From 16882441d15bfd1d26947748c9d50d32c428b49d Mon Sep 17 00:00:00 2001
From: lukechampine <luke.champine@gmail.com>
Date: Thu, 1 Feb 2024 10:48:51 -0400
Subject: [PATCH] coreutils: Add mining helpers

---
 miner.go | 73 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 73 insertions(+)
 create mode 100644 miner.go

diff --git a/miner.go b/miner.go
new file mode 100644
index 0000000..28f1126
--- /dev/null
+++ b/miner.go
@@ -0,0 +1,73 @@
+package coreutils
+
+import (
+	"encoding/binary"
+	"time"
+
+	"go.sia.tech/core/consensus"
+	"go.sia.tech/core/types"
+	"go.sia.tech/coreutils/chain"
+)
+
+// FindBlockNonce attempts to find a nonce for b that meets the PoW target.
+func FindBlockNonce(cs consensus.State, b *types.Block, timeout time.Duration) bool {
+	b.Nonce = 0
+	buf := make([]byte, 32+8+8+32)
+	binary.LittleEndian.PutUint64(buf[32:], b.Nonce)
+	binary.LittleEndian.PutUint64(buf[40:], uint64(b.Timestamp.Unix()))
+	if b.V2 != nil {
+		copy(buf[:32], "sia/id/block|")
+		copy(buf[48:], b.V2.Commitment[:])
+	} else {
+		root := b.MerkleRoot()
+		copy(buf[:32], b.ParentID[:])
+		copy(buf[48:], root[:])
+	}
+	factor := cs.NonceFactor()
+	startBlock := time.Now()
+	for types.BlockID(types.HashBytes(buf)).CmpWork(cs.ChildTarget) < 0 {
+		b.Nonce += factor
+		binary.LittleEndian.PutUint64(buf[32:], b.Nonce)
+		if time.Since(startBlock) > timeout {
+			return false
+		}
+	}
+	return true
+}
+
+// MineBlock constructs a block from the provided address and the transactions
+// in the txpool, and attempts to find a nonce for it that meets the PoW target.
+func MineBlock(cm *chain.Manager, addr types.Address, timeout time.Duration) (types.Block, bool) {
+	cs := cm.TipState()
+	b := types.Block{
+		ParentID:  cs.Index.ID,
+		Timestamp: types.CurrentTimestamp(),
+		MinerPayouts: []types.SiacoinOutput{{
+			Value:   cs.BlockReward(),
+			Address: addr,
+		}},
+	}
+	var weight uint64
+	for _, txn := range cm.PoolTransactions() {
+		if weight += cs.TransactionWeight(txn); weight > cs.MaxBlockWeight() {
+			break
+		}
+		b.Transactions = append(b.Transactions, txn)
+	}
+	for _, txn := range cm.V2PoolTransactions() {
+		if weight += cs.V2TransactionWeight(txn); weight > cs.MaxBlockWeight() {
+			break
+		}
+		if b.V2 == nil {
+			b.V2 = &types.V2BlockData{
+				Height: cs.Index.Height + 1,
+			}
+		}
+		b.V2.Transactions = append(b.V2.Transactions, txn)
+	}
+	if b.V2 != nil {
+		b.V2.Commitment = cs.Commitment(cs.TransactionsCommitment(b.Transactions, b.V2Transactions()), addr)
+	}
+	found := FindBlockNonce(cs, &b, timeout)
+	return b, found
+}