/**
 * reports-view.js — Due-Diligence Reports
 *
 *   1. Accounts Receivable Aging (Stichtag frei wählbar)
 *   2. Invoice-Level Revenue (Zeitraum frei wählbar, optional nach Monat gruppiert)
 *   3. Revenue by Category (Parts/Labor/Subscription, optional Monate als Spalten)
 *
 * Die ersten beiden Reports können Kundennamen pseudonymisieren. Die Anonymisierung
 * passiert ausschließlich serverseitig — dieses Modul bekommt bei aktiver Option gar
 * keine Klarnamen zu sehen und kann sie folglich auch nicht in ein CSV schreiben.
 * Report 3 aggregiert über Kategorien und enthält gar keine Kundennamen.
 *
 * Beträge kommen als numeric-Strings vom Server und werden nur zur Anzeige
 * formatiert. Ins CSV gehen die Rohwerte, damit Excel sauber rechnen kann.
 */

import '../utils/api.js';
import { formatDate } from '../utils/helpers.js';
import {
    fmtMoney, escapeHtml, showError, showLoading,
    todayISO, firstOfMonthISO, lastOfMonthISO, prevMonthISO, firstOfYearISO,
    renderQboReport, initAlpineTree
} from '../utils/report-helpers.js';

// ── State ───────────────────────────────────────────────────────────
const today = new Date().toISOString().split('T')[0];
const startOfYear = `${new Date().getFullYear()}-01-01`;

let arAsOf = today;
let arAnonymize = false;
let arData = null;

let revFrom = startOfYear;
let revTo = today;
let revAnonymize = false;
let revGroupByMonth = false;
let revData = null;

let catFrom = startOfYear;
let catTo = today;
let catGroupByMonth = false;
let catData = null;

// State der aus accounting-view.js übernommenen Reports (1:1)
let plStartDate = null;
let plEndDate = null;
let plAccountingMethod = 'Accrual';

let bsAsOfDate = null;
let bsAccountingMethod = 'Accrual';

let tsMonth = null; // 'YYYY-MM' — selected month for tax summary
let tsAccountingMethod = 'Accrual';

let crStartDate = null;
let crEndDate = null;

const AR_BUCKETS = [
    { key: 'current',  label: 'Current' },
    { key: 'd1_30',    label: '1–30 days' },
    { key: 'd31_60',   label: '31–60 days' },
    { key: 'd61_90',   label: '61–90 days' },
    { key: 'd90_plus', label: '90+ days' }
];
const BUCKET_LABEL = Object.fromEntries(AR_BUCKETS.map(b => [b.key, b.label]));

// ── Local helpers ───────────────────────────────────────────────────
// fmtMoney/escapeHtml/showError/showLoading kommen aus report-helpers.js.

/** showError mit dem Reports-spezifischen Titel. */
function reportError(slotId, message) {
    showError(slotId, message, 'Report Error');
}

function methodologyBox(text, anonymized) {
    return `
        <div class="mb-3 px-3 py-2 bg-gray-50 border border-gray-200 rounded text-xs text-gray-600">
            <span class="font-semibold text-gray-700">Methodology:</span> ${escapeHtml(text)}
            ${anonymized ? '<span class="ml-2 inline-block px-2 py-0.5 bg-amber-100 text-amber-800 rounded font-medium">anonymized</span>' : ''}
        </div>`;
}

function monthLabel(monthKey) {
    const [y, m] = monthKey.split('-').map(Number);
    return new Date(Date.UTC(y, m - 1, 1))
        .toLocaleDateString('en-US', { month: 'long', year: 'numeric', timeZone: 'UTC' });
}

// ── CSV ─────────────────────────────────────────────────────────────

function csvCell(v) {
    if (v == null) return '';
    const s = String(v);
    return /[",\n]/.test(s) ? `"${s.replace(/"/g, '""')}"` : s;
}

function csvRow(cells) {
    return cells.map(csvCell).join(',');
}

function downloadCsv(filename, lines) {
    // BOM, damit Excel UTF-8 korrekt erkennt
    const blob = new Blob(['' + lines.join('\r\n')], { type: 'text/csv;charset=utf-8;' });
    const url = URL.createObjectURL(blob);
    const a = document.createElement('a');
    a.href = url;
    a.download = filename;
    document.body.appendChild(a);
    a.click();
    document.body.removeChild(a);
    URL.revokeObjectURL(url);
}

// ── Shell ───────────────────────────────────────────────────────────

function reportCard(title, bodyHtml) {
    // x-show statt x-if: der Teilbaum bleibt im DOM, damit Datumsfelder und
    // Checkboxen ihren Zustand über das Zu-/Aufklappen hinweg behalten.
    // Das inline display:none verhindert ein Aufblitzen, bis Alpine initialisiert.
    return `
        <div class="bg-white rounded-lg shadow-sm border border-gray-200" x-data="{ open: false }">
            <div class="px-4 py-3 border-b bg-gray-50 flex items-center gap-2 cursor-pointer select-none"
                 @click="open = !open">
                <svg class="w-4 h-4 text-gray-500 transition-transform" :class="open ? 'rotate-90' : ''"
                     fill="none" viewBox="0 0 24 24" stroke="currentColor">
                    <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M9 5l7 7-7 7" />
                </svg>
                <h3 class="font-semibold text-gray-800">${title}</h3>
            </div>
            <div class="p-4" x-show="open" style="display:none">
                ${bodyHtml}
            </div>
        </div>`;
}

export function renderReportsView() {
    const el = document.getElementById('reports-content');
    if (!el) return;

