import { serve } from "https://deno.land/std@0.190.0/http/server.ts";
import { startRequest, endRequest, edgeLogger } from "../_shared/logger.ts";

const corsHeaders = {
  'Access-Control-Allow-Origin': '*',
  'Access-Control-Allow-Headers': 'authorization, x-client-info, apikey, content-type, x-request-id',
};

// Comprehensive list of disposable email domains
const DISPOSABLE_DOMAINS = new Set([
  // Popular disposable email services
  'tempmail.com', 'temp-mail.org', 'temp-mail.io', 'temp-mail.de',
  '10minutemail.com', '10minutemail.net', '10minemail.com',
  'guerrillamail.com', 'guerrillamail.net', 'guerrillamailblock.com',
  'mailinator.com', 'mailinator.net', 'mailinator2.com',
  'throwaway.email', 'throwemail.com', 'throwawaymail.com',
  'yopmail.com', 'yopmail.fr', 'yopmail.net',
  'maildrop.cc', 'mailnesia.com', 'trashmail.com',
  'fakeinbox.com', 'fakemail.net', 'fakemailgenerator.com',
  'getnada.com', 'getairmail.com', 'dispostable.com',
  'mintemail.com', 'mytemp.email', 'mohmal.com',
  'sharklasers.com', 'grr.la', 'guerrillamail.biz',
  'spam4.me', 'tempinbox.com', 'tempr.email',
  'emailondeck.com', 'mailcatch.com', 'mailexpire.com',
  'mailforspam.com', 'mailfreeonline.com', 'mailin8r.com',
  'mailmoat.com', 'mailnull.com', 'mailsac.com',
  'mailscrap.com', 'mailslite.com', 'mailtemp.info',
  'mailtothis.com', 'mailzi.ru', 'mytrashmail.com',
  'no-spam.ws', 'noclickemail.com', 'nodezine.com',
  'nospam.ze.tc', 'nospamfor.us', 'nowmymail.com',
  'objectmail.com', 'obobbo.com', 'oneoffemail.com',
  'onewaymail.com', 'online.ms', 'oopi.org',
  'ordinaryamerican.net', 'otherinbox.com', 'owlpic.com',
  'pancakemail.com', 'pjjkp.com', 'plexolan.de',
  'poofy.org', 'pookmail.com', 'privacy.net',
  'proxymail.eu', 'prtnx.com', 'putthisinyourspamdatabase.com',
  'quickinbox.com', 'rcpt.at', 'recode.me',
  'recursor.net', 'regbypass.com', 'regspaces.tk',
  'rklips.com', 'rmqkr.net', 'robertspcrepair.com',
  'royal.net', 'ruffrey.com', 's0ny.net',
  'safersignup.de', 'safetymail.info', 'safetypost.de',
  'sandelf.de', 'saynotospams.com', 'schafmail.de',
  'schrott-email.de', 'secretemail.de', 'secure-mail.biz',
  'senseless-entertainment.com', 'services391.com', 'sharklasers.com',
  'shiftmail.com', 'shippingterms.org', 'showslow.de',
  'sibmail.com', 'sinnlos-mail.de', 'slapsfromlastnight.com',
  'slaskpost.se', 'smashmail.de', 'smellfear.com',
  'snakemail.com', 'sneakemail.com', 'sneakmail.de',
  'snkmail.com', 'sofimail.com', 'solvemail.info',
  'sogetthis.com', 'soodonims.com', 'spam.la',
  'spam.su', 'spamail.de', 'spamarrest.com',
  'spambob.com', 'spambog.com', 'spambog.de',
  'spambox.us', 'spamcannon.com', 'spamcannon.net',
  'spamcero.com', 'spamcon.org', 'spamcorptastic.com',
  'spamcowboy.com', 'spamcowboy.net', 'spamcowboy.org',
  'spamday.com', 'spamex.com', 'spamfree24.com',
  'spamfree24.de', 'spamfree24.org', 'spamgourmet.com',
  'spamherelots.com', 'spamhereplease.com', 'spamhole.com',
  'spamify.com', 'spaminator.de', 'spamkill.info',
]);

interface ValidateEmailRequest {
  email: string;
}

interface ValidationResult {
  valid: boolean;
  reason?: string;
  suggestions?: string[];
}

const handler = async (req: Request): Promise<Response> => {
  // Handle CORS preflight requests
  if (req.method === 'OPTIONS') {
    return new Response(null, { headers: corsHeaders });
  }

  const tracking = startRequest('validate-email');

  try {
    const { email }: ValidateEmailRequest = await req.json();

    if (!email || typeof email !== 'string') {
      endRequest(tracking, 400, 'Email address is required');
      
      return new Response(
        JSON.stringify({
          valid: false,
          reason: 'Email address is required',
          requestId: tracking.requestId
        } as ValidationResult),
        {
          status: 400,
          headers: { 
            ...corsHeaders, 
            'Content-Type': 'application/json',
            'X-Request-ID': tracking.requestId
          }
        }
      );
    }

    // Basic email format validation
    const emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
    if (!emailRegex.test(email)) {
      endRequest(tracking, 400, 'Invalid email format');
      
      return new Response(
        JSON.stringify({
          valid: false,
          reason: 'Invalid email format',
          requestId: tracking.requestId
        } as ValidationResult),
        {
          status: 400,
          headers: { 
            ...corsHeaders, 
            'Content-Type': 'application/json',
            'X-Request-ID': tracking.requestId
          }
        }
      );
    }

    // Extract domain
    const domain = email.split('@')[1].toLowerCase();

    // Check if domain is disposable
    if (DISPOSABLE_DOMAINS.has(domain)) {
      edgeLogger.info('Blocked disposable email domain', {
        domain,
        requestId: tracking.requestId
      });
      
      endRequest(tracking, 400, 'Disposable email domain blocked');
      
      return new Response(
        JSON.stringify({
          valid: false,
          reason: 'Disposable email addresses are not allowed. Please use a permanent email address.',
          suggestions: [
            'Use a personal email (Gmail, Outlook, Yahoo, etc.)',
            'Use your work or school email address',
            'Use an email from your own domain'
          ],
          requestId: tracking.requestId
        } as ValidationResult),
        {
          status: 400,
          headers: { 
            ...corsHeaders, 
            'Content-Type': 'application/json',
            'X-Request-ID': tracking.requestId
          }
        }
      );
    }

    // Email is valid
    edgeLogger.info('Email validated successfully', {
      email,
      requestId: tracking.requestId
    });
    
    endRequest(tracking, 200);
    
    return new Response(
      JSON.stringify({
        valid: true,
        requestId: tracking.requestId
      } as ValidationResult),
      {
        status: 200,
        headers: { 
          ...corsHeaders, 
          'Content-Type': 'application/json',
          'X-Request-ID': tracking.requestId
        }
      }
    );

  } catch (error) {
    const errorMessage = error instanceof Error ? error.message : String(error);
    edgeLogger.error('Error in validate-email function', {
      error: errorMessage,
      requestId: tracking.requestId
    });
    
    endRequest(tracking, 500, error.message);
    
    return new Response(
      JSON.stringify({
        valid: false,
        reason: 'Internal server error during email validation',
        requestId: tracking.requestId
      } as ValidationResult),
      {
        status: 500,
        headers: { 
          ...corsHeaders, 
          'Content-Type': 'application/json',
          'X-Request-ID': tracking.requestId
        }
      }
    );
  }
};

serve(handler);