<?php
declare(strict_types=1);

ini_set('display_errors', '1');
error_reporting(E_ALL);

const AU_IN_KM = 149597870.7;
const IMPORT_END_TIME = '2049-12-31 00:00:00';

$config = require __DIR__ . '/../../config/database.php';
$dsn = sprintf(
    'mysql:host=%s;dbname=%s;charset=%s',
    $config['host'],
    $config['dbname'],
    $config['charset'] ?? 'utf8mb4'
);

$pdo = new PDO(
    $dsn,
    $config['user'],
    $config['pass'],
    [
        PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
        PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
    ]
);

$pdo->exec("
    CREATE TABLE IF NOT EXISTS `spacecraft_tracks` (
      `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
      `mission_key` varchar(64) NOT NULL,
      `mission_name` varchar(128) NOT NULL,
      `date_tdb` datetime NOT NULL,
      `jd_tdb` decimal(16,9) NOT NULL,
      `x_km` double NOT NULL,
      `y_km` double NOT NULL,
      `z_km` double NOT NULL,
      `vx_km_s` double NOT NULL,
      `vy_km_s` double NOT NULL,
      `vz_km_s` double NOT NULL,
      `distance_km` double NOT NULL,
      `distance_au` double NOT NULL,
      `created_at` datetime NOT NULL DEFAULT current_timestamp(),
      `updated_at` datetime NOT NULL DEFAULT current_timestamp() ON UPDATE current_timestamp(),
      PRIMARY KEY (`id`),
      UNIQUE KEY `uq_spacecraft_tracks_mission_date` (`mission_key`,`date_tdb`),
      KEY `idx_spacecraft_tracks_mission_key` (`mission_key`),
      KEY `idx_spacecraft_tracks_date_tdb` (`date_tdb`)
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci COMMENT='Sonnenzentrierte Horizons-Vektoren fuer Raumsonden'
");

$missions = [
    [
        'key' => 'voyager1',
        'name' => 'Voyager 1',
        'command' => "'-31'",
        'start_time' => '1977-09-05 14:00:00',
        'dense_stop_time' => '1989-12-05 14:00:00',
    ],
    [
        'key' => 'voyager2',
        'name' => 'Voyager 2',
        'command' => "'-32'",
        'start_time' => '1977-08-20 16:29:00',
        'dense_stop_time' => '1993-03-20 16:29:00',
    ],
    [
        'key' => 'new_horizons',
        'name' => 'New Horizons',
        'command' => "'-98'",
        'start_time' => '2006-01-19 19:52:00',
        'dense_stop_time' => '2017-10-19 19:52:00',
    ],
    [
        'key' => 'pioneer10',
        'name' => 'Pioneer 10',
        'command' => "'-23'",
        'start_time' => '1972-03-03 02:56:00',
        'dense_stop_time' => '1986-11-03 02:56:00',
    ],
];

function fetchHorizonsResult(array $extraParams): string
{
    $params = array_merge([
        'format' => 'json',
        'OBJ_DATA' => "'NO'",
        'MAKE_EPHEM' => "'YES'",
        'EPHEM_TYPE' => "'VECTORS'",
        'CENTER' => "'500@10'",
        'REF_SYSTEM' => "'ICRF'",
        'REF_PLANE' => "'ECLIPTIC'",
        'VEC_TABLE' => "'2'",
        'VEC_CORR' => "'NONE'",
        'OUT_UNITS' => "'KM-S'",
        'TIME_TYPE' => "'TDB'",
        'CSV_FORMAT' => "'YES'",
    ], $extraParams);

