const { Builder, By } = require("selenium-webdriver");
const chrome = require("selenium-webdriver/chrome");
const axios = require("axios");
const xml2js = require("xml2js");
const fs = require("fs");
const path = require("path");

// CSV file for Image Alt issues
const csvPath = path.join(__dirname, "image_alt_issues.csv");
fs.writeFileSync(csvPath, "Page URL,Image Src,Alt Text,Issue Type\n", "utf8");

// ==========================
// 1️⃣ Fetch URLs from sitemap.xml
// ==========================
async function getUrlsFromSitemap(sitemapUrl) {
    try {
        const res = await axios.get(sitemapUrl);
        const parsed = await xml2js.parseStringPromise(res.data);
        return parsed.urlset.url.map((u) => u.loc[0]);
    } catch (err) {
        console.error("❌ Failed to load sitemap:", err.message);
        return [];
    }
}

// ==========================
// 2️⃣ Check HTTP Status
// ==========================
async function checkLinkStatus(url) {
    try {
        const res = await axios.get(url, {
            timeout: 10000,
            validateStatus: () => true,
        });
        if (res.status === 200 && res.data.toLowerCase().includes("page not found")) {
            return "Soft 404";
        }
        return res.status;
    } catch (err) {
        return err.response ? err.response.status : "❌ No Response";
    }
}

// ==========================
// 3️⃣ Main SEO + Accessibility + Image Alt Audit
// ==========================
async function checkSEO(url, siteDomain) {
    const options = new chrome.Options();
    options.addArguments("--headless", "--no-sandbox", "--disable-gpu");
    const driver = await new Builder()
        .forBrowser("chrome")
        .setChromeOptions(options)
        .build();

    try {
        const pageStatus = await checkLinkStatus(url);
        if (pageStatus === 404 || pageStatus === "Soft 404") {
            console.log(`\n🚫 ${url} → ❌ Page not found (${pageStatus})`);
            return;
        }

        await driver.get(url);
        const pageSource = await driver.getPageSource();

        // Basic SEO Elements
        const title = await driver.getTitle();
        const descElem = await driver.findElements(By.css('meta[name="description"]'));
        const canonicalElem = await driver.findElements(By.css('link[rel="canonical"]'));
        const robotsElem = await driver.findElements(By.css('meta[name="robots"]'));
        const viewportElem = await driver.findElements(By.css('meta[name="viewport"]'));
        const charset = await driver.findElements(By.css('meta[charset]'));
        const htmlTag = await driver.findElement(By.css("html"));
        const langAttr = await htmlTag.getAttribute("lang").catch(() => "");
        const h1Tags = await driver.findElements(By.css("h1"));
        const h2Tags = await driver.findElements(By.css("h2"));

        // Meta Description
        let descContent = descElem.length > 0 ? await descElem[0].getAttribute("content") : "";
        const descLength = descContent.length;
        const descStatus =
            descLength === 0
                ? "❌ Missing"
                : descLength < 50
                    ? `⚠️ Too short (${descLength})`
                    : descLength > 160
                        ? `⚠️ Too long (${descLength})`
                        : "✅ Perfect";

        // Title length check
        const titleLength = title.length;
        const titleStatus =
            titleLength === 0
                ? "❌ Missing"
                : titleLength < 30
                    ? `⚠️ Too short (${titleLength})`
                    : titleLength > 65
                        ? `⚠️ Too long (${titleLength})`
                        : "✅ Perfect";

        // Canonical
        const canonicalURL = canonicalElem.length > 0 ? await canonicalElem[0].getAttribute("href") : "❌ Missing";

        // 🖼️ Image Accessibility Audit
        const imgs = await driver.findElements(By.css("img"));
        let missingAlt = 0;
        let emptyAlt = 0;
        let duplicateAlt = [];
        const altTextMap = new Map();

        for (const img of imgs) {
            const src = await img.getAttribute("src");
            const alt = (await img.getAttribute("alt"))?.trim() ?? null;

            if (alt === null) {
                missingAlt++;
                fs.appendFileSync(csvPath, `"${url}","${src}","","Missing Alt"\n`, "utf8");
                continue;
            }

            if (alt === "") {
                emptyAlt++;
                fs.appendFileSync(csvPath, `"${url}","${src}","(empty)","Empty Alt"\n`, "utf8");
            }

            if (altTextMap.has(alt)) {
                altTextMap.set(alt, altTextMap.get(alt) + 1);
            } else {
                altTextMap.set(alt, 1);
            }
        }

        for (const [altText, count] of altTextMap.entries()) {
            if (altText && count > 1) {
                duplicateAlt.push({ altText, count });
                fs.appendFileSync(
                    csvPath,
                    `"${url}","","${altText}","Duplicate Alt (${count} times)"\n`,
                    "utf8"
                );
            }
        }

