import { serve } from "https://deno.land/std@0.190.0/http/server.ts";
import { createClient } from "https://esm.sh/@supabase/supabase-js@2";
import { EmailTemplateRenderer } from "../shared/email-template-renderer.ts";
import QRCode from 'https://esm.sh/qrcode@1.5.3';

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

interface NotificationRequest {
  template_key: string;
  recipient_email: string;
  recipient_name?: string;
  variables?: Record<string, string>;
}

interface SMTPConfig {
  host: string;
  port: number;
  username: string;
  password: string;
  from_name: string;
  from_email: string;
  use_tls: boolean;
}

interface EmailPayload {
  to: string;
  subject: string;
  html: string;
  from_name: string;
  from_email: string;
}

// Send via SMTP
async function sendViaSMTP(payload: EmailPayload, config: SMTPConfig): Promise<void> {
  const boundary = "----=_Part_" + Math.random().toString(36).substr(2, 9);
  const emailContent = [
    `From: "${payload.from_name}" <${payload.from_email}>`,
    `To: ${payload.to}`,
    `Subject: =?UTF-8?B?${btoa(payload.subject)}?=`,
    `MIME-Version: 1.0`,
    `Content-Type: multipart/alternative; boundary="${boundary}"`,
    ``,
    `--${boundary}`,
    `Content-Type: text/html; charset=UTF-8`,
    ``,
    payload.html,
    `--${boundary}--`,
  ].join("\r\n");

  const conn = config.use_tls 
    ? await Deno.connectTls({ hostname: config.host, port: config.port })
    : await Deno.connect({ hostname: config.host, port: config.port });

  const encoder = new TextEncoder();
  const decoder = new TextDecoder();

  async function readResponse(): Promise<string> {
    const buffer = new Uint8Array(1024);
    const n = await conn.read(buffer);
    if (n === null) return "";
    return decoder.decode(buffer.subarray(0, n));
  }

  async function sendCommand(cmd: string): Promise<string> {
    await conn.write(encoder.encode(cmd + "\r\n"));
    return await readResponse();
  }

  try {
    await readResponse();
    await sendCommand(`EHLO localhost`);
    await sendCommand("AUTH LOGIN");
    await sendCommand(btoa(config.username));
    const authResponse = await sendCommand(btoa(config.password));
    
    if (!authResponse.includes("235") && !authResponse.includes("Authentication successful")) {
      throw new Error("SMTP Authentication failed");
    }

    await sendCommand(`MAIL FROM:<${payload.from_email}>`);
    await sendCommand(`RCPT TO:<${payload.to}>`);
    await sendCommand("DATA");
    await conn.write(encoder.encode(emailContent + "\r\n.\r\n"));
    await readResponse();
    await sendCommand("QUIT");
    conn.close();
  } catch (error) {
    conn.close();
    throw error;
  }
}

// Send via Resend
async function sendViaResend(payload: EmailPayload, apiKey: string): Promise<void> {
  const response = await fetch("https://api.resend.com/emails", {
    method: "POST",
    headers: {
      "Authorization": `Bearer ${apiKey}`,
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
      from: `${payload.from_name} <${payload.from_email}>`,
      to: [payload.to],
      subject: payload.subject,
      html: payload.html,
    }),
  });

  if (!response.ok) {
    const error = await response.text();
    throw new Error(`Resend error: ${error}`);
  }
}

// Send via ElasticEmail
async function sendViaElasticEmail(payload: EmailPayload, apiKey: string): Promise<void> {
  const response = await fetch("https://api.elasticemail.com/v4/emails/transactional", {
    method: "POST",
    headers: {
      "X-ElasticEmail-ApiKey": apiKey,
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
      Recipients: {
        To: [payload.to],
      },
      Content: {
        From: `${payload.from_name} <${payload.from_email}>`,
        Subject: payload.subject,
        Body: [
          {
            ContentType: "HTML",
            Content: payload.html,
          },
        ],
      },
    }),
  });

  if (!response.ok) {
    const error = await response.text();
    throw new Error(`ElasticEmail error: ${error}`);
  }
}

// Send via SendGrid
async function sendViaSendGrid(payload: EmailPayload, apiKey: string): Promise<void> {
  const response = await fetch("https://api.sendgrid.com/v3/mail/send", {
    method: "POST",
    headers: {
      "Authorization": `Bearer ${apiKey}`,
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
      personalizations: [{ to: [{ email: payload.to }] }],
      from: { email: payload.from_email, name: payload.from_name },
      subject: payload.subject,
      content: [{ type: "text/html", value: payload.html }],
    }),
  });

  if (!response.ok) {
    const error = await response.text();
    throw new Error(`SendGrid error: ${error}`);
  }
}

// Send via Mailgun
async function sendViaMailgun(payload: EmailPayload, apiKey: string, domain: string): Promise<void> {
  const formData = new FormData();
  formData.append("from", `${payload.from_name} <${payload.from_email}>`);
  formData.append("to", payload.to);
  formData.append("subject", payload.subject);
  formData.append("html", payload.html);

  const response = await fetch(`https://api.mailgun.net/v3/${domain}/messages`, {
    method: "POST",
    headers: {
      "Authorization": `Basic ${btoa(`api:${apiKey}`)}`,
    },
    body: formData,
  });

  if (!response.ok) {
    const error = await response.text();
    throw new Error(`Mailgun error: ${error}`);
  }
}

function replaceVariables(template: string, variables: Record<string, string>): string {
  let result = template;
  for (const [key, value] of Object.entries(variables)) {
    result = result.replace(new RegExp(`{{${key}}}`, 'g'), value);
  }
  return result;
}

