@php
    $formMode = $formMode ?? 'create';
    $presetQtyJson = $presetQtyJson ?? [];
    $initialSaleJson = $initialSaleJson ?? null;
@endphp
<script>
(function () {
    const root = document.getElementById(@json($formMode === 'edit' ? 'sretEdit' : 'sretCreate'));
    if (!root) return;

    const lookupUrl = root.dataset.lookupUrl || '';
    const linesBase = root.dataset.linesUrl || '';
    const preselect = parseInt(root.dataset.preselect || '0', 10);
    const presetQty = @json($presetQtyJson);

    let activeTab = 'sale';
    let lineIndex = 0;

    const saleIdInput = document.getElementById('sretSaleId');
    const linesBody = document.getElementById('sretLinesBody');
    const linesScroll = document.getElementById('sretLinesScroll');
    const submitBtn = document.getElementById('sretSubmit');
    const picker = document.getElementById('sretSalePicker');
    const saleSelect = document.getElementById('sretSaleSelect');
    const saleMessage = document.getElementById('sretSaleMessage');
    const saleVerify = document.getElementById('sretSaleVerify');
    const saleVerifyGrid = document.getElementById('sretSaleVerifyGrid');
    const saleVerifyLink = document.getElementById('sretSaleVerifyLink');
    const saleShowBase = String(root.dataset.saleShowUrl || '/garage/sales').replace(/\/$/, '');
    const form = document.getElementById('sretForm');
    const returnFullBtn = document.getElementById('sretReturnFullBtn');

    var SRET_SCROLL_MIN_ROWS = 3;

    function linesColspan() {
        return parseInt(linesBody && linesBody.getAttribute('data-colspan'), 10) || 5;
    }

    function money(n) {
        return (Number(n) || 0).toLocaleString('en-PK', { minimumFractionDigits: 2, maximumFractionDigits: 2 });
    }

    function escapeHtml(s) {
        return String(s || '').replace(/[&<>"']/g, function (c) {
            return ({ '&': '&amp;', '<': '&lt;', '>': '&gt;', '"': '&quot;', "'": '&#39;' })[c];
        });
    }

    function showSaleMessage(text) {
        if (!saleMessage) return;
        if (!text) {
            saleMessage.textContent = '';
            saleMessage.classList.add('d-none');
            return;
        }
        saleMessage.textContent = text;
        saleMessage.classList.remove('d-none');
    }

    function renderSaleVerify(sale) {
        if (!saleVerify || !saleVerifyGrid || !sale) return;
        showSaleMessage('');

        const isCash = (sale.sale_kind || '') === 'cash_sale';
        const fields = [
            ['Sale #', sale.sale_number],
            ['Date', sale.sale_date_display || sale.sale_date],
            ['Type', sale.sale_kind_label || sale.sale_kind],
            ['Status', sale.status_label || sale.status],
            ['Customer', isCash ? '— (cash sale)' : (sale.customer_name || '—')],
        ];
        if (! isCash && sale.customer_code) fields.push(['Customer code', sale.customer_code]);
        if (! isCash && sale.customer_contact) fields.push(['Phone', sale.customer_contact]);
        fields.push(['Vehicle', sale.vehicle_label || sale.vehicle_registration || '—']);
        fields.push(['Subtotal', sale.subtotal_fmt || money(sale.subtotal)]);
        fields.push(['Tax', sale.tax_amount_fmt || money(sale.tax_amount)]);
        if (parseFloat(sale.discount_amount) > 0) {
            fields.push(['Discount', sale.discount_amount_fmt || money(sale.discount_amount)]);
        }
        fields.push(['Invoice total', sale.grand_total_fmt || money(sale.grand_total), true]);
        let pay = sale.payment_status_label || sale.payment_status || '—';
        if (sale.amount_paid_fmt && parseFloat(sale.amount_paid) > 0) {
            pay += ' · ' + sale.amount_paid_fmt;
        }
        fields.push(['Payment', pay]);
        if (sale.comments) fields.push(['Comments', sale.comments]);

