<?php
require_once 'auth.php';
$auth->requireLogin();

$page_title = 'Sales Management';
$success_message = '';
$error_message = '';

// Get edit data if editing
$edit_sale = null;
$edit_sale_items = [];
if (isset($_GET['edit_sale'])) {
    try {
        $edit_stmt = $pdo->prepare("SELECT * FROM sales WHERE id = ?");
        $edit_stmt->execute([$_GET['edit_sale']]);
        $edit_sale = $edit_stmt->fetch(PDO::FETCH_ASSOC);
        
        if ($edit_sale) {
            $edit_items_stmt = $pdo->prepare("
                SELECT si.*, ps.name as product_name 
                FROM sales_items si 
                JOIN products_services ps ON si.product_service_id = ps.id 
                WHERE si.sale_id = ?
            ");
            $edit_items_stmt->execute([$edit_sale['id']]);
            $edit_sale_items = $edit_items_stmt->fetchAll(PDO::FETCH_ASSOC);
        }
    } catch (PDOException $e) {
        $error_message = 'Error fetching sale for editing.';
    }
}

// Handle form submissions
if ($_SERVER['REQUEST_METHOD'] == 'POST' && isset($_POST['action'])) {
    
    if ($_POST['action'] == 'record_sale' || $_POST['action'] == 'edit_sale') {
        $sale_id = $_POST['sale_id'] ?? null;
        $sale_date = $_POST['sale_date'] ?? '';
        $customer_name = trim($_POST['customer_name'] ?? '');
        $customer_phone = trim($_POST['customer_phone'] ?? '');
        $payment_status = $_POST['payment_status'] ?? 'paid';
        $payment_method = $_POST['payment_method'] ?? 'cash';
        $notes = trim($_POST['notes'] ?? '');
        
        // Get line items from individual form fields
        $products = $_POST['product_id'] ?? [];
        $quantities = $_POST['quantity'] ?? [];
        $unit_prices = $_POST['unit_price'] ?? [];
        $line_totals = $_POST['line_total'] ?? [];
        
        // Validation
        if (empty($sale_date)) {
            $error_message = 'Sale date is required.';
        } elseif (empty($products) || !is_array($products)) {
            $error_message = 'At least one product/service must be added.';
        } else {
            // Build line items array
            $line_items = [];
            $total_amount = 0;
            
            for ($i = 0; $i < count($products); $i++) {
                if (!empty($products[$i]) && !empty($quantities[$i]) && isset($unit_prices[$i]) && isset($line_totals[$i])) {
                    $product_id = intval($products[$i]);
                    $quantity = floatval($quantities[$i]);
                    $unit_price = floatval($unit_prices[$i]);
                    $line_total = floatval($line_totals[$i]);
                    
                    if ($product_id > 0 && $quantity > 0 && $unit_price >= 0 && $line_total >= 0) {
                        $line_items[] = [
                            'product_id' => $product_id,
                            'quantity' => $quantity,
                            'unit_price' => $unit_price,
                            'line_total' => $line_total
                        ];
                        $total_amount += $line_total;
                    }
                }
            }
            
            if (empty($line_items)) {
                $error_message = 'At least one valid product/service must be added.';
            } elseif ($total_amount <= 0) {
                $error_message = 'Total amount must be greater than zero.';
            } else {
                try {
                    // Start transaction
                    $pdo->beginTransaction();
                    
                    if ($_POST['action'] == 'edit_sale' && $sale_id) {
                        // Update existing sale
                        $sale_stmt = $pdo->prepare("
                            UPDATE sales SET sale_date = ?, customer_name = ?, customer_phone = ?, 
                                           total_amount = ?, payment_status = ?, payment_method = ?, notes = ?
                            WHERE id = ?
                        ");
                        
                        $sale_stmt->execute([
                            $sale_date, $customer_name, $customer_phone, 
                            $total_amount, $payment_status, $payment_method, $notes, $sale_id
                        ]);
                        
                        // Delete existing line items
                        $delete_items_stmt = $pdo->prepare("DELETE FROM sales_items WHERE sale_id = ?");
                        $delete_items_stmt->execute([$sale_id]);
                        
                        $action_message = 'Sale updated successfully!';
                    } else {
                        // Create new sale
                        $bill_number = 'BILL' . date('YmdHis') . rand(100, 999);
                        
                        $sale_stmt = $pdo->prepare("
                            INSERT INTO sales (bill_number, sale_date, customer_name, customer_phone, 
                                             total_amount, payment_status, payment_method, notes, created_by) 
                            VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)
                        ");
                        
                        $sale_stmt->execute([
                            $bill_number, $sale_date, $customer_name, $customer_phone, 
                            $total_amount, $payment_status, $payment_method, $notes, $_SESSION['user_id']
                        ]);
                        
                        $sale_id = $pdo->lastInsertId();
                        $action_message = 'Sale recorded successfully! Bill: ' . $bill_number;
                    }
                    
