107 lines
3.5 KiB
JavaScript
107 lines
3.5 KiB
JavaScript
'use strict';
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const { getDb } = require('../db/database');
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const { getCycleRange } = require('./statusService');
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const { getUserSettings } = require('./userSettings');
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const MONTHS_BACK = 3;
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const MIN_PAID_MONTHS = 2;
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const MIN_ABS_DELTA = 1.00;
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function median(arr) {
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if (!arr.length) return 0;
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const sorted = [...arr].sort((a, b) => a - b);
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const mid = Math.floor(sorted.length / 2);
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return sorted.length % 2 !== 0
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? sorted[mid]
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: (sorted[mid - 1] + sorted[mid]) / 2;
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}
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function monthEnd(year, month) {
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return new Date(Date.UTC(year, month, 0)).getUTCDate();
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}
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function getDriftReport(userId, now = new Date()) {
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try {
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const db = getDb();
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const settings = getUserSettings(userId);
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const thresholdPct = Math.max(1, Math.min(25,
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parseFloat(settings.drift_threshold_pct ?? '5') || 5
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));
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const bills = db.prepare(`
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SELECT b.*, c.name AS category_name
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FROM bills b
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LEFT JOIN categories c ON c.id = b.category_id
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WHERE b.user_id = ? AND b.active = 1 AND b.deleted_at IS NULL
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`).all(userId);
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const todayStr = now.toISOString().slice(0, 10);
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const drifted = [];
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const mbsStmt = db.prepare(
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'SELECT is_skipped FROM monthly_bill_state WHERE bill_id = ? AND year = ? AND month = ?'
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);
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const payStmt = db.prepare(`
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SELECT COALESCE(SUM(amount), 0) AS total
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FROM payments
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WHERE bill_id = ? AND paid_date BETWEEN ? AND ? AND deleted_at IS NULL
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`);
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for (const bill of bills) {
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if (!bill.expected_amount || bill.expected_amount <= 0) continue;
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if (bill.drift_snoozed_until && bill.drift_snoozed_until > todayStr) continue;
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const monthTotals = [];
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for (let i = 1; i <= MONTHS_BACK; i++) {
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const d = new Date(Date.UTC(now.getUTCFullYear(), now.getUTCMonth() - i, 1));
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const yr = d.getUTCFullYear();
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const mo = d.getUTCMonth() + 1;
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// Skip if bill was created after this month ended
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const monthEndStr = `${yr}-${String(mo).padStart(2,'0')}-${String(monthEnd(yr, mo)).padStart(2,'0')}`;
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if (bill.created_at && bill.created_at.slice(0, 10) > monthEndStr) continue;
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const mbs = mbsStmt.get(bill.id, yr, mo);
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if (mbs?.is_skipped) continue;
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const range = getCycleRange(yr, mo, bill);
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if (!range) continue;
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const { total } = payStmt.get(bill.id, range.start, range.end);
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if (total > 0) monthTotals.push(total);
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}
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if (monthTotals.length < MIN_PAID_MONTHS) continue;
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const recentAmount = median(monthTotals);
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const delta = recentAmount - bill.expected_amount;
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const absDelta = Math.abs(delta);
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const driftPct = (delta / bill.expected_amount) * 100;
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if (absDelta < MIN_ABS_DELTA) continue;
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if (Math.abs(driftPct) < thresholdPct) continue;
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drifted.push({
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id: bill.id,
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name: bill.name,
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category_name: bill.category_name ?? null,
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expected_amount: bill.expected_amount,
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recent_amount: Math.round(recentAmount * 100) / 100,
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drift_pct: Math.round(driftPct * 10) / 10,
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direction: delta > 0 ? 'up' : 'down',
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months_sampled: monthTotals.length,
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drift_snoozed_until: bill.drift_snoozed_until ?? null,
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});
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}
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return { bills: drifted, threshold_pct: thresholdPct };
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} catch (err) {
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console.error('[driftService] getDriftReport error:', err.message);
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return { bills: [], threshold_pct: 5, error: err.message };
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}
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}
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module.exports = { getDriftReport };
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