From 85b33a211a8980647a6045c9e59382066632a7a5 Mon Sep 17 00:00:00 2001
From: Say Cheong <greymistcube@gmail.com>
Date: Thu, 28 Mar 2024 07:34:11 +0900
Subject: [PATCH 1/9] Moved GetBalance from IWorldState to external

---
 Libplanet.Action/State/IWorldExtensions.cs | 32 ++++++++++++++++++++++
 Libplanet.Action/State/IWorldState.cs      | 11 --------
 Libplanet.Action/State/World.cs            | 21 ++++----------
 Libplanet.Action/State/WorldBaseState.cs   | 10 -------
 Libplanet.Mocks/MockWorldState.cs          |  6 ----
 5 files changed, 37 insertions(+), 43 deletions(-)
 create mode 100644 Libplanet.Action/State/IWorldExtensions.cs

diff --git a/Libplanet.Action/State/IWorldExtensions.cs b/Libplanet.Action/State/IWorldExtensions.cs
new file mode 100644
index 00000000000..f7a21dce35c
--- /dev/null
+++ b/Libplanet.Action/State/IWorldExtensions.cs
@@ -0,0 +1,32 @@
+using System.Diagnostics.Contracts;
+using Bencodex.Types;
+using Libplanet.Crypto;
+using Libplanet.Types.Assets;
+using static Libplanet.Action.State.KeyConverters;
+
+namespace Libplanet.Action.State
+{
+    public static class IWorldExtensions
+    {
+        /// <summary>
+        /// Queries <paramref name="address"/>'s balance of the <paramref name="currency"/>.
+        /// </summary>
+        /// <param name="address">The owner address to query.</param>
+        /// <param name="currency">The currency type to query.</param>
+        /// <returns>
+        /// The <paramref name="address"/>'s balance of the <paramref name="currency"/>.
+        /// </returns>
+        [Pure]
+        public static FungibleAssetValue GetBalance(
+            this IWorldState worldState,
+            Address address,
+            Currency currency)
+        {
+            IAccountState account = worldState.GetAccountState(ReservedAddresses.LegacyAccount);
+            IValue? value = account.Trie.Get(ToFungibleAssetKey(address, currency));
+            return value is Integer i
+                ? FungibleAssetValue.FromRawValue(currency, i)
+                : currency * 0;
+        }
+    }
+}
diff --git a/Libplanet.Action/State/IWorldState.cs b/Libplanet.Action/State/IWorldState.cs
index a0231404f7b..0475e7917b2 100644
--- a/Libplanet.Action/State/IWorldState.cs
+++ b/Libplanet.Action/State/IWorldState.cs
@@ -52,17 +52,6 @@ public interface IWorldState
         [Pure]
         IAccountState GetAccountState(Address address);
 
-        /// <summary>
-        /// Queries <paramref name="address"/>'s balance of the <paramref name="currency"/>.
-        /// </summary>
-        /// <param name="address">The owner address to query.</param>
-        /// <param name="currency">The currency type to query.</param>
-        /// <returns>
-        /// The <paramref name="address"/>'s balance of the <paramref name="currency"/>.
-        /// </returns>
-        [Pure]
-        FungibleAssetValue GetBalance(Address address, Currency currency);
-
         /// <summary>
         /// Returns the total supply of a <paramref name="currency"/>.
         /// </summary>
diff --git a/Libplanet.Action/State/World.cs b/Libplanet.Action/State/World.cs
index d87916a3613..52c7305320d 100644
--- a/Libplanet.Action/State/World.cs
+++ b/Libplanet.Action/State/World.cs
@@ -1,5 +1,4 @@
 using System;
-using System.Collections.Immutable;
 using System.Diagnostics.Contracts;
 using System.Numerics;
 using Bencodex.Types;
@@ -68,16 +67,6 @@ public IWorld SetAccount(Address address, IAccount account)
             return new World(_baseState, Delta.SetAccount(address, account));
         }
 
-        /// <inheritdoc cref="IWorldState.GetBalance"/>
-        public FungibleAssetValue GetBalance(Address address, Currency currency)
-        {
-            IAccountState account = GetAccountState(ReservedAddresses.LegacyAccount);
-            IValue? value = account.Trie.Get(ToFungibleAssetKey(address, currency));
-            return value is Integer i
-                ? FungibleAssetValue.FromRawValue(currency, i)
-                : currency * 0;
-        }
-
         /// <inheritdoc cref="IWorldState.GetTotalSupply"/>
         public FungibleAssetValue GetTotalSupply(Currency currency)
         {
@@ -124,7 +113,7 @@ public IWorld MintAsset(IActionContext context, Address recipient, FungibleAsset
                 );
             }
 
-            FungibleAssetValue balance = GetBalance(recipient, currency);
+            FungibleAssetValue balance = this.GetBalance(recipient, currency);
             BigInteger rawBalance = (balance + value).RawValue;
 
             if (currency.TotalSupplyTrackable)
@@ -170,7 +159,7 @@ public IWorld BurnAsset(IActionContext context, Address owner, FungibleAssetValu
                 throw new CurrencyPermissionException(msg, context.Signer, currency);
             }
 
-            FungibleAssetValue balance = GetBalance(owner, currency);
+            FungibleAssetValue balance = this.GetBalance(owner, currency);
 
             if (balance < value)
             {
@@ -251,8 +240,8 @@ private IWorld TransferAssetV0(
             }
 
             Currency currency = value.Currency;
-            FungibleAssetValue senderBalance = GetBalance(sender, currency);
-            FungibleAssetValue recipientBalance = GetBalance(recipient, currency);
+            FungibleAssetValue senderBalance = this.GetBalance(sender, currency);
+            FungibleAssetValue recipientBalance = this.GetBalance(recipient, currency);
 
             if (!allowNegativeBalance && senderBalance < value)
             {
@@ -281,7 +270,7 @@ private IWorld TransferAssetV1(
             }
 
             Currency currency = value.Currency;
-            FungibleAssetValue senderBalance = GetBalance(sender, currency);
+            FungibleAssetValue senderBalance = this.GetBalance(sender, currency);
 
             if (!allowNegativeBalance && senderBalance < value)
             {
diff --git a/Libplanet.Action/State/WorldBaseState.cs b/Libplanet.Action/State/WorldBaseState.cs
index ace4de4c8f3..053f96d0600 100644
--- a/Libplanet.Action/State/WorldBaseState.cs
+++ b/Libplanet.Action/State/WorldBaseState.cs
@@ -49,16 +49,6 @@ public IAccountState GetAccountState(Address address)
             }
         }
 
-        /// <inheritdoc cref="IWorldState.GetBalance"/>
-        public FungibleAssetValue GetBalance(Address address, Currency currency)
-        {
-            IAccountState account = GetAccountState(ReservedAddresses.LegacyAccount);
-            IValue? value = account.Trie.Get(ToFungibleAssetKey(address, currency));
-            return value is Integer i
-                ? FungibleAssetValue.FromRawValue(currency, i)
-                : currency * 0;
-        }
-
         /// <inheritdoc cref="IWorldState.GetTotalSupply"/>
         public FungibleAssetValue GetTotalSupply(Currency currency)
         {
diff --git a/Libplanet.Mocks/MockWorldState.cs b/Libplanet.Mocks/MockWorldState.cs
index 301e281cdef..34b5706236b 100644
--- a/Libplanet.Mocks/MockWorldState.cs
+++ b/Libplanet.Mocks/MockWorldState.cs
@@ -97,12 +97,6 @@ public IAccountState GetAccountState(Address address) =>
                         ? _stateStore.GetStateRoot(new HashDigest<SHA256>(stateRootNotNull))
                         : _stateStore.GetStateRoot(null));
 
-        public FungibleAssetValue GetBalance(Address address, Currency currency) =>
-            GetAccountState(ReservedAddresses.LegacyAccount).Trie
-                .Get(ToFungibleAssetKey(address, currency)) is Integer i
-                    ? FungibleAssetValue.FromRawValue(currency, i)
-                    : currency * 0;
-
         public FungibleAssetValue GetTotalSupply(Currency currency) =>
             GetAccountState(ReservedAddresses.LegacyAccount).Trie
                 .Get(ToTotalSupplyKey(currency)) is Integer i

