<?php
/**
 * On-demand temp file cleanup (admin).
 *
 * POST /admin/actions/cleanup-tmp.php
 *
 * Smart cleanup: detects truly orphaned files by checking:
 *  - filepond dirs: whose PHP session no longer exists (abandoned upload)
 *  - _trash files: whose DB thesis_files row is gone (thesis already hard-deleted)
 *
 * Falls back to time-based (>2h filepond, >30d trash) as safety net.
 * Returns JSON with counts of removed items.
 */

require_once __DIR__ . '/../../../bootstrap.php';
require_once __DIR__ . '/../../../src/AdminAuth.php';

AdminAuth::requireLogin();

if ($_SERVER['REQUEST_METHOD'] !== 'POST'
    || !isset($_POST['csrf_token'], $_SESSION['csrf_token'])
    || !hash_equals($_SESSION['csrf_token'], $_POST['csrf_token'])) {
    http_response_code(403);
    header('Content-Type: application/json; charset=utf-8');
    echo json_encode(['error' => 'CSRF invalide.']);
    exit;
}

require_once __DIR__ . '/../../../src/Database.php';

$storageRoot    = STORAGE_ROOT;
$filepondDir    = $storageRoot . '/tmp/filepond';
$trashDir       = $storageRoot . '/tmp/_trash';
$maxAgeFilepond = 7200;    // 2 hours (fallback)
$maxAgeTrash    = 2592000; // 30 days (fallback)

$now = time();
$filepondRemoved = 0;
$trashRemoved    = 0;
$errors          = [];
$details         = [];

$db  = new Database();
$pdo = $db->getPDO();

// ── Determine PHP session save path ──────────────────────────────────────
$sessionSavePath = session_save_path();
if (!$sessionSavePath || $sessionSavePath === '') {
    $sessionSavePath = sys_get_temp_dir();
}

// ── Cleanup stale filepond dirs ──────────────────────────────────────────
if (is_dir($filepondDir)) {
    $items = @scandir($filepondDir);
    if ($items === false) {
        $errors[] = 'Impossible de lire tmp/filepond/.';
    } else {
        foreach ($items as $item) {
            if ($item === '.' || $item === '..' || $item === '.gitkeep') {
                continue;
            }
            $dirPath = $filepondDir . '/' . $item;
            if (!is_dir($dirPath)) {
                continue;
            }

            $shouldDelete = false;
            $reason       = '';

            $manifestPath = $dirPath . '/manifest.json';
            $mtime        = filemtime($dirPath);
            $ageMinutes   = (int)(($now - $mtime) / 60);

            // Strategy 1: session-based (preferred)
            if (file_exists($manifestPath)) {
                $manifest = json_decode(file_get_contents($manifestPath), true);
                if (is_array($manifest) && !empty($manifest['session_id'])) {
                    $sessionFile = $sessionSavePath . '/sess_' . $manifest['session_id'];
                    if (!file_exists($sessionFile)) {
                        $shouldDelete = true;
                        $reason = "session expirée (" . $manifest['session_id'] . ")";
                    }
                }
            }

            // Strategy 2: time-based fallback (no manifest or session still exists but very old)
            if (!$shouldDelete && $ageMinutes > ($maxAgeFilepond / 60)) {
                $shouldDelete = true;
                $reason = "plus de " . ($maxAgeFilepond / 3600) . "h";
            }

            if ($shouldDelete) {
                rmdirRecursive($dirPath);
                $filepondRemoved++;
                $details[] = "filepond/$item: $reason";
            }
        }
    }
}

// ── Cleanup orphaned _trash files ────────────────────────────────────────
if (is_dir($trashDir)) {
    // Build a set of existing thesis_files IDs for fast lookup
    $existingFileIds = [];
    $stmt = $pdo->query('SELECT id FROM thesis_files');
    while ($row = $stmt->fetch(\PDO::FETCH_ASSOC)) {
        $existingFileIds[(int)$row['id']] = true;
    }

    // Also collect thesis_ids from theses table (a file might refer to a hard-deleted thesis)
    // — but thesis_files rows are CASCADE-deleted when a thesis is hard-deleted, so if the
    // thesis_files row is gone, the trash file is truly orphaned.

    $items = @scandir($trashDir);
    if ($items === false) {
        $errors[] = 'Impossible de lire tmp/_trash/.';
    } else {
        foreach ($items as $item) {
            if ($item === '.' || $item === '..') {
                continue;
            }
            $filePath = $trashDir . '/' . $item;
            if (!is_file($filePath)) {
                continue;
            }

            $shouldDelete = false;
            $reason       = '';

            $mtime      = filemtime($filePath);
            $ageDays    = (int)(($now - $mtime) / 86400);

            // Strategy 1: DB-based — file was trashed by deleteThesisFile(id=N),
            // file is named "N_basename". If thesis_files row N no longer exists, it's orphaned.
            if (preg_match('/^(\d+)_/', $item, $m)) {
                $dbId = (int)$m[1];
                if (!isset($existingFileIds[$dbId])) {
                    $shouldDelete = true;
                    $reason = "ligne DB thesis_files#$dbId supprimée";
                }
            }

            // Strategy 2: time-based fallback
            if (!$shouldDelete && $ageDays > ($maxAgeTrash / 86400)) {
                $shouldDelete = true;
                $reason = "plus de " . ($maxAgeTrash / 86400) . "j";
            }

            if ($shouldDelete) {
                if (!@unlink($filePath)) {
                    $errors[] = "Impossible de supprimer: $item";
                } else {
                    $trashRemoved++;
                    $details[] = "_trash/$item: $reason";
                }
            }
        }
    }
}

$_SESSION['csrf_token'] = bin2hex(random_bytes(32));

header('Content-Type: application/json; charset=utf-8');
echo json_encode([
    'success'          => true,
    'filepond_removed' => $filepondRemoved,
    'trash_removed'    => $trashRemoved,
    'errors'           => $errors,
    'details'          => $details,
]);

// ── Helper ────────────────────────────────────────────────────────────────
function rmdirRecursive(string $dir): void
{
    if (!is_dir($dir)) {
        return;
    }
    $items = @scandir($dir);
    if ($items === false) {
        return;
    }
    foreach ($items as $item) {
        if ($item === '.' || $item === '..') {
            continue;
        }
        $path = $dir . '/' . $item;
        if (is_dir($path)) {
            rmdirRecursive($path);
        } else {
            @unlink($path);
        }
    }
    @rmdir($dir);
}