feat: support for Bitcoin (memo only)

.gitignore

@@ -29,4 +29,4 @@ test-ledger
 localnet.json
 
 .vscode
-.idea
+.idea

src/chains/bitcoin/isBitcoinAvailable.ts

@@ -0,0 +1,11 @@
+import { execSync } from "child_process";
+
+export const isBitcoinAvailable = (): boolean => {
+  try {
+    execSync("bitcoind --version", { stdio: "ignore" });
+    execSync("bitcoin-cli --version", { stdio: "ignore" });
+    return true;
+  } catch {
+    return false;
+  }
+};

src/chains/bitcoin/observer.ts

@@ -0,0 +1,247 @@
+import ansis from "ansis";
+import { execSync } from "child_process";
+import { ethers } from "ethers";
+
+import { addBackgroundProcess } from "../../backgroundProcesses";
+import { NetworkID } from "../../constants";
+import { logger } from "../../logger";
+import { zetachainDeposit } from "../zetachain/deposit";
+import { zetachainDepositAndCall } from "../zetachain/depositAndCall";
+import { resolveBitcoinTssAddress } from "./setup";
+
+type StartObserverOptions = {
+  chainID?: string;
+  foreignCoins?: any[];
+  pollIntervalMs?: number;
+  provider?: any;
+  tssAddress?: string;
+  zetachainContracts?: any;
+};
+
+const tryDecodeMemoHex = (hex: string): string | undefined => {
+  try {
+    if (!hex || typeof hex !== "string") return undefined;
+    // Basic hex validation
+    if (!/^[0-9a-fA-F]+$/.test(hex)) return undefined;
+    const buf = Buffer.from(hex, "hex");
+    // Attempt UTF-8 decode; fallback to hex string if non-printable
+    const text = buf.toString("utf8");
+    // If decoded string contains many replacement chars, prefer hex
+    const replacementCount = (text.match(/\uFFFD/g) || []).length;
+    if (replacementCount > 0) return hex;
+    return text;
+  } catch (_error) {
+    return undefined;
+  }
+};
+
+const getOpReturnPushes = (tx: any): string[] => {
+  try {
+    // NOTE: Unlike the zetaclient implementation, we intentionally skip the extra
+    // unwrap of "outer" outputs. Localnet transactions already surface the OP_RETURN
+    // memo in the top-level vouts and we ignore the additional wrapping anyway, so
+    // walking the raw vout array keeps the local flow simple and still correct.
+    const vouts: any[] = Array.isArray(tx?.vout) ? tx.vout : [];
+    const pushes: string[] = [];
+    for (const vout of vouts) {
+      const spk = vout?.scriptPubKey || {};
+      if (spk?.type === "nulldata" && typeof spk?.asm === "string") {
+        const parts = spk.asm.split(/\s+/).filter(Boolean);
+        for (let i = 1; i < parts.length; i++) {
+          pushes.push(parts[i]);
+        }
+      }
+    }
+    return pushes;
+  } catch (_error) {
+    return [];
+  }
+};
+
+const extractMemoFromTransaction = (tx: any): string | undefined => {
+  for (const maybeHex of getOpReturnPushes(tx)) {
+    const decoded = tryDecodeMemoHex(maybeHex);
+    if (decoded) return decoded;
+  }
+  return undefined;
+};
+
+// Return the first hex push from OP_RETURN as a hex string (no utf-8 decoding)
+const extractMemoHexFromTransaction = (tx: any): string | undefined => {
+  for (const maybeHex of getOpReturnPushes(tx)) {
+    if (/^[0-9a-fA-F]+$/.test(maybeHex) && maybeHex.length % 2 === 0) {
+      return maybeHex.toLowerCase();
+    }
+  }
+  return undefined;
+};
+
+export const startBitcoinObserver = ({
+  tssAddress,
+  pollIntervalMs = 1000,
+  provider,
+  zetachainContracts,
+  foreignCoins,
+}: StartObserverOptions = {}) => {
+  const log = logger.child({ chain: "bitcoin" });
+
+  let watchAddress = tssAddress;
+
+  const seenTxIds = new Set<string>();
+
+  const intervalId = setInterval(async () => {
+    try {
+      // If address is not yet known, try to obtain/create it with RPC wait
+      if (!watchAddress) {
+        try {
+          const addr = resolveBitcoinTssAddress();
+          if (addr) {
+            watchAddress = addr;
+            log.info(`Bitcoin TSS address: ${watchAddress}`);
+            console.log(`Bitcoin TSS address: ${watchAddress}`);
+          } else {
+            log.info(
+              ansis.yellow(
+                "Unable to determine a TSS address; will retry... set BITCOIN_TSS_ADDRESS to override"
+              )
+            );
+            return; // try again on next tick
+          }
+        } catch (_error) {
+          return; // try again on next tick
+        }
+      }
+
+      const mempoolRaw = execSync("bitcoin-cli -regtest getrawmempool", {
+        stdio: ["ignore", "pipe", "ignore"],
+      })
+        .toString()
+        .trim();
+
+      if (!mempoolRaw) return;
+      const txids: string[] = JSON.parse(mempoolRaw);
+      if (!Array.isArray(txids)) return;
+
+      for (const txid of txids) {
+        if (seenTxIds.has(txid)) continue;
+        seenTxIds.add(txid);
+
+        try {
+          const txRaw = execSync(
