<?php
session_start();
if (!isset($_SESSION['user_id'])) {
    header("Location: login.php");
    exit();
}

require_once 'db_connection.php';

$pageTitle = "Sales";

function getBuyers($conn) {
    $query = "SELECT id, name FROM buyers ORDER BY name";
    $result = $conn->query($query);
    return $result->fetch_all(MYSQLI_ASSOC);
}

function getSales($conn, $page = 1, $per_page = 20) {
    $offset = ($page - 1) * $per_page;
    $query = "SELECT s.*, b.name as buyer_name 
              FROM sales s 
              JOIN buyers b ON s.buyer_id = b.id 
              ORDER BY s.date DESC
              LIMIT $offset, $per_page";
    $result = $conn->query($query);
    return $result->fetch_all(MYSQLI_ASSOC);
}

function getTotalSales($conn) {
    $query = "SELECT COUNT(*) as total FROM sales";
    $result = $conn->query($query);
    return $result->fetch_assoc()['total'];
}

if ($_SERVER["REQUEST_METHOD"] == "POST") {
    if (isset($_POST["add_sale"])) {
        $date = $conn->real_escape_string($_POST['date']);
        $buyer_id = $conn->real_escape_string($_POST['buyer_id']);
        $weight_tilapia = floatval($_POST['weight_tilapia']);
        $weight_small_fish = floatval($_POST['weight_small_fish']);
        $weight_big_fish = floatval($_POST['weight_big_fish']);
        $include_delivery = isset($_POST['include_delivery']) ? 1 : 0;
        $final_amount = !empty($_POST['final_amount_override']) ? floatval($_POST['final_amount_override']) : floatval($_POST['final_amount']);
        $harvesting_charges = floatval($_POST['harvesting_charges']);

        $query = "INSERT INTO sales (date, buyer_id, weight_tilapia, weight_small_fish, weight_big_fish, 
                                     include_delivery, final_amount, harvesting_charges) 
                  VALUES (?, ?, ?, ?, ?, ?, ?, ?)";
        
        $stmt = $conn->prepare($query);
        $stmt->bind_param("sidddidd", $date, $buyer_id, $weight_tilapia, $weight_small_fish, $weight_big_fish, 
                          $include_delivery, $final_amount, $harvesting_charges);

        if ($stmt->execute()) {
            $updatedSales = getSales($conn);
            echo json_encode(['success' => true, 'salesRows' => generateSalesRows($updatedSales)]);
        } else {
            echo json_encode(['success' => false, 'error' => $stmt->error]);
        }
        exit;
    } elseif (isset($_POST['delete_sale'])) {
        $sale_id = $conn->real_escape_string($_POST['sale_id']);
        $query = "DELETE FROM sales WHERE id = $sale_id";
        if ($conn->query($query) === TRUE) {
            $updatedSales = getSales($conn);
            echo json_encode(['success' => true, 'salesRows' => generateSalesRows($updatedSales)]);
        } else {
            echo json_encode(['success' => false, 'error' => $conn->error]);
        }
        exit;
    } elseif (isset($_POST['export_csv'])) {
        $query = "SELECT s.date, b.name as buyer_name, s.weight_tilapia, s.weight_small_fish, s.weight_big_fish, 
                         s.include_delivery, s.final_amount, s.harvesting_charges
                  FROM sales s 
                  JOIN buyers b ON s.buyer_id = b.id 
                  ORDER BY s.date DESC";
        $result = $conn->query($query);
        
        $filename = "sales_export_" . date('Y-m-d') . ".csv";
        header('Content-Type: text/csv');
        header('Content-Disposition: attachment; filename="' . $filename . '"');
        
        $output = fopen('php://output', 'w');
        fputcsv($output, ['Date', 'Buyer', 'Tilapia (kg)', 'Small Fish (kg)', 'Big Fish (kg)', 'Delivery Included', 'Final Amount', 'Harvesting Charges']);
        
        while ($row = $result->fetch_assoc()) {
            $row['include_delivery'] = $row['include_delivery'] ? 'Yes' : 'No';
            fputcsv($output, $row);
        }
        
        fclose($output);
        exit;
    } elseif (isset($_POST['get_buyer_rates'])) {
        $buyer_id = $conn->real_escape_string($_POST['buyer_id']);
        $query = "SELECT rate_tilapia, rate_small_fish, rate_big_fish, delivery_rate,
                         harvesting_fee_tilapia, harvesting_fee_small_fish, harvesting_fee_big_fish
                  FROM buyers WHERE id = $buyer_id";
        $result = $conn->query($query);
        $buyer = $result->fetch_assoc();
        echo json_encode($buyer);
        exit;
    }
}

