WIP: restorePSM

toward #6645

packages/inter-protocol/src/proposals/restorePSM.js

@@ -0,0 +1,115 @@
+// @ts-check
+import { AmountMath } from '@agoric/ertp';
+import { Stable } from '@agoric/vats/src/tokens.js';
+import { E } from '@endo/far';
+
+const { entries, values } = Object;
+
+/** @type {<K extends AssetKind>(amts: Amount<K>[]) => Amount<K>} */
+const amountSum = amts => amts.reduce((tot, a) => AmountMath.add(tot, a));
+
+/** @template M @typedef {import('@agoric/governance/src/contractGovernance/typedParamManager.js').ParamRecordsFromTypes<M>} ParamRecordsFromTypes<M> */
+/** @typedef {import('../psm/psm.js').MetricsNotification} MetricsNotification */
+
+/**
+ * @template M
+ * @template G
+ * @typedef {{ metrics: M, governance: ParamRecordsFromTypes<G> }} GovernedContractState
+ */
+
+/**
+ * @typedef {{
+ *    GiveMintedFee: 'ratio',
+ *    WantMintedFee: 'ratio',
+ *    MintLimit: 'amount',
+ * }} PSMParamTypesMap // TODO: factor out of psm.js
+ *
+ * @typedef {GovernedContractState<MetricsNotification, PSMParamTypesMap>} PSMPublishedState
+ * @typedef {Record<string, Record<string, PSMPublishedState>>} PSMChainStorage
+ */
+
+/**
+ * @param {ERef<Issuer>} stableIssuer
+ * @param {Amount<'nat'>[]} feeAmounts
+ * @param {ERef<ZoeService>} zoe
+ * @param {ERef<Installation>} centralSupply
+ * @param {unknown} feeMintAccess
+ */
+const mintTotalFees = async (
+  stableIssuer,
+  feeAmounts,
+  zoe,
+  centralSupply,
+  feeMintAccess,
+) => {
+  const feePurse = E(stableIssuer).makeEmptyPurse();
+
+  const { creatorFacet: supplier } = await E(zoe).startInstance(
+    centralSupply,
+    { [Stable.symbol]: stableIssuer },
+    { bootstrapPaymentValue: amountSum(feeAmounts) },
+    { feeMintAccess },
+  );
+  await E(supplier)
+    .getBootstrapPayment()
+    .then(pmt => E(feePurse).deposit(pmt));
+  return feePurse;
+};
+
+/**
+ * @param {PSMChainStorage} before
+ * @param {BootstrapPowers} powers
+ */
+export const restorePSM = async (before, powers) => {
+  const {
+    consume: { feeMintAccess, zoe },
+    installation: {
+      consume: { centralSupply },
+    },
+    issuer: {
+      consume: { [Stable.symbol]: stableIssuer },
+    },
+    brand: {
+      consume: { [Stable.symbol]: stableBrandP },
+    },
+  } = powers;
+
+  const stableBrand = await stableBrandP;
+  const feeAmounts = values(before).flatMap(a =>
+    values(a).map(({ metrics }) => metrics.feePoolBalance),
+  );
+
+  const feePurse = await mintTotalFees(
+    stableIssuer,
+    feeAmounts,
+    zoe,
+    centralSupply,
+    feeMintAccess,
+  );
+
+  for await (const [keyStable, anchors] of entries(before)) {
+    for await (const [keyAnchor, { metrics, governance }] of entries(anchors)) {
+      console.log('restoring', { keyStable, keyAnchor, metrics, governance });
+
+      const feePoolPmt = await E(feePurse).withdraw(metrics.feePoolBalance);
+      metrics.mintedPoolBalance;
+      /**
+       * 
+mint the balance of the anchor asset (e.g. USDC) - (note Jan 18 design sketch below)
+       
+       */
+      // from packages/vats/src/core/boot-psm.js
+      //
+      // ...anchorAssets.map(anchorOptions =>
+      //     makeAnchorAsset(powersFor('makeAnchorAsset'), {
+      //       options: { anchorOptions },
+      //     }),
+      //   ),
+      //   ...anchorAssets.map(anchorOptions =>
+      //     startPSM(powersFor('startPSM'), {
+      //       options: { anchorOptions },
+      //     }),
+      //   ),
+    }
+  }
+};