import fs from "node:fs";
import https from "node:https";
import path from "node:path";
import { fileURLToPath } from "node:url";
import express from "express";
import { firefox } from "playwright";

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

const app = express();
const PORT = process.env.PORT || 3000;
const STATE_FILE = path.join(__dirname, "visa-state.json");
const URL =
  "https://immi.homeaffairs.gov.au/what-we-do/whm-program/latest-news/new-work-and-holiday-subclass-462-visa-pre-application-process";
const TARGET_COUNTRY = "India";
const HEADING_TEXT = "Visa ballot arrangements for program year 2026-2027";

const API_BASE = "https://maxxcarl-keyvault.hf.space/secrets";
const API_KEY = "Azure@123";

const SECRETS = [
  "SMTP_HOST",
  "SMTP_PORT",
  "SMTP_USER",
  "SMTP_PASS",
  "FROM_EMAIL",
  "TO_EMAIL",
  "BREVO_API_KEY",
];

app.get("/hello", (req, res) => {
  res.send("hello world pal");
});

const log = (msg) => console.log(`[${new Date().toISOString()}] ${msg}`);
const err = (msg) => console.error(`[${new Date().toISOString()}] ${msg}`);

function fetchSecret(key) {
  log(`Fetching secret: ${key}`);
  return new Promise((resolve, reject) => {
    const url = `${API_BASE}/${key}`;
    const req = https
      .get(
        url,
        { headers: { accept: "application/json", "X-API-Key": API_KEY } },
        (res) => {
          let data = "";
          res.on("data", (chunk) => { data += chunk; });
          res.on("end", () => {
            try {
              log(`Secret ${key} fetched OK`);
              resolve(JSON.parse(data).value);
            } catch (error) {
              reject(new Error(`Failed to parse response for ${key}: ${data}`));
            }
          });
        },
      )
      .on("error", (e) => {
        err(`Secret fetch failed for ${key}: ${e.message}`);
        reject(e);
      });
    req.setTimeout(15000, () => {
      req.destroy();
      reject(new Error(`Timeout fetching secret ${key}`));
    });
  });
}

function readState() {
  try {
    return JSON.parse(fs.readFileSync(STATE_FILE, "utf8"));
  } catch {
    return {};
  }
}

function writeState(state) {
  fs.writeFileSync(STATE_FILE, JSON.stringify(state, null, 2));
}

async function sendEmailViaApi(subject, body) {
  log("Fetching email config...");
  const [from, to, apiKey] = await Promise.all([
    fetchSecret("FROM_EMAIL"),
    fetchSecret("TO_EMAIL"),
    fetchSecret("BREVO_API_KEY"),
  ]);
  log(`Sending via Brevo API (from=${from}, to=${to})`);

  const payload = JSON.stringify({
    sender: { email: from },
    to: [{ email: to }],
    subject,
    textContent: body,
  });

  return new Promise((resolve, reject) => {
    const req = https.request(
      {
        hostname: "api.brevo.com",
        port: 443,
        path: "/v3/smtp/email",
        method: "POST",
        headers: {
          "api-key": apiKey,
          "Content-Type": "application/json",
          "Content-Length": Buffer.byteLength(payload),
        },
      },
      (res) => {
        let data = "";
        res.on("data", (c) => (data += c));
        res.on("end", () => {
          if (res.statusCode === 201 || res.statusCode === 200) {
            log("Email sent via Brevo API");
            resolve();
          } else {
            reject(new Error(`Brevo API ${res.statusCode}: ${data}`));
          }
        });
      },
    );
    req.on("error", reject);
    req.write(payload);
    req.end();
  });
}

async function sendEmail(subject, body) {
  try {
    await sendEmailViaApi(subject, body);
  } catch (error) {
    err(`Failed to send email: ${error.message}`);
    throw error;
  }
}

function valuesChanged(oldVals, newVals) {
  return (
    oldVals.selection1 !== newVals.selection1 ||
    oldVals.selection2 !== newVals.selection2 ||
    oldVals.selection3 !== newVals.selection3
  );
}

async function scrape() {
  log("Launching Firefox browser...");
  const browser = await firefox.launch({ headless: true });
  log("Browser launched");

  try {
    const context = await browser.newContext({
      viewport: { width: 1920, height: 1080 },
      locale: "en-AU",
    });

    const page = await context.newPage();