    // Defaults der übernommenen Reports — 1:1 aus injectReportsControls()
    if (!plStartDate) plStartDate = firstOfYearISO();
    if (!plEndDate)   plEndDate   = todayISO();
    if (!bsAsOfDate)  bsAsOfDate  = todayISO();
    if (!tsMonth)     tsMonth     = prevMonthISO();
    if (!crStartDate) crStartDate = firstOfYearISO();
    if (!crEndDate)   crEndDate   = todayISO();

    const arAgingBody = `
        <div class="flex flex-wrap items-end gap-3 mb-3">
            <div>
                <label class="block text-xs font-medium text-gray-700 mb-1">As of</label>
                <input type="date" id="ar-asof" value="${arAsOf}"
                       class="px-3 py-1.5 border border-gray-300 rounded-md text-sm">
            </div>
            <button onclick="window.reportsView.loadArAging()"
                    class="px-3 py-1.5 bg-blue-600 text-white rounded-md text-sm font-medium hover:bg-blue-700">Run</button>
            <button onclick="window.reportsView.exportArAgingCsv()"
                    class="px-3 py-1.5 bg-gray-100 hover:bg-gray-200 text-gray-700 rounded-md text-sm font-medium border border-gray-300">⬇ Export CSV</button>
            <button onclick="window.reportsView.exportArAgingPdf()"
                    class="px-3 py-1.5 bg-gray-100 hover:bg-gray-200 text-gray-700 rounded-md text-sm font-medium border border-gray-300">📄 Export PDF</button>
            <label class="flex items-center gap-1 pt-5 text-xs text-gray-600 cursor-pointer">
                <input type="checkbox" id="ar-anonymize" ${arAnonymize ? 'checked' : ''}
                       class="h-4 w-4 text-blue-600 border-gray-300 rounded">
                Anonymize customers
            </label>
        </div>
        <div id="ar-result"></div>`;

    const revenueBody = `
        <div class="flex flex-wrap items-end gap-3 mb-3">
            <div>
                <label class="block text-xs font-medium text-gray-700 mb-1">From</label>
                <input type="date" id="rev-from" value="${revFrom}"
                       class="px-3 py-1.5 border border-gray-300 rounded-md text-sm">
            </div>
            <div>
                <label class="block text-xs font-medium text-gray-700 mb-1">To</label>
                <input type="date" id="rev-to" value="${revTo}"
                       class="px-3 py-1.5 border border-gray-300 rounded-md text-sm">
            </div>
            <button onclick="window.reportsView.loadRevenue()"
                    class="px-3 py-1.5 bg-blue-600 text-white rounded-md text-sm font-medium hover:bg-blue-700">Run</button>
            <button onclick="window.reportsView.exportRevenueCsv()"
                    class="px-3 py-1.5 bg-gray-100 hover:bg-gray-200 text-gray-700 rounded-md text-sm font-medium border border-gray-300">⬇ Export CSV</button>
            <button onclick="window.reportsView.exportRevenuePdf()"
                    class="px-3 py-1.5 bg-gray-100 hover:bg-gray-200 text-gray-700 rounded-md text-sm font-medium border border-gray-300">📄 Export PDF</button>
            <label class="flex items-center gap-1 pt-5 text-xs text-gray-600 cursor-pointer">
                <input type="checkbox" id="rev-group-month" ${revGroupByMonth ? 'checked' : ''}
                       class="h-4 w-4 text-blue-600 border-gray-300 rounded">
                Group by month
            </label>
            <label class="flex items-center gap-1 pt-5 text-xs text-gray-600 cursor-pointer">
                <input type="checkbox" id="rev-anonymize" ${revAnonymize ? 'checked' : ''}
                       class="h-4 w-4 text-blue-600 border-gray-300 rounded">
                Anonymize customers
            </label>
        </div>
        <div id="rev-result"></div>`;

    const categoryRevenueBody = `
        <div class="flex flex-wrap items-end gap-3 mb-3">
            <div>
                <label class="block text-xs font-medium text-gray-700 mb-1">From</label>
                <input type="date" id="cat-from" value="${catFrom}"
                       class="px-3 py-1.5 border border-gray-300 rounded-md text-sm">
            </div>
            <div>
                <label class="block text-xs font-medium text-gray-700 mb-1">To</label>
                <input type="date" id="cat-to" value="${catTo}"
                       class="px-3 py-1.5 border border-gray-300 rounded-md text-sm">
            </div>
            <button onclick="window.reportsView.loadCategoryRevenue()"
                    class="px-3 py-1.5 bg-blue-600 text-white rounded-md text-sm font-medium hover:bg-blue-700">Run</button>
            <button onclick="window.reportsView.exportCategoryRevenueCsv()"
                    class="px-3 py-1.5 bg-gray-100 hover:bg-gray-200 text-gray-700 rounded-md text-sm font-medium border border-gray-300">⬇ Export CSV</button>
            <button onclick="window.reportsView.exportCategoryRevenuePdf()"
                    class="px-3 py-1.5 bg-gray-100 hover:bg-gray-200 text-gray-700 rounded-md text-sm font-medium border border-gray-300">📄 Export PDF</button>
            <label class="flex items-center gap-1 pt-5 text-xs text-gray-600 cursor-pointer">
                <input type="checkbox" id="cat-group-month" ${catGroupByMonth ? 'checked' : ''}
                       class="h-4 w-4 text-blue-600 border-gray-300 rounded">
                Group by month
            </label>
        </div>
        <div id="cat-result"></div>`;

