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

const headed = process.argv.includes("--headed");
const retryErrors = process.argv.includes("--retry-errors");

function getArgValue(name, defaultValue) {
  const prefix = `--${name}=`;
  const found = process.argv.find(x => x.startsWith(prefix));
  return found ? found.slice(prefix.length) : defaultValue;
}

const inputFile = getArgValue("input-file", "product-urls.txt");
const outputJson = getArgValue("output-json", "prismatic_powders.json");
const progressLog = getArgValue("progress-log", "prismatic-scrape-progress.log");

const minDelaySeconds = parseInt(getArgValue("min-delay-seconds", "8"), 10);
const maxDelaySeconds = parseInt(getArgValue("max-delay-seconds", "18"), 10);
const pageSettleSeconds = parseInt(getArgValue("page-settle-seconds", "4"), 10);
const maxProducts = parseInt(getArgValue("max-products", "0"), 10);

function clean(text) {
  return (text || "").replace(/\s+/g, " ").trim();
}

function cleanUrl(url) {
  return (url || "").split("?")[0].split("#")[0].trim();
}

function sleep(ms) {
  return new Promise(resolve => setTimeout(resolve, ms));
}

function randomDelayMs() {
  const minMs = Math.max(0, minDelaySeconds * 1000);
  const maxMs = Math.max(minMs, maxDelaySeconds * 1000);
  return Math.floor(minMs + Math.random() * (maxMs - minMs + 1));
}

function logLine(message) {
  const line = `[${new Date().toISOString()}] ${message}`;
  console.log(line);
  fs.appendFileSync(progressLog, line + "\r\n", "utf8");
}

function absoluteUrl(baseUrl, maybeUrl) {
  if (!maybeUrl) return "";
  try {
    return new URL(maybeUrl, baseUrl).href;
  } catch {
    return maybeUrl;
  }
}

function loadInputUrls() {
  if (!fs.existsSync(inputFile)) {
    throw new Error(`Input file not found: ${inputFile}`);
  }

  const urls = fs.readFileSync(inputFile, "utf8")
    .split(/\r?\n/)
    .map(cleanUrl)
    .filter(Boolean)
    .filter(x => !x.startsWith("#"))
    .filter(x => /\/shop\/powder-coating-colors\/[A-Z0-9-]+\//i.test(x));

  return [...new Set(urls)];
}

function loadOutput() {
  if (!fs.existsSync(outputJson)) {
    return { results: [], errors: [] };
  }

  try {
    const parsed = JSON.parse(fs.readFileSync(outputJson, "utf8"));

    if (Array.isArray(parsed)) {
      return { results: parsed, errors: [] };
    }

    return {
      results: Array.isArray(parsed.results) ? parsed.results : [],
      errors: Array.isArray(parsed.errors) ? parsed.errors : []
    };
  } catch (err) {
    const backup = `${outputJson}.invalid-${Date.now()}.bak`;
    fs.copyFileSync(outputJson, backup);
    throw new Error(`Could not parse existing ${outputJson}. Backed it up to ${backup}. Error: ${err.message}`);
  }
}

function saveOutput(data) {
  const tempFile = `${outputJson}.tmp`;
  fs.writeFileSync(tempFile, JSON.stringify(data, null, 2), "utf8");
  fs.renameSync(tempFile, outputJson);
}

function parsePriceTiers(plainText) {
  const priceMatches = [...plainText.matchAll(/(\d+\s*-\s*\d+\s*lbs|\d+\s*\+\s*lbs)\s*\$([\d.]+)/gi)];

  return priceMatches.map(m => {
    const rangeText = clean(m[1]);
    const price = parseFloat(m[2]);

    let min = null;
    let max = null;

    const rangeMatch = rangeText.match(/(\d+)\s*-\s*(\d+)/);
    if (rangeMatch) {
      min = parseInt(rangeMatch[1], 10);
      max = parseInt(rangeMatch[2], 10);
    }

    const plusMatch = rangeText.match(/(\d+)\s*\+/);
    if (plusMatch) {
      min = parseInt(plusMatch[1], 10);
      max = null;
    }

    return { min, max, price };
  });
}

async function getLinkByText(page, patterns) {
  const links = await page.locator("a").evaluateAll((anchors) =>
    anchors.map(a => ({
      text: (a.innerText || a.textContent || "").replace(/\s+/g, " ").trim(),
      href: a.getAttribute("href") || ""
    }))
  );

  for (const link of links) {
    if (patterns.some(p => new RegExp(p, "i").test(link.text))) {
      return absoluteUrl(page.url(), link.href);
    }
  }

  return "";
}

async function getSampleImageUrl(page) {
  const imageUrls = await page.locator("img").evaluateAll((imgs) =>
    imgs.map(img =>
      img.currentSrc ||
      img.src ||
      img.getAttribute("src") ||
      img.getAttribute("data-src") ||
      ""
    ).filter(Boolean)
  );

