Events and Indexing

Overview

XPower emits events across all 6 core contracts. Events are critical for tracking state changes: mints, burns, transfers, stakes, unstakes, claims, and parameter updates. All token-standard events (Transfer, Approval, TransferSingle, TransferBatch, ApprovalForAll) are emitted by the inherited OpenZeppelin contracts.

Key Events by Contract

XPower (moe)

Event	Parameters	Indexed	Description
Init	bytes32 blockHash, uint256 timestamp	blockHash	Block hash cached for the current 1-hour interval
Transfer	address from, address to, uint256 value	from, to	ERC20 transfer (inherited)
Approval	address owner, address spender, uint256 value	owner, spender	ERC20 approval (inherited)
Seal	uint256 index	—	MOE immigration sealed for base index
SealAll	—	—	All MOE immigration sealed

XPowerNft (nft)

Event	Parameters	Indexed	Description
ApproveMinting	address account, address operator, bool approved	account, operator	Minting delegation updated
ApproveUpgrading	address account, address operator, bool approved	account, operator	Upgrade delegation updated
TransferSingle	address operator, address from, address to, uint256 id, uint256 value	operator, from, to	ERC1155 single transfer (inherited)
TransferBatch	address operator, address from, address to, uint256[] ids, uint256[] values	operator, from, to	ERC1155 batch transfer (inherited)
ApprovalForAll	address account, address operator, bool approved	account, operator	ERC1155 approval (inherited)
URI	string value, uint256 id	id	Metadata URI updated (inherited)
Seal	uint256 index	—	NFT immigration sealed
SealAll	—	—	All NFT immigration sealed
Migratable	uint256 timestamp	—	NFT emigration opened with effective timestamp
SetRoyal	address beneficiary	—	Royalty beneficiary changed
ApproveMigrate	address account, address operator, bool approved	account, operator	Migration delegation updated

APowerNft (ppt)

Event	Parameters	Indexed	Description
Init	address mty	—	MoeTreasury address set (one-time)

Inherits all ERC1155 events (TransferSingle, TransferBatch, ApprovalForAll, URI) plus migration and royalty events from NftBase.

APower (sov)

Event	Parameters	Indexed	Description
Transfer	address from, address to, uint256 value	from, to	ERC20 transfer (inherited)
Approval	address owner, address spender, uint256 value	owner, spender	ERC20 approval (inherited)

MoeTreasury (mty)

Event	Parameters	Indexed	Description
Claim	address account, uint256 nftId, uint256 amount	—	APOW reward claimed for single NFT
ClaimBatch	address account, uint256[] nftIds, uint256[] amounts	—	APOW rewards claimed for multiple NFTs
SetAPR	uint256 nftId, uint256[] array	—	APR polynomial for an NFT level updated
SetAPB	uint256 nftId, uint256[] array	—	APB polynomial for an NFT level updated
RefreshRates	bool allLevels	—	APR scalars recalculated based on shares
Init	address pool	—	Lending pool address set (inherited from Banq)

NftTreasury (nty)

Event	Parameters	Indexed	Description
Stake	address account, uint256 nftId, uint256 amount	—	Single NFT staked
StakeBatch	address account, uint256[] nftIds, uint256[] amounts	—	Multiple NFTs staked
Unstake	address account, uint256 nftId, uint256 amount	—	Single NFT unstaked
UnstakeBatch	address account, uint256[] nftIds, uint256[] amounts	—	Multiple NFTs unstaked
ApproveStaking	address account, address operator, bool approved	account, operator	Staking delegation updated
ApproveUnstaking	address account, address operator, bool approved	account, operator	Unstaking delegation updated

Event-Driven Architecture

Tracking Minted Supply

Monitor Transfer events from XPower (moe) where from == address(0):

// Each PoW mint produces TWO Transfers from address(0):
// Transfer(address(0), beneficiary, amount)
// Transfer(address(0), treasuryOwner, amount)

The total supply increase per mint() is 2 * (2^zeros - 1) * 1e18.

Tracking Staking Activity

Stake event on NftTreasury:
  └─ TransferSingle: nft from account → nty (XPowerNft deposited)
  └─ TransferSingle: ppt from address(0) → account (APowerNft minted)
  └─ RefreshRates: false (APR scalars recalculated)

Unstake event on NftTreasury:
  └─ TransferSingle: ppt from account → address(0) (APowerNft burned)
  └─ TransferSingle: nft from nty → account (XPowerNft returned)
  └─ RefreshRates: false (APR scalars recalculated)

Tracking Reward Claims

Claim event on MoeTreasury:
  └─ Transfer: sov from address(0) → account (APower minted)
  └─ Transfer: moe from treasury → sov contract (XPOW wrapped)

Indexing Strategies

Option 1: The Graph (Subgraph)

Schema outline:

type XPowerMint @entity {
  id: ID!
  beneficiary: Bytes!
  amount: BigInt!
  blockHash: Bytes!
  interval: BigInt!
  transaction: Bytes!
  blockNumber: BigInt!
  timestamp: BigInt!
}

type Stake @entity {
  id: ID!
  account: Bytes!
  nftId: BigInt!
  amount: BigInt!
  timestamp: BigInt!
}

type Claim @entity {
  id: ID!
  account: Bytes!
  nftId: BigInt!
  amount: BigInt!
  mintedAPOW: BigInt!
  timestamp: BigInt!
}

Event handlers:

# subgraph.yaml (excerpt)
dataSources:
  - kind: ethereum/contract
    name: XPower
    network: avalanche
    source:
      address: "0xa2Ecb675Ad2A2E199c98F5206C5C3fFE5a8D5753"
      abi: XPower
    mapping:
      eventHandlers:
        - event: Transfer(indexed address,indexed address,uint256)
          handler: handleTransfer