From 51a2e72b64c1c34a8ae2206fa4eb93377dff3616 Mon Sep 17 00:00:00 2001
From: Say Cheong <greymistcube@gmail.com>
Date: Thu, 28 Mar 2024 07:38:15 +0900
Subject: [PATCH 2/9] Moved GetTotalSupply from IWorldState to external

---
 Libplanet.Action/State/IWorldExtensions.cs | 26 ++++++++++++++++++++++
 Libplanet.Action/State/IWorldState.cs      | 12 ----------
 Libplanet.Action/State/World.cs            | 19 ++--------------
 Libplanet.Action/State/WorldBaseState.cs   | 15 -------------
 Libplanet.Mocks/MockWorldState.cs          |  6 -----
 5 files changed, 28 insertions(+), 50 deletions(-)

diff --git a/Libplanet.Action/State/IWorldExtensions.cs b/Libplanet.Action/State/IWorldExtensions.cs
index f7a21dce35c..e8b8018d6c3 100644
--- a/Libplanet.Action/State/IWorldExtensions.cs
+++ b/Libplanet.Action/State/IWorldExtensions.cs
@@ -28,5 +28,31 @@ public static FungibleAssetValue GetBalance(
                 ? FungibleAssetValue.FromRawValue(currency, i)
                 : currency * 0;
         }
+
+        /// <summary>
+        /// Returns the total supply of a <paramref name="currency"/>.
+        /// </summary>
+        /// <param name="currency">The currency type to query.</param>
+        /// <returns>The total supply of the <paramref name="currency"/>.
+        /// </returns>
+        /// <exception cref="TotalSupplyNotTrackableException">Thrown when the total supply of the
+        /// given <paramref name="currency"/> is not trackable.</exception>
+        /// <seealso cref="Currency.MaximumSupply"/>
+        [Pure]
+        public static FungibleAssetValue GetTotalSupply(
+            this IWorldState worldState,
+            Currency currency)
+        {
+            if (!currency.TotalSupplyTrackable)
+            {
+                throw TotalSupplyNotTrackableException.WithDefaultMessage(currency);
+            }
+
+            IAccountState account = worldState.GetAccountState(ReservedAddresses.LegacyAccount);
+            IValue? value = account.Trie.Get(ToTotalSupplyKey(currency));
+            return value is Integer i
+                ? FungibleAssetValue.FromRawValue(currency, i)
+                : currency * 0;
+        }
     }
 }
diff --git a/Libplanet.Action/State/IWorldState.cs b/Libplanet.Action/State/IWorldState.cs
index 0475e7917b2..e9589499e7e 100644
--- a/Libplanet.Action/State/IWorldState.cs
+++ b/Libplanet.Action/State/IWorldState.cs
@@ -52,18 +52,6 @@ public interface IWorldState
         [Pure]
         IAccountState GetAccountState(Address address);
 
-        /// <summary>
-        /// Returns the total supply of a <paramref name="currency"/>.
-        /// </summary>
-        /// <param name="currency">The currency type to query.</param>
-        /// <returns>The total supply of the <paramref name="currency"/>.
-        /// </returns>
-        /// <exception cref="TotalSupplyNotTrackableException">Thrown when the total supply of the
-        /// given <paramref name="currency"/> is not trackable.</exception>
-        /// <seealso cref="Currency.MaximumSupply"/>
-        [Pure]
-        FungibleAssetValue GetTotalSupply(Currency currency);
-
         /// <summary>
         /// Returns the validator set.
         /// </summary>
diff --git a/Libplanet.Action/State/World.cs b/Libplanet.Action/State/World.cs
index 52c7305320d..9ac3061cff0 100644
--- a/Libplanet.Action/State/World.cs
+++ b/Libplanet.Action/State/World.cs
@@ -67,21 +67,6 @@ public IWorld SetAccount(Address address, IAccount account)
             return new World(_baseState, Delta.SetAccount(address, account));
         }
 
-        /// <inheritdoc cref="IWorldState.GetTotalSupply"/>
-        public FungibleAssetValue GetTotalSupply(Currency currency)
-        {
-            if (!currency.TotalSupplyTrackable)
-            {
-                throw TotalSupplyNotTrackableException.WithDefaultMessage(currency);
-            }
-
-            IAccountState account = GetAccountState(ReservedAddresses.LegacyAccount);
-            IValue? value = account.Trie.Get(ToTotalSupplyKey(currency));
-            return value is Integer i
-                ? FungibleAssetValue.FromRawValue(currency, i)
-                : currency * 0;
-        }
-
         /// <inheritdoc cref="IWorldState.GetValidatorSet"/>
         public ValidatorSet GetValidatorSet()
         {
@@ -118,7 +103,7 @@ public IWorld MintAsset(IActionContext context, Address recipient, FungibleAsset
 
             if (currency.TotalSupplyTrackable)
             {
-                var currentTotalSupply = GetTotalSupply(currency);
+                var currentTotalSupply = this.GetTotalSupply(currency);
                 if (currency.MaximumSupply < currentTotalSupply + value)
                 {
                     var msg = $"The amount {value} attempted to be minted added to the current"
@@ -171,7 +156,7 @@ public IWorld BurnAsset(IActionContext context, Address owner, FungibleAssetValu
             BigInteger rawBalance = (balance - value).RawValue;
             if (currency.TotalSupplyTrackable)
             {
-                var currentTotalSupply = GetTotalSupply(currency);
+                var currentTotalSupply = this.GetTotalSupply(currency);
                 return UpdateFungibleAssets(
                     owner,
                     currency,
diff --git a/Libplanet.Action/State/WorldBaseState.cs b/Libplanet.Action/State/WorldBaseState.cs
index 053f96d0600..32d33a9fcb1 100644
--- a/Libplanet.Action/State/WorldBaseState.cs
+++ b/Libplanet.Action/State/WorldBaseState.cs
@@ -49,21 +49,6 @@ public IAccountState GetAccountState(Address address)
             }
         }
 
-        /// <inheritdoc cref="IWorldState.GetTotalSupply"/>
-        public FungibleAssetValue GetTotalSupply(Currency currency)
-        {
-            if (!currency.TotalSupplyTrackable)
-            {
-                throw TotalSupplyNotTrackableException.WithDefaultMessage(currency);
-            }
-
-            IAccountState account = GetAccountState(ReservedAddresses.LegacyAccount);
-            IValue? value = account.Trie.Get(ToTotalSupplyKey(currency));
-            return value is Integer i
-                ? FungibleAssetValue.FromRawValue(currency, i)
-                : currency * 0;
-        }
-
         /// <inheritdoc cref="IWorldState.GetValidatorSet"/>
         public ValidatorSet GetValidatorSet()
         {
diff --git a/Libplanet.Mocks/MockWorldState.cs b/Libplanet.Mocks/MockWorldState.cs
index 34b5706236b..2cd342c6c5b 100644
--- a/Libplanet.Mocks/MockWorldState.cs
+++ b/Libplanet.Mocks/MockWorldState.cs
@@ -97,12 +97,6 @@ public IAccountState GetAccountState(Address address) =>
                         ? _stateStore.GetStateRoot(new HashDigest<SHA256>(stateRootNotNull))
                         : _stateStore.GetStateRoot(null));
 
-        public FungibleAssetValue GetTotalSupply(Currency currency) =>
-            GetAccountState(ReservedAddresses.LegacyAccount).Trie
-                .Get(ToTotalSupplyKey(currency)) is Integer i
-                    ? FungibleAssetValue.FromRawValue(currency, i)
-                    : currency * 0;
-
         public ValidatorSet GetValidatorSet() =>
             GetAccountState(ReservedAddresses.LegacyAccount).Trie
                 .Get(ValidatorSetKey) is List l

From 91d3a1359eb078526264a52f50d7657b603f222b Mon Sep 17 00:00:00 2001
From: Say Cheong <greymistcube@gmail.com>
Date: Thu, 28 Mar 2024 07:59:57 +0900
Subject: [PATCH 3/9] Moved GetValidatorSet from IWorldState to external

