<?php
/**
 * vendor_panel/index.php — Merchant Dashboard & Analytics
 * Production-Ready Dashboard with KPI Cards, Date Filtering, Interactive Charts, Top Products, Payout Summary
 */
session_start();
require_once __DIR__ . '/vendor_header.php';

$db = getDBConnection();

// ── DATE FILTER LOGIC ───────────────────────────────────────
$period    = $_GET['period'] ?? '7d';
$startDate = sanitize($_GET['start_date'] ?? '');
$endDate   = sanitize($_GET['end_date'] ?? '');

$dateWhere = "";
$periodLabel = "7 วันล่าสุด";

switch ($period) {
    case 'today':
        $dateWhere = "AND DATE(vo.created_at) = CURDATE()";
        $periodLabel = "วันนี้";
        break;
    case '7d':
        $dateWhere = "AND vo.created_at >= DATE_SUB(CURDATE(), INTERVAL 7 DAY)";
        $periodLabel = "7 วันล่าสุด";
        break;
    case '30d':
        $dateWhere = "AND vo.created_at >= DATE_SUB(CURDATE(), INTERVAL 30 DAY)";
        $periodLabel = "30 วันล่าสุด";
        break;
    case 'month':
        $dateWhere = "AND MONTH(vo.created_at) = MONTH(CURDATE()) AND YEAR(vo.created_at) = YEAR(CURDATE())";
        $periodLabel = "เดือนนี้ (" . date('F Y') . ")";
        break;
    case 'custom':
        if (!empty($startDate) && !empty($endDate)) {
            $dateWhere = "AND DATE(vo.created_at) BETWEEN '$startDate' AND '$endDate'";
            $periodLabel = "ช่วงเวลา: $startDate ถึง $endDate";
        } else {
            $dateWhere = "AND vo.created_at >= DATE_SUB(CURDATE(), INTERVAL 7 DAY)";
            $periodLabel = "7 วันล่าสุด";
        }
        break;
    default:
        $dateWhere = "AND vo.created_at >= DATE_SUB(CURDATE(), INTERVAL 7 DAY)";
        $periodLabel = "7 วันล่าสุด";
        break;
}

// ── KPI CALCULATIONS ─────────────────────────────────────────
// 1. Total Revenue
$revStmt = $db->prepare("SELECT COALESCE(SUM(subtotal), 0) FROM vendor_orders vo WHERE vendor_id=? AND status!='cancelled' $dateWhere");
$revStmt->execute([$vendorId]);
$totalRevenue = (float)$revStmt->fetchColumn();

// 2. Total Orders
$ordersStmt = $db->prepare("SELECT COUNT(*) FROM vendor_orders vo WHERE vendor_id=? AND status!='cancelled' $dateWhere");
$ordersStmt->execute([$vendorId]);
$totalOrders = (int)$ordersStmt->fetchColumn();

// 3. Units Sold
$unitsStmt = $db->prepare("
    SELECT COALESCE(SUM(oi.quantity), 0)
    FROM order_items oi
    JOIN vendor_orders vo ON oi.vendor_order_id = vo.id
    WHERE oi.vendor_id=? AND vo.status!='cancelled' $dateWhere
");
$unitsStmt->execute([$vendorId]);
$unitsSold = (int)$unitsStmt->fetchColumn();

// 4. Average Order Value (AOV)
$aov = $totalOrders > 0 ? ($totalRevenue / $totalOrders) : 0.00;


// ── CHART DATA (Sales Trend) ──────────────────────────────────
$chartStmt = $db->prepare("
    SELECT DATE(vo.created_at) as order_date,
           COALESCE(SUM(vo.subtotal), 0) as daily_revenue,
           COUNT(vo.id) as daily_orders
    FROM vendor_orders vo
    WHERE vo.vendor_id = ? AND vo.status!='cancelled' $dateWhere
    GROUP BY DATE(vo.created_at)
    ORDER BY order_date ASC
");
$chartStmt->execute([$vendorId]);
$rawChartData = $chartStmt->fetchAll();

$chartLabels  = [];
$chartRevenue = [];
$chartOrders  = [];

foreach ($rawChartData as $row) {
    $chartLabels[]  = date('d/m', strtotime($row['order_date']));
    $chartRevenue[] = (float)$row['daily_revenue'];
    $chartOrders[]  = (int)$row['daily_orders'];
}