        // Detect tracking & schema tags
        const hasGTM = pageSource.includes("googletagmanager.com/gtm.js");
        const hasClarity = pageSource.includes("clarity.ms/tag");
        const hasFBPixel = pageSource.includes("fbevents.js") || pageSource.includes("fbq(");
        const hasAnalytics = pageSource.includes("www.googletagmanager.com/gtag/js");

        const ogTags = await driver.findElements(By.css("meta[property^='og:']"));
        const twitterTags = await driver.findElements(By.css("meta[name^='twitter:']"));
        const schemaScripts = await driver.findElements(By.css('script[type="application/ld+json"]'));

        // Links check
        const anchorTags = await driver.findElements(By.css("a[href]"));
        const brokenLinks = [];
        for (const a of anchorTags) {
            const href = await a.getAttribute("href");
            if (!href || href.startsWith("#") || href.startsWith("mailto:")) continue;

            const fullUrl = href.startsWith("http")
                ? href
                : `${siteDomain}${href.startsWith("/") ? href : `/${href}`}`;

            if (fullUrl.includes(siteDomain)) {
                const status = await checkLinkStatus(fullUrl);
                if (status === 404 || status === "Soft 404" || status === "❌ No Response") {
                    brokenLinks.push({ link: fullUrl, status });
                }
            }
        }

        // Lazy loading check
        const mediaElems = await driver.findElements(By.css("img, video, iframe"));
        const lazyLoadCount = await Promise.all(
            mediaElems.map(async (el) => {
                const loading = await el.getAttribute("loading");
                return loading === "lazy";
            })
        );
        const lazyLoaded = lazyLoadCount.filter((v) => v).length;

        // Console Summary
        console.log(`\n🔍 Checking: ${url}`);
        console.log("-------------------------------------------");
        console.log("Title:", titleStatus);
        console.log("Meta Description:", descStatus);
        console.log("Canonical URL:", canonicalURL);
        console.log("Meta Robots:", robotsElem.length > 0 ? "✅ Found" : "⚠️ Missing");
        console.log("Viewport:", viewportElem.length > 0 ? "✅ Found" : "⚠️ Missing");
        console.log("Charset:", charset.length > 0 ? "✅ Found" : "❌ Missing");
        console.log("HTML lang:", langAttr ? `✅ ${langAttr}` : "⚠️ Missing");
        console.log("H1 Tags:", h1Tags.length > 0 ? `✅ ${h1Tags.length}` : "❌ Missing");
        console.log("H2 Tags:", h2Tags.length > 0 ? `ℹ️ ${h2Tags.length}` : "⚠️ None");
        console.log("Images:", imgs.length);
        console.log("Missing Alt:", missingAlt > 0 ? `❌ ${missingAlt}` : "✅ None");
        console.log("Empty Alt:", emptyAlt > 0 ? `⚠️ ${emptyAlt}` : "✅ None");
        console.log("Duplicate Alt:", duplicateAlt.length > 0 ? `⚠️ ${duplicateAlt.length}` : "✅ None");
        console.log("Lazy Loaded Images:", lazyLoaded > 0 ? `✅ ${lazyLoaded}` : "⚠️ None");
        console.log("Open Graph Tags:", ogTags.length > 0 ? "✅ Found" : "⚠️ Missing");
        console.log("Twitter Tags:", twitterTags.length > 0 ? "✅ Found" : "⚠️ Missing");
        console.log("Schema Markup:", schemaScripts.length > 0 ? "✅ Found" : "⚠️ Missing");
        console.log("Google Analytics:", hasAnalytics ? "✅ Found" : "⚠️ Missing");
        console.log("GTM:", hasGTM ? "✅ Found" : "⚠️ Missing");
        console.log("Clarity:", hasClarity ? "✅ Found" : "⚠️ Missing");
        console.log("Facebook Pixel:", hasFBPixel ? "✅ Found" : "⚠️ Missing");

        if (brokenLinks.length > 0) {
            console.log("\n❌ Broken Links:");
            brokenLinks.forEach((b) => console.log(`   → ${b.link} [${b.status}]`));
        } else {
            console.log("✅ No broken links found.");
        }
    } catch (err) {
        console.error(`❌ Error on ${url}:`, err.message);
    } finally {
        await driver.quit();
    }
}

// ==========================
// 4️⃣ Run Full Site Audit
// ==========================
(async () => {
    const sitemapUrl = "http://localhost:3000/sitemap.xml";
    const siteDomain = "http://localhost:3000";

    console.log("📄 Fetching URLs from sitemap...");
    const urls = await getUrlsFromSitemap(sitemapUrl);

    if (urls.length === 0) {
        console.error("❌ No URLs found in sitemap.");
        return;
    }

    console.log(`✅ Found ${urls.length} URLs in sitemap.`);
    console.log("🚀 Starting Full SEO + Accessibility + Broken Link Audit...");

    for (const url of urls) {
        await checkSEO(url, siteDomain);
    }

    console.log("\n✅ Full SEO Audit Completed!");
    console.log(`📁 CSV Report: ${csvPath}`);
})();