    // ── Ab hier 1:1 aus accounting-view.js injectReportsControls() ──
    const profitLossBody = `
        <div class="flex flex-wrap items-end gap-3 mb-3">
            <div><label class="block text-xs font-medium text-gray-700 mb-1">Start</label>
                <input type="date" id="pl-start" value="${plStartDate}" class="px-3 py-1.5 border border-gray-300 rounded-md text-sm"></div>
            <div><label class="block text-xs font-medium text-gray-700 mb-1">End</label>
                <input type="date" id="pl-end" value="${plEndDate}" class="px-3 py-1.5 border border-gray-300 rounded-md text-sm"></div>
            <div><label class="block text-xs font-medium text-gray-700 mb-1">Method</label>
                <select id="pl-method" class="px-3 py-1.5 border border-gray-300 rounded-md text-sm">
                    <option value="Accrual" ${plAccountingMethod === 'Accrual' ? 'selected' : ''}>Accrual</option>
                    <option value="Cash" ${plAccountingMethod === 'Cash' ? 'selected' : ''}>Cash</option>
                </select></div>
            <button onclick="window.reportsView.loadProfitLoss()" class="px-3 py-1.5 bg-blue-600 text-white rounded-md text-sm font-medium hover:bg-blue-700">Run</button>
            <button onclick="window.reportsView.exportProfitLossPdf()" class="px-3 py-1.5 bg-gray-100 hover:bg-gray-200 text-gray-700 rounded-md text-sm font-medium border border-gray-300">📄 PDF</button>
        </div>
        <div id="pl-result"></div>`;

    const balanceSheetBody = `
        <div class="flex flex-wrap items-end gap-3 mb-3">
            <div><label class="block text-xs font-medium text-gray-700 mb-1">As of</label>
                <input type="date" id="bs-asof" value="${bsAsOfDate}" class="px-3 py-1.5 border border-gray-300 rounded-md text-sm"></div>
            <div><label class="block text-xs font-medium text-gray-700 mb-1">Method</label>
                <select id="bs-method" class="px-3 py-1.5 border border-gray-300 rounded-md text-sm">
                    <option value="Accrual" ${bsAccountingMethod === 'Accrual' ? 'selected' : ''}>Accrual</option>
                    <option value="Cash" ${bsAccountingMethod === 'Cash' ? 'selected' : ''}>Cash</option>
                </select></div>
            <button onclick="window.reportsView.loadBalanceSheet()" class="px-3 py-1.5 bg-blue-600 text-white rounded-md text-sm font-medium hover:bg-blue-700">Run</button>
            <button onclick="window.reportsView.exportBalanceSheetPdf()" class="px-3 py-1.5 bg-gray-100 hover:bg-gray-200 text-gray-700 rounded-md text-sm font-medium border border-gray-300">📄 PDF</button>
        </div>
        <div id="bs-result"></div>`;

    const taxSummaryBody = `
        <div class="flex flex-wrap items-end gap-3 mb-3">
            <div><label class="block text-xs font-medium text-gray-700 mb-1">Month</label>
                <input type="month" id="ts-month" value="${tsMonth}" class="px-3 py-1.5 border border-gray-300 rounded-md text-sm"></div>
            <div><label class="block text-xs font-medium text-gray-700 mb-1">Method</label>
                <select id="ts-method" class="px-3 py-1.5 border border-gray-300 rounded-md text-sm">
                    <option value="Accrual" ${tsAccountingMethod === 'Accrual' ? 'selected' : ''}>Accrual</option>
                    <option value="Cash" ${tsAccountingMethod === 'Cash' ? 'selected' : ''}>Cash</option>
                </select></div>
            <button onclick="window.reportsView.loadTaxSummary()" class="px-3 py-1.5 bg-blue-600 text-white rounded-md text-sm font-medium hover:bg-blue-700">Run</button>
            <button onclick="window.reportsView.exportTaxSummaryPdf()" class="px-3 py-1.5 bg-gray-100 hover:bg-gray-200 text-gray-700 rounded-md text-sm font-medium border border-gray-300">📄 PDF</button>
        </div>
        <div id="ts-result"></div>`;

    const customerRevenueBody = `
        <div class="flex flex-wrap items-end gap-3 mb-3">
            <div><label class="block text-xs font-medium text-gray-700 mb-1">Start</label>
                <input type="date" id="cr-start" value="${crStartDate}" class="px-3 py-1.5 border border-gray-300 rounded-md text-sm"></div>
            <div><label class="block text-xs font-medium text-gray-700 mb-1">End</label>
                <input type="date" id="cr-end" value="${crEndDate}" class="px-3 py-1.5 border border-gray-300 rounded-md text-sm"></div>
            <button onclick="window.reportsView.loadCustomerRevenue()" class="px-3 py-1.5 bg-blue-600 text-white rounded-md text-sm font-medium hover:bg-blue-700">Run</button>
            <button onclick="window.reportsView.exportCustomerRevenuePdf()" class="px-3 py-1.5 bg-gray-100 hover:bg-gray-200 text-gray-700 rounded-md text-sm font-medium border border-gray-300">📄 Export PDF</button>
            <label class="flex items-center gap-1 pt-5 text-xs text-gray-600 cursor-pointer">
                <input type="checkbox" id="cr-anonymize" class="h-4 w-4 text-blue-600 border-gray-300 rounded">
                Anonymize
            </label>
        </div>
        <div id="cr-result"></div>`;

    el.innerHTML = `
        <div class="space-y-4">
            ${reportCard('Accounts Receivable Aging', arAgingBody)}
            ${reportCard('Invoice-Level Revenue', revenueBody)}
            ${reportCard('Revenue by Category', categoryRevenueBody)}
            ${reportCard('Customer Revenue (Summary)', customerRevenueBody)}
            ${reportCard('Profit &amp; Loss', profitLossBody)}
            ${reportCard('Balance Sheet', balanceSheetBody)}
            ${reportCard('Sales Tax (QBO)', taxSummaryBody)}
        </div>`;

    // Alpine scannt das DOM nur beim Start — nachgereichtes Markup selbst anmelden.
    initAlpineTree(el);
}