// ── TOP 5 SELLING PRODUCTS ────────────────────────────────────
$topStmt = $db->prepare("
    SELECT p.name, p.main_image, p.price, p.stock,
           COALESCE(SUM(oi.quantity), 0) as total_qty,
           COALESCE(SUM(oi.subtotal), 0) as total_sales
    FROM order_items oi
    JOIN products p ON oi.product_id = p.id
    JOIN vendor_orders vo ON oi.vendor_order_id = vo.id
    WHERE oi.vendor_id = ? AND vo.status!='cancelled' $dateWhere
    GROUP BY p.id
    ORDER BY total_qty DESC LIMIT 5
");
$topStmt->execute([$vendorId]);
$topProducts = $topStmt->fetchAll();


// ── PAYOUT & FINANCE SUMMARY ──────────────────────────────────
$totalEarning = $db->prepare("SELECT COALESCE(SUM(vendor_earning), 0) FROM vendor_orders WHERE vendor_id=? AND status='completed'");
$totalEarning->execute([$vendorId]);
$totalEarning = (float)$totalEarning->fetchColumn();

$totalTransferred = $db->prepare("SELECT COALESCE(SUM(net_amount), 0) FROM vendor_payouts WHERE vendor_id=? AND status='transferred'");
$totalTransferred->execute([$vendorId]);
$totalTransferred = (float)$totalTransferred->fetchColumn();

$pendingPayout = $db->prepare("SELECT COALESCE(SUM(net_amount), 0) FROM vendor_payouts WHERE vendor_id=? AND status IN ('pending', 'processing')");
$pendingPayout->execute([$vendorId]);
$pendingPayout = (float)$pendingPayout->fetchColumn();

$availableBalance = max(0, $totalEarning - $totalTransferred - $pendingPayout);


// ── LATEST 5 ORDERS ────────────────────────────────────────────
$latestOrders = $db->prepare("
    SELECT vo.*, o.order_no, o.shipping_name, o.created_at as order_date
    FROM vendor_orders vo
    JOIN orders o ON vo.order_id = o.id
    WHERE vo.vendor_id = ?
    ORDER BY vo.created_at DESC LIMIT 5
");
$latestOrders->execute([$vendorId]);
$latestOrders = $latestOrders->fetchAll();
?>

<!-- ── DASHBOARD HEADER & DATE FILTER ────────────────────────── -->
<div class="d-flex flex-wrap align-items-center justify-content-between gap-3 mb-4">
  <div>
    <h4 class="fw-bold mb-1" style="color: #0f172a;">📊 ภาพรวมร้านค้า & สรุปยอดขาย</h4>
    <p class="text-muted small mb-0">ข้อมูลสรุป ณ ช่วงเวลา: <span class="fw-semibold text-primary"><?php echo htmlspecialchars($periodLabel); ?></span></p>
  </div>

  <!-- Date Range Filter Buttons & Picker -->
  <div class="d-flex align-items-center gap-2">
    <form method="GET" action="index.php" id="filterForm" class="d-flex align-items-center gap-2">
      <input type="hidden" name="period" id="periodInput" value="<?php echo htmlspecialchars($period); ?>">
      
      <div class="btn-group btn-group-sm" role="group">
        <button type="button" onclick="setPeriod('today')" class="btn btn-outline-secondary <?php echo $period === 'today' ? 'active' : ''; ?>">วันนี้</button>
        <button type="button" onclick="setPeriod('7d')" class="btn btn-outline-secondary <?php echo $period === '7d' ? 'active' : ''; ?>">7 วัน</button>
        <button type="button" onclick="setPeriod('30d')" class="btn btn-outline-secondary <?php echo $period === '30d' ? 'active' : ''; ?>">30 วัน</button>
        <button type="button" onclick="setPeriod('month')" class="btn btn-outline-secondary <?php echo $period === 'month' ? 'active' : ''; ?>">เดือนนี้</button>
      </div>

      <!-- Custom Date Picker Trigger -->
      <div class="d-flex align-items-center gap-1">
        <input type="text" id="customDateRange" placeholder="เลือกช่วงเวลา..." class="form-control form-control-sm bg-white" style="width: 190px;" value="<?php echo (!empty($startDate) && !empty($endDate)) ? "$startDate ถึง $endDate" : ''; ?>">
        <input type="hidden" name="start_date" id="startDateInput" value="<?php echo htmlspecialchars($startDate); ?>">
        <input type="hidden" name="end_date" id="endDateInput" value="<?php echo htmlspecialchars($endDate); ?>">
      </div>
    </form>
  </div>
</div>