---
 Libplanet.Action/State/IWorldExtensions.cs | 16 ++++++++++++++++
 Libplanet.Action/State/IWorldState.cs      |  8 --------
 Libplanet.Action/State/World.cs            | 12 +-----------
 Libplanet.Action/State/WorldBaseState.cs   | 10 ----------
 Libplanet.Mocks/MockWorldState.cs          |  6 ------
 5 files changed, 17 insertions(+), 35 deletions(-)

diff --git a/Libplanet.Action/State/IWorldExtensions.cs b/Libplanet.Action/State/IWorldExtensions.cs
index e8b8018d6c3..4fb465ae496 100644
--- a/Libplanet.Action/State/IWorldExtensions.cs
+++ b/Libplanet.Action/State/IWorldExtensions.cs
@@ -2,6 +2,7 @@
 using Bencodex.Types;
 using Libplanet.Crypto;
 using Libplanet.Types.Assets;
+using Libplanet.Types.Consensus;
 using static Libplanet.Action.State.KeyConverters;
 
 namespace Libplanet.Action.State
@@ -54,5 +55,20 @@ public static FungibleAssetValue GetTotalSupply(
                 ? FungibleAssetValue.FromRawValue(currency, i)
                 : currency * 0;
         }
+
+        /// <summary>
+        /// Returns the validator set.
+        /// </summary>
+        /// <returns>The validator set of type <see cref="ValidatorSet"/>.
+        /// </returns>
+        [Pure]
+        public static ValidatorSet GetValidatorSet(this IWorldState worldState)
+        {
+            IAccountState account = worldState.GetAccountState(ReservedAddresses.LegacyAccount);
+            IValue? value = account.Trie.Get(ValidatorSetKey);
+            return value is List list
+                ? new ValidatorSet(list)
+                : new ValidatorSet();
+        }
     }
 }
diff --git a/Libplanet.Action/State/IWorldState.cs b/Libplanet.Action/State/IWorldState.cs
index e9589499e7e..05b5be32004 100644
--- a/Libplanet.Action/State/IWorldState.cs
+++ b/Libplanet.Action/State/IWorldState.cs
@@ -51,13 +51,5 @@ public interface IWorldState
         /// instead.</returns>
         [Pure]
         IAccountState GetAccountState(Address address);
-
-        /// <summary>
-        /// Returns the validator set.
-        /// </summary>
-        /// <returns>The validator set of type <see cref="ValidatorSet"/>.
-        /// </returns>
-        [Pure]
-        ValidatorSet GetValidatorSet();
     }
 }
diff --git a/Libplanet.Action/State/World.cs b/Libplanet.Action/State/World.cs
index 9ac3061cff0..e1e7e3a109b 100644
--- a/Libplanet.Action/State/World.cs
+++ b/Libplanet.Action/State/World.cs
@@ -67,16 +67,6 @@ public IWorld SetAccount(Address address, IAccount account)
             return new World(_baseState, Delta.SetAccount(address, account));
         }
 
-        /// <inheritdoc cref="IWorldState.GetValidatorSet"/>
-        public ValidatorSet GetValidatorSet()
-        {
-            IAccountState account = GetAccountState(ReservedAddresses.LegacyAccount);
-            IValue? value = account.Trie.Get(ValidatorSetKey);
-            return value is List list
-                ? new ValidatorSet(list)
-                : new ValidatorSet();
-        }
-
         /// <inheritdoc cref="IWorld.MintAsset"/>
         public IWorld MintAsset(IActionContext context, Address recipient, FungibleAssetValue value)
         {
@@ -181,7 +171,7 @@ public IWorld TransferAsset(
 
         /// <inheritdoc cref="IWorld.SetValidator"/>
         public IWorld SetValidator(Validator validator) =>
-            UpdateValidatorSet(GetValidatorSet().Update(validator));
+            UpdateValidatorSet(this.GetValidatorSet().Update(validator));
 
         private IWorld UpdateFungibleAssets(
             Address address,
diff --git a/Libplanet.Action/State/WorldBaseState.cs b/Libplanet.Action/State/WorldBaseState.cs
index 32d33a9fcb1..4f920cefd7e 100644
--- a/Libplanet.Action/State/WorldBaseState.cs
+++ b/Libplanet.Action/State/WorldBaseState.cs
@@ -48,15 +48,5 @@ public IAccountState GetAccountState(Address address)
                     : new AccountState(_stateStore.GetStateRoot(null));
             }
         }
-
-        /// <inheritdoc cref="IWorldState.GetValidatorSet"/>
-        public ValidatorSet GetValidatorSet()
-        {
-            IAccountState account = GetAccountState(ReservedAddresses.LegacyAccount);
-            IValue? value = account.Trie.Get(ValidatorSetKey);
-            return value is List list
-                ? new ValidatorSet(list)
-                : new ValidatorSet();
-        }
     }
 }
diff --git a/Libplanet.Mocks/MockWorldState.cs b/Libplanet.Mocks/MockWorldState.cs
index 2cd342c6c5b..753bcaba738 100644
--- a/Libplanet.Mocks/MockWorldState.cs
+++ b/Libplanet.Mocks/MockWorldState.cs
@@ -97,12 +97,6 @@ public IAccountState GetAccountState(Address address) =>
                         ? _stateStore.GetStateRoot(new HashDigest<SHA256>(stateRootNotNull))
                         : _stateStore.GetStateRoot(null));
 
-        public ValidatorSet GetValidatorSet() =>
-            GetAccountState(ReservedAddresses.LegacyAccount).Trie
-                .Get(ValidatorSetKey) is List l
-                    ? new ValidatorSet(l)
-                    : new ValidatorSet();
-
         /// <summary>
         /// Converts <see cref="MockWorldState"/> to "modern" if <see cref="Legacy"/>
         /// is <see langword="true"/>.  Otherwise, does nothing.

From c51263cfea1f6e8ef9e93affc4578a91ec6dfee3 Mon Sep 17 00:00:00 2001
From: Say Cheong <greymistcube@gmail.com>
Date: Thu, 28 Mar 2024 10:45:58 +0900
Subject: [PATCH 4/9] Moved MintAsset from IWorld to external

---
 Libplanet.Action/State/IWorld.cs           | 22 ------
 Libplanet.Action/State/IWorldExtensions.cs | 92 ++++++++++++++++++++++
 Libplanet.Action/State/World.cs            | 47 -----------
 3 files changed, 92 insertions(+), 69 deletions(-)

diff --git a/Libplanet.Action/State/IWorld.cs b/Libplanet.Action/State/IWorld.cs
index 5746689f099..b54036cf1fc 100644
--- a/Libplanet.Action/State/IWorld.cs
+++ b/Libplanet.Action/State/IWorld.cs
@@ -77,28 +77,6 @@ public interface IWorld : IWorldState
         [Pure]
         IWorld SetAccount(Address address, IAccount account);
 
-        /// <summary>
-        /// Mints the fungible asset <paramref name="value"/> (i.e., in-game monetary),
-        /// and give it to the <paramref name="recipient"/>.
-        /// </summary>
-        /// <param name="context">The <see cref="IActionContext"/> of the <see cref="IAction"/>
-        /// executing this method.</param>
-        /// <param name="recipient">The address who receives the minted asset.</param>
-        /// <param name="value">The asset value to mint.</param>
-        /// <returns>A new <see cref="IWorld"/> instance that the given <paramref
-        /// name="value"/> is added to <paramref name="recipient"/>'s balance.</returns>
-        /// <exception cref="ArgumentOutOfRangeException">Thrown when the <paramref name="value"/>
-        /// is less than or equal to 0.</exception>
-        /// <exception cref="CurrencyPermissionException">Thrown when a transaction signer
-        /// (or a miner in case of block actions) is not a member of the <see
-        /// cref="FungibleAssetValue.Currency"/>'s <see cref="Currency.Minters"/>.</exception>
-        /// <exception cref="SupplyOverflowException">Thrown when the sum of the
-        /// <paramref name="value"/> to be minted and the current total supply amount of the
-        /// <see cref="FungibleAssetValue.Currency"/> exceeds the
-        /// <see cref="Currency.MaximumSupply"/>.</exception>
-        [Pure]
-        IWorld MintAsset(IActionContext context, Address recipient, FungibleAssetValue value);
-
         /// <summary>
         /// Burns the fungible asset <paramref name="value"/> (i.e., in-game monetary) from
         /// <paramref name="owner"/>'s balance.
diff --git a/Libplanet.Action/State/IWorldExtensions.cs b/Libplanet.Action/State/IWorldExtensions.cs
index 4fb465ae496..058ba349b81 100644
--- a/Libplanet.Action/State/IWorldExtensions.cs
+++ b/Libplanet.Action/State/IWorldExtensions.cs
@@ -1,4 +1,6 @@
+using System;
 using System.Diagnostics.Contracts;
+using System.Numerics;
 using Bencodex.Types;
 using Libplanet.Crypto;
 using Libplanet.Types.Assets;
@@ -30,6 +32,77 @@ public static FungibleAssetValue GetBalance(
                 : currency * 0;
         }
 
