<?php
/**
 * Shared cleanup stats data-fetching logic.
 *
 * Used by both cleanup-stats.php (JSON endpoint) and
 * cleanup-stats-fragment.php (HTML fragment).
 */

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';
}

function getCleanupStats(): array
{
    $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;
                }
            }
        }
    }

    return [
        '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),
    ];
}