        saleVerifyGrid.innerHTML = fields.map(function (row) {
            const lbl = row[0];
            const val = row[1];
            const isTotal = !!row[2];
            return '<div class="col-6 col-md-4 gs-sret-verify-field">' +
                '<span class="lbl">' + escapeHtml(lbl) + '</span>' +
                '<span class="val' + (isTotal ? ' is-total' : '') + '">' + escapeHtml(val ?? '—') + '</span></div>';
        }).join('');

        if (saleVerifyLink && sale.id) {
            saleVerifyLink.href = saleShowBase + '/' + sale.id;
            saleVerifyLink.classList.remove('d-none');
        }
        saleVerify.classList.remove('d-none');
    }

    function hideSaleVerify() {
        if (saleVerify) saleVerify.classList.add('d-none');
        if (saleVerifyGrid) saleVerifyGrid.innerHTML = '';
        if (saleVerifyLink) saleVerifyLink.href = '#';
    }

    function refreshReturnTotals() {
        let sub = 0;
        let tax = 0;
        if (linesBody) {
            linesBody.querySelectorAll('tr[data-unit-price]').forEach(tr => {
                const inp = tr.querySelector('.sret-qty');
                if (!inp) return;
                const qty = parseInt(inp.value, 10) || 0;
                const unit = parseFloat(tr.dataset.unitPrice) || 0;
                const taxRate = parseFloat(tr.dataset.taxRate) || 0;
                const lineSub = qty * unit;
                const lineTax = lineSub * (taxRate / 100);
                sub += lineSub;
                tax += lineTax;
                const lc = tr.querySelector('.sret-line-total');
                if (lc) lc.textContent = money(lineSub + lineTax);
            });
        }
        const elSub = document.getElementById('sretSumSub');
        const elTax = document.getElementById('sretSumTax');
        const elTot = document.getElementById('sretSumTot');
        if (elSub) elSub.textContent = money(sub);
        if (elTax) elTax.textContent = money(tax);
        if (elTot) elTot.textContent = money(sub + tax);
    }

    function syncSretTableScroll() {
        if (!linesScroll || !linesBody) return;
        const dataRows = linesBody.querySelectorAll('tr[data-unit-price]').length;
        linesScroll.classList.toggle('is-scrollable', dataRows >= SRET_SCROLL_MIN_ROWS);
    }

    function clampQtyInput(inp) {
        const max = parseInt(inp.getAttribute('max'), 10) || parseInt(inp.dataset.max, 10) || 0;
        let v = parseInt(inp.value, 10);
        if (Number.isNaN(v) || v < 0) v = 0;
        if (max > 0 && v > max) v = max;
        inp.value = String(v);
        inp.classList.toggle('is-invalid', max > 0 && v > max);
    }

    function bindQtyInputs() {
        linesBody.querySelectorAll('.sret-qty').forEach(inp => {
            inp.addEventListener('input', () => {
                clampQtyInput(inp);
                refreshReturnTotals();
                syncReturnFullBtn();
            });
            inp.addEventListener('blur', () => {
                clampQtyInput(inp);
                refreshReturnTotals();
                syncReturnFullBtn();
            });
        });
    }

    function syncReturnFullBtn() {
        if (!returnFullBtn || !linesBody) return;
        const rows = linesBody.querySelectorAll('tr[data-unit-price]');
        if (!rows.length) {
            returnFullBtn.classList.add('d-none');
            returnFullBtn.disabled = true;
            return;
        }
        let hasReturnable = false;
        rows.forEach(tr => {
            const inp = tr.querySelector('.sret-qty');
            if (!inp) return;
            const max = parseInt(inp.dataset.max, 10) || 0;
            if (max > 0) hasReturnable = true;
        });
        if (!hasReturnable) {
            returnFullBtn.classList.add('d-none');
            returnFullBtn.disabled = true;
            return;
        }
        returnFullBtn.classList.remove('d-none');
        returnFullBtn.disabled = false;
    }

    function applyFullInvoiceReturn() {
        if (!linesBody) return;
        const inputs = linesBody.querySelectorAll('.sret-qty');
        let applied = 0;
        inputs.forEach(inp => {
            const max = parseInt(inp.dataset.max, 10) || 0;
            if (max <= 0) return;
            inp.value = String(max);
            inp.classList.remove('is-invalid');
            applied++;
        });
        if (!applied) {
            alert('No returnable quantity left on this sale invoice.');
            return;
        }
        refreshReturnTotals();
        syncReturnFullBtn();
    }