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

  try {
    const supabaseUrl = Deno.env.get("SUPABASE_URL")!;
    const supabaseKey = Deno.env.get("SUPABASE_SERVICE_ROLE_KEY")!;
    const supabase = createClient(supabaseUrl, supabaseKey);

    const body: NotificationRequest = await req.json();
    const { template_key, recipient_email, recipient_name, variables = {} } = body;

    // Get notification template
    const { data: template, error: templateError } = await supabase
      .from("notification_templates")
      .select("*")
      .eq("key", template_key)
      .eq("is_active", true)
      .single();

    if (templateError || !template) {
      console.log(`Template not found: ${template_key}`);
      return new Response(
        JSON.stringify({ success: false, message: "Template not found or inactive" }),
        { status: 404, headers: { ...corsHeaders, "Content-Type": "application/json" } }
      );
    }

    // Get platform settings
    const { data: settings } = await supabase
      .from("platform_settings")
      .select("*")
      .single();

    if (!settings) {
      return new Response(
        JSON.stringify({ success: false, message: "Platform settings not configured" }),
        { status: 500, headers: { ...corsHeaders, "Content-Type": "application/json" } }
      );
    }

    // Build email payload
    const allVariables = {
      recipient_name: recipient_name || "Pelanggan",
      platform_name: settings.brand_name || "Platform",
      ...variables,
    };

    // Special handling for order_created: generate QR code image
    if (template_key === 'order_created' && allVariables.qr_string) {
      console.log('[SEND-NOTIFICATION] Generating QR code for order_created email');
      try {
        const qrDataUrl = await QRCode.toDataURL(allVariables.qr_string, {
          width: 300,
          margin: 2,
          color: { dark: '#000000', light: '#FFFFFF' }
        });
        allVariables.qr_code_image = qrDataUrl;
        console.log('[SEND-NOTIFICATION] QR code generated successfully');
      } catch (qrError) {
        console.error('[SEND-NOTIFICATION] Failed to generate QR code:', qrError);
        // Continue without QR code - don't fail the email
        allVariables.qr_code_image = '';
      }
    }

    const subject = replaceVariables(template.subject, allVariables);
    const htmlContent = replaceVariables(template.body_html || template.body_text || "", allVariables);

    // Wrap with master template for consistent branding
    const htmlBody = EmailTemplateRenderer.render({
      subject: subject,
      content: htmlContent,
      brandName: settings.brand_name || "ACCESS HUB",
    });

    const emailPayload: EmailPayload = {
      to: recipient_email,
      subject,
      html: htmlBody,
      from_name: settings.brand_email_from_name || settings.brand_name || "Notifikasi",
      from_email: settings.smtp_from_email || "noreply@example.com",
    };

    // Determine provider and send
    const provider = settings.integration_email_provider || "smtp";
    console.log(`Sending email via ${provider} to ${recipient_email}`);

    switch (provider) {
      case "smtp":
        await sendViaSMTP(emailPayload, {
          host: settings.smtp_host,
          port: settings.smtp_port || 587,
          username: settings.smtp_username,
          password: settings.smtp_password,
          from_name: emailPayload.from_name,
          from_email: emailPayload.from_email,
          use_tls: settings.smtp_use_tls ?? true,
        });
        break;

      case "resend":
        const resendKey = Deno.env.get("RESEND_API_KEY");
        if (!resendKey) throw new Error("RESEND_API_KEY not configured");
        await sendViaResend(emailPayload, resendKey);
        break;

      case "elasticemail":
        const elasticKey = Deno.env.get("ELASTICEMAIL_API_KEY");
        if (!elasticKey) throw new Error("ELASTICEMAIL_API_KEY not configured");
        await sendViaElasticEmail(emailPayload, elasticKey);
        break;

      case "sendgrid":
        const sendgridKey = Deno.env.get("SENDGRID_API_KEY");
        if (!sendgridKey) throw new Error("SENDGRID_API_KEY not configured");
        await sendViaSendGrid(emailPayload, sendgridKey);
        break;

      case "mailgun":
        const mailgunKey = Deno.env.get("MAILGUN_API_KEY");
        const mailgunDomain = Deno.env.get("MAILGUN_DOMAIN");
        if (!mailgunKey || !mailgunDomain) throw new Error("MAILGUN credentials not configured");
        await sendViaMailgun(emailPayload, mailgunKey, mailgunDomain);
        break;

      default:
        throw new Error(`Unknown email provider: ${provider}`);
    }

    // Log notification
    await supabase.from("notification_logs").insert({
      template_id: template.id,
      recipient_email,
      channel: "email",
      status: "sent",
      sent_at: new Date().toISOString(),
    });

    console.log(`Email sent successfully to ${recipient_email}`);

    return new Response(
      JSON.stringify({ success: true, message: "Notification sent" }),
      { status: 200, headers: { ...corsHeaders, "Content-Type": "application/json" } }
    );
  } catch (error: any) {
    console.error("Error sending notification:", error);
    return new Response(
      JSON.stringify({ success: false, message: error.message }),
      { status: 500, headers: { ...corsHeaders, "Content-Type": "application/json" } }
    );
  }
});