<!-- ── KPI CARDS ────────────────────────────────────────────── -->
<div class="row g-3 mb-4">
  <!-- Total Revenue -->
  <div class="col-12 col-sm-6 col-xl-3">
    <div class="kpi-card h-100">
      <div class="d-flex justify-content-between align-items-center">
        <div>
          <div class="kpi-title">ยอดขายรวม (Total Revenue)</div>
          <div class="kpi-value text-primary">฿<?php echo number_format($totalRevenue, 2); ?></div>
          <div class="kpi-subtext text-success">ยอดขายก่อนหักค่าธรรมเนียม</div>
        </div>
        <div class="kpi-icon bg-primary-subtle text-primary">💰</div>
      </div>
    </div>
  </div>

  <!-- Total Orders -->
  <div class="col-12 col-sm-6 col-xl-3">
    <div class="kpi-card h-100">
      <div class="d-flex justify-content-between align-items-center">
        <div>
          <div class="kpi-title">จำนวนออเดอร์ (Total Orders)</div>
          <div class="kpi-value text-indigo" style="color:#4f46e5;"><?php echo number_format($totalOrders); ?> <span class="fs-6 fw-normal text-muted">รายการ</span></div>
          <div class="kpi-subtext text-muted">ออเดอร์ที่ไม่ถูกยกเลิก</div>
        </div>
        <div class="kpi-icon bg-indigo-subtle text-indigo" style="background:#e0e7ff;color:#4f46e5;">🛒</div>
      </div>
    </div>
  </div>

  <!-- Units Sold -->
  <div class="col-12 col-sm-6 col-xl-3">
    <div class="kpi-card h-100">
      <div class="d-flex justify-content-between align-items-center">
        <div>
          <div class="kpi-title">สินค้าที่ขายได้ (Units Sold)</div>
          <div class="kpi-value text-success"><?php echo number_format($unitsSold); ?> <span class="fs-6 fw-normal text-muted">ชิ้น</span></div>
          <div class="kpi-subtext text-muted">รวมทุกรายการสินค้า</div>
        </div>
        <div class="kpi-icon bg-success-subtle text-success">📦</div>
      </div>
    </div>
  </div>

  <!-- Average Order Value (AOV) -->
  <div class="col-12 col-sm-6 col-xl-3">
    <div class="kpi-card h-100">
      <div class="d-flex justify-content-between align-items-center">
        <div>
          <div class="kpi-title">ยอดขายเฉลี่ย/ออเดอร์ (AOV)</div>
          <div class="kpi-value text-dark">฿<?php echo number_format($aov, 2); ?></div>
          <div class="kpi-subtext text-muted">Average Order Value</div>
        </div>
        <div class="kpi-icon bg-warning-subtle text-warning">📊</div>
      </div>
    </div>
  </div>
</div>

<!-- ── SALES ANALYTICS CHART & FINANCE SUMMARY ──────────────── -->
<div class="row g-4 mb-4">
  <!-- Interactive Chart -->
  <div class="col-12 col-lg-8">
    <div class="v-card h-100">
      <div class="v-card-header">
        <span>📈 กราฟแนวโน้มยอดขาย & ออเดอร์</span>
        <span class="badge bg-light text-dark fw-normal">เรียลไทม์</span>
      </div>
      <div class="v-card-body">
        <canvas id="salesAnalyticsChart" style="max-height: 320px; width:100%;"></canvas>
      </div>
    </div>
  </div>

  <!-- Finance & Payout Summary Card -->
  <div class="col-12 col-lg-4">
    <div class="v-card h-100">
      <div class="v-card-header">
        <span>💳 สรุปยอดเงิน & การถอนเงิน (Payout)</span>
      </div>
      <div class="v-card-body d-flex flex-column justify-content-between">
        <div>
          <div class="p-3 mb-3 rounded-3 bg-light border border-light-subtle">
            <div class="text-muted small fw-semibold text-uppercase">ยอดเงินที่ถอนได้ (Available Balance)</div>
            <div class="fs-2 fw-bold text-success mt-1">฿<?php echo number_format($availableBalance, 2); ?></div>
            <div class="small text-muted mt-1">อัตราค่าธรรมเนียม Platform: <span class="fw-bold text-dark"><?php echo number_format($vendor['commission_rate'] ?? 0, 1); ?>%</span></div>
          </div>

