<?php
/**
 * Relink endpoint — attach an orphaned on-disk file to a thesis.
 *
 * POST /admin/actions/filepond/relink.php
 * Body: JSON { thesis_id: 123, file_path: "documents/2025/FOLDER/file.pdf",
 *              file_name: "file.pdf", file_size: 12345, mime_type: "application/pdf",
 *              queue_type: "tfe", file_type: "main" }
 *
 * Inserts a thesis_files row pointing to the existing on-disk file.
 * The file is NOT copied or moved — it stays where it is.
 */
require_once __DIR__ . '/../../../../bootstrap.php';
require_once __DIR__ . '/../../../../src/AdminAuth.php';
AdminAuth::requireLogin();

// Always return JSON, even on errors
function relinkError(int $code, string $message): never {
    http_response_code($code);
    header('Content-Type: application/json');
    echo json_encode(['ok' => false, 'error' => $message]);
    exit;
}

// CSRF via header
$csrfHeader = $_SERVER['HTTP_X_CSRF_TOKEN'] ?? '';
error_log('[relink] ENTRY | method=' . $_SERVER['REQUEST_METHOD'] . ' | csrf=' . (isset($_SESSION['csrf_token']) ? 'set' : 'missing') . ' | header=' . (strlen($csrfHeader) > 0 ? substr($csrfHeader, 0, 8) . '...' : 'empty') . ' | body_len=' . strlen(file_get_contents('php://input')));
if (!isset($_SESSION['csrf_token'])
    || !hash_equals($_SESSION['csrf_token'], $csrfHeader)) {
    relinkError(403, 'Token CSRF invalide.');
}

if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
    relinkError(405, 'Méthode non autorisée.');
}

$body = json_decode(file_get_contents('php://input'), true);
if (!is_array($body)) {
    relinkError(400, 'JSON invalide.');
}

$thesisId  = filter_var($body['thesis_id'] ?? '', FILTER_VALIDATE_INT);
$filePath  = trim($body['file_path'] ?? '');
$fileName  = trim($body['file_name'] ?? basename($filePath));
$fileSize  = (int)($body['file_size'] ?? 0);
$fileType  = trim($body['file_type'] ?? '');
$queueType = trim($body['queue_type'] ?? '');
$mimeType  = trim($body['mime_type'] ?? 'application/octet-stream');

if (!$thesisId || $filePath === '') {
    relinkError(400, 'Paramètres invalides (thesis_id + file_path requis).');
}

// Security: only allow paths under tfe/ these/ frart/ documents/ or theses/
if (!preg_match('#^(tfe|these|frart|documents|theses)/#', $filePath)) {
    relinkError(403, 'Chemin de fichier non autorisé.');
}

$absPath = STORAGE_ROOT . '/' . $filePath;
$realPath = realpath($absPath);
$realStorage = realpath(STORAGE_ROOT);

if ($realPath === false || !str_starts_with($realPath, $realStorage)) {
    error_log('[relink] FILE NOT FOUND | absPath=' . $absPath . ' | realPath=' . var_export($realPath, true) . ' | realStorage=' . $realStorage);
    relinkError(404, 'Fichier introuvable ou chemin interdit.');
}

if (!is_file($realPath)) {
    relinkError(404, 'Le chemin ne pointe pas vers un fichier.');
}

// Detect MIME if not provided
if ($mimeType === 'application/octet-stream' && class_exists('finfo')) {
    $finfo = new finfo(FILEINFO_MIME_TYPE);
    $detected = $finfo->file($realPath);
    if ($detected !== false && $detected !== '') {
        $mimeType = $detected;
    }
}

// Map queue_type to file_type if not explicitly given
if ($fileType === '') {
    $fileTypeMap = [
        'cover'          => 'cover',
        'note_intention' => 'note_intention',
        'tfe'            => 'main',
        'annexe'         => 'annex',
    ];
    $fileType = $fileTypeMap[$queueType] ?? 'main';
}

require_once APP_ROOT . '/src/Database.php';
$db = Database::getInstance();

// Check if this file is already linked to this thesis (avoid duplicate)
$pdo = $db->getConnection();
$stmt = $pdo->prepare('SELECT id FROM thesis_files WHERE thesis_id = ? AND file_path = ?');
$stmt->execute([$thesisId, $filePath]);
if ($stmt->fetch()) {
    relinkError(409, 'Ce fichier est déjà lié à ce TFE.');
}

$db->insertThesisFile(
    $thesisId,
    $fileType,
    $filePath,
    $fileName,
    $fileSize,
    $mimeType,
    null,
    null
);

// Get the new file's ID
$newId = $pdo->lastInsertId();

error_log("[relink] thesis_id=$thesisId file_path=$filePath file_type=$fileType new_id=$newId");

header('Content-Type: application/json');
echo json_encode([
    'ok'      => true,
    'id'      => (int)$newId,
    'message' => 'Fichier relié avec succès.',
]);
exit;