import { serve } from "https://deno.land/std@0.190.0/http/server.ts";
import { createClient } from "https://esm.sh/@supabase/supabase-js@2";

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

interface SendOTPRequest {
  user_id: string;
  email: string;
}

// Generate 6-digit OTP code
function generateOTP(): string {
  return Math.floor(100000 + Math.random() * 900000).toString();
}

serve(async (req: Request) => {
  if (req.method === "OPTIONS") {
    return new Response(null, { headers: corsHeaders });
  }

  try {
    const { user_id, email }: SendOTPRequest = await req.json();

    // Validate required fields
    if (!user_id || !email) {
      return new Response(
        JSON.stringify({ success: false, message: "Missing required fields: user_id, email" }),
        { status: 400, headers: { ...corsHeaders, "Content-Type": "application/json" } }
      );
    }

    // Basic email validation
    const emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
    if (!emailRegex.test(email)) {
      return new Response(
        JSON.stringify({ success: false, message: "Invalid email format" }),
        { status: 400, headers: { ...corsHeaders, "Content-Type": "application/json" } }
      );
    }

    // Initialize Supabase client with service role
    const supabaseUrl = Deno.env.get('SUPABASE_URL')!;
    const supabaseServiceKey = Deno.env.get('SUPABASE_SERVICE_ROLE_KEY')!;
    const supabase = createClient(supabaseUrl, supabaseServiceKey);

    // Generate OTP code
    const otpCode = generateOTP();
    const expiresAt = new Date(Date.now() + 15 * 60 * 1000); // 15 minutes from now

    console.log(`Generating OTP for user ${user_id}, email ${email}`);

    // Store OTP in database
    const { error: otpError } = await supabase
      .from('auth_otps')
      .insert({
        user_id,
        email,
        otp_code: otpCode,
        expires_at: expiresAt.toISOString(),
      });

    if (otpError) {
      console.error('Error storing OTP:', otpError);
      throw new Error(`Failed to store OTP: ${otpError.message}`);
    }

    // Get notification settings
    const { data: settings, error: settingsError } = await supabase
      .from('notification_settings')
      .select('*')
      .single();

    if (settingsError || !settings) {
      console.error('Error fetching notification settings:', settingsError);
      throw new Error('Notification settings not configured');
    }

    // Get email template
    const { data: template, error: templateError } = await supabase
      .from('notification_templates')
      .select('*')
      .eq('template_key', 'auth_email_verification')
      .single();

    if (templateError || !template) {
      console.error('Error fetching email template:', templateError);
      throw new Error('Email template not found. Please create template with key: auth_email_verification');
    }

    // Get user data from auth.users
    const { data: { user }, error: userError } = await supabase.auth.admin.getUserById(user_id);

    if (userError || !user) {
      console.error('Error fetching user:', userError);
      throw new Error('User not found');
    }

    // Prepare template variables
    const templateVars = {
      platform_name: settings.platform_name || 'Platform',
      nama: user.user_metadata?.name || user.email || 'Pengguna',
      email: email,
      otp_code: otpCode,
      expiry_minutes: '15',
      confirmation_link: '', // Not used for OTP
      year: new Date().getFullYear().toString(),
    };

    // Process shortcodes in subject
    let subject = template.subject;
    Object.entries(templateVars).forEach(([key, value]) => {
      subject = subject.replace(new RegExp(`{${key}}`, 'g'), value);
    });

    // Process shortcodes in HTML body
    let htmlBody = template.html_content;
    Object.entries(templateVars).forEach(([key, value]) => {
      htmlBody = htmlBody.replace(new RegExp(`{${key}}`, 'g'), value);
    });

    // Send email via send-email-v2
    console.log(`Sending OTP email to ${email}`);

    const emailResponse = await fetch(`${supabaseUrl}/functions/v1/send-email-v2`, {
      method: 'POST',
      headers: {
        'Authorization': `Bearer ${supabaseServiceKey}`,
        'Content-Type': 'application/json',
      },
      body: JSON.stringify({
        to: email,
        api_token: settings.mailketing_api_token,
        from_name: settings.from_name,
        from_email: settings.from_email,
        subject: subject,
        html_body: htmlBody,
      }),
    });

    if (!emailResponse.ok) {
      const errorText = await emailResponse.text();
      console.error('Email send error:', emailResponse.status, errorText);
      throw new Error(`Failed to send email: ${emailResponse.status} ${errorText}`);
    }

    const emailResult = await emailResponse.json();
    console.log('Email sent successfully:', emailResult);

    // Log notification
    await supabase
      .from('notification_logs')
      .insert({
        user_id,
        email: email,
        notification_type: 'auth_email_verification',
        status: 'sent',
        provider: 'mailketing',
        error_message: null,
      });

    return new Response(
      JSON.stringify({
        success: true,
        message: 'OTP sent successfully'
      }),
      { status: 200, headers: { ...corsHeaders, "Content-Type": "application/json" } }
    );

  } catch (error: any) {
    console.error("Error sending OTP:", error);

    // Try to log error notification
    try {
      const supabaseUrl = Deno.env.get('SUPABASE_URL')!;
      const supabaseServiceKey = Deno.env.get('SUPABASE_SERVICE_ROLE_KEY')!;
      const supabase = createClient(supabaseUrl, supabaseServiceKey);

      await supabase
        .from('notification_logs')
        .insert({
          user_id: null,
          email: null,
          notification_type: 'auth_email_verification',
          status: 'failed',
          provider: 'mailketing',
          error_message: error.message || 'Unknown error',
        });
    } catch (logError) {
      console.error('Failed to log error:', logError);
    }

    return new Response(
      JSON.stringify({
        success: false,
        message: error.message || "Failed to send OTP"
      }),
      { status: 500, headers: { ...corsHeaders, "Content-Type": "application/json" } }
    );
  }
});