tax rate, version and compose (#70)

resolves #67

Co-authored-by: johba <johba@harb.eth>
Reviewed-on: https://codeberg.org/johba/harb/pulls/70

scripts/sync-tax-rates.mjs

@@ -0,0 +1,106 @@
+#!/usr/bin/env node
+
+/**
+ * Sync TAX_RATE options from the on-chain Stake contract to kraiken-lib.
+ *
+ * The Stake.sol contract defines the canonical TAX_RATES array in basis points (yearly percentage * 100).
+ * This script parses that array and regenerates kraiken-lib/src/taxRates.ts so that all front-end consumers
+ * share a single source of truth that mirrors the deployed contract.
+ */
+
+import { readFileSync, writeFileSync } from 'node:fs';
+import { fileURLToPath } from 'node:url';
+import path from 'node:path';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
+const stakeSourcePath = path.resolve(__dirname, '../onchain/src/Stake.sol');
+const taxRatesDestPath = path.resolve(__dirname, '../kraiken-lib/src/taxRates.ts');
+
+const source = readFileSync(stakeSourcePath, 'utf8');
+
+const match = source.match(/uint256\[]\s+public\s+TAX_RATES\s*=\s*\[([^\]]+)\]/m);
+if (!match) {
+  throw new Error(`Unable to locate TAX_RATES array in ${stakeSourcePath}`);
+}
+
+const rawValues = match[1]
+  .split(',')
+  .map(value => value.trim())
+  .filter(Boolean);
+
+if (rawValues.length === 0) {
+  throw new Error('TAX_RATES array is empty or failed to parse');
+}
+
+const taxRateOptions = rawValues.map((value, index) => {
+  const basisPoints = Number(value.replace(/_/g, ''));
+  if (!Number.isFinite(basisPoints)) {
+    throw new Error(`Invalid TAX_RATES entry "${value}" at index ${index}`);
+  }
+
+  const yearlyPercent = basisPoints;
+  const decimalRate = yearlyPercent / 100;
+  const dailyPercent = yearlyPercent / 365;
+
+  return {
+    index,
+    year: yearlyPercent,
+    daily: Number(dailyPercent.toFixed(5)),
+    decimal: Number(decimalRate.toFixed(2)),
+  };
+});
+
+// Generate checksum for runtime validation
+import { createHash } from 'node:crypto';
+const taxRatesString = rawValues.join(',');
+const checksum = createHash('sha256').update(taxRatesString).digest('hex').slice(0, 16);
+
+const fileHeader = `/**
+ * AUTO-GENERATED FILE — DO NOT EDIT
+ *
+ * Generated by scripts/sync-tax-rates.mjs from onchain/src/Stake.sol.
+ * Run \`node scripts/sync-tax-rates.mjs\` after modifying the contract TAX_RATES array.
+ */
+`;
+
+const interfaceDef = `export interface TaxRateOption {
+  index: number;
+  year: number;
+  daily: number;
+  decimal: number;
+}
+`;
+
+const optionLines = taxRateOptions
+  .map(option => `  { index: ${option.index}, year: ${option.year}, daily: ${option.daily}, decimal: ${option.decimal} }`)
+  .join(',\n');
+
+const content = `${fileHeader}
+${interfaceDef}
+export const TAX_RATE_OPTIONS: TaxRateOption[] = [
+${optionLines}
+];
+
+/**
+ * Checksum of the contract TAX_RATES array (first 16 chars of SHA-256).
+ * Used for runtime validation to ensure kraiken-lib is in sync with deployed contracts.
+ *
+ * To validate at runtime:
+ * 1. Read TAX_RATES array from the Stake contract
+ * 2. Compute checksum: sha256(values.join(',')).slice(0, 16)
+ * 3. Compare with TAX_RATES_CHECKSUM
+ *
+ * If mismatch: Run \`node scripts/sync-tax-rates.mjs\` and rebuild kraiken-lib.
+ */
+export const TAX_RATES_CHECKSUM = '${checksum}';
+
+/**
+ * Array of raw year values (matches contract uint256[] TAX_RATES exactly).
+ * Used for runtime validation without needing to parse options.
+ */
+export const TAX_RATES_RAW = [${rawValues.join(', ')}];
+`;
+
+writeFileSync(taxRatesDestPath, content.trimStart() + '\n');