import { customAlphabet } from '@nanoid';
import { STATUS_CODE, STATUS_TEXT, StatusCode } from '@std/http';

import config from '~config';

import dbClient from 'db/client.ts';

// Using custom alphabet to exclude - and _
const alphabet = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';
const nanoid = customAlphabet(alphabet, 20);

const discordHeaders = new Headers();
discordHeaders.append('Content-Type', 'application/json');
discordHeaders.append('Accept', 'application/json');

const zohoHeaders = new Headers(discordHeaders);
let zohoAuthExpireDT = new Date().getTime();

const genericResponse = (status: StatusCode, customText = '') =>
  new Response(customText || STATUS_TEXT[status], { status: status, statusText: STATUS_TEXT[status] });

Deno.serve({ port: config.api.port }, async (req) => {
  const urlPath = req.url.split('?')[0] ?? '';
  const path = (urlPath.split('api')[1] ?? '').toLowerCase().trim();
  console.log(urlPath, path);

  if (req.method === 'GET') {
    // handle all gets
  } else if (req.method === 'POST' && (path === '/enroll' || path === '/enroll/')) {
    const body = await req.json();

    let readFailure = false;
    const userNameMatches = await dbClient.query('SELECT name FROM users WHERE name = ?', [body.name]).catch(() => {
      readFailure = true;
    });
    if (readFailure) return genericResponse(STATUS_CODE.InternalServerError, "Couldn't read DB.");

    if (userNameMatches.length === 0) {
      if (body.name.length < 4 || body.name.length > 20) return genericResponse(STATUS_CODE.BadRequest, `Name too ${body.name.length < 4 ? 'short' : 'long'}.`);
      if (body.pin.length < 4 || body.pin.length > 20) return genericResponse(STATUS_CODE.BadRequest, `PIN too ${body.pin.length < 4 ? 'short' : 'long'}.`);
      if (body.email.length > 255) return genericResponse(STATUS_CODE.BadRequest, `Email too long.`);

      const id = nanoid();

      let writeFailure = false;
      await dbClient.execute('INSERT INTO users(id,name,pin,email) values(?,?,?,?)', [id, body.name, body.pin, body.email]).catch(() => {
        writeFailure = true;
      });

      if (writeFailure) {
        return genericResponse(STATUS_CODE.InternalServerError, "Couldn't write DB.");
      } else {
        return genericResponse(STATUS_CODE.OK, JSON.stringify({ id }));
      }
    } else {
      return genericResponse(STATUS_CODE.BadRequest, 'Username Taken.');
    }
  } else {
    const body = await req.json();

    let readFailure = false;
    const loginMatch = await dbClient.query('SELECT id, email, deleteCode FROM users WHERE name = ? AND pin = ?', [body.name, body.pin]).catch(() => {
      readFailure = true;
    });
    if (readFailure) return genericResponse(STATUS_CODE.InternalServerError, "Couldn't read DB.");
    if (loginMatch.length === 0) return genericResponse(STATUS_CODE.Forbidden, 'Invalid name/PIN combination.');
    const id = loginMatch[0].id;
    const email = loginMatch[0].email;
    const hasEmail = email.length > 0;
    const deleteCode = loginMatch[0].deleteCode;

    switch (req.method) {
      case 'POST':
        if (path === '/auth' || path === '/auth/') {
          return genericResponse(STATUS_CODE.OK, JSON.stringify({ id, hasEmail }));
        }
        break;
      case 'PUT':
        break;
      case 'DELETE':
        if (path === '/unenroll' || '/unenroll/') {
          if (!hasEmail || body.deleteCode.trim() === deleteCode) {
            let deleteFailure = false;

            await dbClient.execute('DELETE FROM plans WHERE ownerId = ?', [id]).catch(() => {
              deleteFailure = true;
            });
            if (deleteFailure) return genericResponse(STATUS_CODE.InternalServerError, "Couldn't delete plans.");

            await dbClient.execute('DELETE FROM users WHERE id = ?', [id]).catch(() => {
              deleteFailure = true;
            });
            if (deleteFailure) return genericResponse(STATUS_CODE.InternalServerError, "Couldn't delete user.");

            return genericResponse(STATUS_CODE.OK, 'Deleted user and plans.');
          } else if (hasEmail && !deleteCode) {
            let updateFailure = false;

            const newDeleteCode = nanoid();
            await dbClient.execute('UPDATE users SET deleteCode = ? WHERE id = ?', [newDeleteCode, id]).catch(() => {
              updateFailure = true;
            });
            if (updateFailure) return genericResponse(STATUS_CODE.InternalServerError, "Couldn't set deleteCode.");

            const nowDT = new Date().getTime();
            let fetchFailed = false;
            if (zohoAuthExpireDT < nowDT) {
              const getNewAuthToken = await fetch(
                `https://accounts.zoho.com/oauth/v2/token?client_id=${config.email.clientId}&client_secret=${config.email.clientSecret}&grant_type=client_credentials&scope=ZohoMail.messages.CREATE`,
                { method: 'POST' },
              ).catch(() => {
                fetchFailed = true;
              });
              if (fetchFailed || !getNewAuthToken) return genericResponse(STATUS_CODE.InternalServerError, "Couldn't get auth token.");

              const newAuthToken = await getNewAuthToken.json();
              zohoHeaders.set('Authorization', `Zoho-oauthtoken ${newAuthToken.access_token}`);
              zohoAuthExpireDT = nowDT + newAuthToken.expires_in * 1000 - 600000;
            }

            const sendEmailReq = await fetch(`https://mail.zoho.com/api/accounts/${config.email.accountId}/messages`, {
              method: 'POST',
              headers: zohoHeaders,
              body: JSON.stringify({
                fromAddress: config.email.address,
                toAddress: email,
                subject: 'XIVPlan+DB Delete Code',
                content: `Notice: account deletion is permanent and will delete all plans saved under your account.<br/><br/>Please use the following Delete Code to delete your account:<br/><br/>${newDeleteCode}`,
              }),
            }).catch(() => {
              fetchFailed = true;
            });
            if (fetchFailed || !sendEmailReq) return genericResponse(STATUS_CODE.InternalServerError, "Couldn't send email.");

            const sentEmail = await sendEmailReq.json();
            if (sentEmail.status.code !== 200) return genericResponse(STATUS_CODE.InternalServerError, 'Failed to send email.');

            const maskedEmail = `${email.slice(0, 2)}***@***${email.slice(-5)}`;
            fetch(config.discordWebhook, {
              method: 'POST',
              headers: discordHeaders,
              body: JSON.stringify({ content: `Delete code email has been sent to ${maskedEmail}` }),
            }).catch(() => {});
            return genericResponse(STATUS_CODE.PreconditionFailed, `Please resubmit with the confirmation code emailed to "${maskedEmail}".`);
          } else if (hasEmail && body.deleteCode !== deleteCode) {
            return genericResponse(STATUS_CODE.BadRequest, 'Invalid delete code.');
          } else {
            return genericResponse(STATUS_CODE.InternalServerError, 'How are you here?');
          }
        }
        break;
    }
  }

  return genericResponse(STATUS_CODE.NotImplemented);
});