<?php
/**
 * Temp file statistics endpoint (admin).
 *
 * GET /admin/actions/cleanup-stats.php
 *
 * Returns JSON with counts and sizes of tmp/filepond/ and tmp/_trash/,
 * broken down by stale (will be cleaned) vs active (still session-bound).
 */

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

AdminAuth::requireLogin();

if ($_SERVER['REQUEST_METHOD'] !== 'GET') {
    http_response_code(405);
    exit;
}

$storageRoot    = STORAGE_ROOT;
$filepondDir    = $storageRoot . '/tmp/filepond';
$trashDir       = $storageRoot . '/tmp/_trash';
$maxAgeFilepond = 7200;    // 2h
$maxAgeTrash    = 2592000; // 30d

$sessionSavePath = session_save_path();
if (!$sessionSavePath || $sessionSavePath === '') {
    $sessionSavePath = sys_get_temp_dir();
}

$now = time();

// ── FilePond stats ───────────────────────────────────────────────────────
$fpStaleCount  = 0;
$fpStaleSize   = 0;
$fpStaleFiles  = [];
$fpActiveCount = 0;
$fpActiveSize  = 0;

if (is_dir($filepondDir)) {
    $items = @scandir($filepondDir);
    if ($items !== false) {
        foreach ($items as $item) {
            if ($item === '.' || $item === '..' || $item === '.gitkeep') {
                continue;
            }
            $dirPath = $filepondDir . '/' . $item;
            if (!is_dir($dirPath)) {
                continue;
            }

            $size = dirSizeRecursive($dirPath);
            $mtime = filemtime($dirPath);
            $ageMinutes = (int)(($now - $mtime) / 60);

            $stale = false;

            // Session-based detection
            $manifestPath = $dirPath . '/manifest.json';
            if (file_exists($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)) {
                        $stale = true;
                    }
                }
            }

            // Time-based fallback
            if (!$stale && $ageMinutes > ($maxAgeFilepond / 60)) {
                $stale = true;
            }

            if ($stale) {
                $fpStaleCount++;
                $fpStaleSize += $size;
                $fpStaleFiles[] = [
                    'name' => $item,
                    'size' => $size,
                    'human' => humanBytes($size),
                    'age_minutes' => $ageMinutes,
                ];
            } else {
                $fpActiveCount++;
                $fpActiveSize += $size;
            }
        }
    }
}

// ── Trash stats ──────────────────────────────────────────────────────────
require_once __DIR__ . '/../../../src/Database.php';
$db  = new Database();
$pdo = $db->getPDO();

$existingFileIds = [];
$stmt = $pdo->query('SELECT id FROM thesis_files');
while ($row = $stmt->fetch(\PDO::FETCH_ASSOC)) {
    $existingFileIds[(int)$row['id']] = true;
}

$trStaleCount  = 0;
$trStaleSize   = 0;
$trStaleFiles  = [];
$trActiveCount = 0;
$trActiveSize  = 0;

if (is_dir($trashDir)) {
    $items = @scandir($trashDir);
    if ($items !== false) {
        foreach ($items as $item) {
            if ($item === '.' || $item === '..') {
                continue;
            }
            $filePath = $trashDir . '/' . $item;
            if (!is_file($filePath)) {
                continue;
            }

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

            $stale = false;

            if (preg_match('/^(\d+)_/', $item, $m)) {
                $dbId = (int)$m[1];
                if (!isset($existingFileIds[$dbId])) {
                    $stale = true;
                }
            }

            if (!$stale && $ageDays > ($maxAgeTrash / 86400)) {
                $stale = true;
            }

            if ($stale) {
                $trStaleCount++;
                $trStaleSize += $size;
                $trStaleFiles[] = [
                    'name' => $item,
                    'size' => $size,
                    'human' => humanBytes($size),
                    'age_days' => $ageDays,
                ];
            } else {
                $trActiveCount++;
                $trActiveSize += $size;
            }
        }
    }
}

header('Content-Type: application/json; charset=utf-8');
echo json_encode([
    'filepond_stale_count'  => $fpStaleCount,
    'filepond_stale_size'   => $fpStaleSize,
    'filepond_stale_human'  => humanBytes($fpStaleSize),
    'filepond_stale_files'  => $fpStaleFiles,
    'filepond_active_count' => $fpActiveCount,
    'filepond_active_size'  => $fpActiveSize,
    'filepond_active_human' => humanBytes($fpActiveSize),
    'trash_stale_count'     => $trStaleCount,
    'trash_stale_size'      => $trStaleSize,
    'trash_stale_human'     => humanBytes($trStaleSize),
    'trash_stale_files'     => $trStaleFiles,
    'trash_active_count'    => $trActiveCount,
    'trash_active_size'     => $trActiveSize,
    'trash_active_human'    => humanBytes($trActiveSize),
]);

// ── Helpers ───────────────────────────────────────────────────────────────
function dirSizeRecursive(string $dir): int
{
    $size = 0;
    if (!is_dir($dir)) {
        return 0;
    }
    $items = @scandir($dir);
    if ($items === false) {
        return 0;
    }
    foreach ($items as $item) {
        if ($item === '.' || $item === '..') {
            continue;
        }
        $path = $dir . '/' . $item;
        if (is_dir($path)) {
            $size += dirSizeRecursive($path);
        } else {
            $size += filesize($path);
        }
    }
    return $size;
}

function humanBytes(int $bytes): string
{
    if ($bytes > 1073741824) {
        return number_format($bytes / 1073741824, 1) . ' GB';
    }
    if ($bytes > 1048576) {
        return number_format($bytes / 1048576, 1) . ' MB';
    }
    return number_format($bytes / 1024, 1) . ' KB';
}