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/add-expense.tsx

@@ -0,0 +1,80 @@
+import { Handlers } from 'fresh/server.ts';
+
+import { Budget, Expense, FreshContextState } from '/lib/types.ts';
+import { createExpense, getBudgets, getExpenses } from '/lib/data/expenses.ts';
+
+interface Data {}
+
+export interface RequestBody {
+  cost: number;
+  description: string;
+  budget: string;
+  date: string;
+  is_recurring: boolean;
+  month: string;
+}
+
+export interface ResponseBody {
+  success: boolean;
+  newExpenses: Expense[];
+  newBudgets: Budget[];
+}
+
+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.cost || Number.isNaN(requestBody.cost) || !requestBody.description || !requestBody.month ||
+      !requestBody.month.match(/^\d{4}-\d{2}$/)
+    ) {
+      return new Response('Bad request', { status: 400 });
+    }
+
+    if (!requestBody.budget) {
+      requestBody.budget = 'Misc';
+    }
+
+    if (!requestBody.date) {
+      requestBody.date = new Date().toISOString().substring(0, 10);
+    }
+
+    if (!requestBody.date.match(/^\d{4}-\d{2}-\d{2}$/)) {
+      return new Response('Bad request', { status: 400 });
+    }
+
+    if (!requestBody.is_recurring) {
+      requestBody.is_recurring = false;
+    }
+
+    try {
+      const newExpense = await createExpense(
+        context.state.user.id,
+        requestBody.cost,
+        requestBody.description,
+        requestBody.budget,
+        requestBody.date,
+        requestBody.is_recurring,
+      );
+
+      if (!newExpense) {
+        throw new Error('Failed to add expense!');
+      }
+    } 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));
+  },
+};