$page = isset($_GET['page']) ? (int)$_GET['page'] : 1;
$per_page = 20;
$total_sales = getTotalSales($conn);
$total_pages = ceil($total_sales / $per_page);

$buyers = getBuyers($conn);
$sales = getSales($conn, $page, $per_page);

function generateBuyerOptions($buyers) {
    $options = '';
    foreach ($buyers as $buyer) {
        $options .= "<option value='{$buyer['id']}'>{$buyer['name']}</option>";
    }
    return $options;
}

function generateSalesRows($sales) {
    $rows = '';
    foreach ($sales as $sale) {
        $deliveryIncluded = $sale['include_delivery'] ? 'Yes' : 'No';
        
        // Format amounts with commas for better readability
        $formattedAmount = '₹' . number_format($sale['final_amount'], 2);
        $formattedHarvestCharges = '₹' . number_format($sale['harvesting_charges'], 2);
        
        $rows .= "<tr>
            <td data-label='Date'>" . date('Y-m-d', strtotime($sale['date'])) . "</td>
            <td data-label='Buyer'>{$sale['buyer_name']}</td>
            <td data-label='Tilapia'>" . number_format($sale['weight_tilapia'], 2) . "</td>
            <td data-label='Small Fish'>" . number_format($sale['weight_small_fish'], 2) . "</td>
            <td data-label='Big Fish'>" . number_format($sale['weight_big_fish'], 2) . "</td>
            <td data-label='Delivery'>{$deliveryIncluded}</td>
            <td data-label='Amount' class='amount-column'>{$formattedAmount}</td>
            <td data-label='Harvest Charges'>{$formattedHarvestCharges}</td>
            <td data-label='Actions' class='actions-column'>
                <a href='edit_sale.php?id={$sale['id']}' class='edit-sale btn-sm'><i class='fas fa-edit'></i></a>
                <a href='#' class='delete-sale btn-sm' data-id='{$sale['id']}'><i class='fas fa-trash'></i></a>
            </td>
        </tr>";
    }
    return $rows;
}

function generatePagination($current_page, $total_pages) {
    // Keep pagination manageable by showing limited page numbers
    $display_range = 5; // Number of pages to show before and after current page
    
    $pagination = '<div class="pagination">';
    
    // First page link
    if ($current_page > 1) {
        $pagination .= "<a href='?page=1' title='First page'><i class='fas fa-angle-double-left'></i></a>";
    }
    
    // Previous page link
    if ($current_page > 1) {
        $pagination .= "<a href='?page=" . ($current_page - 1) . "' title='Previous page'><i class='fas fa-angle-left'></i></a>";
    }
    
    // Calculate range of page numbers to display
    $start_range = max(1, $current_page - $display_range);
    $end_range = min($total_pages, $current_page + $display_range);
    
    // Always show first page if not in range
    if ($start_range > 1) {
        $pagination .= "<a href='?page=1'>1</a>";
        if ($start_range > 2) {
            $pagination .= "<span class='pagination-ellipsis'>...</span>";
        }
    }
    
    // Page numbers
    for ($i = $start_range; $i <= $end_range; $i++) {
        if ($i == $current_page) {
            $pagination .= "<a href='?page=$i' class='active'>$i</a>";
        } else {
            $pagination .= "<a href='?page=$i'>$i</a>";
        }
    }
    
    // Always show last page if not in range
    if ($end_range < $total_pages) {
        if ($end_range < $total_pages - 1) {
            $pagination .= "<span class='pagination-ellipsis'>...</span>";
        }
        $pagination .= "<a href='?page=$total_pages'>$total_pages</a>";
    }
    
    // Next page link
    if ($current_page < $total_pages) {
        $pagination .= "<a href='?page=" . ($current_page + 1) . "' title='Next page'><i class='fas fa-angle-right'></i></a>";
    }
    
    // Last page link
    if ($current_page < $total_pages) {
        $pagination .= "<a href='?page=$total_pages' title='Last page'><i class='fas fa-angle-double-right'></i></a>";
    }
    