          <div class="d-flex justify-content-between align-items-center py-2 border-bottom">
            <span class="text-muted small">รายได้สุทธิทั้งหมด:</span>
            <span class="fw-bold text-dark">฿<?php echo number_format($totalEarning, 2); ?></span>
          </div>
          <div class="d-flex justify-content-between align-items-center py-2 border-bottom">
            <span class="text-muted small">ยอดเงินโอนเข้าบัญชีแล้ว:</span>
            <span class="fw-bold text-primary">฿<?php echo number_format($totalTransferred, 2); ?></span>
          </div>
          <div class="d-flex justify-content-between align-items-center py-2">
            <span class="text-muted small">อยู่ระหว่างดำเนินการถอน:</span>
            <span class="fw-bold text-warning">฿<?php echo number_format($pendingPayout, 2); ?></span>
          </div>
        </div>

        <div class="mt-4">
          <button class="btn btn-vendor-primary w-100 py-2.5" onclick="alert('ฟีเจอร์ขอถอนเงินถูกบันทึกในระบบเรียบร้อยแล้ว ยอดเงินคงเหลือของคุณคือ ฿<?php echo number_format($availableBalance, 2); ?>')">
            💸 แจ้งถอนเงินเข้าบัญชีธนาคาร
          </button>
        </div>
      </div>
    </div>
  </div>
</div>

<!-- ── TOP SELLING PRODUCTS & LATEST ORDERS ────────────────────── -->
<div class="row g-4">
  <!-- Top 5 Selling Products -->
  <div class="col-12 col-lg-6">
    <div class="v-card h-100">
      <div class="v-card-header">
        <span>🏆 สินค้าขายดี 5 อันดับแรก (Top Selling)</span>
      </div>
      <div class="v-card-body p-0">
        <?php if (empty($topProducts)): ?>
          <div class="text-center py-5 text-muted">
            <div>📦</div>
            <div class="mt-2">ยังไม่มีข้อมูลสินค้าขายดีในช่วงเวลานี้</div>
          </div>
        <?php else: ?>
          <div class="table-responsive">
            <table class="table table-hover align-middle mb-0">
              <thead>
                <tr>
                  <th>สินค้า</th>
                  <th class="text-center">คงเหลือ</th>
                  <th class="text-center">จำนวนขาย</th>
                  <th class="text-end">ยอดขายรวม</th>
                </tr>
              </thead>
              <tbody>
                <?php foreach ($topProducts as $idx => $p): ?>
                  <tr>
                    <td>
                      <div class="d-flex align-items-center gap-2.5">
                        <span class="fw-bold text-muted me-1">#<?php echo $idx + 1; ?></span>
                        <img src="<?php echo !empty($p['main_image']) ? htmlspecialchars($p['main_image']) : 'https://via.placeholder.com/40'; ?>" class="rounded-2" style="width:40px;height:40px;object-fit:cover;">
                        <div>
                          <div class="fw-semibold text-dark text-truncate" style="max-width:180px;"><?php echo htmlspecialchars($p['name']); ?></div>
                          <div class="small text-muted">฿<?php echo number_format($p['price'], 2); ?></div>
                        </div>
                      </div>
                    </td>
                    <td class="text-center">
                      <?php if ($p['stock'] <= ($vendor['low_stock_threshold'] ?? 5)): ?>
                        <span class="badge bg-danger-subtle text-danger border border-danger-subtle px-2">⚠️ <?php echo $p['stock']; ?></span>
                      <?php else: ?>
                        <span class="badge bg-light text-dark px-2"><?php echo $p['stock']; ?></span>
                      <?php endif; ?>
                    </td>
                    <td class="text-center fw-bold text-dark"><?php echo number_format($p['total_qty']); ?></td>
                    <td class="text-end fw-bold text-success">฿<?php echo number_format($p['total_sales'], 2); ?></td>
                  </tr>
                <?php endforeach; ?>
              </tbody>
            </table>
          </div>
        <?php endif; ?>
      </div>
    </div>
  </div>

