initial commit

convex/loans.ts

@@ -0,0 +1,198 @@
+import { query, mutation } from "./_generated/server";
+import { v } from "convex/values";
+import { assertOwned, requireUserId } from "./lib/helpers";
+import {
+  buildSchedule,
+  computePaymentFromTerm,
+  computeTermFromPayment,
+  currentBalanceFromSchedule,
+} from "./lib/amortization";
+
+const loanValidator = v.object({
+  _id: v.id("loans"),
+  _creationTime: v.number(),
+  userId: v.id("users"),
+  name: v.string(),
+  lender: v.optional(v.string()),
+  accountId: v.optional(v.id("accounts")),
+  categoryId: v.optional(v.id("categories")),
+  principal: v.number(),
+  annualInterestRate: v.number(),
+  monthlyPayment: v.optional(v.number()),
+  termMonths: v.optional(v.number()),
+  startDate: v.string(),
+  currentBalance: v.optional(v.number()),
+  status: v.union(v.literal("aktiv"), v.literal("abbezahlt"), v.literal("pausiert")),
+  notes: v.optional(v.string()),
+});
+
+function normalizeLoanFields(args: {
+  principal: number;
+  annualInterestRate: number;
+  monthlyPayment?: number;
+  termMonths?: number;
+}) {
+  let { monthlyPayment, termMonths } = args;
+  if (monthlyPayment !== undefined && termMonths === undefined) {
+    termMonths = computeTermFromPayment(args.principal, args.annualInterestRate, monthlyPayment);
+  } else if (termMonths !== undefined && monthlyPayment === undefined) {
+    monthlyPayment = computePaymentFromTerm(args.principal, args.annualInterestRate, termMonths);
+  } else if (monthlyPayment === undefined && termMonths === undefined) {
+    throw new Error("Entweder Rate oder Laufzeit angeben");
+  }
+  return { monthlyPayment, termMonths };
+}
+
+export const list = query({
+  args: {},
+  returns: v.array(loanValidator),
+  handler: async (ctx) => {
+    const userId = await requireUserId(ctx);
+    return await ctx.db
+      .query("loans")
+      .withIndex("by_user", (q) => q.eq("userId", userId))
+      .collect();
+  },
+});
+
+export const create = mutation({
+  args: {
+    name: v.string(),
+    lender: v.optional(v.string()),
+    accountId: v.optional(v.id("accounts")),
+    categoryId: v.optional(v.id("categories")),
+    principal: v.number(),
+    annualInterestRate: v.number(),
+    monthlyPayment: v.optional(v.number()),
+    termMonths: v.optional(v.number()),
+    startDate: v.string(),
+    currentBalance: v.optional(v.number()),
+    status: v.union(v.literal("aktiv"), v.literal("abbezahlt"), v.literal("pausiert")),
+    notes: v.optional(v.string()),
+  },
+  returns: v.id("loans"),
+  handler: async (ctx, args) => {
+    const userId = await requireUserId(ctx);
+    const normalized = normalizeLoanFields(args);
+    return await ctx.db.insert("loans", {
+      userId,
+      name: args.name,
+      lender: args.lender,
+      accountId: args.accountId,
+      categoryId: args.categoryId,
+      principal: args.principal,
+      annualInterestRate: args.annualInterestRate,
+      monthlyPayment: normalized.monthlyPayment,
+      termMonths: normalized.termMonths,
+      startDate: args.startDate,
+      currentBalance: args.currentBalance,
+      status: args.status,
+      notes: args.notes,
+    });
+  },
+});
+
+export const update = mutation({
+  args: {
+    id: v.id("loans"),
+    name: v.optional(v.string()),
+    lender: v.optional(v.string()),
+    accountId: v.optional(v.id("accounts")),
+    categoryId: v.optional(v.id("categories")),
+    principal: v.optional(v.number()),
+    annualInterestRate: v.optional(v.number()),
+    monthlyPayment: v.optional(v.number()),
+    termMonths: v.optional(v.number()),
+    startDate: v.optional(v.string()),
+    currentBalance: v.optional(v.number()),
+    status: v.optional(
+      v.union(v.literal("aktiv"), v.literal("abbezahlt"), v.literal("pausiert")),
+    ),
+    notes: v.optional(v.string()),
+  },
+  returns: v.null(),
+  handler: async (ctx, args) => {
+    const userId = await requireUserId(ctx);
+    const loan = await assertOwned(await ctx.db.get("loans", args.id), userId, "Kredit");
+    const merged = {
+      principal: args.principal ?? loan.principal,
+      annualInterestRate: args.annualInterestRate ?? loan.annualInterestRate,
+      monthlyPayment: args.monthlyPayment ?? loan.monthlyPayment,
+      termMonths: args.termMonths ?? loan.termMonths,
+    };
+    const normalized = normalizeLoanFields(merged);
+
+    const patch: Record<string, unknown> = {
+      monthlyPayment: normalized.monthlyPayment,
+      termMonths: normalized.termMonths,
+    };
+    for (const key of [
+      "name",
+      "lender",
+      "accountId",
+      "categoryId",
+      "principal",
+      "annualInterestRate",
+      "startDate",
+      "currentBalance",
+      "status",
+      "notes",
+    ] as const) {
+      if (args[key] !== undefined) patch[key] = args[key];
+    }
+
+    await ctx.db.patch(args.id, patch);
+    return null;
+  },
+});
+
+export const remove = mutation({
+  args: { id: v.id("loans") },
+  returns: v.null(),
+  handler: async (ctx, args) => {
+    const userId = await requireUserId(ctx);
+    await assertOwned(await ctx.db.get("loans", args.id), userId, "Kredit");
+    await ctx.db.delete(args.id);
+    return null;
+  },
+});
+
+export const computeSummary = query({
+  args: { id: v.id("loans") },
+  returns: v.object({
+    currentBalance: v.number(),
+    payoffDate: v.string(),
+    totalInterest: v.number(),
+    remainingMonths: v.number(),
+  }),
+  handler: async (ctx, args) => {
+    const userId = await requireUserId(ctx);
+    const loan = await assertOwned(await ctx.db.get("loans", args.id), userId, "Kredit");
+    const startDate = new Date(loan.startDate);
+    const scheduleResult = buildSchedule({
+      principal: loan.principal,
+      annualRate: loan.annualInterestRate,
+      startDate,
+      monthlyPayment: loan.monthlyPayment,
+      termMonths: loan.termMonths,
+    });
+    const balance =
+      loan.currentBalance ??
+      currentBalanceFromSchedule(scheduleResult.schedule, startDate);
+    const remainingMonths = scheduleResult.schedule.filter(
+      (_, idx) =>
+        idx >=
+        Math.max(
+          0,
+          (new Date().getFullYear() - startDate.getFullYear()) * 12 +
+            (new Date().getMonth() - startDate.getMonth()),
+        ),
+    ).length;
+    return {
+      currentBalance: balance,
+      payoffDate: scheduleResult.payoffDate.toISOString().slice(0, 10),
+      totalInterest: scheduleResult.totalInterest,
+      remainingMonths,
+    };
+  },
+});