<?php
require_once(__DIR__ . '/auth_check.php');
header('Content-Type: application/json');
require_once(__DIR__ . '/../../class/db-functions.php');

try {
    if (!isset($_POST['deadline_id']) || !is_numeric($_POST['deadline_id'])) {
        echo json_encode(['success' => false, 'message' => 'ID scadenza non valido.']);
        exit;
    }
    if (empty($_FILES['files']['name'][0])) {
        echo json_encode(['success' => false, 'message' => 'Nessun file selezionato.']);
        exit;
    }

    $deadlineId = (int)$_POST['deadline_id'];

    $db = DBHandlerSelect::getInstance();
    $pdo = $db->getConnection();

    // Verify deadline exists
    $check = $pdo->prepare("SELECT id FROM scad_deadlines WHERE id = ?");
    $check->execute([$deadlineId]);
    if (!$check->fetch()) {
        echo json_encode(['success' => false, 'message' => 'Scadenza non trovata.']);
        exit;
    }

    $uploadDir = __DIR__ . '/../attachments/';
    if (!is_dir($uploadDir)) {
        mkdir($uploadDir, 0755, true);
    }

    $inserted = [];
    $pdo->beginTransaction();

    $stmt = $pdo->prepare("
        INSERT INTO scad_deadline_attachments (deadline_id, original_name, stored_name, mime_type, size, uploaded_by)
        VALUES (?, ?, ?, ?, ?, ?)
    ");
    $histStmt = $pdo->prepare("INSERT INTO scad_deadline_histories (deadline_id, user_id, action, notes) VALUES (?, ?, 'attachment_added', ?)");

    $fileCount = count($_FILES['files']['name']);
    for ($i = 0; $i < $fileCount; $i++) {
        if ($_FILES['files']['error'][$i] !== UPLOAD_ERR_OK) continue;

        $originalName = $_FILES['files']['name'][$i];
        $mimeType = $_FILES['files']['type'][$i];
        $size = $_FILES['files']['size'][$i];
        $storedName = uniqid('att_') . '_' . preg_replace('/[^a-zA-Z0-9._-]/', '_', $originalName);

        if (!move_uploaded_file($_FILES['files']['tmp_name'][$i], $uploadDir . $storedName)) {
            continue;
        }

        $stmt->execute([$deadlineId, $originalName, $storedName, $mimeType, $size, $currentUserId]);
        $histStmt->execute([$deadlineId, $currentUserId, $originalName]);
        $inserted[] = ['id' => $pdo->lastInsertId(), 'original_name' => $originalName, 'stored_name' => $storedName];
    }

    $pdo->commit();

    echo json_encode([
        'success' => true,
        'message' => count($inserted) . ' file caricato/i con successo.',
        'files' => $inserted
    ]);

} catch (Exception $e) {
    if (isset($pdo) && $pdo->inTransaction()) $pdo->rollBack();
    echo json_encode(['success' => false, 'message' => 'Errore: ' . $e->getMessage()]);
}