<?php
/**
 * API: Logistik-Analytics (Einzelauftrags-Logging)
 *
 * POST /api/logistik-analytics
 *   Body: {
 *     levelId:         int      — Pflicht
 *     contractCode:    string   — Pflicht, max 32 Zeichen
 *     assignedVehicle: string   — optional, max 32
 *     state:           string   — Pflicht: DELIVERED|LATE|FAILED|CANCELLED
 *     finalBalance:    int      — optional (Kontostand des Durchgangs beim Abschluss)
 *     lateMinutes:     int      — optional, default 0
 *     hintUsages:      int      — optional, default 0
 *     intermodal:      bool     — optional, default false
 *     routeDistanceKm: int      — optional
 *     routeMode:       string   — optional: TRUCK_SMALL|TRUCK_LARGE|TRAIN
 *   }
 *   -> schreibt Eintrag in lg_contracts_log
 *
 * GET /api/logistik-analytics?scope=me|class|level
 *   Liefert aggregierte Kennzahlen:
 *     scope=me     (default)     -> eigene letzten 50 Auftraege
 *     scope=class  (Lehrer only) -> pro Schuelersession aggregiert
 *     scope=level  (Lehrer only) -> pro Level aggregiert (state-Verteilung)
 *
 * Security:
 *   - POST erfordert gueltige Schueler-Session (Cookie gegen student_sessions)
 *   - Keine Fremd-Session-IDs schreibbar (session_id kommt IMMER aus Cookie)
 *   - class/level-Scopes erfordern Lehrer-Login
 */

$method = $_SERVER['REQUEST_METHOD'];
$db = Database::get();

function lga_requireValidStudent(): string {
    $sid = Session::requireStudent();
    $db = Database::get();
    $row = $db->fetchOne('SELECT id FROM student_sessions WHERE id = ?', [$sid]);
    if (!$row) {
        http_response_code(401);
        echo json_encode(['error' => 'Session ungueltig']);
        exit;
    }
    return $sid;
}

$VALID_STATES = ['DELIVERED', 'LATE', 'FAILED', 'CANCELLED'];
$VALID_MODES  = ['TRUCK_SMALL', 'TRUCK_LARGE', 'TRAIN'];

if ($method === 'POST') {
    $sid = lga_requireValidStudent();
    $body = json_decode(file_get_contents('php://input'), true);
    if (!is_array($body)) Response::error('Body fehlt oder kein JSON', 400);

    $levelId = (int)($body['levelId'] ?? 0);
    $contractCode = substr(trim($body['contractCode'] ?? ''), 0, 32);
    $state = strtoupper(trim($body['state'] ?? ''));

    if ($levelId < 1)                            Response::error('levelId fehlt', 400);
    if ($contractCode === '')                    Response::error('contractCode fehlt', 400);
    if (!in_array($state, $VALID_STATES, true))  Response::error('state ungueltig', 400);

    $assignedVehicle = isset($body['assignedVehicle']) ? substr((string)$body['assignedVehicle'], 0, 32) : null;
    $finalBalance    = isset($body['finalBalance']) ? (int)$body['finalBalance'] : null;
    $lateMinutes     = max(0, (int)($body['lateMinutes'] ?? 0));
    $hintUsages      = max(0, (int)($body['hintUsages'] ?? 0));
    $intermodal      = !empty($body['intermodal']) ? 1 : 0;
    $routeDistanceKm = isset($body['routeDistanceKm']) ? max(0, (int)$body['routeDistanceKm']) : null;
    $routeMode = null;
    if (isset($body['routeMode'])) {
        $m = strtoupper((string)$body['routeMode']);
        if (in_array($m, $VALID_MODES, true)) $routeMode = $m;
    }

    $db->execute(
        'INSERT INTO lg_contracts_log
           (session_id, level_id, contract_code, assigned_vehicle, state,
            final_balance, late_minutes, hint_usages, intermodal,
            route_distance_km, route_mode)
         VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)',
        [$sid, $levelId, $contractCode, $assignedVehicle, $state,
         $finalBalance, $lateMinutes, $hintUsages, $intermodal,
         $routeDistanceKm, $routeMode]
    );

    Response::ok(['logged' => true]);
}

if ($method === 'GET') {
    $scope = $_GET['scope'] ?? 'me';

    if ($scope === 'me') {
        $sid = lga_requireValidStudent();
        $rows = $db->fetchAll(
            'SELECT level_id, contract_code, assigned_vehicle, state,
                    final_balance, late_minutes, hint_usages, intermodal,
                    route_distance_km, route_mode, completed_at
             FROM lg_contracts_log
             WHERE session_id = ?
             ORDER BY completed_at DESC
             LIMIT 50',
            [$sid]
        );
        Response::ok(['scope' => 'me', 'rows' => $rows]);
    }

    if ($scope === 'class') {
        Session::requireTeacher();
        $levelId = (int)($_GET['levelId'] ?? 0);
        $where = $levelId > 0 ? 'WHERE level_id = ?' : '';
        $params = $levelId > 0 ? [$levelId] : [];
        $rows = $db->fetchAll(
            "SELECT session_id,
                    COUNT(*) AS total,
                    SUM(state = 'DELIVERED') AS delivered,
                    SUM(state = 'LATE')      AS late,
                    SUM(state = 'FAILED')    AS failed,
                    SUM(state = 'CANCELLED') AS cancelled,
                    AVG(late_minutes)        AS avg_late_min,
                    SUM(intermodal)          AS intermodal_count
             FROM lg_contracts_log
             $where
             GROUP BY session_id
             ORDER BY total DESC
             LIMIT 200",
            $params
        );
        Response::ok(['scope' => 'class', 'rows' => $rows]);
    }

    if ($scope === 'level') {
        Session::requireTeacher();
        $rows = $db->fetchAll(
            "SELECT level_id,
                    COUNT(*) AS total,
                    SUM(state = 'DELIVERED') AS delivered,
                    SUM(state = 'LATE')      AS late,
                    SUM(state = 'FAILED')    AS failed,
                    SUM(state = 'CANCELLED') AS cancelled,
                    AVG(late_minutes)        AS avg_late_min,
                    AVG(route_distance_km)   AS avg_km
             FROM lg_contracts_log
             GROUP BY level_id
             ORDER BY level_id"
        );
        Response::ok(['scope' => 'level', 'rows' => $rows]);
    }

    Response::error('Unbekannter scope', 400);
}

Response::error('Methode nicht erlaubt', 405);