+        /// <summary>
+        /// Mints the fungible asset <paramref name="value"/> (i.e., in-game monetary),
+        /// and give it to the <paramref name="recipient"/>.
+        /// </summary>
+        /// <param name="context">The <see cref="IActionContext"/> of the <see cref="IAction"/>
+        /// executing this method.</param>
+        /// <param name="recipient">The address who receives the minted asset.</param>
+        /// <param name="value">The asset value to mint.</param>
+        /// <returns>A new <see cref="IWorld"/> instance that the given <paramref
+        /// name="value"/> is added to <paramref name="recipient"/>'s balance.</returns>
+        /// <exception cref="ArgumentOutOfRangeException">Thrown when the <paramref name="value"/>
+        /// is less than or equal to 0.</exception>
+        /// <exception cref="CurrencyPermissionException">Thrown when a transaction signer
+        /// (or a miner in case of block actions) is not a member of the <see
+        /// cref="FungibleAssetValue.Currency"/>'s <see cref="Currency.Minters"/>.</exception>
+        /// <exception cref="SupplyOverflowException">Thrown when the sum of the
+        /// <paramref name="value"/> to be minted and the current total supply amount of the
+        /// <see cref="FungibleAssetValue.Currency"/> exceeds the
+        /// <see cref="Currency.MaximumSupply"/>.</exception>
+        [Pure]
+        public static IWorld MintAsset(
+            this IWorld world,
+            IActionContext context,
+            Address recipient,
+            FungibleAssetValue value)
+        {
+            if (value.Sign <= 0)
+            {
+                throw new ArgumentOutOfRangeException(
+                    nameof(value),
+                    "The value to mint has to be greater than zero."
+                );
+            }
+
+            Currency currency = value.Currency;
+            if (!currency.AllowsToMint(context.Signer))
+            {
+                throw new CurrencyPermissionException(
+                    $"The account {context.Signer} has no permission to mint currency {currency}.",
+                    context.Signer,
+                    currency
+                );
+            }
+
+            FungibleAssetValue balance = GetBalance(world, recipient, currency);
+            BigInteger rawBalance = (balance + value).RawValue;
+
+            if (currency.TotalSupplyTrackable)
+            {
+                var currentTotalSupply = GetTotalSupply(world, currency);
+                if (currency.MaximumSupply < currentTotalSupply + value)
+                {
+                    var msg = $"The amount {value} attempted to be minted added to the current"
+                              + $" total supply of {currentTotalSupply} exceeds the"
+                              + $" maximum allowed supply of {currency.MaximumSupply}.";
+                    throw new SupplyOverflowException(msg, value);
+                }
+
+                return UpdateFungibleAssets(
+                    world,
+                    recipient,
+                    currency,
+                    rawBalance,
+                    (currentTotalSupply + value).RawValue);
+            }
+            else
+            {
+                return UpdateFungibleAssets(world, recipient, currency, rawBalance);
+            }
+        }
+
         /// <summary>
         /// Returns the total supply of a <paramref name="currency"/>.
         /// </summary>
@@ -70,5 +143,24 @@ public static ValidatorSet GetValidatorSet(this IWorldState worldState)
                 ? new ValidatorSet(list)
                 : new ValidatorSet();
         }
+
+        private static IWorld UpdateFungibleAssets(
+            IWorld world,
+            Address address,
+            Currency currency,
+            BigInteger amount,
+            BigInteger? supplyAmount = null)
+        {
+            IAccount account = supplyAmount is { } sa
+                ? new Account(new AccountState(
+                    world.GetAccount(ReservedAddresses.LegacyAccount).Trie
+                        .Set(ToFungibleAssetKey(address, currency), new Integer(amount))
+                        .Set(ToTotalSupplyKey(currency), new Integer(sa))))
+                : new Account(new AccountState(
+                    world.GetAccount(ReservedAddresses.LegacyAccount).Trie
+                        .Set(ToFungibleAssetKey(address, currency), new Integer(amount))));
+
+            return world.SetAccount(ReservedAddresses.LegacyAccount, account);
+        }
     }
 }
diff --git a/Libplanet.Action/State/World.cs b/Libplanet.Action/State/World.cs
index e1e7e3a109b..ca8c320be5f 100644
--- a/Libplanet.Action/State/World.cs
+++ b/Libplanet.Action/State/World.cs
@@ -67,53 +67,6 @@ public IWorld SetAccount(Address address, IAccount account)
             return new World(_baseState, Delta.SetAccount(address, account));
         }
 
-        /// <inheritdoc cref="IWorld.MintAsset"/>
-        public IWorld MintAsset(IActionContext context, Address recipient, FungibleAssetValue value)
-        {
-            if (value.Sign <= 0)
-            {
-                throw new ArgumentOutOfRangeException(
-                    nameof(value),
-                    "The value to mint has to be greater than zero."
-                );
-            }
-
-            Currency currency = value.Currency;
-            if (!currency.AllowsToMint(context.Signer))
-            {
-                throw new CurrencyPermissionException(
-                    $"The account {context.Signer} has no permission to mint currency {currency}.",
-                    context.Signer,
-                    currency
-                );
-            }
-
-            FungibleAssetValue balance = this.GetBalance(recipient, currency);
-            BigInteger rawBalance = (balance + value).RawValue;
-
-            if (currency.TotalSupplyTrackable)
-            {
-                var currentTotalSupply = this.GetTotalSupply(currency);
-                if (currency.MaximumSupply < currentTotalSupply + value)
-                {
-                    var msg = $"The amount {value} attempted to be minted added to the current"
-                              + $" total supply of {currentTotalSupply} exceeds the"
-                              + $" maximum allowed supply of {currency.MaximumSupply}.";
-                    throw new SupplyOverflowException(msg, value);
-                }
-
-                return UpdateFungibleAssets(
-                    recipient,
-                    currency,
-                    rawBalance,
-                    (currentTotalSupply + value).RawValue);
-            }
-            else
-            {
-                return UpdateFungibleAssets(recipient, currency, rawBalance);
-            }
-        }
-
         /// <inheritdoc cref="IWorld.BurnAsset"/>
         public IWorld BurnAsset(IActionContext context, Address owner, FungibleAssetValue value)
         {

From fa9a10860972b47e94c7d74d1f9c87ebb9956f2a Mon Sep 17 00:00:00 2001
From: Say Cheong <greymistcube@gmail.com>
Date: Thu, 28 Mar 2024 10:48:58 +0900
Subject: [PATCH 5/9] Moved BurnAsset from IWorld to external

---
 Libplanet.Action/State/IWorld.cs           | 20 -------
 Libplanet.Action/State/IWorldExtensions.cs | 67 ++++++++++++++++++++++
 Libplanet.Action/State/World.cs            | 45 ---------------
 3 files changed, 67 insertions(+), 65 deletions(-)

diff --git a/Libplanet.Action/State/IWorld.cs b/Libplanet.Action/State/IWorld.cs
index b54036cf1fc..ed15156ea2c 100644
--- a/Libplanet.Action/State/IWorld.cs
+++ b/Libplanet.Action/State/IWorld.cs
@@ -77,26 +77,6 @@ public interface IWorld : IWorldState
         [Pure]
         IWorld SetAccount(Address address, IAccount account);
 
