const { TrackingToken, Company, MailTemplate } = require('../models');
const { generateTrackingToken } = require('../utils/tokenGenerator');
const mailService = require('./mail.service');
const logger = require('../config/logger');

class TokenService {
  async createToken(data) {
    const { company_id, target_email, employee_name, template_type, from_name } = data;

    // Generate unique token
    let token = generateTrackingToken();
    let isUnique = false;
    let attempts = 0;

    // Ensure token is unique
    while (!isUnique && attempts < 5) {
      const existing = await TrackingToken.findOne({ where: { token } });
      if (!existing) {
        isUnique = true;
      } else {
        token = generateTrackingToken();
        attempts++;
      }
    }

    if (!isUnique) {
      throw new Error('Failed to generate unique token');
    }

    // Get company and template
    const company = await Company.findByPk(company_id);
    if (!company) {
      throw new Error('Company not found');
    }

    const template = await MailTemplate.findOne({ where: { template_type } });
    if (!template) {
      throw new Error('Mail template not found');
    }

    // Create tracking token
    const trackingToken = await TrackingToken.create({
      token,
      company_id,
      target_email,
      employee_name,
      template_type,
      from_name: from_name || null,
      mail_subject: template.subject_template.replace('{{company_name}}', company.name),
    });

    // Update company stats
    await company.increment('total_tokens');

    logger.info(`Token created: ${token} for ${target_email}`);

    return trackingToken;
  }

  async sendMail(tokenId) {
    const token = await TrackingToken.findByPk(tokenId, {
      include: [{ model: Company, as: 'company' }],
    });

    if (!token) {
      throw new Error('Token not found');
    }

    if (token.mail_sent) {
      throw new Error('Mail already sent for this token');
    }

    // Get mail template
    const template = await MailTemplate.findOne({
      where: { template_type: token.template_type },
    });

    if (!template) {
      throw new Error('Mail template not found');
    }

    // Get base URL from settings or env
    const { Settings } = require('../models');
    const baseUrlSetting = await Settings.findOne({ where: { key: 'base_url' } });
    const baseUrl = baseUrlSetting?.value || process.env.BASE_URL || 'http://localhost:3000';

    // Prepare template data
    const trackingUrl = `${baseUrl}/t/${token.token}`;
    const currentDate = new Date().toLocaleDateString('tr-TR', {
      year: 'numeric',
      month: 'long',
      day: 'numeric',
    });
    const currentYear = new Date().getFullYear();

    const templateData = {
      company_name: token.company.name,
      employee_name: token.employee_name,
      tracking_url: trackingUrl,
      current_date: currentDate,
      current_year: currentYear,
    };

    // Render mail body
    const htmlBody = mailService.renderTemplate(template.body_html, templateData);
    const subject = mailService.renderTemplate(template.subject_template, templateData);

    // Send mail with custom from_name if provided
    await mailService.sendMail(token.target_email, subject, htmlBody, token.from_name);

    // Update token
    await token.update({
      mail_sent: true,
      sent_at: new Date(),
    });

    logger.info(`Mail sent for token: ${token.token} to ${token.target_email}`);

    return token;
  }

  async updateCompanyStats(companyId) {
    const company = await Company.findByPk(companyId);
    if (!company) return;

    // Count tokens
    const totalTokens = await TrackingToken.count({
      where: { company_id: companyId },
    });

    const clickedTokens = await TrackingToken.count({
      where: { company_id: companyId, clicked: true },
    });

    const totalClicks = await TrackingToken.sum('click_count', {
      where: { company_id: companyId },
    });

    const clickRate = totalTokens > 0 ? ((clickedTokens / totalTokens) * 100).toFixed(2) : 0;

    await company.update({
      total_tokens: totalTokens,
      total_clicks: totalClicks || 0,
      click_rate: clickRate,
    });

    logger.info(`Company stats updated for: ${company.name}`);
  }
}

module.exports = new TokenService();