/**
 * Copyright (c) 2026 Niolla
 * All rights reserved.
 */

// app/utils/pdfGenerator.js

const path = require("path");
const ejs = require("ejs");
const puppeteer = require("puppeteer");
const fs = require("fs");
const { imageToBase64 } = require("./imageToBase64.utill");
const { log, runningEnvironment } = require("./consoleLog.utill");

let browser;

let executablePath = null;

const isProd = runningEnvironment();

if (isProd) {
  executablePath = "/usr/bin/chromium";
} else {
  executablePath = puppeteer.executablePath();
}


/**
 * Launch or reuse Puppeteer browser safely
 */
async function getBrowser() {
  if (!browser || !browser.isConnected?.()) {
    console.log("🚀 Launching Chromium from Docker system path...");

    browser = await puppeteer.launch({
      headless: "new",
      executablePath: executablePath,
      args: [
        "--no-sandbox",
        "--disable-setuid-sandbox",
        "--disable-dev-shm-usage",
        "--disable-gpu",
        "--no-zygote"
      ],
    });

    console.log("✅ Browser launched");
  }

  return browser;
}

/**
 * Close browser safely
 */
async function closeBrowser() {
  if (browser) {
    try {
      await browser.close();
    } catch (e) {}
    browser = null;
  }
}

/**
 * Core PDF renderer
 */
async function renderPdf(templateFile, data = {}, opts = {}) {
  const templatePath = path.join(__dirname, "../templates", templateFile);

  console.log("📝 Rendering:", templateFile);

  // Convert image to base64 if needed
  if (data.logoUrl && !data.logoBase64) {
    try {
      data.logoBase64 = await imageToBase64(data.logoUrl);
    } catch (err) {
      console.error("❌ Logo conversion failed:", err.message);
      data.logoBase64 = null;
    }
  }

  const html = await ejs.renderFile(templatePath, data);

  const browserInstance = await getBrowser();
  const page = await browserInstance.newPage();

  try {
    // Safety timeouts
    await page.setDefaultTimeout(60000);
    await page.setDefaultNavigationTimeout(60000);

    await page.setViewport({ width: 1200, height: 800 });

    console.log("📄 Loading HTML...");
    await page.setContent(html, { waitUntil: "networkidle0" });

    await page.emulateMediaType("print");

    // Wait for fonts
    await page.evaluate(() => document.fonts?.ready || Promise.resolve());

    const margin = {
      top: 20,
      bottom: 20,
      left: 10,
      right: 10,
      ...opts.margin,
    };

    // Optional: measure content (kept for logging only)
    const contentHeightPx = await page.evaluate(() => {
      const body = document.body;
      const htmlEl = document.documentElement;

      return Math.max(
        body.scrollHeight,
        body.offsetHeight,
        htmlEl.scrollHeight,
        htmlEl.offsetHeight
      );
    });

    console.log("📏 Content height:", contentHeightPx, "px");

    // ❗ REMOVED scaling logic (causes PDF distortion in production)

    const showPageNumbers = opts.showPageNumbers === true;

    console.log("⚙️ Generating PDF...");

    const pdfBuffer = await page.pdf({
      format: "A4",
      printBackground: true,
      preferCSSPageSize: true,
      margin: {
        top: `${margin.top}mm`,
        bottom: `${margin.bottom}mm`,
        left: `${margin.left}mm`,
        right: `${margin.right}mm`,
      },
      displayHeaderFooter: showPageNumbers,
      headerTemplate: `<div></div>`,
      footerTemplate: showPageNumbers
        ? `
          <div style="font-size:10px;width:100%;text-align:center;">
            Page <span class="pageNumber"></span> / <span class="totalPages"></span>
          </div>`
        : `<div></div>`,
    });

    console.log("✅ PDF generated");

    return pdfBuffer;
  } catch (err) {
    console.error("❌ PDF generation error:", err.message);
    throw err;
  } finally {
    await page.close().catch(() => {});
  }
}

/**
 * Helpers
 */
const generatePdfFromPreCost = (data) =>
  renderPdf("documents/precost/precost.ejs", data);

const generatePdfFromInvoice = (data) =>
  renderPdf("documents/invoice/invoice.ejs", data);

const generatePdfFromDispatchNote = (data) =>
  renderPdf("documents/dispatchNote/dispatchNote.ejs", data);

const generatePdfFromDeliveryNote = (data) =>
  renderPdf("documents/deliveryNote/deliveryNote.ejs", data);

const generatePdfFromPO = (data) =>
  renderPdf("documents/po/po.ejs", data);

const generatePdfFromCustomDocument = (data) =>
  renderPdf("documents/customDocument/customDocument.ejs", data);

const generatePdfFromCreditNote = (data) =>
  renderPdf("documents/creditNote/creditNote.ejs", data);

module.exports = {
  generatePdfFromPreCost,
  generatePdfFromInvoice,
  generatePdfFromDispatchNote,
  generatePdfFromDeliveryNote,
  generatePdfFromPO,
  generatePdfFromCustomDocument,
  generatePdfFromCreditNote,
  renderPdf,
  closeBrowser,
};