// ── Report 1: AR Aging ──────────────────────────────────────────────

export async function loadArAging() {
    arAsOf = document.getElementById('ar-asof').value || today;
    arAnonymize = document.getElementById('ar-anonymize')?.checked || false;
    showLoading('ar-result', 'Loading receivables…');
    try {
        const data = await window.API.reports.getArAging(arAsOf, arAnonymize);
        if (data.error) return reportError('ar-result', data.error);
        arData = data;
        renderArAging(data);
    } catch (err) {
        reportError('ar-result', err.message || 'Failed to load AR aging');
    }
}

function renderArAging(data) {
    if (!data.rows.length) {
        document.getElementById('ar-result').innerHTML =
            methodologyBox(data.methodology, data.anonymized) +
            '<p class="text-sm text-gray-500">No open receivables as of this date.</p>';
        return;
    }

    let rowsHtml = '';
    for (const r of data.rows) {
        const overdue = r.bucket !== 'current';
        rowsHtml += `<tr class="border-t hover:bg-gray-50">
            <td class="px-3 py-2 text-sm font-medium">${escapeHtml(r.customer_name || '—')}</td>
            <td class="px-3 py-2 text-sm">${escapeHtml(r.invoice_number || '—')}</td>
            <td class="px-3 py-2 text-sm text-gray-600">${formatDate(r.invoice_date)}</td>
            <td class="px-3 py-2 text-sm text-gray-600">${formatDate(r.due_date)}</td>
            <td class="px-3 py-2 text-sm text-right">${fmtMoney(r.original_amount)}</td>
            <td class="px-3 py-2 text-sm text-right font-medium">${fmtMoney(r.open_amount)}</td>
            <td class="px-3 py-2 text-sm text-center ${overdue ? 'text-red-700 font-medium' : 'text-gray-500'}">
                ${BUCKET_LABEL[r.bucket] || r.bucket}
            </td>
        </tr>`;
    }

    const t = data.totals;
    rowsHtml += `<tr class="border-t-2 border-gray-300 bg-gray-50 font-semibold">
        <td class="px-3 py-2 text-sm" colspan="4">TOTAL (${t.invoice_count} invoices)</td>
        <td class="px-3 py-2 text-sm text-right">${fmtMoney(t.original_amount)}</td>
        <td class="px-3 py-2 text-sm text-right">${fmtMoney(t.open_amount)}</td>
        <td></td>
    </tr>`;

    let bucketCells = '';
    for (const b of AR_BUCKETS) {
        const entry = data.buckets[b.key];
        bucketCells += `<tr class="border-t">
            <td class="px-3 py-2 text-sm">${b.label}</td>
            <td class="px-3 py-2 text-sm text-center text-gray-600">${entry.invoice_count}</td>
            <td class="px-3 py-2 text-sm text-right">${fmtMoney(entry.open_amount)}</td>
        </tr>`;
    }

    document.getElementById('ar-result').innerHTML =
        methodologyBox(data.methodology, data.anonymized) + `
        <div class="mb-4 max-w-md">
            <div class="overflow-x-auto border border-gray-200 rounded">
                <table class="min-w-full text-sm">
                    <thead class="bg-gray-50">
                        <tr>
                            <th class="px-3 py-2 text-left font-medium text-gray-700">Bucket</th>
                            <th class="px-3 py-2 text-center font-medium text-gray-700">Invoices</th>
                            <th class="px-3 py-2 text-right font-medium text-gray-700">Open</th>
                        </tr>
                    </thead>
                    <tbody>
                        ${bucketCells}
                        <tr class="border-t-2 border-gray-300 bg-gray-50 font-semibold">
                            <td class="px-3 py-2 text-sm">Total</td>
                            <td class="px-3 py-2 text-sm text-center">${t.invoice_count}</td>
                            <td class="px-3 py-2 text-sm text-right">${fmtMoney(t.open_amount)}</td>
                        </tr>
                    </tbody>
                </table>
            </div>
        </div>
        <div class="overflow-x-auto border border-gray-200 rounded">
            <table class="min-w-full text-sm">
                <thead class="bg-gray-50">
                    <tr>
                        <th class="px-3 py-2 text-left font-medium text-gray-700">Customer</th>
                        <th class="px-3 py-2 text-left font-medium text-gray-700">Invoice #</th>
                        <th class="px-3 py-2 text-left font-medium text-gray-700">Date</th>
                        <th class="px-3 py-2 text-left font-medium text-gray-700">Due</th>
                        <th class="px-3 py-2 text-right font-medium text-gray-700">Original</th>
                        <th class="px-3 py-2 text-right font-medium text-gray-700">Open</th>
                        <th class="px-3 py-2 text-center font-medium text-gray-700">Bucket</th>
                    </tr>
                </thead>
                <tbody>${rowsHtml}</tbody>
            </table>
        </div>`;
}

export function exportArAgingCsv() {
    if (!arData || !arData.rows.length) {
        return reportError('ar-result', 'Run the report first — there is nothing to export.');
    }
    const lines = [];
    lines.push(csvRow([`Accounts Receivable Aging as of ${arData.asOf}`]));
    lines.push(csvRow([`Methodology: ${arData.methodology}`]));
    lines.push('');
    lines.push(csvRow(['Customer', 'Invoice #', 'Invoice Date', 'Due Date', 'Original Amount', 'Open Amount', 'Bucket']));

    for (const r of arData.rows) {
        lines.push(csvRow([
            r.customer_name || '',
            r.invoice_number || '',
            String(r.invoice_date).split('T')[0],
            String(r.due_date).split('T')[0],
            r.original_amount,
            r.open_amount,
            BUCKET_LABEL[r.bucket] || r.bucket
        ]));
    }

    const t = arData.totals;
    lines.push(csvRow(['TOTAL', '', '', '', t.original_amount, t.open_amount, `${t.invoice_count} invoices`]));
    lines.push('');
    lines.push(csvRow(['Bucket Summary', 'Invoices', 'Open Amount']));
    for (const b of AR_BUCKETS) {
        const entry = arData.buckets[b.key];
        lines.push(csvRow([b.label, entry.invoice_count, entry.open_amount]));
    }
    lines.push(csvRow(['Total', t.invoice_count, t.open_amount]));

    downloadCsv(`ar-aging-${arData.asOf}${arData.anonymized ? '-anonymized' : ''}.csv`, lines);
}