                    // Insert line items
                    $item_stmt = $pdo->prepare("
                        INSERT INTO sales_items (sale_id, product_service_id, quantity, unit_price, line_total) 
                        VALUES (?, ?, ?, ?, ?)
                    ");
                    
                    foreach ($line_items as $item) {
                        $item_stmt->execute([
                            $sale_id, $item['product_id'], $item['quantity'], 
                            $item['unit_price'], $item['line_total']
                        ]);
                    }
                    
                    $pdo->commit();
                    $_SESSION['success_message'] = $action_message;
                    
                    // Redirect to prevent form resubmission
                    header("Location: sales.php");
                    exit();
                    
                } catch (Exception $e) {
                    $pdo->rollBack();
                    $error_message = 'Error processing sale: ' . $e->getMessage();
                }
            }
        }
    }
    
    elseif ($_POST['action'] == 'delete_sale') {
        $sale_id = intval($_POST['sale_id'] ?? 0);
        
        if ($sale_id > 0) {
            try {
                $pdo->beginTransaction();
                
                // Delete sales items first
                $delete_items_stmt = $pdo->prepare("DELETE FROM sales_items WHERE sale_id = ?");
                $delete_items_stmt->execute([$sale_id]);
                
                // Delete sale
                $delete_sale_stmt = $pdo->prepare("DELETE FROM sales WHERE id = ?");
                $result = $delete_sale_stmt->execute([$sale_id]);
                
                if ($result) {
                    $pdo->commit();
                    $_SESSION['success_message'] = 'Sale deleted successfully.';
                } else {
                    $pdo->rollBack();
                    $_SESSION['error_message'] = 'Failed to delete sale.';
                }
                
            } catch (Exception $e) {
                $pdo->rollBack();
                $_SESSION['error_message'] = 'Error deleting sale: ' . $e->getMessage();
            }
        }
        
        header("Location: sales.php");
        exit();
    }
    
    elseif ($_POST['action'] == 'export_sales') {
        $export_detailed = $_POST['export_detailed'] ?? '0';
        $export_dashboard = $_POST['export_dashboard'] ?? '0';
        $export_filter_date_from = $_POST['export_filter_date_from'] ?? '';
        $export_filter_date_to = $_POST['export_filter_date_to'] ?? '';
        $export_filter_product = $_POST['export_filter_product'] ?? '';
        
        // Build export query with same filters
        $export_where_clause = "1=1";
        $export_params = [];
        
        if (!empty($export_filter_date_from)) {
            $export_where_clause .= " AND s.sale_date >= ?";
            $export_params[] = $export_filter_date_from;
        }
        
        if (!empty($export_filter_date_to)) {
            $export_where_clause .= " AND s.sale_date <= ?";
            $export_params[] = $export_filter_date_to;
        }
        
        if (!empty($export_filter_product)) {
            $export_where_clause .= " AND EXISTS (SELECT 1 FROM sales_items si WHERE si.sale_id = s.id AND si.product_service_id = ?)";
            $export_params[] = $export_filter_product;
        }
        
        try {
            if ($export_dashboard == '1') {
                // Export dashboard - product-wise summary
                $export_stmt = $pdo->prepare("
                    SELECT ps.name as product_name,
                           un.unit_symbol,
                           COUNT(DISTINCT s.id) as total_bills,
                           SUM(si.quantity) as total_quantity,
                           AVG(si.unit_price) as avg_unit_price,
                           SUM(si.line_total) as total_sales_amount
                    FROM sales s
                    JOIN sales_items si ON s.id = si.sale_id
                    JOIN products_services ps ON si.product_service_id = ps.id
                    JOIN units un ON ps.unit_id = un.id
                    WHERE $export_where_clause
                    GROUP BY ps.id, ps.name, un.unit_symbol
                    ORDER BY total_sales_amount DESC
                ");
                $export_stmt->execute($export_params);
                $export_data = $export_stmt->fetchAll(PDO::FETCH_ASSOC);
                
                // Get totals
                $totals_stmt = $pdo->prepare("
                    SELECT COUNT(DISTINCT s.id) as total_bills,
                           SUM(s.total_amount) as grand_total
                    FROM sales s
                    WHERE $export_where_clause
                ");
                $totals_stmt->execute($export_params);
                $totals = $totals_stmt->fetch(PDO::FETCH_ASSOC);
                
                $filename = 'sales_dashboard_' . date('Y-m-d_H-i-s') . '.csv';
                
                // Generate CSV
                header('Content-Type: text/csv');
                header('Content-Disposition: attachment; filename="' . $filename . '"');
                
                $output = fopen('php://output', 'w');
                