    $pagination .= '</div>';
    
    // Add page info
    $pagination .= '<div class="pagination-info">Page ' . $current_page . ' of ' . $total_pages . '</div>';
    
    return $pagination;
}

$buyerOptions = generateBuyerOptions($buyers);
$salesRows = generateSalesRows($sales);
$pagination = generatePagination($page, $total_pages);

$content = <<<HTML
<div class="page-header">
    <h1>Sales Management</h1>
    <form action="" method="POST" class="export-form">
        <input type="hidden" name="export_csv" value="1">
        <button type="submit"><i class="fas fa-file-download"></i> Export to CSV</button>
    </form>
</div>

<div class="card">
    <div class="card-header">
        <h2><i class="fas fa-plus-circle"></i> Add Sale</h2>
    </div>
    <div class="card-body">
        <form action="" method="POST" id="sales-form" class="compact-form">
            <input type="hidden" name="add_sale" value="1">
            
            <div class="form-row">
                <div class="form-group">
                    <label for="date"><i class="far fa-calendar-alt"></i> Date:</label>
                    <input type="date" id="date" name="date" required>
                </div>
                
                <div class="form-group">
                    <label for="buyer_id"><i class="fas fa-user"></i> Buyer:</label>
                    <select id="buyer_id" name="buyer_id" required>
                        <option value="">Select</option>
                        $buyerOptions
                    </select>
                </div>
            </div>
            
            <div class="form-row">
                <div class="form-group">
                    <label for="weight_tilapia"><i class="fas fa-weight"></i> Tilapia (kg):</label>
                    <input type="number" id="weight_tilapia" name="weight_tilapia" step="0.01" required>
                </div>
                
                <div class="form-group">
                    <label for="weight_small_fish"><i class="fas fa-fish"></i> Small Fish (kg):</label>
                    <input type="number" id="weight_small_fish" name="weight_small_fish" step="0.01" required>
                </div>
                
                <div class="form-group">
                    <label for="weight_big_fish"><i class="fas fa-fish"></i> Big Fish (kg):</label>
                    <input type="number" id="weight_big_fish" name="weight_big_fish" step="0.01" required>
                </div>
            </div>
            
            <div class="form-row">
                <div class="form-group checkbox-group">
                    <label for="include_delivery">
                        <input type="checkbox" id="include_delivery" name="include_delivery">
                        <i class="fas fa-truck"></i> Include Delivery
                    </label>
                </div>
                
                <div class="form-group">
                    <label for="final_amount_override"><i class="fas fa-edit"></i> Override Amount:</label>
                    <input type="number" id="final_amount_override" name="final_amount_override" step="0.01">
                </div>
                
                <div class="form-group" id="total-amount-display">
                    <label><i class="fas fa-calculator"></i> Total Amount:</label>
                    <span class="amount">₹<span id="total-amount">0.00</span></span>
                </div>
            </div>
            
            <input type="hidden" id="final_amount" name="final_amount" value="0">
            <input type="hidden" id="harvesting_charges" name="harvesting_charges" value="0">
            
            <div class="form-actions">
                <button type="submit" class="submit-btn"><i class="fas fa-save"></i> Add Sale</button>
            </div>
        </form>
    </div>
</div>

<div class="card mt-4">
    <div class="card-header">
        <h2><i class="fas fa-list"></i> Sales List</h2>
    </div>
    <div class="card-body">
        <div class="table-responsive">
            <table class="data-table">
                <thead>
                    <tr>
                        <th>Date</th>
                        <th>Buyer</th>
                        <th>Tilapia (kg)</th>
                        <th>Small Fish (kg)</th>
                        <th>Big Fish (kg)</th>
                        <th>Delivery</th>
                        <th>Final Amount</th>
                        <th>Harvesting Charges</th>
                        <th>Actions</th>
                    </tr>
                </thead>
                <tbody id="sales-list">
                    $salesRows
                </tbody>
            </table>
        </div>
        $pagination
    </div>
</div>

<div id="notification" class="notification" style="display: none;">
    <span id="notification-message"></span>
    <button id="notification-close"><i class="fas fa-times"></i></button>
</div>

<style>
.page-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    margin-bottom: 20px;
}

.card {
    background-color: #ffffff;
    border-radius: 8px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    margin-bottom: 20px;
    overflow: hidden;
}