/**
 * PDF-Export nach dem Muster von exportCustomerRevenuePdf: Parameter direkt
 * aus den Eingabefeldern, der Server holt die Daten neu. Der Report muss
 * dafür nicht vorher ausgeführt worden sein.
 */
export function exportArAgingPdf() {
    const asOfEl = document.getElementById('ar-asof');
    if (!asOfEl?.value) return alert('Please select an as-of date first.');
    const anonymize = document.getElementById('ar-anonymize')?.checked || false;
    let url = `/api/reports/ar-aging/pdf?asOf=${asOfEl.value}`;
    if (anonymize) url += '&anonymize=true';
    window.open(url, '_blank');
}

// ── Report 2: Invoice-Level Revenue ─────────────────────────────────

export async function loadRevenue() {
    revFrom = document.getElementById('rev-from').value;
    revTo = document.getElementById('rev-to').value;
    revAnonymize = document.getElementById('rev-anonymize')?.checked || false;
    revGroupByMonth = document.getElementById('rev-group-month')?.checked || false;

    if (!revFrom || !revTo) return reportError('rev-result', 'Please select both a from and a to date.');
    if (revFrom > revTo) return reportError('rev-result', 'The from date must not be after the to date.');

    showLoading('rev-result', 'Loading revenue…');
    try {
        const data = await window.API.reports.getRevenue(revFrom, revTo, revAnonymize, revGroupByMonth);
        if (data.error) return reportError('rev-result', data.error);
        revData = data;
        renderRevenue(data);
    } catch (err) {
        reportError('rev-result', err.message || 'Failed to load revenue');
    }
}

function revenueRowHtml(r) {
    return `<tr class="border-t hover:bg-gray-50">
        <td class="px-3 py-2 text-sm font-medium">${escapeHtml(r.customer_name || '—')}</td>
        <td class="px-3 py-2 text-sm">${escapeHtml(r.invoice_number || '—')}</td>
        <td class="px-3 py-2 text-sm text-gray-600">${formatDate(r.invoice_date)}</td>
        <td class="px-3 py-2 text-sm text-right">${fmtMoney(r.subtotal)}</td>
        <td class="px-3 py-2 text-sm text-right">${fmtMoney(r.tax_amount)}</td>
        <td class="px-3 py-2 text-sm text-right font-medium">${fmtMoney(r.total)}</td>
        <td class="px-3 py-2 text-sm text-right">${fmtMoney(r.paid_amount)}</td>
        <td class="px-3 py-2 text-sm text-right">${fmtMoney(r.open_amount)}</td>
        <td class="px-3 py-2 text-sm text-center text-gray-500">${escapeHtml(r.payment_status || '—')}</td>
    </tr>`;
}

function revenueSummaryRow(label, s, extraClass) {
    return `<tr class="${extraClass}">
        <td class="px-3 py-2 text-sm" colspan="3">${escapeHtml(label)} (${s.invoice_count} invoices)</td>
        <td class="px-3 py-2 text-sm text-right">${fmtMoney(s.subtotal)}</td>
        <td class="px-3 py-2 text-sm text-right">${fmtMoney(s.tax_amount)}</td>
        <td class="px-3 py-2 text-sm text-right">${fmtMoney(s.total)}</td>
        <td class="px-3 py-2 text-sm text-right">${fmtMoney(s.paid_amount)}</td>
        <td class="px-3 py-2 text-sm text-right">${fmtMoney(s.open_amount)}</td>
        <td></td>
    </tr>`;
}

function renderRevenue(data) {
    if (!data.rows.length) {
        document.getElementById('rev-result').innerHTML =
            methodologyBox(data.methodology, data.anonymized) +
            '<p class="text-sm text-gray-500">No invoices found in this period.</p>';
        return;
    }

    let rowsHtml = '';
    if (data.groupByMonth) {
        // Monats-Zwischensummen kommen aus SQL, nicht aus JS-Addition
        const sumsByMonth = new Map(data.months.map(m => [m.month_key, m]));
        const groupClass = 'bg-gray-50 border-t-2 border-gray-300 font-semibold text-gray-700';
        let currentMonth = null;

        for (const r of data.rows) {
            if (r.month_key !== currentMonth) {
                if (currentMonth !== null) {
                    rowsHtml += revenueSummaryRow('Group Total', sumsByMonth.get(currentMonth), groupClass);
                }
                currentMonth = r.month_key;
                rowsHtml += `<tr class="bg-blue-50"><td colspan="9" class="px-3 py-2 text-sm font-bold text-blue-800">📅 ${escapeHtml(monthLabel(r.month_key))}</td></tr>`;
            }
            rowsHtml += revenueRowHtml(r);
        }
        if (currentMonth !== null) {
            rowsHtml += revenueSummaryRow('Group Total', sumsByMonth.get(currentMonth), groupClass);
        }
    } else {
        for (const r of data.rows) rowsHtml += revenueRowHtml(r);
    }

    rowsHtml += revenueSummaryRow('TOTAL', data.totals, 'border-t-2 border-gray-400 bg-gray-100 font-bold');

    document.getElementById('rev-result').innerHTML =
        methodologyBox(data.methodology, data.anonymized) + `
        <div class="overflow-x-auto border border-gray-200 rounded">
            <table class="min-w-full text-sm">
                <thead class="bg-gray-50">
                    <tr>
                        <th class="px-3 py-2 text-left font-medium text-gray-700">Customer</th>
                        <th class="px-3 py-2 text-left font-medium text-gray-700">Invoice #</th>
                        <th class="px-3 py-2 text-left font-medium text-gray-700">Date</th>
                        <th class="px-3 py-2 text-right font-medium text-gray-700">Subtotal</th>
                        <th class="px-3 py-2 text-right font-medium text-gray-700">Tax</th>
                        <th class="px-3 py-2 text-right font-medium text-gray-700">Total</th>
                        <th class="px-3 py-2 text-right font-medium text-gray-700">Paid</th>
                        <th class="px-3 py-2 text-right font-medium text-gray-700">Open</th>
                        <th class="px-3 py-2 text-center font-medium text-gray-700">Status</th>
                    </tr>
                </thead>
                <tbody>${rowsHtml}</tbody>
            </table>
        </div>`;
}