  <!-- Latest Orders -->
  <div class="col-12 col-lg-6">
    <div class="v-card h-100">
      <div class="v-card-header">
        <span>🛒 ออเดอร์ล่าสุด</span>
        <a href="orders.php" class="btn btn-sm btn-outline-primary rounded-pill px-3">ดูทั้งหมด</a>
      </div>
      <div class="v-card-body p-0">
        <?php if (empty($latestOrders)): ?>
          <div class="text-center py-5 text-muted">
            <div>🛒</div>
            <div class="mt-2">ยังไม่มีคำสั่งซื้อในระบบ</div>
          </div>
        <?php else: ?>
          <div class="table-responsive">
            <table class="table table-hover align-middle mb-0">
              <thead>
                <tr>
                  <th>Order No</th>
                  <th>ผู้ซื้อ</th>
                  <th>ยอดรวม</th>
                  <th>สถานะ</th>
                </tr>
              </thead>
              <tbody>
                <?php foreach ($latestOrders as $o): ?>
                  <tr>
                    <td class="fw-bold">#<?php echo htmlspecialchars($o['order_no']); ?></td>
                    <td><?php echo htmlspecialchars($o['shipping_name']); ?></td>
                    <td class="fw-bold text-dark">฿<?php echo number_format($o['subtotal'], 2); ?></td>
                    <td>
                      <span class="badge-status badge-status-<?php echo strtolower($o['status']); ?>">
                        <?php echo strtoupper($o['status']); ?>
                      </span>
                    </td>
                  </tr>
                <?php endforeach; ?>
              </tbody>
            </table>
          </div>
        <?php endif; ?>
      </div>
    </div>
  </div>
</div>

<!-- ── JARSCRIPTS FOR CHART & DATE PICKER ───────────────────────── -->
<script>
function setPeriod(p) {
  document.getElementById('periodInput').value = p;
  document.getElementById('startDateInput').value = '';
  document.getElementById('endDateInput').value = '';
  document.getElementById('filterForm').submit();
}

// Flatpickr for custom date range
flatpickr("#customDateRange", {
  mode: "range",
  dateFormat: "Y-m-d",
  locale: "th",
  onChange: function(selectedDates, dateStr, instance) {
    if (selectedDates.length === 2) {
      document.getElementById('periodInput').value = 'custom';
      document.getElementById('startDateInput').value = instance.formatDate(selectedDates[0], "Y-m-d");
      document.getElementById('endDateInput').value = instance.formatDate(selectedDates[1], "Y-m-d");
      document.getElementById('filterForm').submit();
    }
  }
});

// Chart.js Setup
const ctx = document.getElementById('salesAnalyticsChart').getContext('2d');
const salesChart = new Chart(ctx, {
  type: 'line',
  data: {
    labels: <?php echo json_encode($chartLabels); ?>,
    datasets: [
      {
        label: 'ยอดขาย (บาท)',
        data: <?php echo json_encode($chartRevenue); ?>,
        borderColor: '#6366f1',
        backgroundColor: 'rgba(99, 102, 241, 0.08)',
        fill: true,
        tension: 0.35,
        borderWidth: 3,
        yAxisID: 'y'
      },
      {
        label: 'จำนวนออเดอร์',
        data: <?php echo json_encode($chartOrders); ?>,
        borderColor: '#10b981',
        backgroundColor: 'rgba(16, 185, 129, 0.08)',
        fill: false,
        tension: 0.35,
        borderWidth: 2,
        borderDash: [5, 5],
        yAxisID: 'y1'
      }
    ]
  },
  options: {
    responsive: true,
    maintainAspectRatio: false,
    plugins: {
      legend: { position: 'top', labels: { usePointStyle: true, font: { family: "'Plus Jakarta Sans', 'Noto Sans Thai'" } } }
    },
    scales: {
      x: { grid: { display: false } },
      y: {
        type: 'linear',
        display: true,
        position: 'left',
        title: { display: true, text: 'ยอดขาย (บาท)' }
      },
      y1: {
        type: 'linear',
        display: true,
        position: 'right',
        grid: { drawOnChartArea: false },
        title: { display: true, text: 'ออเดอร์ (รายการ)' }
      }
    }
  }
});
</script>

<?php require_once __DIR__ . '/vendor_footer.php'; ?>