  - kind: ethereum/contract
    name: NftTreasury
    network: avalanche
    source:
      address: "0xF113c3fb6b557d84B5A96E19b7918ba8fc21a741"
      abi: NftTreasury
    mapping:
      eventHandlers:
        - event: Stake(address,uint256,uint256)
          handler: handleStake
        - event: Unstake(address,uint256,uint256)
          handler: handleUnstake

Option 2: Dune Analytics

Query XPower mints (from Transfer events where from = 0x0):

SELECT
  evt_block_time,
  evt_tx_hash,
  "to" AS beneficiary,
  value / 1e18 AS amount_xpow
FROM erc20_avalanche_c.evt_Transfer
WHERE contract_address = 0xa2Ecb675Ad2A2E199c98F5206C5C3fFE5a8D5753
  AND "from" = 0x0000000000000000000000000000000000000000
ORDER BY evt_block_time DESC
LIMIT 100;

Query stake events:

SELECT
  evt_block_time,
  evt_tx_hash,
  account,
  nftId,
  amount / 1e18 AS amount
FROM nft_treasury_avalanche_c.Stake
ORDER BY evt_block_time DESC;

Option 3: Custom Indexer

Using ethers.js event filters with block range batching:

import { ethers } from "ethers";

const provider = new ethers.JsonRpcProvider(RPC_URL);
const mty = new ethers.Contract(MTY_ADDRESS, mtyABI, provider);

const BATCH_SIZE = 2000n; // blocks per query

async function indexClaims(fromBlock: bigint, toBlock: bigint) {
  for (let block = fromBlock; block < toBlock; block += BATCH_SIZE) {
    const endBlock = block + BATCH_SIZE - 1n < toBlock ? block + BATCH_SIZE - 1n : toBlock;
    const filter = mty.filters.Claim();
    const events = await mty.queryFilter(filter, block, endBlock);
    for (const event of events) {
      const { account, nftId, amount } = event.args;
      // process: store in database
      console.log({ account, nftId: nftId.toString(), amount: amount.toString(), tx: event.transactionHash });
    }
  }
}

Block Range Batching Best Practices

• Avalanche C-Chain: Recommended batch size is 2,000–5,000 blocks per query. The chain has ~2s block time (~43,200 blocks/day).
• Rate limiting: Public RPC endpoints may throttle. Use a delay of 200–500ms between batches.
• Concurrent queries: Run queries for different contracts in parallel since they are independent.
• Checkpointing: Store lastIndexedBlock persistently and resume from there on restart.

async function indexWithCheckpoint(
  contract: ethers.Contract,
  eventFilter: ethers.EventFilter,
  fromBlock: bigint,
  toBlock: bigint,
  getCheckpoint: () => Promise<bigint>,
  setCheckpoint: (block: bigint) => Promise<void>
) {
  let current = await getCheckpoint();
  if (current < fromBlock) current = fromBlock;

  while (current < toBlock) {
    const end = current + BATCH_SIZE < toBlock ? current + BATCH_SIZE : toBlock;
    const events = await contract.queryFilter(eventFilter, current, end);
    for (const event of events) {
      // process event
    }
    current = end + 1n;
    await setCheckpoint(current);
  }
}

Event Topic Signatures

For raw log filtering:

Event	Topic (keccak256)
Init(bytes32,uint256) (XPower)	0xc1dd22814b5e76a3e53de884431909a44dc43d0a1e7f4c61cc436987b47b2c83
Claim(address,uint256,uint256)	0x5566dbe175d7364c1fbbb585b4b86543b15e2f452a7add83fca4b9b893e4dfc5
ClaimBatch(address,uint256[],uint256[])	0x14819e25def18df36ee84e1b86d7206b1cabaa9f57098ef74f0e83e5a648cf0f
Stake(address,uint256,uint256)	0x70dbb5fa6cf95c4b3c0ed42016dd260f329f8ff8b16a820fbc88202fe410cefa
Unstake(address,uint256,uint256)	0xe7fe8d8b54deb85547e1cc803e1a85275f2a6162a68026015e2b36c3f626997a
StakeBatch(address,uint256[],uint256[])	0x2d920b12edc44b31303e15352e3ea530149c675aabf144329d87596647c9d7cf
UnstakeBatch(address,uint256[],uint256[])	0xbd0efb5fca19ce3794cad7e6ca2a32eaf8a85e4efd9e78bb7d400f5b0c5b6f46
ApproveStaking(address,address,bool)	0x24d653d53f4a25a7f5af297a775bb38338205e39b06a29445eb4e1ca1a4ba3e3
ApproveUnstaking(address,address,bool)	0x8fcf7cb09dc916d34d5862100988a50566410d1c25ca238661db43dbed257fb5
ApproveMinting(address,address,bool)	0xd11b26b9c3e719cf8d93ed6d6ccd82e5ec1a1bd82f8c8e69163221b8dc909079
ApproveUpgrading(address,address,bool)	0xa20c8a1ed79fd4a20a3cab04f3c2d0e352f730edb1e16ea3288438ff7313fdb7
SetAPR(uint256,uint256[])	0xffd6f0739d2c09957769abfd54b3dc271098a4538f73b8b2a0f9b1e29f55da8e
SetAPB(uint256,uint256[])	0xa373dc54beafc1e4e85c2d61465a854b9a9c20eae8e6c38bcdae5936439642c0
RefreshRates(bool)	0x223815674cebd405654f76ca26d72785ce98838138a2cf823afb449e18ba55bb

To compute topic signatures at runtime:

const topicHash = ethers.id("Claim(address,uint256,uint256)");