    if (returnFullBtn) {
        returnFullBtn.addEventListener('click', applyFullInvoiceReturn);
    }

    function validateReturnQtys() {
        const inputs = linesBody.querySelectorAll('.sret-qty');
        let any = false;
        for (const inp of inputs) {
            clampQtyInput(inp);
            const v = parseInt(inp.value, 10) || 0;
            const max = parseInt(inp.dataset.max, 10) || 0;
            if (v <= 0) continue;
            any = true;
            if (max > 0 && v > max) {
                const part = inp.closest('tr') && inp.closest('tr').querySelector('.sret-part-name');
                const label = part ? part.textContent.trim() : 'line';
                alert('Return qty for “' + label + '” cannot exceed returnable (' + max + ').');
                inp.focus();
                return false;
            }
        }
        if (!any) {
            alert('Enter return quantity for at least one line (cannot exceed returnable qty).');
            return false;
        }
        return true;
    }

    if (@json($formMode === 'create')) {
        document.querySelectorAll('[data-sret-tab]').forEach(btn => {
            btn.addEventListener('click', () => {
                activeTab = btn.dataset.sretTab;
                document.querySelectorAll('[data-sret-tab]').forEach(b => b.classList.toggle('active', b === btn));
                document.querySelectorAll('.sret-panel').forEach(p => {
                    p.classList.toggle('d-none', p.dataset.sretPanel !== activeTab);
                });
                if (activeTab === 'customer' && window.jQuery && window.jQuery.fn.chosen) {
                    var $cust = window.jQuery('#sretCustomerId');
                    if ($cust.length && $cust.data('chosen')) {
                        $cust.trigger('chosen:updated');
                    }
                }
            });
        });

        const searchBtn = document.getElementById('sretSearchBtn');
        if (searchBtn) searchBtn.addEventListener('click', runSearch);
        if (saleSelect) {
            saleSelect.addEventListener('change', () => {
                const id = parseInt(saleSelect.value, 10);
                if (id) loadSale(id);
            });
        }
    }

    async function runSearch() {
        const params = new URLSearchParams();
        if (activeTab === 'sale') {
            const q = document.getElementById('sretSaleSearch').value.trim();
            if (!q) return alert('Enter a sale number.');
            params.set('sale_number', q);
        } else if (activeTab === 'customer') {
            const cid = document.getElementById('sretCustomerId').value;
            if (!cid) return alert('Select a customer.');
            params.set('customer_ledger_id', cid);
        } else {
            const q = document.getElementById('sretPartSearch').value.trim();
            if (!q) return alert('Enter part search.');
            params.set('part_search', q);
        }

        const res = await fetch(lookupUrl + '?' + params.toString(), { headers: { 'Accept': 'application/json' } });
        const data = await res.json();

        if (data.sale && data.lines) {
            setSale(data.sale);
            renderLines(data.lines);
            if (picker) picker.classList.add('d-none');
            return;
        }

        const list = data.sales || [];
        if (!list.length) {
            if (picker) picker.classList.add('d-none');
            hideSaleVerify();
            showSaleMessage('No matching sales found.');
            clearLines();
            return;
        }
        showSaleMessage('');

        if (list.length === 1) {
            loadSale(list[0].id);
            if (picker) picker.classList.add('d-none');
            return;
        }

        if (picker) picker.classList.remove('d-none');
        saleSelect.innerHTML = list.map(s =>
            '<option value="' + s.id + '">' + s.sale_number + ' — ' + (s.customer_name || 'Customer') + ' (' + s.sale_date + ')</option>'
        ).join('');
        loadSale(parseInt(saleSelect.value, 10));
    }

    async function loadSale(id) {
        const res = await fetch(linesBase + '/' + id + '/lines', { headers: { 'Accept': 'application/json' } });
        if (!res.ok) {
            hideSaleVerify();
            showSaleMessage('Sale not found or not eligible for return.');
            clearLines();
            return;
        }
        const data = await res.json();
        setSale(data.sale);
        renderLines(data.lines);
    }

    function setSale(sale) {
        if (saleIdInput) saleIdInput.value = sale.id;
        renderSaleVerify(sale);
        if (submitBtn) submitBtn.disabled = false;
    }