-        /// <summary>
-        /// Burns the fungible asset <paramref name="value"/> (i.e., in-game monetary) from
-        /// <paramref name="owner"/>'s balance.
-        /// </summary>
-        /// <param name="context">The <see cref="IActionContext"/> of the <see cref="IAction"/>
-        /// executing this method.</param>
-        /// <param name="owner">The address who owns the fungible asset to burn.</param>
-        /// <param name="value">The fungible asset <paramref name="value"/> to burn.</param>
-        /// <returns>A new <see cref="IWorld"/> instance that the given <paramref
-        /// name="value"/> is subtracted from <paramref name="owner"/>'s balance.</returns>
-        /// <exception cref="ArgumentOutOfRangeException">Thrown when the <paramref name="value"/>
-        /// is less than or equal to zero.</exception>
-        /// <exception cref="CurrencyPermissionException">Thrown when a transaction signer
-        /// (or a miner in case of block actions) is not a member of the <see
-        /// cref="FungibleAssetValue.Currency"/>'s <see cref="Currency.Minters"/>.</exception>
-        /// <exception cref="InsufficientBalanceException">Thrown when the <paramref name="owner"/>
-        /// has insufficient balance than <paramref name="value"/> to burn.</exception>
-        [Pure]
-        IWorld BurnAsset(IActionContext context, Address owner, FungibleAssetValue value);
-
         /// <summary>
         /// Transfers the fungible asset <paramref name="value"/> (i.e., in-game monetary)
         /// from the <paramref name="sender"/> to the <paramref name="recipient"/>.
diff --git a/Libplanet.Action/State/IWorldExtensions.cs b/Libplanet.Action/State/IWorldExtensions.cs
index 058ba349b81..3f6f94ea53a 100644
--- a/Libplanet.Action/State/IWorldExtensions.cs
+++ b/Libplanet.Action/State/IWorldExtensions.cs
@@ -103,6 +103,73 @@ public static IWorld MintAsset(
             }
         }
 
+        /// <summary>
+        /// Burns the fungible asset <paramref name="value"/> (i.e., in-game monetary) from
+        /// <paramref name="owner"/>'s balance.
+        /// </summary>
+        /// <param name="context">The <see cref="IActionContext"/> of the <see cref="IAction"/>
+        /// executing this method.</param>
+        /// <param name="owner">The address who owns the fungible asset to burn.</param>
+        /// <param name="value">The fungible asset <paramref name="value"/> to burn.</param>
+        /// <returns>A new <see cref="IWorld"/> instance that the given <paramref
+        /// name="value"/> is subtracted from <paramref name="owner"/>'s balance.</returns>
+        /// <exception cref="ArgumentOutOfRangeException">Thrown when the <paramref name="value"/>
+        /// is less than or equal to zero.</exception>
+        /// <exception cref="CurrencyPermissionException">Thrown when a transaction signer
+        /// (or a miner in case of block actions) is not a member of the <see
+        /// cref="FungibleAssetValue.Currency"/>'s <see cref="Currency.Minters"/>.</exception>
+        /// <exception cref="InsufficientBalanceException">Thrown when the <paramref name="owner"/>
+        /// has insufficient balance than <paramref name="value"/> to burn.</exception>
+        [Pure]
+        public static IWorld BurnAsset(
+            this IWorld world,
+            IActionContext context,
+            Address owner,
+            FungibleAssetValue value)
+        {
+            string msg;
+            if (value.Sign <= 0)
+            {
+                throw new ArgumentOutOfRangeException(
+                    nameof(value),
+                    "The value to burn has to be greater than zero."
+                );
+            }
+
+            Currency currency = value.Currency;
+            if (!currency.AllowsToMint(context.Signer))
+            {
+                msg = $"The account {context.Signer} has no permission to burn assets of " +
+                      $"the currency {currency}.";
+                throw new CurrencyPermissionException(msg, context.Signer, currency);
+            }
+
+            FungibleAssetValue balance = world.GetBalance(owner, currency);
+
+            if (balance < value)
+            {
+                msg = $"The account {owner}'s balance of {currency} is insufficient to burn: " +
+                      $"{balance} < {value}.";
+                throw new InsufficientBalanceException(msg, owner, balance);
+            }
+
+            BigInteger rawBalance = (balance - value).RawValue;
+            if (currency.TotalSupplyTrackable)
+            {
+                var currentTotalSupply = world.GetTotalSupply(currency);
+                return UpdateFungibleAssets(
+                    world,
+                    owner,
+                    currency,
+                    rawBalance,
+                    (currentTotalSupply - value).RawValue);
+            }
+            else
+            {
+                return UpdateFungibleAssets(world, owner, currency, rawBalance);
+            }
+        }
+
         /// <summary>
         /// Returns the total supply of a <paramref name="currency"/>.
         /// </summary>
diff --git a/Libplanet.Action/State/World.cs b/Libplanet.Action/State/World.cs
index ca8c320be5f..a4bf5d3c725 100644
--- a/Libplanet.Action/State/World.cs
+++ b/Libplanet.Action/State/World.cs
@@ -67,51 +67,6 @@ public IWorld SetAccount(Address address, IAccount account)
             return new World(_baseState, Delta.SetAccount(address, account));
         }
 
-        /// <inheritdoc cref="IWorld.BurnAsset"/>
-        public IWorld BurnAsset(IActionContext context, Address owner, FungibleAssetValue value)
-        {
-            string msg;
-            if (value.Sign <= 0)
-            {
-                throw new ArgumentOutOfRangeException(
-                    nameof(value),
-                    "The value to burn has to be greater than zero."
-                );
-            }
-
-            Currency currency = value.Currency;
-            if (!currency.AllowsToMint(context.Signer))
-            {
-                msg = $"The account {context.Signer} has no permission to burn assets of " +
-                      $"the currency {currency}.";
-                throw new CurrencyPermissionException(msg, context.Signer, currency);
-            }
-
-            FungibleAssetValue balance = this.GetBalance(owner, currency);
-
-            if (balance < value)
-            {
-                msg = $"The account {owner}'s balance of {currency} is insufficient to burn: " +
-                      $"{balance} < {value}.";
-                throw new InsufficientBalanceException(msg, owner, balance);
-            }
-
-            BigInteger rawBalance = (balance - value).RawValue;
-            if (currency.TotalSupplyTrackable)
-            {
-                var currentTotalSupply = this.GetTotalSupply(currency);
-                return UpdateFungibleAssets(
-                    owner,
-                    currency,
-                    rawBalance,
-                    (currentTotalSupply - value).RawValue);
-            }
-            else
-            {
-                return UpdateFungibleAssets(owner, currency, rawBalance);
-            }
-        }
-
         /// <inheritdoc cref="IWorld.TransferAsset"/>
         public IWorld TransferAsset(
             IActionContext context,

From 9788ca9c6fdaac1fd46b36c1aea551ee645b684c Mon Sep 17 00:00:00 2001
From: Say Cheong <greymistcube@gmail.com>
Date: Thu, 28 Mar 2024 11:19:06 +0900
Subject: [PATCH 6/9] Moved TransferAsset from IWorld to external

---
 Libplanet.Action/State/IWorld.cs           |  37 --------
 Libplanet.Action/State/IWorldExtensions.cs | 104 +++++++++++++++++++++
 Libplanet.Action/State/IWorldState.cs      |   2 -
 Libplanet.Action/State/World.cs            |  91 ------------------
 Libplanet.Action/State/WorldBaseState.cs   |   2 -
 5 files changed, 104 insertions(+), 132 deletions(-)

diff --git a/Libplanet.Action/State/IWorld.cs b/Libplanet.Action/State/IWorld.cs
index ed15156ea2c..633376f4597 100644
--- a/Libplanet.Action/State/IWorld.cs
+++ b/Libplanet.Action/State/IWorld.cs
@@ -1,9 +1,7 @@
 using System;
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Diagnostics.Contracts;
 using Libplanet.Crypto;
-using Libplanet.Types.Assets;
 using Libplanet.Types.Consensus;
 
 namespace Libplanet.Action.State
@@ -77,41 +75,6 @@ public interface IWorld : IWorldState
         [Pure]
         IWorld SetAccount(Address address, IAccount account);
 