+            `bitcoin-cli -regtest getrawtransaction ${txid} true`,
+            {
+              stdio: ["ignore", "pipe", "ignore"],
+            }
+          )
+            .toString()
+            .trim();
+          const tx = JSON.parse(txRaw);
+          const memo = extractMemoFromTransaction(tx);
+          const memoHex = extractMemoHexFromTransaction(tx);
+          const vouts: any[] = Array.isArray(tx?.vout) ? tx.vout : [];
+          for (const vout of vouts) {
+            const spk = vout?.scriptPubKey || {};
+            const addr: string | undefined =
+              spk.address ||
+              (Array.isArray(spk.addresses) ? spk.addresses[0] : undefined);
+            if (addr && addr === watchAddress) {
+              const amount = vout?.value;
+              const message = `Observed Bitcoin tx to TSS: txid=${txid} to=${addr} amount=${amount}`;
+              console.log(message);
+              log.info(message);
+              if (memo) {
+                const memoMsg = `Memo: ${memo}`;
+                console.log(memoMsg);
+                log.info(memoMsg);
+              }
+
+              // If memo hex is present, interpret first 20 bytes as receiver on ZetaChain
+              if (
+                memoHex &&
+                /^[0-9a-fA-F]+$/.test(memoHex) &&
+                memoHex.length % 2 === 0
+              ) {
+                const bytesLen = memoHex.length / 2;
+                if (bytesLen >= 20) {
+                  try {
+                    const recvHex = `0x${memoHex.slice(0, 40)}`;
+                    const receiver = ethers.getAddress(recvHex);
+                    const payloadHex = memoHex.slice(40);
+                    const payload =
+                      payloadHex.length > 0 ? `0x${payloadHex}` : "0x";
+                    if (!provider || !zetachainContracts || !foreignCoins) {
+                      log.info(
+                        "Zeta context not ready (provider/contracts/foreignCoins missing); skipping",
+                        { chain: "bitcoin" }
+                      );
+                      break;
+                    }
+
+                    const sender = ethers.ZeroAddress;
+                    // Convert BTC value (in whole BTC) to 18 decimals for dev testing
+                    const amountWei = ethers.parseUnits(
+                      String(amount ?? 0),
+                      18
+                    );
+                    const asset = ethers.ZeroAddress; // treat as gas token on source chain
+
+                    if (bytesLen === 20) {
+                      log.info(
+                        `Triggering ZetaChain deposit to ${receiver} (no payload)`,
+                        { chain: "bitcoin" }
+                      );
+                      await zetachainDeposit({
+                        args: [sender, receiver, amountWei, asset],
+                        chainID: NetworkID.Bitcoin,
+                        foreignCoins,
+                        zetachainContracts,
+                      });
+                    } else {
+                      log.info(
+                        `Triggering ZetaChain depositAndCall to ${receiver} with payload length ${
+                          payloadHex.length / 2
+                        } bytes`,
+                        { chain: "bitcoin" }
+                      );
+                      await zetachainDepositAndCall({
+                        args: [sender, receiver, amountWei, asset, payload],
+                        chainID: NetworkID.Bitcoin,
+                        foreignCoins,
+                        provider,
+                        zetachainContracts,
+                      });
+                    }
+                  } catch (btcMemoErr) {
+                    log.error(
+                      `Failed to process memo for tx ${txid}: ${btcMemoErr}`
+                    );
+                  }
+                }
+              }
+              break; // one match is enough
+            }
+          }
+        } catch (innerErr) {
+          // Ignore individual tx parsing errors
+          if (typeof log.debug === "function") {
+            log.debug("Failed to process bitcoin tx", {
+              chain: "bitcoin",
+              error:
+                innerErr instanceof Error ? innerErr.message : String(innerErr),
+            });
+          }
+        }
+      }
+    } catch (err) {
+      // Swallow polling errors to keep observer running in dev
+      if (typeof log.debug === "function") {
+        log.debug("Bitcoin observer polling error", {
+          chain: "bitcoin",
+          error: err instanceof Error ? err.message : String(err),
+        });
+      }
+    }
+  }, pollIntervalMs);
+
+  addBackgroundProcess(intervalId);
+};