                // Dashboard header
                fputcsv($output, ['SALES DASHBOARD REPORT']);
                fputcsv($output, ['Generated on: ' . date('F j, Y g:i A')]);
                if (!empty($export_filter_date_from) || !empty($export_filter_date_to)) {
                    $period = 'Period: ';
                    if (!empty($export_filter_date_from)) $period .= 'From ' . date('M j, Y', strtotime($export_filter_date_from));
                    if (!empty($export_filter_date_to)) $period .= ' To ' . date('M j, Y', strtotime($export_filter_date_to));
                    fputcsv($output, [$period]);
                }
                if (!empty($export_filter_product)) {
                    $product_name = '';
                    foreach ($products_services as $ps) {
                        if ($ps['id'] == $export_filter_product) {
                            $product_name = $ps['name'];
                            break;
                        }
                    }
                    fputcsv($output, ['Product Filter: ' . $product_name]);
                }
                fputcsv($output, ['']); // Empty row
                
                // Summary totals
                fputcsv($output, ['SUMMARY']);
                fputcsv($output, ['Total Bills', $totals['total_bills']]);
                fputcsv($output, ['Grand Total Sales', number_format($totals['grand_total'], 2)]);
                fputcsv($output, ['']); // Empty row
                
                // Product-wise details
                fputcsv($output, ['PRODUCT-WISE SALES BREAKDOWN']);
                fputcsv($output, ['Product Name', 'Unit', 'Total Bills', 'Total Quantity', 'Avg Unit Price', 'Total Sales Amount']);
                
                foreach ($export_data as $row) {
                    fputcsv($output, [
                        $row['product_name'],
                        $row['unit_symbol'],
                        $row['total_bills'],
                        number_format($row['total_quantity'], 3),
                        number_format($row['avg_unit_price'], 2),
                        number_format($row['total_sales_amount'], 2)
                    ]);
                }
                
                fclose($output);
                exit();
                
            } elseif ($export_detailed == '1') {
                // Export detailed view
                $export_stmt = $pdo->prepare("
                    SELECT s.bill_number, s.sale_date, s.customer_name, s.customer_phone,
                           ps.name as product_name, si.quantity, un.unit_symbol,
                           si.unit_price, si.line_total, s.payment_status, s.payment_method, s.notes
                    FROM sales s
                    JOIN sales_items si ON s.id = si.sale_id
                    JOIN products_services ps ON si.product_service_id = ps.id
                    JOIN units un ON ps.unit_id = un.id
                    WHERE $export_where_clause
                    ORDER BY s.created_at DESC, s.id, si.id
                ");
                $export_stmt->execute($export_params);
                $export_data = $export_stmt->fetchAll(PDO::FETCH_ASSOC);
                
                $filename = 'sales_detailed_' . date('Y-m-d_H-i-s') . '.csv';
                $headers = ['Bill Number', 'Date', 'Customer Name', 'Customer Phone', 'Product', 'Quantity', 'Unit', 'Unit Price', 'Line Total', 'Payment Status', 'Payment Method', 'Notes'];
            } else {
                // Export summary view
                $export_stmt = $pdo->prepare("
                    SELECT s.bill_number, s.sale_date, s.customer_name, s.customer_phone,
                           s.total_amount, s.payment_status, s.payment_method, s.notes,
                           GROUP_CONCAT(CONCAT(ps.name, ' (', si.quantity, ' ', un.unit_symbol, ')') SEPARATOR ', ') as items
                    FROM sales s
                    LEFT JOIN sales_items si ON s.id = si.sale_id
                    LEFT JOIN products_services ps ON si.product_service_id = ps.id
                    LEFT JOIN units un ON ps.unit_id = un.id
                    WHERE $export_where_clause
                    GROUP BY s.id
                    ORDER BY s.created_at DESC
                ");
                $export_stmt->execute($export_params);
                $export_data = $export_stmt->fetchAll(PDO::FETCH_ASSOC);
                
                $filename = 'sales_summary_' . date('Y-m-d_H-i-s') . '.csv';
                $headers = ['Bill Number', 'Date', 'Customer Name', 'Customer Phone', 'Items', 'Total Amount', 'Payment Status', 'Payment Method', 'Notes'];
            }
            
            if ($export_dashboard != '1') {
                // Generate CSV for detailed/summary views
                header('Content-Type: text/csv');
                header('Content-Disposition: attachment; filename="' . $filename . '"');
                
                $output = fopen('php://output', 'w');
                fputcsv($output, $headers);
                
                foreach ($export_data as $row) {
                    if ($export_detailed == '1') {
                        fputcsv($output, [
                            $row['bill_number'],
                            $row['sale_date'],
                            $row['customer_name'],
                            $row['customer_phone'],
                            $row['product_name'],
                            $row['quantity'],
                            $row['unit_symbol'],
                            $row['unit_price'],
                            $row['line_total'],
                            $row['payment_status'],
                            $row['payment_method'],
                            $row['notes']
                        ]);
                    } else {
                        fputcsv($output, [
                            $row['bill_number'],
                            $row['sale_date'],
                            $row['customer_name'],
                            $row['customer_phone'],
                            $row['items'],
                            $row['total_amount'],
                            $row['payment_status'],
                            $row['payment_method'],
                            $row['notes']
                        ]);
                    }
                }
                
                fclose($output);
                exit();
            }
            
        } catch (PDOException $e) {
            $error_message = 'Error exporting data: ' . $e->getMessage();
        }
    }
}

