver
+const _mainResolver = new CompositeAddressResolver();
+_mainResolver.addResolver(new ENSAddressResolver());
+
+export const mainResolver: IAddressResolver = _mainResolver;
+
+export const batchPopulate = async (
+  provider: BaseProvider,
+  addresses: string[]
+): Promise<ENSReverseCache> => {
+  const solvers: Promise<string | undefined>[] = [];
+  for (const a of addresses) {
+    solvers.push(mainResolver.resolveAddress(provider, a));
+  }
+
+  const results = await Promise.all(solvers);
+  const cache: ENSReverseCache = {};
+  for (let i = 0; i < results.length; i++) {
+    const r = results[i];
+    if (r === undefined) {
+      continue;
+    }
+    cache[addresses[i]] = r;
+  }
+
+  return cache;
+};
diff --git a/src/types.ts b/src/types.ts
index 5904b31..76a1944 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -32,9 +32,7 @@ export type TransactionChunk = {
   lastPage: boolean;
 };
 
-export type ENSReverseCache = {
-  [address: string]: string;
-};
+export type ENSReverseCache = Record<string, string>;
 
 export type TransactionData = {
   transactionHash: string;
diff --git a/src/useReverseCache.ts b/src/useReverseCache.ts
index 365888a..fa0ca1a 100644
--- a/src/useReverseCache.ts
+++ b/src/useReverseCache.ts
@@ -1,6 +1,7 @@
 import { useState, useEffect } from "react";
 import { JsonRpcProvider } from "@ethersproject/providers";
 import { ENSReverseCache, ProcessedTransaction } from "./types";
+import { batchPopulate } from "./api/address-resolver";
 
 export const useENSCache = (
   provider?: JsonRpcProvider,
@@ -25,20 +26,7 @@ export const useENSCache = (
     const addresses = Array.from(addrSet);
 
     const reverseResolve = async () => {
-      const solvers: Promise<string | null>[] = [];
-      for (const a of addresses) {
-        solvers.push(provider.lookupAddress(a));
-      }
-
-      const results = await Promise.all(solvers);
-      const cache: ENSReverseCache = {};
-      for (let i = 0; i < results.length; i++) {
-        const r = results[i];
-        if (r === null) {
-          continue;
-        }
-        cache[addresses[i]] = r;
-      }
+      const cache = await batchPopulate(provider, addresses);
       setReverseCache(cache);
     };
     reverseResolve();