const fs = require('fs');
const path = require('path');

async function getDirLatestModifyTime(dirPath) {
    let latestTime = 0;
    
    const items = await fs.readdir(dirPath, { withFileTypes: true });
    for (const item of items) {
        const itemPath = path.join(dirPath, item.name);
        const stats = await fs.stat(itemPath);
        
        // Update latest time if current item is newer
        if (stats.mtimeMs > latestTime) {
            latestTime = stats.mtimeMs;
        }
        
        // Recursively check sub-directories
        if (item.isDirectory()) {
            const subDirLatest = await getDirLatestModifyTime(itemPath);
            if (subDirLatest > latestTime) {
                latestTime = subDirLatest;
            }
        }
    }
    
    // If directory is empty, use its own modification time
    return latestTime || (await fs.stat(dirPath)).mtimeMs;
}

async function cleanExpiredJobDirs(maxAge = 24 * 3600000) {
    const resultsDir = path.join(__dirname, 'results');
    const now = Date.now();

    try {
        // Iterate through all job directories
        const jobDirs = await fs.readdir(resultsDir, { withFileTypes: true });
        for (const dir of jobDirs) {
            if (dir.isDirectory()) {
                const jobPath = path.join(resultsDir, dir.name);
                const jobLatestTime = await getDirLatestModifyTime(jobPath);
                const jobAge = now - jobLatestTime;

                // Delete folder if it exceeds max retention time
                if (jobAge > maxAge) {
                    // Recursively delete folder and all contents
                    await fs.rm(jobPath, { recursive: true, force: true });
                    console.log(`Expired job folder deleted: ${jobPath} (Latest update: ${new Date(jobLatestTime).toLocaleString()})`);
                }
            }
        }
    } catch (error) {
        console.error(`Cleanup failed: ${error.message}`);
    }
}

// Export functions for use by other modules
module.exports = {
    cleanExpiredJobDirs
};