phase-7: code restructure

server/services/PersonalFinanceAnalyzer.ts

@@ -0,0 +1,53 @@
+import type { CategoryBreakdown, FinanceAnalysis, SimpleFINAccount } from '../types';
+
+export class PersonalFinanceAnalyzer {
+  analyze(accounts: SimpleFINAccount[]): FinanceAnalysis {
+    const assets = accounts.filter((a) => !['CREDIT', 'LOAN'].includes(a.type));
+    const liabilities = accounts.filter((a) => ['CREDIT', 'LOAN'].includes(a.type));
+
+    const totalAssets = assets.reduce((s, a) => s + Math.max(0, a.balance), 0);
+    const totalLiabilities = liabilities.reduce((s, a) => s + Math.abs(Math.min(0, a.balance)), 0);
+    const netWorth = totalAssets - totalLiabilities;
+
+    const cash = accounts.filter((a) => ['CHECKING', 'SAVINGS'].includes(a.type));
+    const investments = accounts.filter((a) => a.type === 'INVESTMENT');
+    const totalCash = cash.reduce((s, a) => s + Math.max(0, a.balance), 0);
+    const totalInvest = investments.reduce((s, a) => s + Math.max(0, a.balance), 0);
+
+    const allTx = accounts.flatMap((a) => a.transactions);
+    const spending = allTx.filter((tx) => tx.amount < 0 && tx.category !== 'Transfer');
+    const income = allTx.filter((tx) => tx.amount > 0 && tx.category === 'Income');
+
+    const totalSpend = spending.reduce((s, tx) => s + Math.abs(tx.amount), 0);
+    const totalIncome = income.reduce((s, tx) => s + tx.amount, 0);
+
+    const byCategory: Record<string, number> = {};
+    for (const tx of spending) {
+      byCategory[tx.category] = (byCategory[tx.category] ?? 0) + Math.abs(tx.amount);
+    }
+
+    const categoryBreakdown: CategoryBreakdown[] = Object.entries(byCategory)
+      .sort((a, b) => b[1] - a[1])
+      .map(([category, amount]) => ({
+        category,
+        amount,
+        pct: totalSpend > 0 ? ((amount / totalSpend) * 100).toFixed(1) : '0',
+      }));
+
+    return {
+      netWorth,
+      totalAssets,
+      totalLiabilities,
+      totalCash,
+      totalInvestments: totalInvest,
+      cashPct: totalAssets > 0 ? ((totalCash / totalAssets) * 100).toFixed(1) : '0',
+      investPct: totalAssets > 0 ? ((totalInvest / totalAssets) * 100).toFixed(1) : '0',
+      totalIncome,
+      totalSpend,
+      savingsRate:
+        totalIncome > 0 ? (((totalIncome - totalSpend) / totalIncome) * 100).toFixed(1) : null,
+      categoryBreakdown,
+      accounts,
+    };
+  }
+}