import { z } from "zod";
import { listTransactions } from "./list-transactions.js";
import type { Transaction } from "../types.js";
export const spendingSummarySchema = z.object({
connectionId: z.string().optional(),
dateFrom: z.string().optional(),
dateTo: z.string().optional(),
groupBy: z
.enum(["merchant", "category"])
.optional()
.describe('Group expenses by "merchant" (default) or "category".'),
limit: z
.number()
.optional()
.describe("Max groups to return (default 20, sorted by total spent)."),
});
interface SpendingGroup {
name: string;
totalSpent: number;
transactionCount: number;
currency: string;
}
export async function spendingSummary(
args: z.infer<typeof spendingSummarySchema>,
): Promise<{ groups: SpendingGroup[]; totalSpent: number; currency: string; period: string }> {
const transactions = await listTransactions({
connectionId: args.connectionId,
dateFrom: args.dateFrom,
dateTo: args.dateTo,
type: "debit",
});
const groupBy = args.groupBy || "merchant";
const limit = args.limit || 20;
// Group expenses
const groups = new Map<string, { total: number; count: number; currency: string }>();
for (const tx of transactions) {
const key =
groupBy === "merchant"
? tx.merchantName || tx.description || "Unknown"
: tx.category || "uncategorized";
const existing = groups.get(key) || { total: 0, count: 0, currency: tx.currency };
existing.total += Math.abs(tx.amount);
existing.count += 1;
groups.set(key, existing);
}
// Sort by total spent descending
const sorted = [...groups.entries()]
.map(([name, data]) => ({
name,
totalSpent: Math.round(data.total * 100) / 100,
transactionCount: data.count,
currency: data.currency,
}))
.sort((a, b) => b.totalSpent - a.totalSpent)
.slice(0, limit);
const totalSpent =
Math.round(transactions.reduce((sum, t) => sum + Math.abs(t.amount), 0) * 100) / 100;
const currency = transactions[0]?.currency || "PLN";
const dateFrom = args.dateFrom || defaultDateFrom(90);
const dateTo = args.dateTo || today();
return {
groups: sorted,
totalSpent,
currency,
period: `${dateFrom} to ${dateTo}`,
};
}
function defaultDateFrom(days: number): string {
const d = new Date();
d.setDate(d.getDate() - days);
return d.toISOString().slice(0, 10);
}
function today(): string {
return new Date().toISOString().slice(0, 10);
}
