<?php
/**
 * get_price_gap_heatmap.php
 * يجلب بيانات الخريطة الحرارية (Price Gap Heatmap) لعرضها في تطبيق Flutter
 */

require_once __DIR__ . '/../../connect.php';

if ($role !== 'admin' && $role !== 'super_admin') {
    http_response_code(403);
    echo json_encode(['status' => 'failure', 'message' => 'Unauthorized']);
    exit;
}

try {
    $countryCode = resolveAdminCountry(filterRequest('country_code'), $role, $admin_country ?? null);
    
    if (!$countryCode) {
        jsonError("Missing required parameter: country_code");
        exit;
    }

    // Determine current Siro speed price
    $sqlKazan = "SELECT speedPrice FROM kazan WHERE country = :country LIMIT 1";
    $stmtKazan = $con->prepare($sqlKazan);
    $countryNameMap = ['SY' => 'Syria', 'JO' => 'Jordan', 'EG' => 'Egypt', 'IQ' => 'Iraq'];
    $stmtKazan->execute([':country' => $countryNameMap[strtoupper($countryCode)] ?? 'Syria']);
    $kazanRow = $stmtKazan->fetch(PDO::FETCH_ASSOC);
    $currentSpeedPrice = $kazanRow ? (float)$kazanRow['speedPrice'] : 0;

    if ($currentSpeedPrice <= 0) {
        jsonError("Siro base price not configured for this country.");
        exit;
    }

    // Aggregate competitor data by geographical grid (approx 1.5km x 1.5km)
    $sql = "SELECT 
                ROUND(from_latitude * 74, 0) / 74 AS lat_group,
                ROUND(from_longitude * 74, 0) / 74 AS lng_group,
                AVG(price_per_km) as avg_competitor_price_per_km,
                COUNT(*) as trip_count
            FROM competitor_prices 
            WHERE country_code = :country 
              AND distance_km > 0
              AND created_at >= DATE_SUB(NOW(), INTERVAL 7 DAY)
            GROUP BY lat_group, lng_group
            HAVING trip_count >= 3"; // Require at least 3 trips for a reliable heatmap point
            
    $stmt = $con->prepare($sql);
    $stmt->execute([':country' => strtoupper($countryCode)]);
    $grids = $stmt->fetchAll(PDO::FETCH_ASSOC);

    $heatmapData = [];
    
    foreach ($grids as $grid) {
        $compPricePerKm = (float)$grid['avg_competitor_price_per_km'];
        if ($compPricePerKm <= 0) continue;

        // Calculate PCI for this specific grid
        // PCI < 1 means we are cheaper. PCI > 1 means we are more expensive.
        $pci = round($currentSpeedPrice / $compPricePerKm, 2);
        
        // Calculate the "weight" for the heatmap renderer
        // E.g. -1 (We are 100% cheaper) to +1 (We are 100% more expensive)
        $weight = round($pci - 1.0, 2);
        // Clamp between -1 and 1
        $weight = max(-1.0, min(1.0, $weight));

        $heatmapData[] = [
            'lat' => (float)$grid['lat_group'],
            'lng' => (float)$grid['lng_group'],
            'pci' => $pci,
            'weight' => $weight, // Negative = Green (Cheaper), Positive = Red (More expensive)
            'sample_size' => (int)$grid['trip_count']
        ];
    }

    jsonSuccess([
        'total_heatmap_points' => count($heatmapData),
        'current_siro_price_per_km' => $currentSpeedPrice,
        'heatmap_data' => $heatmapData
    ]);

} catch (Exception $e) {
    error_log("[get_price_gap_heatmap] Error: " . $e->getMessage());
    jsonError("Failed to generate heatmap data");
}