XO Integration Part II

packages/stack/src/blockchain/blockchain-inmemory.ts

@@ -9,6 +9,7 @@ import {
 
 import {
   Address,
+  BlockHeader,
   ExtMap,
   Outpoint,
   Transaction,
@@ -30,6 +31,7 @@ export class BlockchainInMemory extends BaseBlockchain {
     return blockchain as InstanceType<T>;
   }
 
+  private blockHeaders: Array<BlockHeader>;
   private transactions: BlockchainTransactions;
   private addressSubscriptions: Map<string, Set<BlockchainCallback>>;
   private transactionSubscriptions: Map<string, Set<BlockchainCallback>>;
@@ -40,6 +42,7 @@ export class BlockchainInMemory extends BaseBlockchain {
     this.transactions = new ExtMap<BlockchainTransaction>();
     this.addressSubscriptions = new Map();
     this.transactionSubscriptions = new Map();
+    this.blockHeaders = [];
   }
 
   async start() {}
@@ -89,6 +92,17 @@ export class BlockchainInMemory extends BaseBlockchain {
     });
   }
 
+  async fetchBlockHeader(blockHeight: number) {
+    const blockHeader = this.blockHeaders[blockHeight];
+
+    if (!blockHeader) {
+      throw new Error(`No block available for height ${blockHeight}`);
+    }
+
+    // Return the block header.
+    return blockHeader;
+  }
+
   async broadcastTransaction(
     tx: Transaction | Uint8Array | string,
     opts: { skipValidation: boolean } = { skipValidation: false },
@@ -326,6 +340,14 @@ export class BlockchainInMemory extends BaseBlockchain {
   }
 
   async mineBlock(outputs: Array<Output>): Promise<void> {
+    // Create a block header from the current timestamp.
+    const newBlockHeader = BlockHeader.generateRandom(
+      Math.floor(Date.now() / 1000),
+    );
+
+    // Add it to our list of block headers.
+    this.blockHeaders.push(newBlockHeader);
+
     // Create a transaction that pays to our subscribed address.
     const transaction = Transaction.fromRaw({
       version: 2,