    $query = http_build_query($params, '', '&');
    $query = str_replace(
        ['%27', '%40', '%3A', '+'],
        ["'", '@', ':', '%20'],
        $query
    );
    $url = 'https://ssd.jpl.nasa.gov/api/horizons.api?' . $query;
    $json = false;

    if (function_exists('curl_init')) {
        $curlHandle = curl_init($url);
        if ($curlHandle !== false) {
            curl_setopt_array($curlHandle, [
                CURLOPT_RETURNTRANSFER => true,
                CURLOPT_FOLLOWLOCATION => true,
                CURLOPT_CONNECTTIMEOUT => 30,
                CURLOPT_TIMEOUT => 180,
                CURLOPT_USERAGENT => 'skyview-spacecraft-import/1.0',
            ]);
            $curlResponse = curl_exec($curlHandle);
            $curlError = curl_error($curlHandle);
            $httpCode = (int) curl_getinfo($curlHandle, CURLINFO_RESPONSE_CODE);
            curl_close($curlHandle);

            if ($curlResponse !== false && $httpCode >= 200 && $httpCode < 300) {
                $json = $curlResponse;
            } elseif ($curlError !== '') {
                $json = false;
            }
        }
    }

    if ($json === false) {
        $context = stream_context_create([
            'http' => [
                'method' => 'GET',
                'timeout' => 180,
                'header' => "User-Agent: skyview-spacecraft-import/1.0\r\n",
            ],
        ]);
        $json = @file_get_contents($url, false, $context);
    }

    if ($json === false) {
        $escapedUrl = str_replace('"', '\"', $url);
        $command = 'curl.exe --silent --show-error --location --globoff "' . $escapedUrl . '"';
        $shellResponse = shell_exec($command);
        if (is_string($shellResponse) && $shellResponse !== '') {
            $json = $shellResponse;
        }
    }

    if ($json === false) {
        throw new RuntimeException('Horizons API konnte nicht geladen werden: ' . $url);
    }

    $payload = json_decode($json, true);
    if (!is_array($payload)) {
        throw new RuntimeException('Horizons API lieferte kein gueltiges JSON.');
    }

    $result = (string) ($payload['result'] ?? '');
    if (isset($payload['error']) && $payload['error'] !== '') {
        throw new RuntimeException($result !== '' ? $result : (string) $payload['error']);
    }

    return $result;
}

function parseHorizonsVectorRows(string $result): array
{
    $start = strpos($result, '$$SOE');
    $end = strpos($result, '$$EOE');
    if ($start === false || $end === false || $end <= $start) {
        throw new RuntimeException('Horizons-Antwort enthaelt keinen $$SOE/$$EOE-Block.');
    }

    $block = trim(str_replace("\r", '', substr($result, $start + 5, $end - ($start + 5))));
    if ($block === '') {
        return [];
    }

    $rows = [];
    foreach (explode("\n", $block) as $rawLine) {
        $line = trim($rawLine);
        if ($line === '') {
            continue;
        }

        $parts = array_map('trim', explode(',', $line));
        if (end($parts) === '') {
            array_pop($parts);
        }
        if (count($parts) !== 8) {
            continue;
        }

        $jdTdb = (float) $parts[0];
        $dateTdbRaw = (string) $parts[1];
        $dateTdbNormalized = preg_replace('/^A\.D\.\s+/i', '', $dateTdbRaw) ?? $dateTdbRaw;
        $date = DateTimeImmutable::createFromFormat('Y-M-d H:i:s.u', $dateTdbNormalized, new DateTimeZone('UTC'));
        if (!$date instanceof DateTimeImmutable) {
            continue;
        }

        $xKm = (float) $parts[2];
        $yKm = (float) $parts[3];
        $zKm = (float) $parts[4];
        $vxKmS = (float) $parts[5];
        $vyKmS = (float) $parts[6];
        $vzKmS = (float) $parts[7];
        $distanceKm = sqrt(($xKm ** 2) + ($yKm ** 2) + ($zKm ** 2));

