From caf8d956b5985e9d3dd882efd36635871fc69bef Mon Sep 17 00:00:00 2001
From: Miguel Medeiros <miguel@miguelmedeiros.com.br>
Date: Fri, 23 Jul 2021 17:37:28 -0300
Subject: [PATCH] Add difficulty adjustment endpoints methods.

---
 examples/nodejs/index.ts             |  6 ++++--
 src/app/bitcoin/difficulty.ts        | 16 ++++++++++++++++
 src/index.ts                         |  2 ++
 src/interfaces/bitcoin/difficulty.ts | 13 +++++++++++++
 src/interfaces/index.ts              |  2 ++
 5 files changed, 37 insertions(+), 2 deletions(-)
 create mode 100644 src/app/bitcoin/difficulty.ts
 create mode 100644 src/interfaces/bitcoin/difficulty.ts

diff --git a/examples/nodejs/index.ts b/examples/nodejs/index.ts
index 099250c9c..2731e163d 100644
--- a/examples/nodejs/index.ts
+++ b/examples/nodejs/index.ts
@@ -2,7 +2,7 @@ import mempoolJS from "@mempool/mempool.js";
 
 const init = async () => {
     const { bitcoin } = mempoolJS({
-        hostname:'mempool.ninja'
+        hostname:'localhost:4200'
     });
     
     const feesRecommended = await bitcoin.fees.getFeesRecommended();
@@ -10,8 +10,10 @@ const init = async () => {
 
     const hash = "0000000000000000000065bda8f8a88f2e1e00d9a6887a43d640e52a4c7660f2";
     const block = await bitcoin.blocks.getBlockHeader({hash});
-
     console.log(block);
+
+    const difficultyAdjustment = await bitcoin.difficulty.getDifficultyAdjustment();
+    console.log(difficultyAdjustment);
 };
 
 init();
\ No newline at end of file
diff --git a/src/app/bitcoin/difficulty.ts b/src/app/bitcoin/difficulty.ts
new file mode 100644
index 000000000..b01fbff23
--- /dev/null
+++ b/src/app/bitcoin/difficulty.ts
@@ -0,0 +1,16 @@
+import { AxiosInstance } from 'axios';
+import {
+  Adjustment,
+  DifficultyInstance,
+} from '../../interfaces/bitcoin/difficulty';
+
+export const useDifficulty = (api: AxiosInstance): DifficultyInstance => {
+  const getDifficultyAdjustment = async () => {
+    const { data } = await api.get<Adjustment>(`/difficulty-adjustment`);
+    return data;
+  };
+
+  return {
+    getDifficultyAdjustment,
+  };
+};
diff --git a/src/index.ts b/src/index.ts
index 646740e68..90863a066 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -7,6 +7,7 @@ import {
 
 import { useAddresses } from './app/bitcoin/addresses';
 import { useBlocks } from './app/bitcoin/blocks';
+import { useDifficulty } from './app/bitcoin/difficulty';
 import { useFees } from './app/bitcoin/fees';
 import { useMempool } from './app/bitcoin/mempool';
 import { useTransactions } from './app/bitcoin/transactions';
@@ -45,6 +46,7 @@ const mempool = (
     bitcoin: {
       addresses: useAddresses(apiBitcoin),
       blocks: useBlocks(apiBitcoin),
+      difficulty: useDifficulty(apiBitcoin),
       fees: useFees(apiBitcoin),
       mempool: useMempool(apiBitcoin),
       transactions: useTransactions(apiBitcoin),
diff --git a/src/interfaces/bitcoin/difficulty.ts b/src/interfaces/bitcoin/difficulty.ts
new file mode 100644
index 000000000..d248ce817
--- /dev/null
+++ b/src/interfaces/bitcoin/difficulty.ts
@@ -0,0 +1,13 @@
+
+export interface Adjustment {
+  progressPercent: number,
+  difficultyChange: number,
+  estimatedRetargetDate: number,
+  remainingBlocks: number,
+  remainingTime: number,
+  previousRetarget: number,
+}
+
+export interface DifficultyInstance {
+  getDifficultyAdjustment: () => Promise<Adjustment>;
+}
diff --git a/src/interfaces/index.ts b/src/interfaces/index.ts
index 9fe6fad6d..ca2d83a8d 100644
--- a/src/interfaces/index.ts
+++ b/src/interfaces/index.ts
@@ -1,5 +1,6 @@
 import { AddressInstance } from './bitcoin/addresses';
 import { BlockInstance } from './bitcoin/blocks';
+import { DifficultyInstance } from './bitcoin/difficulty';
 import { FeeInstance } from './bitcoin/fees';
 import { MempoolInstance } from './bitcoin/mempool';
 import { TxInstance } from './bitcoin/transactions';
@@ -21,6 +22,7 @@ export interface MempoolReturn {
   bitcoin: {
     addresses: AddressInstance;
     blocks: BlockInstance;
+    difficulty: DifficultyInstance;
     fees: FeeInstance;
     mempool: MempoolInstance;
     transactions: TxInstance;