const { chromium } = require("playwright-chromium");

let browser;
let context;

const BLOCK_LIST = [
    "google-analytics", "doubleclick", "facebook", "twitter",
    "adsystem", "analytics", "tracker", "pixel", "quantserve", "newrelic",
    "hotjar", "yandex", "ads", "widgets", "gravatar", "fonts.googleapis",
    "map", "cdn.ampproject.org", "googletagmanager"
];

const ALLOWED_SCRIPTS = [];

async function initHeadless() {
    if (browser && browser.isConnected()) return;

    try {
        browser = await chromium.launch({
            headless: true,
            args: [
                "--no-sandbox",
                "--disable-setuid-sandbox",
                "--disable-dev-shm-usage",
                "--disable-gpu",
                "--disable-extensions",
                "--disable-background-networking",
                "--disable-sync",
                "--disable-translate",
                "--mute-audio",
                "--no-first-run",
                "--no-zygote",
                "--single-process",
                "--disable-software-rasterizer",
                "--disable-client-side-phishing-detection",
                "--no-default-browser-check",
                "--no-experiments"
            ]
        });

        context = await browser.newContext({
            userAgent:
                "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 Chrome/122.0.0.0 Safari/537.36"
        });
    } catch (error) {
        console.error("Error al inicializar browser:", error);
        throw error;
    }
}

async function turboScroll(page) {
    try {
        await page.evaluate(() => {
            return new Promise((resolve) => {
                let last = 0;
                let same = 0;
                const timer = setInterval(() => {
                    const h = document.body.scrollHeight;
                    window.scrollTo(0, h);
                    if (h === last) {
                        same++;
                        if (same >= 5) {
                            clearInterval(timer);
                            resolve();
                        }
                    } else {
                        same = 0;
                        last = h;
                    }
                }, 20);

                // Safety timeout
                setTimeout(() => {
                    clearInterval(timer);
                    resolve();
                }, 10000);
            });
        });
    } catch (error) {
        console.error("Error en turboScroll:", error.message);
        // No lanzamos el error, continuamos
    }
}

async function scrape(url, handler, options = {}) {
    const {
        waitUntil = "domcontentloaded",
        waitSelector = null,
        timeout = 15000,
        scrollToBottom = false,
        renderWaitTime = 0,
        loadImages = true,
        blockScripts = true,
        retries = 3,
        retryDelay = 1000
    } = options;

    let lastError = null;

    for (let attempt = 1; attempt <= retries; attempt++) {
        let page = null;

        try {
            // Verificar que el browser esté activo
            if (!browser || !browser.isConnected()) {
                await initHeadless();
            }

            page = await context.newPage();
            const requests = [];

            // Listener para requests
            page.on("request", req => {
                requests.push({
                    url: req.url(),
                    method: req.method(),
                    type: req.resourceType()
                });
            });

            // Route para bloquear recursos
            await page.route("**/*", (route) => {
                const req = route.request();
                const resUrl = req.url().toLowerCase();
                const type = req.resourceType();

                if (
                    type === "font" ||
                    type === "stylesheet" ||
                    type === "media" ||
                    type === "manifest" ||
                    type === "other" ||
                    (blockScripts && type === "script" && !ALLOWED_SCRIPTS.some(k => resUrl.includes(k)))
                ) {
                    return route.abort("blockedbyclient");
                }

                if (BLOCK_LIST.some(k => resUrl.includes(k))) {
                    return route.abort("blockedbyclient");
                }

                if (!loadImages && (
                    type === "image" || resUrl.match(/\.(jpg|jpeg|png|gif|webp|svg)$/)
                )) {
                    return route.abort("blockedbyclient");
                }

                route.continue();
            });

            // Navegar a la URL
            await page.goto(url, { waitUntil, timeout });

            // Esperar selector si se especifica
            if (waitSelector) {
                try {
                    await page.waitForSelector(waitSelector, { timeout: Math.min(timeout, 5000) });
                } catch (e) {
                    console.warn(`Selector '${waitSelector}' no encontrado, continuando...`);
                }
            }

            // Scroll si es necesario
            if (scrollToBottom) {
                await turboScroll(page);
            }

            // Tiempo de espera adicional para renderizado
            if (renderWaitTime > 0) {
                await page.waitForTimeout(renderWaitTime);
            }

            // Ejecutar el handler personalizado
            const result = await handler(page);

            // Cerrar la página antes de retornar
            await page.close();

            return { result, requests };

        } catch (error) {
            lastError = error;
            console.error(`[Intento ${attempt}/${retries}] Error durante el scraping de ${url}:`, error.message);

            // Cerrar página si está abierta
            if (page && !page.isClosed()) {
                try {
                    await page.close();
                } catch (closeError) {
                    console.error("Error al cerrar página:", closeError.message);
                }
            }

            // Si el browser está cerrado, limpiar referencias
            if (error.message.includes("closed") || error.message.includes("Target closed")) {
                console.log("Browser cerrado detectado, reiniciando...");
                await closeScraper();
            }

            // Si no es el último intento, esperar antes de reintentar
            if (attempt < retries) {
                const delay = retryDelay * attempt; // Backoff exponencial
                console.log(`Reintentando en ${delay}ms...`);
                await new Promise(r => setTimeout(r, delay));
            }
        }
    }

    // Si llegamos aquí, todos los intentos fallaron
    console.error(`Todos los intentos fallaron para ${url}`);
    throw lastError || new Error("Scraping failed after all retries");
}

async function closeScraper() {
    try {
        if (context) {
            await context.close();
            context = null;
        }
    } catch (error) {
        console.error("Error cerrando context:", error.message);
    }

    try {
        if (browser) {
            await browser.close();
            browser = null;
        }
    } catch (error) {
        console.error("Error cerrando browser:", error.message);
    }
}

module.exports = {
    initHeadless,
    scrape,
    closeScraper
};