-        /// <summary>
-        /// Transfers the fungible asset <paramref name="value"/> (i.e., in-game monetary)
-        /// from the <paramref name="sender"/> to the <paramref name="recipient"/>.
-        /// </summary>
-        /// <param name="context">The <see cref="IActionContext"/> of the <see cref="IAction"/>
-        /// executing this method.</param>
-        /// <param name="sender">The address who sends the fungible asset to
-        /// the <paramref name="recipient"/>.</param>
-        /// <param name="recipient">The address who receives the fungible asset from
-        /// the <paramref name="sender"/>.</param>
-        /// <param name="value">The asset value to transfer.</param>
-        /// <param name="allowNegativeBalance">Turn on to allow <paramref name="sender"/>'s balance
-        /// less than zero.  Turned off by default.</param>
-        /// <returns>A new <see cref="IWorld"/> instance that the given <paramref
-        /// name="value"/>  is subtracted from <paramref name="sender"/>'s balance and added to
-        /// <paramref name="recipient"/>'s balance.</returns>
-        /// <exception cref="ArgumentOutOfRangeException">Thrown when the <paramref name="value"/>
-        /// is less than or equal to zero.</exception>
-        /// <exception cref="InsufficientBalanceException">Thrown when the <paramref name="sender"/>
-        /// has insufficient balance than <paramref name="value"/> to transfer and
-        /// the <paramref name="allowNegativeBalance"/> option is turned off.</exception>
-        /// <remarks>
-        /// The behavior is different depending on <paramref name="context"/>'s
-        /// <see cref="IActionContext.BlockProtocolVersion"/>.  There is a bug for version 0
-        /// where this may not act as intended.  Such behavior is left intact for backward
-        /// compatibility.
-        /// </remarks>
-        [Pure]
-        IWorld TransferAsset(
-            IActionContext context,
-            Address sender,
-            Address recipient,
-            FungibleAssetValue value,
-            bool allowNegativeBalance = false);
-
         /// <summary>
         /// Sets <paramref name="validator"/> to the stored <see cref="ValidatorSet"/>.
         /// If 0 is given as its power, removes the validator from the <see cref="ValidatorSet"/>.
diff --git a/Libplanet.Action/State/IWorldExtensions.cs b/Libplanet.Action/State/IWorldExtensions.cs
index 3f6f94ea53a..d116d6c337d 100644
--- a/Libplanet.Action/State/IWorldExtensions.cs
+++ b/Libplanet.Action/State/IWorldExtensions.cs
@@ -170,6 +170,44 @@ public static IWorld BurnAsset(
             }
         }
 
+        /// <summary>
+        /// Transfers the fungible asset <paramref name="value"/> (i.e., in-game monetary)
+        /// from the <paramref name="sender"/> to the <paramref name="recipient"/>.
+        /// </summary>
+        /// <param name="context">The <see cref="IActionContext"/> of the <see cref="IAction"/>
+        /// executing this method.</param>
+        /// <param name="sender">The address who sends the fungible asset to
+        /// the <paramref name="recipient"/>.</param>
+        /// <param name="recipient">The address who receives the fungible asset from
+        /// the <paramref name="sender"/>.</param>
+        /// <param name="value">The asset value to transfer.</param>
+        /// <param name="allowNegativeBalance">Turn on to allow <paramref name="sender"/>'s balance
+        /// less than zero.  Turned off by default.</param>
+        /// <returns>A new <see cref="IWorld"/> instance that the given <paramref
+        /// name="value"/>  is subtracted from <paramref name="sender"/>'s balance and added to
+        /// <paramref name="recipient"/>'s balance.</returns>
+        /// <exception cref="ArgumentOutOfRangeException">Thrown when the <paramref name="value"/>
+        /// is less than or equal to zero.</exception>
+        /// <exception cref="InsufficientBalanceException">Thrown when the <paramref name="sender"/>
+        /// has insufficient balance than <paramref name="value"/> to transfer and
+        /// the <paramref name="allowNegativeBalance"/> option is turned off.</exception>
+        /// <remarks>
+        /// The behavior is different depending on <paramref name="context"/>'s
+        /// <see cref="IActionContext.BlockProtocolVersion"/>.  There is a bug for version 0
+        /// where this may not act as intended.  Such behavior is left intact for backward
+        /// compatibility.
+        /// </remarks>
+        [Pure]
+        public static IWorld TransferAsset(
+            this IWorld world,
+            IActionContext context,
+            Address sender,
+            Address recipient,
+            FungibleAssetValue value,
+            bool allowNegativeBalance = false) => context.BlockProtocolVersion > 0
+                ? TransferAssetV1(world, sender, recipient, value, allowNegativeBalance)
+                : TransferAssetV0(world, sender, recipient, value, allowNegativeBalance);
+
         /// <summary>
         /// Returns the total supply of a <paramref name="currency"/>.
         /// </summary>
@@ -229,5 +267,71 @@ private static IWorld UpdateFungibleAssets(
 
             return world.SetAccount(ReservedAddresses.LegacyAccount, account);
         }
+
+        private static IWorld TransferAssetV0(
+            IWorld world,
+            Address sender,
+            Address recipient,
+            FungibleAssetValue value,
+            bool allowNegativeBalance = false)
+        {
+            if (value.Sign <= 0)
+            {
+                throw new ArgumentOutOfRangeException(
+                    nameof(value),
+                    "The value to transfer has to be greater than zero."
+                );
+            }
+
+            Currency currency = value.Currency;
+            FungibleAssetValue senderBalance = world.GetBalance(sender, currency);
+            FungibleAssetValue recipientBalance = world.GetBalance(recipient, currency);
+
+            if (!allowNegativeBalance && senderBalance < value)
+            {
+                var msg = $"The account {sender}'s balance of {currency} is insufficient to " +
+                          $"transfer: {senderBalance} < {value}.";
+                throw new InsufficientBalanceException(msg, sender, senderBalance);
+            }
+
+            IWorld intermediate = UpdateFungibleAssets(
+                world, sender, currency, (senderBalance - value).RawValue);
+            return UpdateFungibleAssets(
+                intermediate, recipient, currency, (recipientBalance + value).RawValue);
+        }
+
+        [Pure]
+        private static IWorld TransferAssetV1(
+            IWorld world,
+            Address sender,
+            Address recipient,
+            FungibleAssetValue value,
+            bool allowNegativeBalance = false)
+        {
+            if (value.Sign <= 0)
+            {
+                throw new ArgumentOutOfRangeException(
+                    nameof(value),
+                    "The value to transfer has to be greater than zero."
+                );
+            }
+
+            Currency currency = value.Currency;
+            FungibleAssetValue senderBalance = world.GetBalance(sender, currency);
+
+            if (!allowNegativeBalance && senderBalance < value)
+            {
+                var msg = $"The account {sender}'s balance of {currency} is insufficient to " +
+                          $"transfer: {senderBalance} < {value}.";
+                throw new InsufficientBalanceException(msg, sender, senderBalance);
+            }
+
+            BigInteger senderRawBalance = (senderBalance - value).RawValue;
+            IWorld intermediate = UpdateFungibleAssets(world, sender, currency, senderRawBalance);
+            FungibleAssetValue recipientBalance = intermediate.GetBalance(recipient, currency);
+            BigInteger recipientRawBalance = (recipientBalance + value).RawValue;
+
+            return UpdateFungibleAssets(intermediate, recipient, currency, recipientRawBalance);
+        }
     }
 }
diff --git a/Libplanet.Action/State/IWorldState.cs b/Libplanet.Action/State/IWorldState.cs
index 05b5be32004..2ed9dbce3a4 100644
--- a/Libplanet.Action/State/IWorldState.cs
+++ b/Libplanet.Action/State/IWorldState.cs
@@ -2,8 +2,6 @@
 using System.Diagnostics.Contracts;
 using Libplanet.Crypto;
 using Libplanet.Store.Trie;
-using Libplanet.Types.Assets;
-using Libplanet.Types.Consensus;
 
 namespace Libplanet.Action.State
 {
diff --git a/Libplanet.Action/State/World.cs b/Libplanet.Action/State/World.cs
index a4bf5d3c725..cdbd51c0803 100644
--- a/Libplanet.Action/State/World.cs
+++ b/Libplanet.Action/State/World.cs
@@ -67,38 +67,10 @@ public IWorld SetAccount(Address address, IAccount account)
             return new World(_baseState, Delta.SetAccount(address, account));
         }
 
-        /// <inheritdoc cref="IWorld.TransferAsset"/>
-        public IWorld TransferAsset(
-            IActionContext context,
-            Address sender,
-            Address recipient,
-            FungibleAssetValue value,
-            bool allowNegativeBalance = false) => context.BlockProtocolVersion > 0
-                ? TransferAssetV1(sender, recipient, value, allowNegativeBalance)
-                : TransferAssetV0(sender, recipient, value, allowNegativeBalance);
-
         /// <inheritdoc cref="IWorld.SetValidator"/>
         public IWorld SetValidator(Validator validator) =>
             UpdateValidatorSet(this.GetValidatorSet().Update(validator));
 