export function exportRevenueCsv() {
    if (!revData || !revData.rows.length) {
        return reportError('rev-result', 'Run the report first — there is nothing to export.');
    }
    const lines = [];
    lines.push(csvRow([`Invoice-Level Revenue ${revData.from} to ${revData.to}`]));
    lines.push(csvRow([`Methodology: ${revData.methodology}`]));
    lines.push('');

    const header = ['Customer', 'Invoice #', 'Invoice Date', 'Subtotal', 'Tax', 'Total', 'Paid', 'Open', 'Payment Status'];
    if (revData.groupByMonth) header.unshift('Month');
    lines.push(csvRow(header));

    for (const r of revData.rows) {
        const cells = [
            r.customer_name || '',
            r.invoice_number || '',
            String(r.invoice_date).split('T')[0],
            r.subtotal, r.tax_amount, r.total, r.paid_amount, r.open_amount,
            r.payment_status || ''
        ];
        if (revData.groupByMonth) cells.unshift(r.month_key);
        lines.push(csvRow(cells));
    }

    const t = revData.totals;
    const totalCells = [`TOTAL (${t.invoice_count} invoices)`, '', '',
        t.subtotal, t.tax_amount, t.total, t.paid_amount, t.open_amount, ''];
    if (revData.groupByMonth) totalCells.unshift('');
    lines.push(csvRow(totalCells));

    if (revData.groupByMonth && revData.months.length) {
        lines.push('');
        lines.push(csvRow(['Month', 'Invoices', 'Subtotal', 'Tax', 'Total', 'Paid', 'Open']));
        for (const m of revData.months) {
            lines.push(csvRow([m.month_key, m.invoice_count, m.subtotal, m.tax_amount, m.total, m.paid_amount, m.open_amount]));
        }
    }

    downloadCsv(`revenue-${revData.from}_to_${revData.to}${revData.anonymized ? '-anonymized' : ''}.csv`, lines);
}

export function exportRevenuePdf() {
    const fromEl = document.getElementById('rev-from');
    const toEl   = document.getElementById('rev-to');
    if (!fromEl?.value || !toEl?.value) return alert('Please select both a from and a to date.');
    if (fromEl.value > toEl.value) return alert('The from date must not be after the to date.');
    const anonymize    = document.getElementById('rev-anonymize')?.checked || false;
    const groupByMonth = document.getElementById('rev-group-month')?.checked || false;
    let url = `/api/reports/revenue/pdf?from=${fromEl.value}&to=${toEl.value}`;
    if (anonymize) url += '&anonymize=true';
    if (groupByMonth) url += '&groupByMonth=true';
    window.open(url, '_blank');
}

// ── Report 3: Revenue by Category ───────────────────────────────────

const MONTH_ABBR = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
                    'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'];

/** 'YYYY-MM' → { m: 'Mar', y: '2026' } — reine String-Zerlegung, kein Date. */
function monthParts(monthKey) {
    return { m: MONTH_ABBR[Number(monthKey.slice(5, 7)) - 1], y: monthKey.slice(0, 4) };
}

/**
 * Spaltenmodell der Matrix: Monate in Jahresblöcken, je Block optional eine
 * Jahressumme, dahinter Gesamt und Prozentanteil. Identisch zu
 * categoryColumns() in report-pdf-service.js — Bildschirm, CSV und PDF zeigen
 * damit dieselben Spalten in derselben Reihenfolge.
 */
function categoryColumns(data) {
    const cols = [];
    if (data.groupByMonth) {
        for (const y of data.years) {
            for (const m of y.months) cols.push({ type: 'month', key: m });
            if (data.showYearColumns) cols.push({ type: 'year', key: y.year });
        }
    }
    cols.push({ type: 'total' });
    cols.push({ type: 'pct' });
    return cols;
}

/** Wert einer Kategoriezeile in einer Spalte; null = Prozentspalte. */
function categoryCell(data, catKey, col) {
    if (col.type === 'month') return data.cells[catKey][col.key];
    if (col.type === 'year')  return data.yearCells[catKey][col.key];
    if (col.type === 'total') return data.categoryTotals[catKey].revenue;
    return null;
}

/** Wert der TOTAL-Zeile in einer Spalte. */
function categoryTotalCell(data, col) {
    if (col.type === 'month') return data.monthTotals[col.key];
    if (col.type === 'year')  return data.yearTotals[col.key];
    if (col.type === 'total') return data.grandTotal;
    return null;
}

/** Spaltenüberschrift für Bildschirm und CSV (dort einzeilig). */
function categoryColumnLabel(col, oneLine) {
    if (col.type === 'month') {
        const p = monthParts(col.key);
        return oneLine ? `${p.m} ${p.y}` : `${p.m}<br><span class="font-normal text-gray-500">${p.y}</span>`;
    }
    if (col.type === 'year') {
        return oneLine ? `${col.key} Total`
                       : `${col.key}<br><span class="font-normal text-gray-500">Total</span>`;
    }
    if (col.type === 'total') return 'Total';
    return oneLine ? '% of Total' : '% of<br><span class="font-normal text-gray-500">Total</span>';
}

export async function loadCategoryRevenue() {
    catFrom = document.getElementById('cat-from').value;
    catTo = document.getElementById('cat-to').value;
    catGroupByMonth = document.getElementById('cat-group-month')?.checked || false;

    if (!catFrom || !catTo) return reportError('cat-result', 'Please select both a from and a to date.');
    if (catFrom > catTo) return reportError('cat-result', 'The from date must not be after the to date.');

    showLoading('cat-result', 'Loading category revenue…');
    try {
        const data = await window.API.reports.getCategoryRevenue(catFrom, catTo, catGroupByMonth);
        if (data.error) return reportError('cat-result', data.error);
        catData = data;
        renderCategoryRevenue(data);
    } catch (err) {
        reportError('cat-result', err.message || 'Failed to load category revenue');
    }
}