        $rows[$date->format('Y-m-d H:i:s')] = [
            'date_tdb' => $date->format('Y-m-d H:i:s'),
            'jd_tdb' => $jdTdb,
            'x_km' => $xKm,
            'y_km' => $yKm,
            'z_km' => $zKm,
            'vx_km_s' => $vxKmS,
            'vy_km_s' => $vyKmS,
            'vz_km_s' => $vzKmS,
            'distance_km' => $distanceKm,
            'distance_au' => $distanceKm / AU_IN_KM,
        ];
    }

    ksort($rows);
    return array_values($rows);
}

$insertStatement = $pdo->prepare("
    INSERT INTO `spacecraft_tracks` (
        `mission_key`,
        `mission_name`,
        `date_tdb`,
        `jd_tdb`,
        `x_km`,
        `y_km`,
        `z_km`,
        `vx_km_s`,
        `vy_km_s`,
        `vz_km_s`,
        `distance_km`,
        `distance_au`
    ) VALUES (
        :mission_key,
        :mission_name,
        :date_tdb,
        :jd_tdb,
        :x_km,
        :y_km,
        :z_km,
        :vx_km_s,
        :vy_km_s,
        :vz_km_s,
        :distance_km,
        :distance_au
    )
    ON DUPLICATE KEY UPDATE
        `mission_name` = VALUES(`mission_name`),
        `jd_tdb` = VALUES(`jd_tdb`),
        `x_km` = VALUES(`x_km`),
        `y_km` = VALUES(`y_km`),
        `z_km` = VALUES(`z_km`),
        `vx_km_s` = VALUES(`vx_km_s`),
        `vy_km_s` = VALUES(`vy_km_s`),
        `vz_km_s` = VALUES(`vz_km_s`),
        `distance_km` = VALUES(`distance_km`),
        `distance_au` = VALUES(`distance_au`)
");

$deleteStatement = $pdo->prepare('DELETE FROM `spacecraft_tracks` WHERE `mission_key` = :mission_key');

foreach ($missions as $mission) {
    $denseRows = parseHorizonsVectorRows(fetchHorizonsResult([
        'COMMAND' => $mission['command'],
        'START_TIME' => "'" . $mission['start_time'] . "'",
        'STOP_TIME' => "'" . $mission['dense_stop_time'] . "'",
        'STEP_SIZE' => "'1 d'",
    ]));

    $monthlyRows = parseHorizonsVectorRows(fetchHorizonsResult([
        'COMMAND' => $mission['command'],
        'START_TIME' => "'" . $mission['dense_stop_time'] . "'",
        'STOP_TIME' => "'" . IMPORT_END_TIME . "'",
        'STEP_SIZE' => "'1 mo'",
    ]));

    $finalRows = parseHorizonsVectorRows(fetchHorizonsResult([
        'COMMAND' => $mission['command'],
        'TLIST' => "'" . IMPORT_END_TIME . "'",
    ]));

    $rowsByDate = [];
    foreach (array_merge($denseRows, $monthlyRows, $finalRows) as $row) {
        $rowsByDate[$row['date_tdb']] = $row;
    }
    ksort($rowsByDate);
    $rows = array_values($rowsByDate);

    $pdo->beginTransaction();
    try {
        $deleteStatement->execute([
            ':mission_key' => $mission['key'],
        ]);

        foreach ($rows as $row) {
            $insertStatement->execute([
                ':mission_key' => $mission['key'],
                ':mission_name' => $mission['name'],
                ':date_tdb' => $row['date_tdb'],
                ':jd_tdb' => $row['jd_tdb'],
                ':x_km' => $row['x_km'],
                ':y_km' => $row['y_km'],
                ':z_km' => $row['z_km'],
                ':vx_km_s' => $row['vx_km_s'],
                ':vy_km_s' => $row['vy_km_s'],
                ':vz_km_s' => $row['vz_km_s'],
                ':distance_km' => $row['distance_km'],
                ':distance_au' => $row['distance_au'],
            ]);
        }

        $pdo->commit();
    } catch (Throwable $e) {
        $pdo->rollBack();
        throw $e;
    }

    echo $mission['name'] . ': ' . count($rows) . " Zeilen importiert.\n";
}

echo "Import abgeschlossen.\n";