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

// If Main Redis is not available, return empty array
if (!isset($redis) || $redis === null) {
    echo json_encode([]);
    exit();
}

$grid_size = 0.0135;
$keys = [];

try {
    // Prefix 'siro:' is automatically applied by $redis
    $keys = $redis->keys("demand:grid:*");
} catch (Exception $e) {
    error_log("[heatmap_live.php] Redis keys error: " . $e->getMessage());
    echo json_encode([]);
    exit();
}

$heatmap_data = [];

foreach ($keys as $key) {
    // The keys returned by $redis->keys() will actually contain the 'siro:' prefix
    // e.g. siro:demand:grid:33.5135_36.2735
    $parts = explode(":", $key);
    $coords = explode("_", end($parts));
    
    if (count($coords) == 2) {
        $lat = (float)$coords[0];
        $lng = (float)$coords[1];
        
        // We must strip 'siro:' to use $redis->get() because $redis auto-prefixes everything!
        // Actually, $redis->keys() returns the physical key "siro:demand:grid:X"
        // But $redis->get("demand:grid:X") automatically prepends "siro:".
        // So we must strip the "siro:" part before passing to get()
        $clean_key = str_replace("siro:", "", $key);
        $count = (int)$redis->get($clean_key);
        
        // Fetch active drivers using Location Redis
        $available_drivers = 0;
        try {
            global $redisLocation;
            if (isset($redisLocation) && $redisLocation !== null) {
                $drivers = $redisLocation->georadius('geo:drivers:available', $lng, $lat, 0.75, 'km');
                $availableDrivers = count($drivers);
            }
        } catch (Exception $e) {}

        $intensity = 'low';
        $surge_ratio = ($available_drivers > 0) ? ($count / $available_drivers) : $count;

        if ($surge_ratio > 2.0 || $count >= 5) {
            $intensity = 'high';
        } else if ($surge_ratio > 1.2 || $count >= 3) {
            $intensity = 'medium';
        }

        $heatmap_data[] = [
            "lat" => $lat,
            "lng" => $lng,
            "count" => $count,
            "intensity" => $intensity
        ];
    }
}

// Output the JSON array as expected by home_captain_controller.dart
header('Content-Type: application/json');
echo json_encode($heatmap_data);
?>