Add Expenses app

A UI based on [Budget Zen](https://github.com/BrunoBernardino/budgetzen-web) but slightly updated and adjusted for bewCloud. It also features a chart with available money and spent by budgets.

This is useful for envelope-based budgeting.

routes/api/expenses/import-expenses.tsx

@@ -0,0 +1,82 @@
+import { Handlers } from 'fresh/server.ts';
+
+import { Budget, Expense, FreshContextState } from '/lib/types.ts';
+import { concurrentPromises } from '/lib/utils/misc.ts';
+import {
+  createBudget,
+  createExpense,
+  deleteAllBudgetsAndExpenses,
+  getBudgets,
+  getExpenses,
+} from '/lib/data/expenses.ts';
+
+interface Data {}
+
+export interface RequestBody {
+  budgets: Pick<Budget, 'name' | 'month' | 'value'>[];
+  expenses: Pick<Expense, 'cost' | 'description' | 'budget' | 'date' | 'is_recurring'>[];
+  month: string;
+  replace: boolean;
+}
+
+export interface ResponseBody {
+  success: boolean;
+  newBudgets: Budget[];
+  newExpenses: Expense[];
+}
+
+export const handler: Handlers<Data, FreshContextState> = {
+  async POST(request, context) {
+    if (!context.state.user) {
+      return new Response('Unauthorized', { status: 401 });
+    }
+
+    const requestBody = await request.clone().json() as RequestBody;
+
+    if (
+      (requestBody.budgets.length === 0 && requestBody.expenses.length === 0) || !requestBody.month ||
+      !requestBody.month.match(/^\d{4}-\d{2}$/)
+    ) {
+      return new Response('Bad request', { status: 400 });
+    }
+
+    if (requestBody.replace) {
+      await deleteAllBudgetsAndExpenses(context.state.user.id);
+    }
+
+    try {
+      await concurrentPromises(
+        requestBody.budgets.map((budget) => () =>
+          createBudget(context.state.user!.id, budget.name, budget.month, budget.value)
+        ),
+        5,
+      );
+
+      await concurrentPromises(
+        requestBody.expenses.map((expense) => () =>
+          createExpense(
+            context.state.user!.id,
+            expense.cost,
+            expense.description,
+            expense.budget,
+            expense.date,
+            expense.is_recurring ?? false,
+            { skipRecalculation: true, skipBudgetMatching: true, skipBudgetCreation: true },
+          )
+        ),
+        5,
+      );
+    } catch (error) {
+      console.error(error);
+      return new Response(`${error}`, { status: 500 });
+    }
+
+    const newExpenses = await getExpenses(context.state.user.id, requestBody.month);
+
+    const newBudgets = await getBudgets(context.state.user.id, requestBody.month);
+
+    const responseBody: ResponseBody = { success: true, newExpenses, newBudgets };
+
+    return new Response(JSON.stringify(responseBody));
+  },
+};