// Fetch products/services
try {
    $products_stmt = $pdo->prepare("
        SELECT ps.*, u.unit_name, u.unit_symbol 
        FROM products_services ps 
        JOIN units u ON ps.unit_id = u.id 
        WHERE ps.status = 'active' 
        ORDER BY ps.name
    ");
    $products_stmt->execute();
    $products_services = $products_stmt->fetchAll(PDO::FETCH_ASSOC);
} catch (PDOException $e) {
    $products_services = [];
}

// Fetch sales with filters
$filter_date_from = $_GET['filter_date_from'] ?? '';
$filter_date_to = $_GET['filter_date_to'] ?? '';
$filter_product = $_GET['filter_product'] ?? '';
$detailed_view = $_GET['detailed_view'] ?? '0';

$where_clause = "1=1";
$params = [];

if (!empty($filter_date_from)) {
    $where_clause .= " AND s.sale_date >= ?";
    $params[] = $filter_date_from;
}

if (!empty($filter_date_to)) {
    $where_clause .= " AND s.sale_date <= ?";
    $params[] = $filter_date_to;
}

if (!empty($filter_product)) {
    $where_clause .= " AND EXISTS (SELECT 1 FROM sales_items si WHERE si.sale_id = s.id AND si.product_service_id = ?)";
    $params[] = $filter_product;
}

try {
    // Get sales stats
    $stats_stmt = $pdo->prepare("
        SELECT 
            COUNT(*) as total_sales,
            COALESCE(SUM(total_amount), 0) as total_revenue,
            COALESCE(SUM(CASE WHEN payment_status = 'paid' THEN total_amount ELSE 0 END), 0) as paid_amount
        FROM sales s WHERE $where_clause
    ");
    $stats_stmt->execute($params);
    $stats = $stats_stmt->fetch(PDO::FETCH_ASSOC);
    
    if ($detailed_view == '1') {
        // Get detailed view - each line item as separate row
        $sales_stmt = $pdo->prepare("
            SELECT s.*, u.full_name as created_by_name,
                   si.quantity, si.unit_price, si.line_total,
                   ps.name as product_name, un.unit_symbol
            FROM sales s
            JOIN users u ON s.created_by = u.id
            JOIN sales_items si ON s.id = si.sale_id
            JOIN products_services ps ON si.product_service_id = ps.id
            JOIN units un ON ps.unit_id = un.id
            WHERE $where_clause
            ORDER BY s.created_at DESC, s.id, si.id
            LIMIT 200
        ");
        $sales_stmt->execute($params);
        $sales = $sales_stmt->fetchAll(PDO::FETCH_ASSOC);
    } else {
        // Get sales records with items (summary view)
        $sales_stmt = $pdo->prepare("
            SELECT s.*, u.full_name as created_by_name,
                   (SELECT GROUP_CONCAT(
                       CONCAT(ps.name, ': ', si.quantity, ' ', u.unit_symbol, ' @ ₹', si.unit_price, ' = ₹', si.line_total) 
                       SEPARATOR '|'
                   )
                    FROM sales_items si 
                    JOIN products_services ps ON si.product_service_id = ps.id 
                    JOIN units u ON ps.unit_id = u.id 
                    WHERE si.sale_id = s.id) as items_summary
            FROM sales s
            JOIN users u ON s.created_by = u.id
            WHERE $where_clause
            ORDER BY s.created_at DESC
            LIMIT 50
        ");
        $sales_stmt->execute($params);
        $sales = $sales_stmt->fetchAll(PDO::FETCH_ASSOC);
    }
    
} catch (PDOException $e) {
    $stats = ['total_sales' => 0, 'total_revenue' => 0, 'paid_amount' => 0];
    $sales = [];
    $error_message = 'Error fetching sales data.';
}

include 'includes/header.php';
?>

<div class="page-header">
    <h1 class="page-title">Sales Management</h1>
    <p class="page-subtitle">Record and track your fish sales</p>
</div>

<?php if ($error_message): ?>
    <div class="alert alert-error"><?php echo htmlspecialchars($error_message); ?></div>
<?php endif; ?>

<!-- Stats -->
<div class="dashboard-grid mb-3">
    <div class="stat-card">
        <div class="stat-number"><?php echo $stats['total_sales']; ?></div>
        <div class="stat-label">Total Sales</div>
    </div>
    <div class="stat-card">
        <div class="stat-number">₹<?php echo number_format($stats['total_revenue'], 2); ?></div>
        <div class="stat-label">Total Revenue</div>
    </div>
    <div class="stat-card" style="background: linear-gradient(135deg, #4caf50 0%, #66bb6a 100%);">
        <div class="stat-number">₹<?php echo number_format($stats['paid_amount'], 2); ?></div>
        <div class="stat-label">Paid Amount</div>
    </div>
</div>