-        private IWorld UpdateFungibleAssets(
-            Address address,
-            Currency currency,
-            BigInteger amount,
-            BigInteger? supplyAmount = null)
-        {
-            IAccount account = supplyAmount is { } sa
-                ? new Account(new AccountState(
-                    GetAccount(ReservedAddresses.LegacyAccount).Trie
-                        .Set(ToFungibleAssetKey(address, currency), new Integer(amount))
-                        .Set(ToTotalSupplyKey(currency), new Integer(sa))))
-                : new Account(new AccountState(
-                    GetAccount(ReservedAddresses.LegacyAccount).Trie
-                        .Set(ToFungibleAssetKey(address, currency), new Integer(amount))));
-
-            return SetAccount(ReservedAddresses.LegacyAccount, account);
-        }
-
         private IWorld UpdateValidatorSet(ValidatorSet validatorSet)
         {
             IAccount account = GetAccount(ReservedAddresses.LegacyAccount);
@@ -107,68 +79,5 @@ private IWorld UpdateValidatorSet(ValidatorSet validatorSet)
                 new Account(new AccountState(
                     account.Trie.Set(ValidatorSetKey, validatorSet.Bencoded))));
         }
-
-        private IWorld TransferAssetV0(
-            Address sender,
-            Address recipient,
-            FungibleAssetValue value,
-            bool allowNegativeBalance = false)
-        {
-            if (value.Sign <= 0)
-            {
-                throw new ArgumentOutOfRangeException(
-                    nameof(value),
-                    "The value to transfer has to be greater than zero."
-                );
-            }
-
-            Currency currency = value.Currency;
-            FungibleAssetValue senderBalance = this.GetBalance(sender, currency);
-            FungibleAssetValue recipientBalance = this.GetBalance(recipient, currency);
-
-            if (!allowNegativeBalance && senderBalance < value)
-            {
-                var msg = $"The account {sender}'s balance of {currency} is insufficient to " +
-                          $"transfer: {senderBalance} < {value}.";
-                throw new InsufficientBalanceException(msg, sender, senderBalance);
-            }
-
-            return ((World)UpdateFungibleAssets(sender, currency, (senderBalance - value).RawValue))
-                .UpdateFungibleAssets(recipient, currency, (recipientBalance + value).RawValue);
-        }
-
-        [Pure]
-        private IWorld TransferAssetV1(
-            Address sender,
-            Address recipient,
-            FungibleAssetValue value,
-            bool allowNegativeBalance = false)
-        {
-            if (value.Sign <= 0)
-            {
-                throw new ArgumentOutOfRangeException(
-                    nameof(value),
-                    "The value to transfer has to be greater than zero."
-                );
-            }
-
-            Currency currency = value.Currency;
-            FungibleAssetValue senderBalance = this.GetBalance(sender, currency);
-
-            if (!allowNegativeBalance && senderBalance < value)
-            {
-                var msg = $"The account {sender}'s balance of {currency} is insufficient to " +
-                          $"transfer: {senderBalance} < {value}.";
-                throw new InsufficientBalanceException(msg, sender, senderBalance);
-            }
-
-            BigInteger senderRawBalance = (senderBalance - value).RawValue;
-            IWorld intermediate = UpdateFungibleAssets(sender, currency, senderRawBalance);
-            FungibleAssetValue recipientBalance = intermediate.GetBalance(recipient, currency);
-            BigInteger recipientRawBalance = (recipientBalance + value).RawValue;
-
-            return ((World)intermediate).UpdateFungibleAssets(
-                recipient, currency, recipientRawBalance);
-        }
     }
 }
diff --git a/Libplanet.Action/State/WorldBaseState.cs b/Libplanet.Action/State/WorldBaseState.cs
index 4f920cefd7e..997ac86f4d1 100644
--- a/Libplanet.Action/State/WorldBaseState.cs
+++ b/Libplanet.Action/State/WorldBaseState.cs
@@ -4,8 +4,6 @@
 using Libplanet.Crypto;
 using Libplanet.Store;
 using Libplanet.Store.Trie;
-using Libplanet.Types.Assets;
-using Libplanet.Types.Consensus;
 using static Libplanet.Action.State.KeyConverters;
 
 namespace Libplanet.Action.State

From abd22579ecb93ff79c920bd2a9b85ed763ef4b1a Mon Sep 17 00:00:00 2001
From: Say Cheong <greymistcube@gmail.com>
Date: Thu, 28 Mar 2024 11:29:15 +0900
Subject: [PATCH 7/9] Moved SetValidator from IWorld to external

---
 Libplanet.Action/ActionEvaluator.cs        |  6 ++----
 Libplanet.Action/State/IWorld.cs           | 11 -----------
 Libplanet.Action/State/IWorldExtensions.cs | 23 ++++++++++++++++++++++
 Libplanet.Action/State/World.cs            | 20 +------------------
 4 files changed, 26 insertions(+), 34 deletions(-)

diff --git a/Libplanet.Action/ActionEvaluator.cs b/Libplanet.Action/ActionEvaluator.cs
index 4bc94099e60..f5fe07d8e00 100644
--- a/Libplanet.Action/ActionEvaluator.cs
+++ b/Libplanet.Action/ActionEvaluator.cs
@@ -575,8 +575,7 @@ private static IWorld CommitLegacyWorld(IWorld prevWorld, IStateStore stateStore
             return new World(
                 new WorldBaseState(
                     stateStore.Commit(prevWorld.GetAccount(ReservedAddresses.LegacyAccount).Trie),
-                    stateStore),
-                new WorldDelta());
+                    stateStore));
         }
 
         private static IWorld CommitWorld(IWorld prevWorld, IStateStore stateStore)
@@ -590,8 +589,7 @@ private static IWorld CommitWorld(IWorld prevWorld, IStateStore stateStore)
             }
 
             return new World(
-                new WorldBaseState(stateStore.Commit(worldTrie), stateStore),
-                new WorldDelta());
+                new WorldBaseState(stateStore.Commit(worldTrie), stateStore));
         }
 
         [Pure]
diff --git a/Libplanet.Action/State/IWorld.cs b/Libplanet.Action/State/IWorld.cs
index 633376f4597..96d44413f91 100644
--- a/Libplanet.Action/State/IWorld.cs
+++ b/Libplanet.Action/State/IWorld.cs
@@ -2,7 +2,6 @@
 using System.Collections.Generic;
 using System.Diagnostics.Contracts;
 using Libplanet.Crypto;
-using Libplanet.Types.Consensus;
 
 namespace Libplanet.Action.State
 {
@@ -74,15 +73,5 @@ public interface IWorld : IWorldState
         /// </exception>
         [Pure]
         IWorld SetAccount(Address address, IAccount account);
-
-        /// <summary>
-        /// Sets <paramref name="validator"/> to the stored <see cref="ValidatorSet"/>.
-        /// If 0 is given as its power, removes the validator from the <see cref="ValidatorSet"/>.
-        /// </summary>
-        /// <param name="validator">The <see cref="Validator"/> instance to write.</param>
-        /// <returns>A new <see cref="IWorld"/> instance with
-        /// <paramref name="validator"/> set.</returns>
-        [Pure]
-        IWorld SetValidator(Validator validator);
     }
 }
diff --git a/Libplanet.Action/State/IWorldExtensions.cs b/Libplanet.Action/State/IWorldExtensions.cs
index d116d6c337d..d534d8ba1db 100644
--- a/Libplanet.Action/State/IWorldExtensions.cs
+++ b/Libplanet.Action/State/IWorldExtensions.cs
@@ -249,6 +249,18 @@ public static ValidatorSet GetValidatorSet(this IWorldState worldState)
                 : new ValidatorSet();
         }
 