  return (
    imageUrls.find(src => /images\.nicindustries\.com/i.test(src) && !/thumbnail/i.test(src)) ||
    imageUrls.find(src => /images\.nicindustries\.com/i.test(src)) ||
    imageUrls.find(src => /prismatic|powder|color/i.test(src)) ||
    ""
  );
}

async function parseProduct(page, url) {
  logLine(`Scraping ${url}`);

  const response = await page.goto(url, {
    waitUntil: "domcontentloaded",
    timeout: 60000
  });

  await page.waitForTimeout(pageSettleSeconds * 1000);

  const status = response ? response.status() : 0;
  const pageTitle = clean(await page.title().catch(() => ""));
  const plainText = clean(await page.locator("body").innerText().catch(() => ""));

  logLine(`HTTP status ${status}; title "${pageTitle}"`);

  if (status === 403 || /^403 Forbidden$/i.test(pageTitle) || /^403 Forbidden$/i.test(plainText)) {
    throw new Error("403 Forbidden returned by site.");
  }

  if (status === 404 || /404|Page Not Found/i.test(pageTitle)) {
    throw new Error("404 Not Found returned by site.");
  }

  const title = clean(await page.locator("h1").first().innerText().catch(() => ""));

  const skuMatch = plainText.match(/Item:\s*([A-Z0-9-]+)/i);
  const sku = skuMatch ? skuMatch[1] : "";

  if (!sku && !title) {
    throw new Error("Could not find SKU or title on product page.");
  }

  const descMatch = plainText.match(/Description:\s*(.*?)(WARNING:|What does this match\?|$)/is);
  const description = descMatch ? clean(descMatch[1]) : "";

  const priceTiers = parsePriceTiers(plainText);

  const safetyDataSheetUrl = await getLinkByText(page, ["Safety Data Sheet", "\\bSDS\\b"]);
  const applicationGuideUrl = await getLinkByText(page, ["Application Guide"]);
  const technicalDataSheetUrl = await getLinkByText(page, ["Tech Data Sheet", "Technical Data Sheet", "\\bTDS\\b"]);
  const sampleImageUrl = await getSampleImageUrl(page);

  return {
    sku,
    color_name: title,
    description,
    price_tiers: priceTiers,
    safety_data_sheet_url: safetyDataSheetUrl,
    technical_data_sheet_url: technicalDataSheetUrl,
    application_guide_url: applicationGuideUrl,
    sample_image_url: sampleImageUrl,
    product_url: url,
    scraped_at: new Date().toISOString()
  };
}

(async () => {
  const allUrls = loadInputUrls();
  const data = loadOutput();

  const completedUrls = new Set(data.results.map(r => cleanUrl(r.product_url)).filter(Boolean));
  const errorUrls = new Set(data.errors.map(e => cleanUrl(e.product_url)).filter(Boolean));

  let remainingUrls = allUrls.filter(url => {
    if (completedUrls.has(url)) return false;
    if (!retryErrors && errorUrls.has(url)) return false;
    return true;
  });

  if (maxProducts > 0) {
    remainingUrls = remainingUrls.slice(0, maxProducts);
  }

  logLine(`Input URLs: ${allUrls.length}`);
  logLine(`Already scraped: ${completedUrls.size}`);
  logLine(`Existing errors: ${errorUrls.size}`);
  logLine(`Retry errors: ${retryErrors ? "yes" : "no"}`);
  logLine(`This run target count: ${remainingUrls.length}`);
  logLine(`Delay range: ${minDelaySeconds}-${maxDelaySeconds} seconds; page settle: ${pageSettleSeconds} seconds`);

  if (remainingUrls.length === 0) {
    logLine("Nothing to scrape. Done.");
    saveOutput(data);
    return;
  }

  const browser = await chromium.launch({
    headless: !headed
  });

  const context = await browser.newContext({
    userAgent: "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0.0.0 Safari/537.36",
    viewport: { width: 1365, height: 900 },
    locale: "en-US",
    timezoneId: "America/New_York"
  });

  const page = await context.newPage();

  let processedThisRun = 0;

  for (const url of remainingUrls) {
    try {
      const row = await parseProduct(page, url);

      // If retrying an old error, keep the old error history but avoid duplicate successful result.
      if (!completedUrls.has(url)) {
        data.results.push(row);
        completedUrls.add(url);
      }

      processedThisRun++;
      saveOutput(data);

      logLine(`Saved result ${processedThisRun}/${remainingUrls.length}: ${row.sku || "(no sku)"} ${row.color_name || ""}`);
    } catch (err) {
      const errorRecord = {
        product_url: url,
        error: err.message,
        scraped_at: new Date().toISOString()
      };

      data.errors.push(errorRecord);
      saveOutput(data);

      logLine(`ERROR ${url}: ${err.message}`);
    }

    const delay = randomDelayMs();
    logLine(`Waiting ${(delay / 1000).toFixed(1)} seconds before next product...`);
    await sleep(delay);
  }

  await browser.close();

  logLine(`Done. Results: ${data.results.length}; Errors: ${data.errors.length}; Output: ${outputJson}`);
})();