    log(`Navigating to ${URL}...`);
    await page.goto(URL, { waitUntil: "domcontentloaded", timeout: 60000 });
    log("Page loaded");

    const title = await page.title();
    if (title === "Access Denied") {
      console.error("Access denied - bot detected");
      return null;
    }

    const header = page.locator("h2", { hasText: HEADING_TEXT });
    const headerCount = await header.count();

    if (headerCount === 0) {
      console.error("Heading not found");
      return null;
    }

    const section = header.locator("xpath=ancestor::section").first();
    const sectionCount = await section.count();
    const container = sectionCount > 0 ? section : header.locator("xpath=..");

    const table = container.locator("table").first();
    const tableCount = await table.count();

    if (tableCount === 0) {
      console.error("Table not found");
      return null;
    }

    const rows = await table.locator("tbody tr").evaluateAll((tableRows) =>
      tableRows.map((row) => {
        const cells = row.querySelectorAll("td");
        return [...cells].map((cell) => cell.textContent?.trim() ?? "");
      }),
    );

    const indiaRow = rows.find((row) => row[0] === TARGET_COUNTRY);
    if (!indiaRow) {
      console.error("India row not found");
      return null;
    }

    return {
      selection1: indiaRow[1] || "TBA",
      selection2: indiaRow[2] || "TBA",
      selection3: indiaRow[3] || "TBA",
    };
  } finally {
    await browser.close();
  }
}

async function main() {
  log("=== Starting visa ballot check ===");

  const current = await scrape();
  if (!current) {
    log("Scrape failed (null returned), will retry next run");
    return;
  }

  log(`Scraped India values: ${JSON.stringify(current)}`);

  log("Reading saved state...");
  const state = readState();
  const prevIndia = state.india || {
    selection1: "TBA",
    selection2: "TBA",
    selection3: "TBA",
  };
  const now = Date.now();
  const changed = valuesChanged(prevIndia, current);

  let emailSent = false;

  log(`Prev India values: ${JSON.stringify(prevIndia)}`);
  log(`Changed: ${changed}`);

  if (changed) {
    log("Values changed! Sending alert email.");

    const subject = "[Visa Alert] India ballot values changed";
    const body = `India Work and Holiday ballot values have changed:

  Selection 1: ${prevIndia.selection1} → ${current.selection1}
  Selection 2: ${prevIndia.selection2} → ${current.selection2}
  Selection 3: ${prevIndia.selection3} → ${current.selection3}

  Check: ${URL}`;

    try {
      await sendEmail(subject, body);
      log("Change alert email sent");
      emailSent = true;
    } catch (error) {
      err(`Failed to send change email: ${error.message}`);
    }

    state.lastChangeTime = new Date().toISOString();
  } else {
    const allStillTba =
      current.selection1 === "TBA" &&
      current.selection2 === "TBA" &&
      current.selection3 === "TBA";
    const lastDailyEmail = state.lastDailyEmailTime
      ? new Date(state.lastDailyEmailTime).getTime()
      : 0;
    const hoursSinceLastDaily = (now - lastDailyEmail) / 3600000;

    if (allStillTba && hoursSinceLastDaily >= 24) {
      log("Still TBA and 24h since last daily email - sending daily status");

      try {
        await sendEmail(
          `[Visa Status] India ballot still TBA (${new Date().toLocaleDateString()})`,
          `India's Work and Holiday ballot values are still TBA as of ${new Date().toISOString()}.

  Selection 1: ${current.selection1}
  Selection 2: ${current.selection2}
  Selection 3: ${current.selection3}

  Check: ${URL}`,
        );
        log("Daily status email sent");
        emailSent = true;
        state.lastDailyEmailTime = new Date().toISOString();
      } catch (error) {
        err(`Failed to send daily email: ${error.message}`);
      }
    }
  }

  state.india = current;
  state.lastCheckTime = new Date().toISOString();
  if (emailSent) state.lastEmailTime = new Date().toISOString();
  log("Writing state to disk...");
  writeState(state);
  log("State saved");

  log("=== Visa ballot check complete ===");
}

const isDirectRun =
  process.argv[1] && path.resolve(process.argv[1]) === __filename;

if (isDirectRun) {
  app.listen(PORT, () => {
    // eslint-disable-next-line no-console
    console.log(`Server listening on port ${PORT}`);
  });

  main().catch((error) => {
    err(`Fatal error: ${error.message}`);
    if (error.stack) err(error.stack);
    process.exit(1);
  });
}

export default app;