<!-- Record Sale -->
<div class="card">
    <div class="card-header">
        <h2 class="card-title"><?php echo $edit_sale ? 'Edit Sale' : 'Record New Sale'; ?></h2>
    </div>
    
    <?php if (empty($products_services)): ?>
        <div class="alert alert-warning">
            Please <a href="settings.php#products-section">create products or services</a> first.
        </div>
    <?php else: ?>
        <form method="POST" id="saleForm" onsubmit="return validateForm();">
            <input type="hidden" name="action" value="<?php echo $edit_sale ? 'edit_sale' : 'record_sale'; ?>">
            <?php if ($edit_sale): ?>
                <input type="hidden" name="sale_id" value="<?php echo $edit_sale['id']; ?>">
            <?php endif; ?>
            
            <!-- Sale Info -->
            <div style="display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); gap: 1rem; margin-bottom: 2rem;">
                <div class="form-group">
                    <label class="form-label">Sale Date</label>
                    <input type="date" name="sale_date" class="form-input" value="<?php echo $edit_sale ? $edit_sale['sale_date'] : date('Y-m-d'); ?>" required>
                </div>
                <div class="form-group">
                    <label class="form-label">Customer Name</label>
                    <input type="text" name="customer_name" class="form-input" placeholder="Optional" value="<?php echo htmlspecialchars($edit_sale['customer_name'] ?? ''); ?>">
                </div>
                <div class="form-group">
                    <label class="form-label">Customer Phone</label>
                    <input type="text" name="customer_phone" class="form-input" placeholder="Optional" value="<?php echo htmlspecialchars($edit_sale['customer_phone'] ?? ''); ?>">
                </div>
            </div>
            
            <!-- Line Items -->
            <div class="card-header">
                <h3 class="card-title">Products/Services</h3>
            </div>
            
            <div id="lineItems">
                <?php if ($edit_sale && !empty($edit_sale_items)): ?>
                    <?php foreach ($edit_sale_items as $index => $item): ?>
                        <div class="line-item" style="display: grid; grid-template-columns: 1fr; gap: 1rem; margin-bottom: 1rem; padding: 1rem; background: #f9f9f9; border-radius: 8px;">
                            <div style="display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 1rem;">
                                <div class="form-group">
                                    <label class="form-label">Product/Service</label>
                                    <select name="product_id[]" class="form-select product-select" onchange="updatePrice(this)" required>
                                        <option value="">Select Product/Service</option>
                                        <?php foreach ($products_services as $ps): ?>
                                            <option value="<?php echo $ps['id']; ?>" 
                                                    data-rate="<?php echo $ps['unit_rate']; ?>"
                                                    data-symbol="<?php echo $ps['unit_symbol']; ?>"
                                                    <?php echo $item['product_service_id'] == $ps['id'] ? 'selected' : ''; ?>>
                                                <?php echo htmlspecialchars($ps['name']); ?> - ₹<?php echo number_format($ps['unit_rate'], 2); ?>/<?php echo $ps['unit_symbol']; ?>
                                            </option>
                                        <?php endforeach; ?>
                                    </select>
                                </div>
                                <div class="form-group">
                                    <label class="form-label">Quantity</label>
                                    <input type="number" name="quantity[]" class="form-input quantity-input" step="0.001" min="0.001" onchange="calculateTotal(this)" value="<?php echo $item['quantity']; ?>" required>
                                </div>
                                <div class="form-group">
                                    <label class="form-label">Unit Price (₹)</label>
                                    <input type="number" name="unit_price[]" class="form-input price-input" step="0.01" min="0" onchange="calculateTotal(this)" value="<?php echo $item['unit_price']; ?>" required>
                                </div>
                                <div class="form-group">
                                    <label class="form-label">Line Total (₹)</label>
                                    <input type="number" name="line_total[]" class="form-input total-input" step="0.01" min="0" onchange="updateGrandTotal()" value="<?php echo $item['line_total']; ?>" required>
                                </div>
                            </div>
                            <div style="text-align: center; margin-top: 0.5rem;">
                                <button type="button" class="btn btn-danger" onclick="removeLineItem(this)">Remove Item</button>
                            </div>
                        </div>
                    <?php endforeach; ?>
                <?php else: ?>
                    <!-- First line item -->
                    <div class="line-item" style="display: grid; grid-template-columns: 1fr; gap: 1rem; margin-bottom: 1rem; padding: 1rem; background: #f9f9f9; border-radius: 8px;">
                        <div style="display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 1rem;">
                            <div class="form-group">
                                <label class="form-label">Product/Service</label>
                                <select name="product_id[]" class="form-select product-select" onchange="updatePrice(this)" required>
                                    <option value="">Select Product/Service</option>
                                    <?php foreach ($products_services as $ps): ?>
                                        <option value="<?php echo $ps['id']; ?>" 
                                                data-rate="<?php echo $ps['unit_rate']; ?>"
                                                data-symbol="<?php echo $ps['unit_symbol']; ?>">
                                            <?php echo htmlspecialchars($ps['name']); ?> - ₹<?php echo number_format($ps['unit_rate'], 2); ?>/<?php echo $ps['unit_symbol']; ?>
                                        </option>
                                    <?php endforeach; ?>
                                </select>
                            </div>
                            <div class="form-group">
                                <label class="form-label">Quantity</label>
                                <input type="number" name="quantity[]" class="form-input quantity-input" step="0.001" min="0.001" onchange="calculateTotal(this)" required>
                            </div>
                            <div class="form-group">
                                <label class="form-label">Unit Price (₹)</label>
                                <input type="number" name="unit_price[]" class="form-input price-input" step="0.01" min="0" onchange="calculateTotal(this)" required>
                            </div>
                            <div class="form-group">
                                <label class="form-label">Line Total (₹)</label>
                                <input type="number" name="line_total[]" class="form-input total-input" step="0.01" min="0" onchange="updateGrandTotal()" required>
                            </div>
                        </div>
                        <div style="text-align: center; margin-top: 0.5rem;">
                            <button type="button" class="btn btn-danger" onclick="removeLineItem(this)">Remove Item</button>
                        </div>
                    </div>
                <?php endif; ?>
            </div>
            
