From 858793b385c735893a29a8f4a36b5a096be39275 Mon Sep 17 00:00:00 2001
From: Chris Duncan <chris@zoso.dev>
Date: Tue, 5 Aug 2025 21:04:37 -0700
Subject: [PATCH] Add chaining functions for handling receivables.

---
 src/lib/block.ts | 85 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 85 insertions(+)

diff --git a/src/lib/block.ts b/src/lib/block.ts
index b70e1d7..e4e8a6d 100644
--- a/src/lib/block.ts
+++ b/src/lib/block.ts
@@ -96,6 +96,38 @@ abstract class Block {
 		}
 	}
 
+	/**
+	* Set a block hash as the source send of a receive block.
+	*
+	* @param {string} hash - Hash of send block to be received
+	* @returns {Block} This block so that additional calls can be chained
+	*/
+	from (hash: string): Block
+	/**
+	* Set a send block as the source of a receive block.
+	*
+	* @param {Block} block - Send block to be received
+	* @returns {Block} This block so that additional calls can be chained
+	*/
+	from (block: Block): Block
+	from (send: unknown): Block {
+		try {
+			if (typeof send !== 'string' && !(send instanceof Block)) {
+				throw new TypeError('Invalid send to be received')
+			}
+			if (this.subtype !== 'receive') {
+				throw new TypeError('Invalid subtype')
+			}
+			this.link = (typeof send === 'string')
+				? send
+				: send.hash
+			this.representative = this.account.representative
+			return this
+		} catch (err) {
+			throw new Error('Failed to receive a corresponding send', { cause: err })
+		}
+	}
+
 	/**
 	* Calculates proof-of-work using a pool of Web Workers.
 	*
@@ -147,6 +179,59 @@ abstract class Block {
 		return res.hash
 	}
 
+	/**
+	* Set the amount of nano that this block will receive from a paired send.
+	*
+	* @param {bigint} amount - Amount that was sent from sender in raw
+	* @returns {Block} This block so that additional calls can be chained
+	*/
+	receive (amount: bigint): Block
+	/**
+	* Set the amount of nano that this block will receive from a paired send.
+	*
+	* @param {number} amount - Amount that was sent from sender in nano (10³⁰ raw)
+	* @returns {Block} This block so that additional calls can be chained
+	*/
+	receive (amount: number): Block
+	/**
+	* Set the amount of nano that this block will receive from a paired send.
+	*
+	* @param {string} amount - Amount that was sent from sender in raw
+	* @returns {Block} This block so that additional calls can be chained
+	*/
+	receive (amount: string): Block
+	receive (amount: unknown): Block {
+		const currentBalance = this.balance
+		try {
+			if (this.subtype != null) {
+				throw new Error(`Block is already configured as ${this.subtype}`)
+			}
+			this.subtype = 'receive'
+			switch (typeof amount) {
+				case 'bigint': {
+					this.balance += amount
+					break
+				}
+				case 'number': {
+					this.balance += BigInt(amount) * (1n << 30n)
+					break
+				}
+				case 'string': {
+					this.balance += BigInt(amount)
+					break
+				}
+				default: {
+					throw new TypeError('Invalid amount')
+				}
+			}
+			return this
+		} catch (err) {
+			this.subtype = undefined
+			this.balance = currentBalance
+			throw new TypeError('Failed to configure receive block', { cause: err })
+		}
+	}
+
 	/**
 	* Set the amount of nano that this block will send to a recipient account.
 	*
-- 
2.47.3