Oracles

fn get_price(token: Address) -> (i128 /* USD, 1e18 */, u64 /* unix seconds */);
fn is_stale(token: Address) -> bool;

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When to use which

• Use the SEP-40 adapter whenever the asset has a public price feed. For a vault’s financially consequential math (liquidations, NAV), a decentralized price removes the single Ankara-controlled key as a point of failure.
• Keep manual-oracle for assets without one. Most Ankara RWA tokens (a specific farm, a single invoice, one building) will never be on a public feed. An appraiser, warehouse or registrar posting a valuation is the right model for them.
• Mixed vaults: use the adapter with manual-oracle as its fallback. A vault has only one oracle address, so the adapter checks the feed first and falls back to manual-oracle when the feed has no fresh price for a token. One address covers both kinds of asset.

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sep40-oracle-adapter

• Asset mapping: by default a token is looked up on the feed as Stellar(token). Map it to a different SAC, or to an off-chain ticker such as Other("XAU"), with set_token_feed. For example, a gold-receipt commodity token can be priced off the feed’s gold price.
• Scaling: feed prices are rescaled from the feed’s decimals() (14 for Reflector) to Ankara’s 1e18 convention. The feed’s base asset must be USD (or a USD stablecoin) for the result to be a USD price.
• TWAP: twap_records = n averages the last n feed records, which damps short-lived spikes before they reach liquidation logic. The limit is 20.
• Timestamps: normalized to seconds. Feeds that report milliseconds are detected.
• Staleness: a feed price older than staleness_threshold counts as missing, and the fallback (if any) takes over.

import { Sep40OracleAdapter, CollateralVault } from "@ankarachain/sdk";

const oracle = new Sep40OracleAdapter(adminAdapter, ADAPTER);
await oracle.setTokenFeed(GOLD_RECEIPT_TOKEN, { asset: { kind: "other", symbol: "XAU" }, twapRecords: 5 });

await new CollateralVault(adminAdapter, VAULT).setOracle(ADAPTER);
console.log(await oracle.isUsingFallback(FARMLAND_TOKEN)); // true: priced by manual-oracle

ADAPTER=$(stellar contract deploy --wasm target/wasm32v1-none/release/sep40_oracle_adapter.wasm --source deployer --network testnet)
stellar contract invoke --id $ADAPTER --source deployer --network testnet -- initialize \
  --admin <ADMIN> --feed <REFLECTOR_FEED_CONTRACT> --staleness_threshold 3600 --fallback "\"<MANUAL_ORACLE>\""
# point existing consumers at it
stellar contract invoke --id <COLLATERAL_VAULT> --source deployer --network testnet -- set_oracle --new_oracle $ADAPTER