From e0d22ee170f8af9542f2c7dcb5d1eb0c28c1e72c Mon Sep 17 00:00:00 2001
From: "Jonathan \"Duke\" Leto" <jonathan@leto.net>
Date: Thu, 9 Jun 2022 03:00:50 -0700
Subject: [PATCH] Enable z_anonsetblockdelta to calculate a delta for a block
 range; ignore coinbase txs as optimization

---
 src/wallet/rpcwallet.cpp | 63 +++++++++++++++++++++++++++++++++++-----
 1 file changed, 56 insertions(+), 7 deletions(-)

diff --git a/src/wallet/rpcwallet.cpp b/src/wallet/rpcwallet.cpp
index 189d668f3..3a5498f19 100644
--- a/src/wallet/rpcwallet.cpp
+++ b/src/wallet/rpcwallet.cpp
@@ -3657,12 +3657,15 @@ UniValue z_anonsetblockdelta(const UniValue& params, bool fHelp, const CPubKey&
     if (!EnsureWalletIsAvailable(fHelp))
         return NullUniValue;
 
-    if (fHelp || params.size() != 1)
+    if (fHelp || params.size() < 1 || params.size() > 2)
         throw runtime_error(
             "z_anonsetblockdelta\n"
-            "\nReturns delta (difference) in the anonset for a given block height.\n"
+            "\nReturns delta (difference) in the anonset for a given block height. A delta > 0 increases the anonset,\n"
+            "\na delta < 0 reduces the anonset and a delta=0 leaves the anonset the same. Given a single block height\n"
+            "\nwe calculate the delta for that block. Given two block heights, we calculate the delta for that range of blocks.\n"
             "\nArguments:\n"
             "1. \"height\"    (number, required) The block height\n"
+            "1. \"end_height\"    (number, optional) The ending block height\n"
             "\nResult:\n"
             "\"delta\"          (integer) An integer number.\n"
             "\nExamples:\n"
@@ -3698,10 +3701,55 @@ UniValue z_anonsetblockdelta(const UniValue& params, bool fHelp, const CPubKey&
         throw JSONRPCError(RPC_INTERNAL_ERROR, "Can't read block from disk");
 
     int delta = 0;
-    BOOST_FOREACH(const CTransaction&tx, block.vtx)
-    {
-        // delta = shielded outputs - shielded inputs
-        delta += tx.vShieldedOutput.size() - tx.vShieldedSpend.size();
+
+    // given a single block height, we calculate delta for that height
+    if (params.size() == 1) {
+        BOOST_FOREACH(const CTransaction&tx, block.vtx)
+        {
+            // delta = shielded outputs - shielded inputs
+            if(!tx.IsCoinBase()) {
+                delta += tx.vShieldedOutput.size() - tx.vShieldedSpend.size();
+            }
+        }
+    } else {
+        // given two blocks, we calculate delta for that range
+        std::string strHeight2 = params[1].get_str();
+        int nHeight2 = -1;
+        try {
+            nHeight = std::stoi(strHeight2);
+        } catch (const std::exception &e) {
+            throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid ending block height parameter");
+        }
+
+        if (nHeight2 < 0 || nHeight2 > chainActive.Height()) {
+            throw JSONRPCError(RPC_INVALID_PARAMETER, "Ending block height out of range");
+        }
+
+        // get the delta for every block in the range
+        for(int currentHeight = nHeight; currentHeight <= nHeight2; currentHeight++) {
+            auto strHash = chainActive[currentHeight]->GetBlockHash().GetHex();
+            uint256 hash(uint256S(strHash));
+
+            if (mapBlockIndex.count(hash) == 0)
+                throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Block not found");
+
+            CBlock block;
+            CBlockIndex* pblockindex = mapBlockIndex[hash];
+
+            if (fHavePruned && !(pblockindex->nStatus & BLOCK_HAVE_DATA) && pblockindex->nTx > 0)
+                throw JSONRPCError(RPC_INTERNAL_ERROR, "Block not available (pruned data)");
+
+            if(!ReadBlockFromDisk(block, pblockindex,1))
+                throw JSONRPCError(RPC_INTERNAL_ERROR, "Can't read block from disk");
+
+            BOOST_FOREACH(const CTransaction&tx, block.vtx)
+            {
+                // delta = shielded outputs - shielded inputs
+                if(!tx.IsCoinBase()) {
+                    delta += tx.vShieldedOutput.size() - tx.vShieldedSpend.size();
+                }
+            }
+        }
     }
     return delta;
 }
@@ -3714,7 +3762,8 @@ UniValue z_anonsettxdelta(const UniValue& params, bool fHelp, const CPubKey& myp
     if (fHelp || params.size() != 1)
         throw runtime_error(
             "z_anonsettxdelta\n"
-            "\nReturns delta (difference) in the anonset for a given txid.\n"
+            "\nReturns delta (difference) in the anonset for a given txid. A delta > 0 increases the anonset,\n"
+            "\na delta < 0 reduces the anonset and a delta=0 leaves the anonset the same.\n"
             "\nArguments:\n"
             "1. \"txid\"    (string, required) The transaction id\n"
             "\nResult:\n"