            <button type="button" class="btn btn-secondary" onclick="addLineItem()" style="margin-bottom: 2rem;">Add Another Item</button>
            
            <!-- Grand Total -->
            <div style="text-align: right; margin-bottom: 2rem;">
                <h3>Grand Total: ₹<span id="grandTotal">0.00</span></h3>
            </div>
            
            <!-- Payment Info -->
            <div style="display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); gap: 1rem; margin-bottom: 2rem;">
                <div class="form-group">
                    <label class="form-label">Payment Status</label>
                    <select name="payment_status" class="form-select">
                        <option value="paid" <?php echo ($edit_sale['payment_status'] ?? '') == 'paid' ? 'selected' : ''; ?>>Paid</option>
                        <option value="pending" <?php echo ($edit_sale['payment_status'] ?? '') == 'pending' ? 'selected' : ''; ?>>Pending</option>
                        <option value="partial" <?php echo ($edit_sale['payment_status'] ?? '') == 'partial' ? 'selected' : ''; ?>>Partial</option>
                    </select>
                </div>
                <div class="form-group">
                    <label class="form-label">Payment Method</label>
                    <select name="payment_method" class="form-select">
                        <option value="cash" <?php echo ($edit_sale['payment_method'] ?? '') == 'cash' ? 'selected' : ''; ?>>Cash</option>
                        <option value="upi" <?php echo ($edit_sale['payment_method'] ?? '') == 'upi' ? 'selected' : ''; ?>>UPI</option>
                    </select>
                </div>
            </div>
            
            <div class="form-group">
                <label class="form-label">Notes</label>
                <textarea name="notes" class="form-textarea" rows="3" placeholder="Optional notes..."><?php echo htmlspecialchars($edit_sale['notes'] ?? ''); ?></textarea>
            </div>
            
            <div style="display: flex; gap: 1rem; flex-wrap: wrap;">
                <button type="submit" class="btn btn-primary" id="submitBtn"><?php echo $edit_sale ? 'Update Sale' : 'Record Sale'; ?></button>
                <?php if ($edit_sale): ?>
                    <a href="sales.php" class="btn btn-secondary">Cancel</a>
                <?php endif; ?>
            </div>
        </form>
    <?php endif; ?>
</div>

<!-- Filters -->
<div class="card">
    <div class="card-header">
        <h2 class="card-title">Filter & Export Sales</h2>
    </div>
    
    <div style="display: grid; grid-template-columns: 1fr auto; gap: 2rem; align-items: start;">
        <!-- Filters Form -->
        <form method="GET">
            <div style="display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 1rem; margin-bottom: 1rem;">
                <div class="form-group">
                    <label class="form-label">From Date</label>
                    <input type="date" name="filter_date_from" class="form-input" value="<?php echo htmlspecialchars($filter_date_from); ?>">
                </div>
                <div class="form-group">
                    <label class="form-label">To Date</label>
                    <input type="date" name="filter_date_to" class="form-input" value="<?php echo htmlspecialchars($filter_date_to); ?>">
                </div>
                <div class="form-group">
                    <label class="form-label">Product Filter</label>
                    <select name="filter_product" class="form-select">
                        <option value="">All Products</option>
                        <?php foreach ($products_services as $ps): ?>
                            <option value="<?php echo $ps['id']; ?>" <?php echo $filter_product == $ps['id'] ? 'selected' : ''; ?>>
                                <?php echo htmlspecialchars($ps['name']); ?>
                            </option>
                        <?php endforeach; ?>
                    </select>
                </div>
            </div>
            <div style="display: flex; gap: 1rem; flex-wrap: wrap;">
                <button type="submit" class="btn btn-primary">Apply Filter</button>
                <a href="sales.php" class="btn btn-secondary">Clear Filters</a>
            </div>
            <input type="hidden" name="detailed_view" value="<?php echo htmlspecialchars($detailed_view); ?>">
        </form>
        
