const nodemailer = require("nodemailer");
const fetch = require('cross-fetch');
const { Pool } = require('pg');
var parse = require('pg-connection-string').parse;

var config = parse(process.env.DATABASE_URL);
const pool = new Pool(config);


// ***** update daily top 3 news

// const updateEmailNews = async (req, res) => {
//   try {

//     const catList = ["science", "india", 'business',
//       "sports", "entertainment", "technology", "world"];

//     catList.forEach(async (cat) => {

//       const data = await getTopNews(cat);

//       data.forEach(async (d) => {

//         const summary = await getSummary(d.article_url);

//         //set news in database
//         try {
//           const query = `
//                   update top_news set 
//                   title = $1, article_url = $2, source =  $3, summary =  $4, published_date = $5 where category = '${cat}_${data.indexOf(d) + 1}' ;
//               `;
//           const values = [
//             d.title,
//             d.article_url,
//             d.source_name,
//             summary,
//             d.published_date
//           ];

//           await pool.query(query, values);
//         } catch (er) {
//           console.log(er);
//         }

//       });

//     });

//     res.send({ "status": "running" });


//   } catch (e) {
//     console.log(e);
//   }

// }

const updateEmailNews = async (req, res) => {
  try {
    const catList = ["science", "india", 'business',
      "sports", "entertainment", "technology", "world"];

    const promises = catList.map(async (cat) => {
      const data = await getTopNews(cat);

      const articlePromises = data.map(async (d) => {
        try {
          const summary = await getSummary(d.article_url);

          const query = `
            UPDATE top_news SET 
            title = $1, article_url = $2, source =  $3, summary =  $4, published_date = $5
            WHERE category = '${cat}_${data.indexOf(d) + 1}';
          `;
          const values = [
            d.title,
            d.article_url,
            d.source_name,
            summary,
            d.published_date
          ];

          await pool.query(query, values);
        } catch (er) {
          console.log(er);
        }
      });

      
      await Promise.all(articlePromises);
    });

    
    await Promise.all(promises);

    
    res.send({ "status": "completed" });

  } catch (e) {
    console.log(e);
    res.status(500).send({ "error": "An error occurred" });
  }
}


async function getTopNews(category) {
  const query = `
                select title, article_url, category, source_name, published_date from news  where category like '%${category}%' order by published_date desc limit 3;
            `;

  const data = await pool.query(query);

  return data.rows;
}

async function getSummary(url) {

  //console.log(url)
  const apiUrl = 'https://yashxx07-summarize-articles.hf.space/summarize-v1';
  const options = {
    method: 'POST',
    headers: {
      'content-type': 'application/json',
    },
    body: JSON.stringify({
      "url": url,
      "max_tokens": 500
    })
  };

  try {
    const response = await fetch(apiUrl, options);

    const result = await response.text();
    //console.log(result);
    return result;
  } catch (error) {
    console.error(error);
  }

}


// const transporter = nodemailer.createTransport({
//   host: 'smtp.mailchimp.com',
//   port: 587, // Mailchimp SMTP port
//   secure: false, // true for 465, false for other ports
//   auth: {
//     user: 'your_mailchimp_username',
//     pass: 'your_mailchimp_password'
//   }
// });


const transporter = nodemailer.createTransport({
  host: "smtp.elasticemail.com",
  port: 2525,
  auth: {
    user: process.env.ID,
    pass: process.env.PASS,
  },
});


async function sendToUser(email, mailContent) {
  try {
    await transporter.sendMail({
      from: {
        name: "RapidRecap",
        address: process.env.EMAIL
      },
      to: email,
      subject: "Today's Top News",
      html: mailContent
    });

    return "Email sent successfully!";
  } catch (error) {
    console.error(error);
  }
}

async function getEmailsList(time) {

  try {
    const query = `
                select * from subs  where time = '${time}';`;
    const data = await pool.query(query);
    return data.rows;

  } catch (e) {
    console.log(e);
  }

}

async function getAllNews() {
  try {
    const query = `
                select * from top_news;
            `;
    const data = await pool.query(query);
    return data.rows;

  } catch (e) {
    console.log(e);
  }
}

function craftEmailTemplate(user, newsList) {

  const filteredNews = newsList.filter(item => user.category.includes(item.category.slice(0, -2)) && item.summary != `""`);
  shuffleArray(filteredNews);

  // Construct the mail content
  const mailContent = filteredNews.slice(0, 3).map(doc => `
    <div style='line-height: 1.4;max-width:400px;background:white;margin-top:5px;color:#545454;padding:5px;border:1px solid black; text-align:left; border-radius:2px '>
      <a href='${doc.article_url}' style='color:Black;text-decoration:none;'><h1 style='margin:0'>${doc.title}</h1></a>
      <div style='display:flex;justify-content:start;align-items:center;'>
        <p style='text-align:left;margin:0;color:#545454;text-decoration:none;'><strong>Source: </strong>${doc.source}<p>
      </div>
      <div style='display:flex;justify-content:start;align-items:center;'>
        <p style='text-align:left;margin:0;color:#545454;text-decoration:none;'><strong>Published On: </strong>${convertToDateString(doc.published_date)}<p>
      </div>
      <p style='text-align:left;margin:0'>${doc.summary.slice(2, -1)}</p>
    </div>`
  ).join('');

  return mailContent;
}

function convertToDateString(publishedDate) {
  const date = new Date(publishedDate);

  const year = date.getFullYear();
  const month = date.getMonth() + 1;
  const day = date.getDate();

  
  const formattedDate = `${year}-${month.toString().padStart(2, '0')}-${day.toString().padStart(2, '0')}`;

  return formattedDate;
}

function shuffleArray(array) {
  for (let i = array.length - 1; i > 0; i--) {
    const j = Math.floor(Math.random() * (i + 1));
    [array[i], array[j]] = [array[j], array[i]];
  }
}

async function sendEmail(req, res) {

  try {
    const time = req.query.time;
    const emailsList = await getEmailsList(time);
    const newsList = await getAllNews();

    emailsList.forEach(async (user) => {

      const mailTemplate = craftEmailTemplate(user, newsList);
      //res.send(mailTemplate);
      await sendToUser(user.email, mailTemplate);

    });
    //const result = await sendEmail();
    res.send({ "news": newsList, "emails": emailsList });
  } catch (error) {
    console.log(error);
    res.status(500).send("Error sending email.");
  }

}


module.exports = { updateEmailNews, sendEmail }