.card-header {
    background-color: #f8f9fa;
    padding: 15px;
    border-bottom: 1px solid #e9ecef;
}

.card-header h2 {
    margin: 0;
    font-size: 1.25rem;
    color: #000080;
}

.card-body {
    padding: 15px;
}

.mt-4 {
    margin-top: 1.5rem;
}

.compact-form {
    background: none;
    box-shadow: none;
    padding: 0;
    margin: 0;
}

.form-actions {
    display: flex;
    justify-content: flex-end;
    margin-top: 15px;
}

.submit-btn {
    background-color: #000080;
    color: #ffff00;
    border: none;
    padding: 10px 15px;
    border-radius: 4px;
    cursor: pointer;
    font-weight: 500;
    transition: background-color 0.3s;
}

.submit-btn:hover {
    background-color: #000066;
}

.btn-sm {
    padding: 5px 10px;
    margin-right: 5px;
    border-radius: 3px;
    font-size: 0.9rem;
    color: #fff;
    text-decoration: none;
    display: inline-block;
}

.edit-sale {
    background-color: #007bff;
    color: white;
}

.delete-sale {
    background-color: #dc3545;
    color: white;
}

#total-amount-display {
    display: flex;
    flex-direction: column;
    justify-content: center;
}

#total-amount-display .amount {
    font-size: 1.2rem;
    font-weight: bold;
    color: #28a745;
}

/* Mobile responsive data-table */
@media screen and (max-width: 768px) {
    .data-table thead {
        display: none;
    }
    
    .data-table, 
    .data-table tbody, 
    .data-table tr {
        display: block;
        width: 100%;
    }
    
    .data-table tr {
        margin-bottom: 15px;
        border: 1px solid #ddd;
        border-radius: 5px;
        box-shadow: 0 1px 3px rgba(0,0,0,0.1);
    }
    
    .data-table td {
        display: flex;
        justify-content: space-between;
        align-items: center;
        padding: 10px;
        border-bottom: 1px solid #eee;
        text-align: right;
    }
    
    .data-table td:last-child {
        border-bottom: none;
    }
    
    .data-table td::before {
        content: attr(data-label);
        font-weight: bold;
        flex: 1;
        text-align: left;
        margin-right: 10px;
    }
    
    .data-table td[data-label="Actions"] {
        justify-content: flex-start;
    }
    
    .export-form {
        margin-bottom: 10px;
    }
}

/* Notification styling */
.notification {
    position: fixed;
    bottom: 20px;
    right: 20px;
    padding: 15px 20px;
    border-radius: 4px;
    color: white;
    display: flex;
    align-items: center;
    justify-content: space-between;
    max-width: 90%;
    box-shadow: 0 4px 8px rgba(0,0,0,0.2);
    z-index: 1000;
    transition: opacity 0.3s ease;
}

.notification.success {
    background-color: #28a745;
}

.notification.error {
    background-color: #dc3545;
}

#notification-message {
    margin-right: 15px;
    flex: 1;
}

#notification-close {
    background: none;
    border: none;
    color: white;
    cursor: pointer;
    font-size: 1rem;
}

@media (max-width: 600px) {
    .notification {
        left: 20px;
        right: 20px;
        bottom: 20px;
        max-width: calc(100% - 40px);
    }
}
</style>

<script src="https://code.jquery.com/jquery-3.6.0.min.js"></script>
<script>
$(document).ready(function() {
    var buyerRates = {};
    // Set today's date as default
    var today = new Date().toISOString().split('T')[0];
    $('#date').val(today);

    function calculateTotal() {
        var buyerId = $('#buyer_id').val();
        var weightTilapia = parseFloat($('#weight_tilapia').val()) || 0;
        var weightSmallFish = parseFloat($('#weight_small_fish').val()) || 0;
        var weightBigFish = parseFloat($('#weight_big_fish').val()) || 0;
        var includeDelivery = $('#include_delivery').is(':checked');

        if (buyerId && buyerRates[buyerId]) {
            var buyer = buyerRates[buyerId];
            var total = (weightTilapia * buyer.rate_tilapia) +
                        (weightSmallFish * buyer.rate_small_fish) +
                        (weightBigFish * buyer.rate_big_fish);
            
            if (includeDelivery) {
                total += parseFloat(buyer.delivery_rate);
            }
            
            var harvestingCharges = (weightTilapia * buyer.harvesting_fee_tilapia) +
                                    (weightSmallFish * buyer.harvesting_fee_small_fish) +
                                    (weightBigFish * buyer.harvesting_fee_big_fish);
            