        <!-- Export Form -->
        <div style="border-left: 2px solid #e0e0e0; padding-left: 1rem; min-width: 200px;">
            <div class="form-group">
                <label class="form-label">Export Options</label>
                
                <!-- Current View Export -->
                <form method="POST" style="margin-bottom: 0.5rem;">
                    <input type="hidden" name="action" value="export_sales">
                    <input type="hidden" name="export_detailed" value="<?php echo htmlspecialchars($detailed_view); ?>">
                    <input type="hidden" name="export_filter_date_from" value="<?php echo htmlspecialchars($filter_date_from); ?>">
                    <input type="hidden" name="export_filter_date_to" value="<?php echo htmlspecialchars($filter_date_to); ?>">
                    <input type="hidden" name="export_filter_product" value="<?php echo htmlspecialchars($filter_product); ?>">
                    
                    <button type="submit" class="btn btn-success" style="width: 100%; margin-bottom: 0.5rem;">
                        Export Current View
                        <?php echo $detailed_view == '1' ? '(Detailed)' : '(Summary)'; ?>
                    </button>
                </form>
                
                <!-- Dashboard Export -->
                <form method="POST">
                    <input type="hidden" name="action" value="export_sales">
                    <input type="hidden" name="export_dashboard" value="1">
                    <input type="hidden" name="export_filter_date_from" value="<?php echo htmlspecialchars($filter_date_from); ?>">
                    <input type="hidden" name="export_filter_date_to" value="<?php echo htmlspecialchars($filter_date_to); ?>">
                    <input type="hidden" name="export_filter_product" value="<?php echo htmlspecialchars($filter_product); ?>">
                    
                    <button type="submit" class="btn btn-primary" style="width: 100%;">
                        Export Dashboard Report
                    </button>
                </form>
            </div>
        </div>
    </div>
</div>

<!-- Sales List -->
<div class="card">
    <div class="card-header" style="display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 1rem;">
        <h2 class="card-title">Sales Records</h2>
        <div style="display: flex; gap: 0.5rem; flex-wrap: wrap;">
            <?php 
            $filter_params = http_build_query([
                'filter_date_from' => $filter_date_from,
                'filter_date_to' => $filter_date_to,
                'filter_product' => $filter_product
            ]);
            ?>
            <?php if ($detailed_view == '1'): ?>
                <a href="sales.php?<?php echo $filter_params; ?>&detailed_view=0" class="btn btn-secondary">Summary View</a>
            <?php else: ?>
                <a href="sales.php?<?php echo $filter_params; ?>&detailed_view=1" class="btn btn-primary">Detailed View</a>
            <?php endif; ?>
        </div>
    </div>
    
    <?php if (empty($sales)): ?>
        <div class="empty-state">
            <h3>No Sales Found</h3>
            <p>Record your first sale using the form above.</p>
        </div>
    <?php else: ?>
        <div class="table-container">
            <table class="table">
                <thead>
                    <tr>
                        <th>Bill#</th>
                        <th>Date</th>
                        <?php if ($detailed_view == '1'): ?>
                            <th>Product</th>
                            <th>Quantity</th>
                            <th>Unit Price</th>
                            <th>Line Total</th>
                        <?php else: ?>
                            <th>Items</th>
                            <th>Total</th>
                        <?php endif; ?>
                        <th>Customer</th>
                        <th>Payment</th>
                        <th>Actions</th>
                    </tr>
                </thead>
                <tbody>
                    <?php foreach ($sales as $sale): ?>
                        <tr>
                            <td><strong><?php echo htmlspecialchars($sale['bill_number']); ?></strong></td>
                            <td><?php echo date('M j, Y', strtotime($sale['sale_date'])); ?></td>
                            
                            <?php if ($detailed_view == '1'): ?>
                                <td><?php echo htmlspecialchars($sale['product_name']); ?></td>
                                <td><?php echo number_format($sale['quantity'], 3); ?> <?php echo $sale['unit_symbol']; ?></td>
                                <td>₹<?php echo number_format($sale['unit_price'], 2); ?></td>
                                <td><strong>₹<?php echo number_format($sale['line_total'], 2); ?></strong></td>
                            <?php else: ?>
                                <td>
                                    <?php 
                                    if ($sale['items_summary']) {
                                        $items = explode('|', $sale['items_summary']);
                                        foreach ($items as $item) {
                                            echo '<div style="margin-bottom: 4px; font-size: 0.9rem;">' . htmlspecialchars($item) . '</div>';
                                        }
                                    } else {
                                        echo '<div style="color: var(--dark-gray);">No items</div>';
                                    }
                                    ?>
                                </td>
                                <td><strong>₹<?php echo number_format($sale['total_amount'], 2); ?></strong></td>
                            <?php endif; ?>
                            