+        /// <summary>
+        /// Sets <paramref name="validator"/> to the stored <see cref="ValidatorSet"/>.
+        /// If 0 is given as its power, removes the validator from the <see cref="ValidatorSet"/>.
+        /// </summary>
+        /// <param name="validator">The <see cref="Validator"/> instance to write.</param>
+        /// <returns>A new <see cref="IWorld"/> instance with
+        /// <paramref name="validator"/> set.</returns>
+        [Pure]
+        public static IWorld SetValidator(this IWorld world, Validator validator) =>
+            UpdateValidatorSet(world, world.GetValidatorSet().Update(validator));
+
+        [Pure]
         private static IWorld UpdateFungibleAssets(
             IWorld world,
             Address address,
@@ -268,6 +280,7 @@ private static IWorld UpdateFungibleAssets(
             return world.SetAccount(ReservedAddresses.LegacyAccount, account);
         }
 
+        [Pure]
         private static IWorld TransferAssetV0(
             IWorld world,
             Address sender,
@@ -333,5 +346,15 @@ private static IWorld TransferAssetV1(
 
             return UpdateFungibleAssets(intermediate, recipient, currency, recipientRawBalance);
         }
+
+        [Pure]
+        private static IWorld UpdateValidatorSet(IWorld world, ValidatorSet validatorSet)
+        {
+            IAccount account = world.GetAccount(ReservedAddresses.LegacyAccount);
+            return world.SetAccount(
+                ReservedAddresses.LegacyAccount,
+                new Account(new AccountState(
+                    account.Trie.Set(ValidatorSetKey, validatorSet.Bencoded))));
+        }
     }
 }
diff --git a/Libplanet.Action/State/World.cs b/Libplanet.Action/State/World.cs
index cdbd51c0803..c0c9de8b95f 100644
--- a/Libplanet.Action/State/World.cs
+++ b/Libplanet.Action/State/World.cs
@@ -1,12 +1,7 @@
 using System;
 using System.Diagnostics.Contracts;
-using System.Numerics;
-using Bencodex.Types;
 using Libplanet.Crypto;
 using Libplanet.Store.Trie;
-using Libplanet.Types.Assets;
-using Libplanet.Types.Consensus;
-using static Libplanet.Action.State.KeyConverters;
 
 namespace Libplanet.Action.State
 {
@@ -23,7 +18,7 @@ public World(IWorldState baseState)
         {
         }
 
-        public World(IWorldState baseState, IWorldDelta delta)
+        private World(IWorldState baseState, IWorldDelta delta)
         {
             _baseState = baseState;
             Delta = delta;
@@ -66,18 +61,5 @@ public IWorld SetAccount(Address address, IAccount account)
 
             return new World(_baseState, Delta.SetAccount(address, account));
         }
-
-        /// <inheritdoc cref="IWorld.SetValidator"/>
-        public IWorld SetValidator(Validator validator) =>
-            UpdateValidatorSet(this.GetValidatorSet().Update(validator));
-
-        private IWorld UpdateValidatorSet(ValidatorSet validatorSet)
-        {
-            IAccount account = GetAccount(ReservedAddresses.LegacyAccount);
-            return SetAccount(
-                ReservedAddresses.LegacyAccount,
-                new Account(new AccountState(
-                    account.Trie.Set(ValidatorSetKey, validatorSet.Bencoded))));
-        }
     }
 }

From 016d6ff62d33254e2146f964b9aa83a2f6d101d4 Mon Sep 17 00:00:00 2001
From: Say Cheong <greymistcube@gmail.com>
Date: Thu, 28 Mar 2024 12:10:14 +0900
Subject: [PATCH 8/9] Changelog

---
 CHANGES.md | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/CHANGES.md b/CHANGES.md
index 12578d9ba0b..74ab08f6174 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -14,6 +14,10 @@ To be released.
     type `IReadOnlyList<ITransaction>?` to `IActionContext`.  [[#3713]]
  -  (Libplanet.Action) Removed `TotalFungibleAssets` property from
     `IWorld`.  [[#3714]]
+ -  (Libplanet.Action) Changed `GetBalance()`, `GetTotalSupply()`, and
+    `GetValidatorSet()` of `IWorldState` to extension methods.  [[#3715]]
+ -  (Libplanet.Action) Changed `MintAsset()`, `BurnAsset()`, `TransferAsset()`,
+    and `SetValidator()` of `IWorld` to extension methods.  [[#3715]]
 
 ### Backward-incompatible network protocol changes
 
@@ -31,6 +35,7 @@ To be released.
 
 [#3713]: https://github.com/planetarium/libplanet/pull/3713
 [#3714]: https://github.com/planetarium/libplanet/pull/3714
+[#3715]: https://github.com/planetarium/libplanet/pull/3715
 
 
 Version 4.2.0

From ba40e76eb90023bf43f5a3391920018083e48ffe Mon Sep 17 00:00:00 2001
From: Say Cheong <greymistcube@gmail.com>
Date: Thu, 28 Mar 2024 16:40:17 +0900
Subject: [PATCH 9/9] Updated docs

---
 Libplanet.Action/State/IWorldExtensions.cs | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Libplanet.Action/State/IWorldExtensions.cs b/Libplanet.Action/State/IWorldExtensions.cs
index d534d8ba1db..8de5fe62253 100644
--- a/Libplanet.Action/State/IWorldExtensions.cs
+++ b/Libplanet.Action/State/IWorldExtensions.cs
@@ -14,6 +14,7 @@ public static class IWorldExtensions
         /// <summary>
         /// Queries <paramref name="address"/>'s balance of the <paramref name="currency"/>.
         /// </summary>
+        /// <param name="worldState">The <see cref="IWorldState"/> to read from.</param>
         /// <param name="address">The owner address to query.</param>
         /// <param name="currency">The currency type to query.</param>
         /// <returns>
@@ -36,6 +37,7 @@ public static FungibleAssetValue GetBalance(
         /// Mints the fungible asset <paramref name="value"/> (i.e., in-game monetary),
         /// and give it to the <paramref name="recipient"/>.
         /// </summary>
+        /// <param name="world">The <see cref="IWorld"/> to manipulate.</param>
         /// <param name="context">The <see cref="IActionContext"/> of the <see cref="IAction"/>
         /// executing this method.</param>
         /// <param name="recipient">The address who receives the minted asset.</param>
@@ -107,6 +109,7 @@ public static IWorld MintAsset(
         /// Burns the fungible asset <paramref name="value"/> (i.e., in-game monetary) from
         /// <paramref name="owner"/>'s balance.
         /// </summary>
+        /// <param name="world">The <see cref="IWorld"/> to manipulate.</param>
         /// <param name="context">The <see cref="IActionContext"/> of the <see cref="IAction"/>
         /// executing this method.</param>
         /// <param name="owner">The address who owns the fungible asset to burn.</param>
@@ -174,6 +177,7 @@ public static IWorld BurnAsset(
         /// Transfers the fungible asset <paramref name="value"/> (i.e., in-game monetary)
         /// from the <paramref name="sender"/> to the <paramref name="recipient"/>.
         /// </summary>
+        /// <param name="world">The <see cref="IWorld"/> to manipulate.</param>
         /// <param name="context">The <see cref="IActionContext"/> of the <see cref="IAction"/>
         /// executing this method.</param>
         /// <param name="sender">The address who sends the fungible asset to
@@ -211,6 +215,7 @@ public static IWorld TransferAsset(
         /// <summary>
         /// Returns the total supply of a <paramref name="currency"/>.
         /// </summary>
+        /// <param name="worldState">The <see cref="IWorldState"/> to read from.</param>
         /// <param name="currency">The currency type to query.</param>
         /// <returns>The total supply of the <paramref name="currency"/>.
         /// </returns>
@@ -237,6 +242,7 @@ public static FungibleAssetValue GetTotalSupply(
         /// <summary>
         /// Returns the validator set.
         /// </summary>
+        /// <param name="worldState">The <see cref="IWorldState"/> to read from.</param>
         /// <returns>The validator set of type <see cref="ValidatorSet"/>.
         /// </returns>
         [Pure]
@@ -253,6 +259,7 @@ public static ValidatorSet GetValidatorSet(this IWorldState worldState)
         /// Sets <paramref name="validator"/> to the stored <see cref="ValidatorSet"/>.
         /// If 0 is given as its power, removes the validator from the <see cref="ValidatorSet"/>.
         /// </summary>
+        /// <param name="world">The <see cref="IWorld"/> to manipulate.</param>
         /// <param name="validator">The <see cref="Validator"/> instance to write.</param>
         /// <returns>A new <see cref="IWorld"/> instance with
         /// <paramref name="validator"/> set.</returns>