    function clearLines() {
        if (!linesBody) return;
        linesBody.innerHTML = '';
        if (submitBtn) submitBtn.disabled = true;
        if (saleIdInput) saleIdInput.value = '';
        hideSaleVerify();
        refreshReturnTotals();
        syncSretTableScroll();
        syncReturnFullBtn();
    }

    function renderLines(lines) {
        linesBody.innerHTML = '';
        lineIndex = 0;
        const cs = linesColspan();
        if (!lines || !lines.length) {
            linesBody.innerHTML = '<tr><td colspan="' + cs + '" class="text-center text-muted gs-ro-empty-cell">No returnable part lines on this sale.</td></tr>';
            if (submitBtn) submitBtn.disabled = true;
            refreshReturnTotals();
            syncSretTableScroll();
            syncReturnFullBtn();
            return;
        }

        lines.forEach(line => {
            const idx = lineIndex++;
            const max = parseInt(line.returnable_qty, 10) || 0;
            const preset = parseInt(presetQty[line.id], 10) || 0;
            const val = Math.min(preset > 0 ? preset : 0, max);
            const unit = parseFloat(line.unit_price) || 0;
            const taxRate = parseFloat(line.tax_rate) || 0;
            const tr = document.createElement('tr');
            tr.dataset.unitPrice = String(unit);
            tr.dataset.taxRate = String(taxRate);
            tr.innerHTML =
                '<td><input type="hidden" name="items[' + idx + '][garage_sale_item_id]" value="' + line.id + '">' +
                '<span class="fw-semibold sret-part-name">' + (line.part_name || 'Part') + '</span>' +
                '<span class="text-muted small d-block">' + (line.part_number || '') + '</span></td>' +
                '<td class="text-center fw-semibold text-primary">' + max + '</td>' +
                '<td class="text-center">' + (line.quantity ?? 0) + '</td>' +
                '<td><input type="number" class="form-control form-control-sm text-center sret-qty" name="items[' + idx + '][quantity]"' +
                ' min="0" max="' + max + '" value="' + val + '" data-max="' + max + '" title="Max ' + max + '"></td>' +
                '<td class="text-end sret-line-total small fw-semibold">0.00</td>';
            linesBody.appendChild(tr);
        });
        bindQtyInputs();
        if (submitBtn) submitBtn.disabled = false;
        refreshReturnTotals();
        syncSretTableScroll();
        syncReturnFullBtn();
    }

    if (form) {
        form.addEventListener('submit', function (e) {
            if (!validateReturnQtys()) {
                e.preventDefault();
            }
        });
    }

    const initialSaleFromServer = @json($initialSaleJson);
    if (initialSaleFromServer && initialSaleFromServer.id) {
        renderSaleVerify(initialSaleFromServer);
        if (submitBtn) submitBtn.disabled = false;
    }

    if (@json($formMode === 'edit')) {
        loadSaleLinesFromUrl();
    } else if (preselect > 0 && linesBase) {
        loadSale(preselect);
    }

    async function loadSaleLinesFromUrl() {
        if (!linesBase) return;
        linesBody.innerHTML = '<tr><td colspan="' + linesColspan() + '" class="text-center text-muted gs-ro-empty-cell">Loading…</td></tr>';
        const res = await fetch(linesBase, { headers: { 'Accept': 'application/json' } });
        if (!res.ok) {
            linesBody.innerHTML = '<tr><td colspan="' + linesColspan() + '" class="text-center text-muted gs-ro-empty-cell">Could not load return lines.</td></tr>';
            syncSretTableScroll();
            syncReturnFullBtn();
            return;
        }
        const data = await res.json();
        if (data.sale) {
            setSale(data.sale);
        }
        if (!data.lines || !data.lines.length) {
            linesBody.innerHTML = '<tr><td colspan="' + linesColspan() + '" class="text-center text-muted gs-ro-empty-cell">No returnable lines.</td></tr>';
            if (submitBtn) submitBtn.disabled = true;
            syncSretTableScroll();
            syncReturnFullBtn();
            return;
        }
        renderLines(data.lines);
    }

    syncReturnFullBtn();
})();
</script>