                            <td>
                                <?php if ($sale['customer_name']): ?>
                                    <?php echo htmlspecialchars($sale['customer_name']); ?>
                                    <?php if ($sale['customer_phone']): ?>
                                        <br><small><?php echo htmlspecialchars($sale['customer_phone']); ?></small>
                                    <?php endif; ?>
                                <?php else: ?>
                                    -
                                <?php endif; ?>
                            </td>
                            <td>
                                <span style="color: <?php echo $sale['payment_status'] == 'paid' ? '#4caf50' : '#ff9800'; ?>">
                                    <?php echo ucfirst($sale['payment_status']); ?>
                                </span>
                                <br><small><?php echo $sale['payment_method'] == 'upi' ? 'UPI' : 'Cash'; ?></small>
                            </td>
                            <td>
                                <div style="display: flex; gap: 0.5rem; flex-wrap: wrap;">
                                    <?php if ($detailed_view != '1'): ?>
                                        <a href="sales.php?edit_sale=<?php echo $sale['id']; ?>" class="btn btn-secondary" style="padding: 0.3rem 0.6rem; font-size: 0.75rem;">Edit</a>
                                    <?php endif; ?>
                                    <form method="POST" style="display: inline;" onsubmit="return confirm('Delete this sale?');">
                                        <input type="hidden" name="action" value="delete_sale">
                                        <input type="hidden" name="sale_id" value="<?php echo $sale['id']; ?>">
                                        <button type="submit" class="btn btn-danger" style="padding: 0.3rem 0.6rem; font-size: 0.75rem;">Delete</button>
                                    </form>
                                </div>
                            </td>
                        </tr>
                        <?php if ($sale['notes'] && $detailed_view != '1'): ?>
                            <tr>
                                <td colspan="<?php echo $detailed_view == '1' ? '9' : '7'; ?>" style="background: #f9f9f9; padding: 0.5rem 1rem; font-style: italic;">
                                    <strong>Notes:</strong> <?php echo htmlspecialchars($sale['notes']); ?>
                                </td>
                            </tr>
                        <?php endif; ?>
                    <?php endforeach; ?>
                </tbody>
            </table>
        </div>
    <?php endif; ?>
</div>

<script>
let isSubmitting = false;

function updatePrice(selectElement) {
    const row = selectElement.closest('.line-item');
    const priceInput = row.querySelector('.price-input');
    const selected = selectElement.options[selectElement.selectedIndex];
    
    if (selected.value) {
        priceInput.value = selected.dataset.rate || '';
        calculateTotal(priceInput);
    } else {
        priceInput.value = '';
    }
}

function calculateTotal(input) {
    const row = input.closest('.line-item');
    const quantity = parseFloat(row.querySelector('.quantity-input').value) || 0;
    const price = parseFloat(row.querySelector('.price-input').value) || 0;
    const totalInput = row.querySelector('.total-input');
    
    totalInput.value = (quantity * price).toFixed(2);
    updateGrandTotal();
}

function updateGrandTotal() {
    const totalInputs = document.querySelectorAll('.total-input');
    let grandTotal = 0;
    
    totalInputs.forEach(input => {
        grandTotal += parseFloat(input.value) || 0;
    });
    
    document.getElementById('grandTotal').textContent = grandTotal.toFixed(2);
}

function addLineItem() {
    const container = document.getElementById('lineItems');
    const firstItem = container.querySelector('.line-item');
    const newItem = firstItem.cloneNode(true);
    
    // Reset values
    newItem.querySelectorAll('select, input').forEach(el => {
        el.value = '';
        if (el.type !== 'hidden') el.removeAttribute('required');
    });
    
    // Make first select required
    newItem.querySelector('.product-select').required = true;
    
    container.appendChild(newItem);
    updateGrandTotal();
}

function removeLineItem(button) {
    const container = document.getElementById('lineItems');
    if (container.children.length > 1) {
        button.closest('.line-item').remove();
        updateGrandTotal();
    } else {
        alert('At least one item is required.');
    }
}

function validateForm() {
    if (isSubmitting) {
        return false;
    }
    
    const grandTotal = parseFloat(document.getElementById('grandTotal').textContent);
    if (grandTotal <= 0) {
        alert('Please add at least one valid item.');
        return false;
    }
    
    isSubmitting = true;
    const submitBtn = document.getElementById('submitBtn');
    submitBtn.disabled = true;
    submitBtn.textContent = 'Processing...';
    
    return true;
}

// Initialize
document.addEventListener('DOMContentLoaded', function() {
    updateGrandTotal();
    
    // If editing, trigger calculations for existing items
    const existingItems = document.querySelectorAll('.total-input');
    if (existingItems.length > 0) {
        existingItems.forEach(input => {
            if (input.value) {
                updateGrandTotal();
            }
        });
    }
});
</script>

<?php include 'includes/footer.php'; ?>