function renderCategoryRevenue(data) {
    if (!data.hasData) {
        document.getElementById('cat-result').innerHTML =
            methodologyBox(data.methodology, false) +
            '<p class="text-sm text-gray-500">No invoices found in this period.</p>';
        return;
    }

    const cols = categoryColumns(data);
    const colClass = c => c.type === 'year'  ? ' bg-blue-50 font-semibold'
                        : c.type === 'total' ? ' bg-gray-100 font-semibold' : '';

    const headHtml = `<th class="px-3 py-2 text-left font-medium text-gray-700">Category</th>` +
        cols.map(c => `<th class="px-3 py-2 text-right font-medium text-gray-700 whitespace-nowrap${colClass(c)}">${categoryColumnLabel(c, false)}</th>`).join('');

    let rowsHtml = '';
    for (const cat of data.categories) {
        const cells = cols.map(c => c.type === 'pct'
            ? `<td class="px-3 py-2 text-sm text-right text-gray-500">${data.categoryTotals[cat.key].pct}%</td>`
            : `<td class="px-3 py-2 text-sm text-right whitespace-nowrap${colClass(c)}">${fmtMoney(categoryCell(data, cat.key, c))}</td>`
        ).join('');
        rowsHtml += `<tr class="border-t hover:bg-gray-50">
            <td class="px-3 py-2 text-sm font-medium whitespace-nowrap">${escapeHtml(cat.label)}</td>${cells}</tr>`;
    }

    // 100.0 % per Definition (Gesamt/Gesamt), nicht als Summe der gerundeten
    // Kategorieanteile.
    const totalCells = cols.map(c => c.type === 'pct'
        ? `<td class="px-3 py-2 text-sm text-right">100.0%</td>`
        : `<td class="px-3 py-2 text-sm text-right whitespace-nowrap${colClass(c)}">${fmtMoney(categoryTotalCell(data, c))}</td>`
    ).join('');
    rowsHtml += `<tr class="border-t-2 border-gray-400 bg-gray-100 font-bold">
        <td class="px-3 py-2 text-sm whitespace-nowrap">TOTAL (${data.invoiceCount} invoices)</td>${totalCells}</tr>`;

    document.getElementById('cat-result').innerHTML =
        methodologyBox(data.methodology, false) + `
        <div class="overflow-x-auto border border-gray-200 rounded">
            <table class="min-w-full text-sm">
                <thead class="bg-gray-50"><tr>${headHtml}</tr></thead>
                <tbody>${rowsHtml}</tbody>
            </table>
        </div>`;
}

export function exportCategoryRevenueCsv() {
    if (!catData || !catData.hasData) {
        return reportError('cat-result', 'Run the report first — there is nothing to export.');
    }
    const data = catData;
    const cols = categoryColumns(data);
    const lines = [];
    lines.push(csvRow([`Revenue by Category ${data.from} to ${data.to}`]));
    lines.push(csvRow([`Methodology: ${data.methodology}`]));
    lines.push('');
    lines.push(csvRow(['Category', ...cols.map(c => categoryColumnLabel(c, true))]));

    for (const cat of data.categories) {
        lines.push(csvRow([cat.label, ...cols.map(c => c.type === 'pct'
            ? data.categoryTotals[cat.key].pct
            : categoryCell(data, cat.key, c))]));
    }
    lines.push(csvRow([`TOTAL (${data.invoiceCount} invoices)`,
        ...cols.map(c => c.type === 'pct' ? '100.0' : categoryTotalCell(data, c))]));

    downloadCsv(`category-revenue-${data.from}_to_${data.to}.csv`, lines);
}

export function exportCategoryRevenuePdf() {
    const fromEl = document.getElementById('cat-from');
    const toEl   = document.getElementById('cat-to');
    if (!fromEl?.value || !toEl?.value) return alert('Please select both a from and a to date.');
    if (fromEl.value > toEl.value) return alert('The from date must not be after the to date.');
    const groupByMonth = document.getElementById('cat-group-month')?.checked || false;
    let url = `/api/reports/category-revenue/pdf?from=${fromEl.value}&to=${toEl.value}`;
    if (groupByMonth) url += '&groupByMonth=true';
    window.open(url, '_blank');
}

// ────────────────────────────────────────────────────────────────────
// Aus accounting-view.js übernommene Reports
// Funktionskörper 1:1; geändert wurden nur die onclick-Namespaces im
// zugehörigen Markup und der Titel-Parameter von showError.
// ────────────────────────────────────────────────────────────────────

export async function loadProfitLoss() {
    plStartDate = document.getElementById('pl-start').value;
    plEndDate   = document.getElementById('pl-end').value;
    plAccountingMethod = document.getElementById('pl-method').value;
    showLoading('pl-result', 'Loading P&L from QBO…');
    try {
        const data = await window.API.accounting.getProfitAndLoss(plStartDate, plEndDate, plAccountingMethod);
        if (data.error) return showError('pl-result', data.error);
        document.getElementById('pl-result').innerHTML = renderQboReport(data);
    } catch (err) { showError('pl-result', err.message || 'Failed to load P&L'); }
}

export async function loadBalanceSheet() {
    bsAsOfDate = document.getElementById('bs-asof').value;
    bsAccountingMethod = document.getElementById('bs-method').value;
    showLoading('bs-result', 'Loading Balance Sheet from QBO…');
    try {
        const data = await window.API.accounting.getBalanceSheet(bsAsOfDate, bsAccountingMethod);
        if (data.error) return showError('bs-result', data.error);
        document.getElementById('bs-result').innerHTML = renderQboReport(data);
    } catch (err) { showError('bs-result', err.message || 'Failed to load Balance Sheet'); }
}

