<?php
require_once __DIR__ . '/../db/config.php';

header('Content-Type: application/json');
ini_set('display_errors', 0);

// --- Utility Functions ---

function pointInPolygon($point, $polygon) {
    $inside = false;
    $x = $point[0];
    $y = $point[1];
    for ($i = 0, $j = count($polygon) - 1; $i < count($polygon); $j = $i++) {
        $xi = $polygon[$i][0]; $yi = $polygon[$i][1];
        $xj = $polygon[$j][0]; $yj = $polygon[$j][1];
        $intersect = (($yi > $y) != ($yj > $y)) && ($x < ($xj - $xi) * ($y - $yi) / ($yj - $yi) + $xi);
        if ($intersect) $inside = !$inside;
    }
    return $inside;
}

function haversineDistance($lat1, $lon1, $lat2, $lon2) {
    $earthRadius = 6371; // km
    $dLat = deg2rad($lat2 - $lat1);
    $dLon = deg2rad($lon2 - $lon1);
    $a = sin($dLat / 2) * sin($dLat / 2) + cos(deg2rad($lat1)) * cos(deg2rad($lat2)) * sin($dLon / 2) * sin($dLon / 2);
    $c = 2 * atan2(sqrt($a), sqrt(1 - $a));
    return $earthRadius * $c;
}

// --- Risk Calculation Functions ---

function getWildfireRisk($lat, $lon) {
    try {
        $wildfireUrl = 'https://services3.arcgis.com/T4QMspbfLg3qTGWY/arcgis/rest/services/WFIGS_Interagency_Fire_Perimeters_Current/FeatureServer/0/query?where=1%3D1&outFields=poly_IncidentName,poly_GISAcres,attr_InitialLatitude,attr_InitialLongitude&outSR=4326&f=json';
        $context = stream_context_create(['http' => ['timeout' => 10]]);
        $wildfireDataJson = @file_get_contents($wildfireUrl, false, $context);
        if (!$wildfireDataJson) throw new Exception('Could not fetch wildfire data from source.');

        $wildfireData = json_decode($wildfireDataJson, true);
        if (!$wildfireData || !isset($wildfireData['features'])) return ['score' => 0, 'details' => 'No active wildfires found or data invalid.'];

        $risk = 0;
        $closest_distance = PHP_INT_MAX;
        $closest_fire = null;

        foreach ($wildfireData['features'] as $fire) {
            $fireLat = $fire['attributes']['attr_InitialLatitude'];
            $fireLon = $fire['attributes']['attr_InitialLongitude'];
            if ($fireLat && $fireLon) {
                $distance = haversineDistance($lat, $lon, $fireLat, $fireLon);
                if ($distance < $closest_distance) {
                    $closest_distance = $distance;
                    $closest_fire = $fire['attributes']['poly_IncidentName'];
                }
            }
        }

        if ($closest_distance < 50) { // 50km threshold
            $risk = 100 - ($closest_distance / 50) * 100;
        }

        return ['score' => round($risk), 'details' => $closest_fire ? "Closest fire: {$closest_fire} (" . round($closest_distance) . " km away)" : "No fires within 50km."];
    } catch (Exception $e) {
        error_log("Wildfire Risk Error: " . $e->getMessage());
        return ['score' => 0, 'details' => 'Error calculating wildfire risk.'];
    }
}

function getHurricaneRisk($lat, $lon) {
    try {
        $localApiUrl = 'http://localhost/api/hurricanes.php';
        $context = stream_context_create(['http' => ['timeout' => 15]]);
        $geoJsonData = @file_get_contents($localApiUrl, false, $context);
        if (!$geoJsonData) throw new Exception('Could not fetch local hurricane data.');

        $hurricaneData = json_decode($geoJsonData, true);
        if (!$hurricaneData || empty($hurricaneData['features'])) return ['score' => 0, 'details' => 'No active hurricane data found.'];

        $risk = 0;
        $details = [];
        $point = [(float)$lon, (float)$lat];

        foreach ($hurricaneData['features'] as $feature) {
            if (isset($feature['properties']['layer']) && $feature['properties']['layer'] === 'cone' && $feature['geometry']['type'] === 'Polygon') {
                $polygon = $feature['geometry']['coordinates'][0];
                if (pointInPolygon($point, $polygon)) {
                    $risk = 100;
                    $stormName = $feature['properties']['STORMNAME'] ?? 'Unnamed Storm';
                    $details[] = "Inside the forecast cone for " . $stormName;
                    break;
                }
            }
        }
        return ['score' => $risk, 'details' => !empty($details) ? implode(', ', $details) : 'Not in any active hurricane forecast cones.'];
    } catch (Exception $e) {
        error_log("Hurricane Risk Error: " . $e->getMessage());
        return ['score' => 0, 'details' => 'Error calculating hurricane risk.'];
    }
}

function getHistoricalHurricaneRisk($lat, $lon) {
    try {
        $pdo = db();
        if (!$pdo) return ['score' => 0, 'details' => 'Database connection failed.'];

        $radius = 1.0; 
        $stmt = $pdo->prepare("SELECT COUNT(DISTINCT storm_id) as storm_count FROM hurricanes WHERE ABS(lat - :lat) < :radius AND ABS(lon - :lon) < :radius");
        $stmt->execute(['lat' => $lat, 'lon' => $lon, 'radius' => $radius]);
        $result = $stmt->fetch(PDO::FETCH_ASSOC);
        $count = $result['storm_count'] ?? 0;
        $score = min($count * 10, 100);
        return ['score' => $score, 'details' => "{$count} historical storms passed within ~111km."];
    } catch (Exception $e) {
        error_log("Historical Hurricane Risk Error: " . $e->getMessage());
        return ['score' => 0, 'details' => 'Error calculating historical hurricane risk.'];
    }
}

function calculateRiskScore($lat, $lon) {
    $wildfireRisk = getWildfireRisk((float)$lat, (float)$lon);
    $hurricaneRisk = getHurricaneRisk((float)$lat, (float)$lon);
    $historicalRisk = getHistoricalHurricaneRisk((float)$lat, (float)$lon);
    $totalScore = ($wildfireRisk['score'] * 0.4) + ($hurricaneRisk['score'] * 0.4) + ($historicalRisk['score'] * 0.2);
    return round($totalScore);
}

try {
    $pdo = db();
    $method = $_SERVER['REQUEST_METHOD'];

    if ($method === 'GET') {
        $stmt = $pdo->query('SELECT id, name, latitude, longitude, city, state FROM facilities ORDER BY created_at DESC');
        $allFacilities = $stmt->fetchAll(PDO::FETCH_ASSOC);

        $sampleSize = ceil(count($allFacilities) * 0.1);
        if ($sampleSize < 1 && count($allFacilities) > 0) $sampleSize = 1;
        
        shuffle($allFacilities);
        $facilitiesSample = array_slice($allFacilities, 0, $sampleSize);

        $facilitiesWithRisk = [];
        foreach ($facilitiesSample as $facility) {
            $facility['risk'] = calculateRiskScore($facility['latitude'], $facility['longitude']);
            $facilitiesWithRisk[] = $facility;
        }

        echo json_encode(['success' => true, 'facilities' => $facilitiesWithRisk]);

    } else {
        http_response_code(405);
        echo json_encode(['success' => false, 'error' => 'Method Not Allowed']);
    }
} catch (Exception $e) {
    http_response_code(500);
    $error = [
        'success' => false,
        'error' => 'An unexpected error occurred in facilities API.',
        'message' => $e->getMessage(),
    ];
    error_log(print_r($error, true));
    echo json_encode($error);
}
?>