Reading data on networks without a subgraph

Not every network FairWins deploys to has a hosted Graph indexer. Ethereum Classic / Mordor (chain 63) is the motivating case: no Graph provider supports it, so the app cannot read wagers from a subgraph and must read directly from the chain over RPC.

This document describes the strategy the frontend uses to serve those networks transparently, so adding another un-indexed chain in the future is a config change rather than a code change.

Strategy: per-chain data-source selection

The "does this chain have an indexer?" decision is per-network metadata, not a global flag. Each network in frontend/src/config/networks.js declares a subgraphUrl:

Chain	subgraphUrl	Wager reads served by
Polygon (137)	Studio endpoint (default/env)	SubgraphSource (The Graph)
Polygon Amoy (80002)	Studio endpoint (default/env)	SubgraphSource (The Graph)
Ethereum Classic Mordor (63)	null	RegistrySource (RPC)
Hardhat (1337)	null	RegistrySource (RPC)

Two helpers expose this:

import { getSubgraphUrl, hasSubgraph } from '../config/networks'

getSubgraphUrl(63) // → null  (Mordor has no subgraph)
hasSubgraph(137)   // → true

Resolution is strictly per-chain: a subgraph URL configured for one network can never be queried while the wallet is on another (so a Polygon endpoint is never hit while connected to Mordor).

The data sources

The UI never talks to a source directly — it goes through WagerRepository, which is bound to a chain id and picks the source for that chain:

• SubgraphSource — GraphQL against the chain's subgraphUrl. Used when hasSubgraph(chainId) is true. If the endpoint errors or is unreachable, it falls back to RegistrySource (not the retired events source).
• RegistrySource — direct RPC reads of the v2 WagerRegistry using its purpose-built pagination views (getUserWagerCount, getUserWagerIds, getUserWagers, getWager). No eth_getLogs block-range scanning, so it works on public RPCs (Amoy, Mordor) that reject wide log ranges. This is the default for any chain without a subgraph.
• EventsSource — legacy. Reads the retired FriendGroupMarketFactory and is no longer wired into the automatic fallback path. Retained only behind an explicit VITE_WAGER_SOURCE=events override.

Both live sources emit the same mapped Wager shape, so the list, detail, and report views are agnostic to which one produced a page.

useMyWagers / useAccountStats / reportDataSource
        │  (chainId)
        ▼
   WagerRepository(chainId)
        │
  hasSubgraph(chainId) ? SubgraphSource ─(on error)─▶ RegistrySource (RPC)
                       : RegistrySource (RPC)

Threading the chain id

Reads are keyed on the wallet's connected chain so a user on testnet never sees mainnet wagers (or vice versa):

• useMyWagers reads the active chain from wagmi's useChainId() (override with the chainId option) and builds a per-chain repository.
• useAccountStats and reportDataSource pass their chainId to getDefaultWagerRepository(chainId).

Reporting

The tax/activity report (reportDataSource) prefers the indexed listTransfers path where a subgraph exists. On a chain without one it returns null from listTransfers and enumerates wagers via the RPC repository (enumerateWagers), then does a bounded on-chain event scan per wager. No hard dependency on the subgraph remains.

Membership / roles

Role reads (hasRoleOnChain) and the Quick Start membership banner have always read from the MembershipManager over RPC and are already chain-aware, so they work on un-indexed networks. The banner is additionally gated on blockchainSynced so it only renders once the wallet's roles are confirmed on-chain — it won't linger for a member while the RPC read resolves.

Adding another un-indexed network

1. Add the network to networks.js with subgraphUrl: null (or a VITE_SUBGRAPH_URL_<NET> override if you stand up your own indexer later).
2. Ensure wagerRegistry (and membershipManager) addresses are recorded for the chain in contracts.js / deployments/.

No source code changes are required — WagerRepository will route the chain to RegistrySource automatically.