export async function loadTaxSummary() {
    tsMonth = document.getElementById('ts-month').value;
    tsAccountingMethod = document.getElementById('ts-method').value;
    if (!tsMonth) return showError('ts-result', 'Please select a month.');
    const [y, m] = tsMonth.split('-').map(Number);
    const startDate = firstOfMonthISO(y, m - 1);
    const endDate = lastOfMonthISO(y, m - 1);
    showLoading('ts-result', 'Loading Sales Tax Liability from QBO…');
    try {
        const data = await window.API.accounting.getTaxSummary(startDate, endDate, tsAccountingMethod);
        if (data.error) return showError('ts-result', data.error);
        document.getElementById('ts-result').innerHTML = renderQboReport(data);
    } catch (err) { showError('ts-result', err.message || 'Failed to load Tax Summary'); }
}

export async function loadCustomerRevenue() {
    crStartDate = document.getElementById('cr-start').value;
    crEndDate   = document.getElementById('cr-end').value;
    const anonymize = document.getElementById('cr-anonymize')?.checked || false;
    if (!crStartDate || !crEndDate) return showError('cr-result', 'Please select both start and end dates.');
    showLoading('cr-result', 'Loading customer revenue...');
    const maskName = (name) => anonymize ? name.charAt(0) : name;
    try {
        const data = await window.API.accounting.getCustomerRevenue(crStartDate, crEndDate);
        if (data.error) return showError('cr-result', data.error);
        if (!data.length) {
            document.getElementById('cr-result').innerHTML = '<p class="text-sm text-gray-500">No invoices found in this period.</p>';
            return;
        }
        const grandTotal = parseFloat(data[0].grand_total) || 0;
        const totalInvoices = data.reduce((s, r) => s + parseInt(r.invoice_count), 0);
        let rowsHtml = '';
        let rank = 0;
        for (const r of data) {
            rank++;
            const rev = parseFloat(r.total_revenue) || 0;
            const pct = grandTotal > 0 ? ((rev / grandTotal) * 100).toFixed(1) : '0.0';
            rowsHtml += `<tr class="border-t hover:bg-gray-50">
                <td class="px-3 py-2 text-sm font-medium">${rank}. ${escapeHtml(maskName(r.customer_name))}</td>
                <td class="px-3 py-2 text-sm text-center">${r.invoice_count}</td>
                <td class="px-3 py-2 text-sm text-right">${fmtMoney(rev)}</td>
                <td class="px-3 py-2 text-sm text-right text-gray-500">${pct}%</td>
            </tr>`;
        }
        rowsHtml += `<tr class="border-t bg-gray-50 font-semibold">
            <td class="px-3 py-2 text-sm">TOTAL (${data.length} customers)</td>
            <td class="px-3 py-2 text-sm text-center">${totalInvoices}</td>
            <td class="px-3 py-2 text-sm text-right">${fmtMoney(grandTotal)}</td>
            <td class="px-3 py-2 text-sm text-right">100.0%</td>
        </tr>`;

        document.getElementById('cr-result').innerHTML = `
            <div class="overflow-x-auto border border-gray-200 rounded">
                <table class="min-w-full text-sm">
                    <thead class="bg-gray-50">
                        <tr>
                            <th class="px-3 py-2 text-left font-medium text-gray-700">Customer</th>
                            <th class="px-3 py-2 text-center font-medium text-gray-700">Invoices</th>
                            <th class="px-3 py-2 text-right font-medium text-gray-700">Revenue (net)</th>
                            <th class="px-3 py-2 text-right font-medium text-gray-700">% of Total</th>
                        </tr>
                    </thead>
                    <tbody>${rowsHtml}</tbody>
                </table>
            </div>`;
    } catch (err) { showError('cr-result', err.message || 'Failed to load revenue report'); }
}

export function exportCustomerRevenuePdf() {
    const startEl = document.getElementById('cr-start');
    const endEl   = document.getElementById('cr-end');
    const anonymize = document.getElementById('cr-anonymize')?.checked || false;
    if (!startEl?.value || !endEl?.value) return alert('Please select start and end dates first.');
    let url = `/api/accounting/reports/customer-revenue/pdf?startDate=${startEl.value}&endDate=${endEl.value}`;
    if (anonymize) url += '&anonymize=true';
    window.open(url, '_blank');
}

export function exportProfitLossPdf() {
    const startEl = document.getElementById('pl-start');
    const endEl   = document.getElementById('pl-end');
    const method  = document.getElementById('pl-method')?.value || 'Accrual';
    if (!startEl?.value || !endEl?.value) return alert('Please select start and end dates first.');
    window.open(`/api/accounting/reports/profit-loss/pdf?startDate=${startEl.value}&endDate=${endEl.value}&accountingMethod=${method}`, '_blank');
}

export function exportBalanceSheetPdf() {
    const asOf = document.getElementById('bs-asof');
    const method = document.getElementById('bs-method')?.value || 'Accrual';
    if (!asOf?.value) return alert('Please select an as-of date first.');
    window.open(`/api/accounting/reports/balance-sheet/pdf?asOfDate=${asOf.value}&accountingMethod=${method}`, '_blank');
}

export function exportTaxSummaryPdf() {
    const monthEl = document.getElementById('ts-month');
    const method  = document.getElementById('ts-method')?.value || 'Accrual';
    if (!monthEl?.value) return alert('Please select a month first.');
    const [y, m] = monthEl.value.split('-').map(Number);
    const startDate = firstOfMonthISO(y, m - 1);
    const endDate = lastOfMonthISO(y, m - 1);
    window.open(`/api/accounting/reports/tax-summary/pdf?startDate=${startDate}&endDate=${endDate}&accountingMethod=${method}`, '_blank');
}

// ── Expose for onclick handlers ─────────────────────────────────────

window.reportsView = {
    renderReportsView,
    loadArAging,
    exportArAgingCsv,
    exportArAgingPdf,
    loadRevenue,
    exportRevenueCsv,
    exportRevenuePdf,
    loadCategoryRevenue,
    exportCategoryRevenueCsv,
    exportCategoryRevenuePdf,
    loadProfitLoss,
    loadBalanceSheet,
    loadTaxSummary,
    loadCustomerRevenue,
    exportProfitLossPdf,
    exportBalanceSheetPdf,
    exportTaxSummaryPdf,
    exportCustomerRevenuePdf
};