Support custom chain IDs (#155)

Sources/Starknet/Data/StarknetChainId.swift

@@ -1,14 +1,27 @@
 import BigInt
 import Foundation
 
-public enum StarknetChainId: String, Codable, Equatable {
-    case mainnet = "0x534e5f4d41494e"
-    case goerli = "0x534e5f474f45524c49"
-    case sepolia = "0x534e5f5345504f4c4941"
-    case integration_sepolia = "0x534e5f494e544547524154494f4e5f5345504f4c4941"
-
-    public var feltValue: Felt {
-        Felt(fromHex: self.rawValue)!
+public struct StarknetChainId: Codable, Equatable {
+    public let value: Felt
+
+    public static let main = StarknetChainId(fromHex: "0x534e5f4d41494e")
+    public static let goerli = StarknetChainId(fromHex: "0x534e5f474f45524c49")
+    public static let sepolia = StarknetChainId(fromHex: "0x534e5f5345504f4c4941")
+    public static let integration_sepolia = StarknetChainId(fromHex: "0x534e5f494e544547524154494f4e5f5345504f4c4941")
+
+    public init(_ value: Felt) {
+        self.value = value
+    }
+
+    public init(from decoder: Decoder) throws {
+        let container = try decoder.singleValueContainer()
+        let value = try container.decode(String.self)
+        self.value = Felt(fromHex: value)!
+    }
+
+    public func encode(to encoder: Encoder) throws {
+        var container = encoder.singleValueContainer()
+        try container.encode(self.value)
     }
 
     enum CodingKeys: String, CodingKey {
@@ -18,3 +31,17 @@ public enum StarknetChainId: String, Codable, Equatable {
         case integration_sepolia = "0x534e5f494e544547524154494f4e5f5345504f4c4941"
     }
 }
+
+public extension StarknetChainId {
+    init(fromHex hex: String) {
+        self.value = Felt(fromHex: hex)!
+    }
+
+    init(fromNetworkName networkName: String) {
+        self.value = Felt.fromShortString(networkName)!
+    }
+
+    func toNetworkName() -> String {
+        self.value.toShortString()
+    }
+}

Sources/Starknet/Data/Transaction/TransactionHash.swift

@@ -21,7 +21,7 @@ public class StarknetTransactionHashCalculator {
             entryPointSelector,
             StarknetCurve.pedersenOn(calldata),
             maxFee,
-            chainId.feltValue,
+            chainId.value,
             nonce
         )
     }
@@ -45,7 +45,7 @@ public class StarknetTransactionHashCalculator {
                     + StarknetTransactionHashCalculator.resourceBoundsForFee(resourceBounds)
             ),
             StarknetPoseidon.poseidonHash(paymasterData),
-            chainId.feltValue,
+            chainId.value,
             nonce,
             StarknetTransactionHashCalculator.dataAvailabilityModes(
                 feeDataAvailabilityMode: feeDataAvailabilityMode,

Tests/StarknetTests/Data/StarknetChainIdTests.swift

@@ -0,0 +1,64 @@
+import XCTest
+
+@testable import Starknet
+
+final class StarknetChainIdTests: XCTestCase {
+    static var chainIdCases: [(StarknetChainId, String, String)] = []
+
+    override class func setUp() {
+        self.chainIdCases = [
+            (StarknetChainId.main, "SN_MAIN", "0x534e5f4d41494e"),
+            (StarknetChainId.goerli, "SN_GOERLI", "0x534e5f474f45524c49"),
+            (StarknetChainId.sepolia, "SN_SEPOLIA", "0x534e5f5345504f4c4941"),
+            (StarknetChainId.integration_sepolia, "SN_INTEGRATION_SEPOLIA", "0x534e5f494e544547524154494f4e5f5345504f4c4941"),
+        ]
+    }
+
+    func testFromHexInitializer() {
+        for (chainId, _, hex) in Self.chainIdCases {
+            XCTAssertEqual(StarknetChainId(fromHex: hex), chainId)
+        }
+    }
+
+    func testFromNetworkNameInitializer() {
+        for (chainId, name, _) in Self.chainIdCases {
+            XCTAssertEqual(StarknetChainId(fromNetworkName: name), chainId)
+        }
+    }
+
+    func testToNetworkName() {
+        for (chainId, name, _) in Self.chainIdCases {
+            XCTAssertEqual(chainId.toNetworkName(), name)
+        }
+    }
+
+    func testEncoding() {
+        for (chainId, _, hexString) in Self.chainIdCases {
+            do {
+                let data = try JSONEncoder().encode(chainId)
+                let expectedData = Data("\"\(hexString)\"".utf8)
+                XCTAssertEqual(data, expectedData)
+            } catch {
+                XCTFail("Failed to encode \(chainId)")
+            }
+        }
+    }
+
+    func testDecoding() {
+        for (chainId, _, hexString) in Self.chainIdCases {
+            do {
+                let data = Data("\"\(hexString)\"".utf8)
+                let decoded = try JSONDecoder().decode(StarknetChainId.self, from: data)
+                XCTAssertEqual(decoded, chainId)
+            } catch {
+                XCTFail("Failed to decode \(chainId)")
+            }
+        }
+    }
+
+    func testCustomChainId() {
+        let chainIdFromHex = StarknetChainId(fromHex: "0x4b4154414e41")
+        let chainIdFromNetworkName = StarknetChainId(fromNetworkName: "KATANA")
+        XCTAssertEqual(chainIdFromHex, chainIdFromNetworkName)
+    }
+}