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

// Configuration
const LINKS_FILE = path.join(__dirname, '../themes/Ying/static/json/link_lite.json');
const CONCURRENCY = 10; // Check 10 links at a time
const TIMEOUT = 10000; // 10 seconds timeout

async function checkLink(link) {
    const controller = new AbortController();
    const timeoutId = setTimeout(() => controller.abort(), TIMEOUT);
    
    try {
        // Some blogs block headless requests, so we fake a User-Agent
        const response = await fetch(link.url, {
            method: 'HEAD', // Try HEAD first to save bandwidth
            signal: controller.signal,
            headers: {
                'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36'
            }
        });
        
        clearTimeout(timeoutId);
        
        if (response.ok) {
            return { link, status: 'OK', code: response.status };
        } else if (response.status === 405 || response.status === 403 || response.status === 503) {
            // Some servers reject HEAD or block bots, try GET
            const controllerGet = new AbortController();
            const timeoutIdGet = setTimeout(() => controllerGet.abort(), TIMEOUT);
            try {
                const responseGet = await fetch(link.url, {
                    method: 'GET',
                    signal: controllerGet.signal,
                    headers: {
                        'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36'
                    }
                });
                clearTimeout(timeoutIdGet);
                if (responseGet.ok) {
                    return { link, status: 'OK', code: responseGet.status };
                } else {
                    return { link, status: 'FAIL', code: responseGet.status };
                }
            } catch (err) {
                clearTimeout(timeoutIdGet);
                return { link, status: 'ERROR', error: err.message };
            }
        } else {
            return { link, status: 'FAIL', code: response.status };
        }
    } catch (error) {
        clearTimeout(timeoutId);
        // Retry with GET if HEAD failed with network error (sometimes happens)
        if (error.name !== 'AbortError') {
             const controllerGet = new AbortController();
             const timeoutIdGet = setTimeout(() => controllerGet.abort(), TIMEOUT);
             try {
                 const responseGet = await fetch(link.url, {
                     method: 'GET',
                     signal: controllerGet.signal,
                     headers: {
                         'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36'
                     }
                 });
                 clearTimeout(timeoutIdGet);
                 if (responseGet.ok) {
                     return { link, status: 'OK', code: responseGet.status };
                 } else {
                    return { link, status: 'ERROR', error: error.message }; // Return original error if GET also fails or is not tried properly
                 }
             } catch (err) {
                 clearTimeout(timeoutIdGet);
                 return { link, status: 'ERROR', error: error.message };
             }
        }
        return { link, status: 'ERROR', error: error.message };
    }
}

async function main() {
    console.log('Starting friend link check...');
    console.log(`Reading links from: ${LINKS_FILE}`);

    if (!fs.existsSync(LINKS_FILE)) {
        console.error('Error: Link file not found!');
        process.exit(1);
    }

    let links;
    try {
        const fileContent = fs.readFileSync(LINKS_FILE, 'utf8');
        links = JSON.parse(fileContent);
    } catch (e) {
        console.error('Error parsing JSON:', e.message);
        process.exit(1);
    }

    console.log(`Found ${links.length} links. Checking...`);

    const results = [];
    const failedLinks = [];
    
    // Process in chunks
    for (let i = 0; i < links.length; i += CONCURRENCY) {
        const chunk = links.slice(i, i + CONCURRENCY);
        const chunkResults = await Promise.all(chunk.map(checkLink));
        
        chunkResults.forEach(res => {
            if (res.status === 'OK') {
                process.stdout.write('.'); // Progress indicator
            } else {
                process.stdout.write('F');
                failedLinks.push(res);
            }
            results.push(res);
        });
    }

    console.log('\n\nCheck completed!');
    console.log('---------------------------------------------------');
    
    if (failedLinks.length === 0) {
        console.log('✅ All links are accessible!');
    } else {
        console.log(`⚠️  Found ${failedLinks.length} inaccessible links:\n`);
        failedLinks.forEach((item, index) => {
            console.log(`${index + 1}. ${item.link.name} (${item.link.url})`);
            if (item.code) {
                console.log(`   Status Code: ${item.code}`);
            } else {
                console.log(`   Error: ${item.error}`);
            }
            console.log('');
        });
    }
}

main();