            $('#total-amount').text(total.toFixed(2));
            $('#final_amount').val(total.toFixed(2));
            $('#harvesting_charges').val(harvestingCharges.toFixed(2));
        }
    }

    $('#buyer_id').on('change', function() {
        var buyerId = $(this).val();
        if (buyerId && !buyerRates[buyerId]) {
            $.ajax({
                url: 'sales.php',
                method: 'POST',
                data: { get_buyer_rates: 1, buyer_id: buyerId },
                dataType: 'json',
                success: function(buyer) {
                    buyerRates[buyerId] = buyer;
                    calculateTotal();
                }
            });
        } else {
            calculateTotal();
        }
    });

    $('#weight_tilapia, #weight_small_fish, #weight_big_fish, #include_delivery').on('input change', calculateTotal);

    $('#final_amount_override').on('input', function() {
        var override = $(this).val();
        if (override) {
            $('#total-amount').text(parseFloat(override).toFixed(2));
            $('#final_amount').val(parseFloat(override).toFixed(2));
        } else {
            calculateTotal();
        }
    });

    // Show notification
    function showNotification(message, isSuccess = true) {
        const notification = $('#notification');
        const messageEl = $('#notification-message');
        
        messageEl.text(message);
        notification.removeClass('success error');
        notification.addClass(isSuccess ? 'success' : 'error');
        notification.fadeIn();
        
        setTimeout(function() {
            notification.fadeOut();
        }, 5000);
    }
    
    // Close notification
    $('#notification-close').on('click', function() {
        $('#notification').fadeOut();
    });

    $('#sales-form').on('submit', function(e) {
        e.preventDefault();
        
        // Basic validation
        var buyerId = $('#buyer_id').val();
        if (!buyerId) {
            showNotification('Please select a buyer', false);
            return;
        }
        
        $.ajax({
            url: 'sales.php',
            method: 'POST',
            data: $(this).serialize(),
            dataType: 'json',
            success: function(response) {
                if (response.success) {
                    $('#sales-list').html(response.salesRows);
                    $('#sales-form')[0].reset();
                    $('#total-amount').text('0.00');
                    $('#date').val(today); // Reset date to today
                    showNotification('Sale added successfully!');
                } else {
                    showNotification('Error adding sale: ' + response.error, false);
                }
            },
            error: function() {
                showNotification('An error occurred. Please try again.', false);
            }
        });
    });

    // Handle delete with confirmation
    $(document).on('click', '.delete-sale', function(e) {
        e.preventDefault();
        if (confirm('Are you sure you want to delete this sale?')) {
            var saleId = $(this).data('id');
            $.ajax({
                url: 'sales.php',
                method: 'POST',
                data: { delete_sale: 1, sale_id: saleId },
                dataType: 'json',
                success: function(response) {
                    if (response.success) {
                        $('#sales-list').html(response.salesRows);
                        showNotification('Sale deleted successfully!');
                    } else {
                        showNotification('Error deleting sale: ' + response.error, false);
                    }
                },
                error: function() {
                    showNotification('An error occurred. Please try again.', false);
                }
            });
        }
    });

    // Pagination scroll buttons
    $('.page-scroll').on('click', function(e) {
        e.preventDefault();
        var direction = $(this).data('direction');
        var currentPage = parseInt($('.pagination a.active').text());
        var targetPage = direction === 'left' ? currentPage - 10 : currentPage + 10;
        window.location.href = '?page=' + targetPage;
    });
    
    // Additional mobile optimizations
    function adjustForMobile() {
        if (window.innerWidth <= 768) {
            // Enhance touch targets
            $('.data-table a').css('padding', '10px');
            
            // Auto-scroll to form on small screens after submission
            $('#sales-form').on('submit', function() {
                $('html, body').animate({
                    scrollTop: $('.card:first').offset().top - 20
                }, 300);
            });
        }
    }
    
    // Run mobile optimizations
    adjustForMobile();
    $(window).on('resize', adjustForMobile);
    
    // Initialize the total calculator
    calculateTotal();
});
</script>
HTML;

include 'main_layout.php';
?>