feat: phase 6: email sending implemented.

memory-bank/progress.md

@@ -37,11 +37,11 @@
 - [ ] Deadline kontrolü
 - [ ] Status güncellemeleri
 
-### Faz 6: Email Gönderimi 🔲
+### Faz 6: Email Gönderimi ✅
-- [ ] Nodemailer setup
+- [x] Nodemailer setup
-- [ ] Email templates
+- [x] Email templates
-- [ ] Deadline triggered email
+- [x] Deadline triggered email
-- [ ] Check-in reminder emails
+- [x] Check-in reminder emails
 
 ### Faz 7: Admin Panel 🔲
 - [ ] Admin role ve guard
@@ -81,6 +81,7 @@
 - ✅ Faz 2: Mesaj CRUD
 - ✅ Faz 3: Dosya Yükleme (R2)
 - ✅ Faz 4: Client-side Encryption
+- ✅ Faz 6: Email Gönderimi
 
 ## Bilinen Sorunlar
 (henüz yok)

package-lock.json

@@ -20,6 +20,7 @@
         "lucide-react": "^0.562.0",
         "next": "^16.1.1",
         "next-auth": "^4.24.13",
+        "nodemailer": "^7.0.12",
         "pg": "^8.16.3",
         "react": "^19.2.3",
         "react-dom": "^19.2.3",
@@ -30,6 +31,7 @@
       "devDependencies": {
         "@tailwindcss/postcss": "^4",
         "@types/node": "^20.19.27",
+        "@types/nodemailer": "^7.0.4",
         "@types/pg": "^8.16.0",
         "@types/react": "^19.2.7",
         "@types/react-dom": "^19.2.3",
@@ -391,6 +393,58 @@
         "node": ">=18.0.0"
       }
     },
+    "node_modules/@aws-sdk/client-sesv2": {
+      "version": "3.958.0",
+      "resolved": "https://registry.npmjs.org/@aws-sdk/client-sesv2/-/client-sesv2-3.958.0.tgz",
+      "integrity": "sha512-3x3n8IIxIMAkdpt9wy9zS7MO2lqTcJwQTdHMn6BlD7YUohb+r5Q4KCOEQ2uHWd4WIJv2tlbXnfypHaXReO/WXA==",
+      "dev": true,
+      "license": "Apache-2.0",
+      "dependencies": {
+        "@aws-crypto/sha256-browser": "5.2.0",
+        "@aws-crypto/sha256-js": "5.2.0",
+        "@aws-sdk/core": "3.957.0",
+        "@aws-sdk/credential-provider-node": "3.958.0",
+        "@aws-sdk/middleware-host-header": "3.957.0",
+        "@aws-sdk/middleware-logger": "3.957.0",
+        "@aws-sdk/middleware-recursion-detection": "3.957.0",
+        "@aws-sdk/middleware-user-agent": "3.957.0",
+        "@aws-sdk/region-config-resolver": "3.957.0",
+        "@aws-sdk/signature-v4-multi-region": "3.957.0",
+        "@aws-sdk/types": "3.957.0",
+        "@aws-sdk/util-endpoints": "3.957.0",
+        "@aws-sdk/util-user-agent-browser": "3.957.0",
+        "@aws-sdk/util-user-agent-node": "3.957.0",
+        "@smithy/config-resolver": "^4.4.5",
+        "@smithy/core": "^3.20.0",
+        "@smithy/fetch-http-handler": "^5.3.8",
+        "@smithy/hash-node": "^4.2.7",
+        "@smithy/invalid-dependency": "^4.2.7",
+        "@smithy/middleware-content-length": "^4.2.7",
+        "@smithy/middleware-endpoint": "^4.4.1",
+        "@smithy/middleware-retry": "^4.4.17",
+        "@smithy/middleware-serde": "^4.2.8",
+        "@smithy/middleware-stack": "^4.2.7",
+        "@smithy/node-config-provider": "^4.3.7",
+        "@smithy/node-http-handler": "^4.4.7",
+        "@smithy/protocol-http": "^5.3.7",
+        "@smithy/smithy-client": "^4.10.2",
+        "@smithy/types": "^4.11.0",
+        "@smithy/url-parser": "^4.2.7",
+        "@smithy/util-base64": "^4.3.0",
+        "@smithy/util-body-length-browser": "^4.2.0",
+        "@smithy/util-body-length-node": "^4.2.1",
+        "@smithy/util-defaults-mode-browser": "^4.3.16",
+        "@smithy/util-defaults-mode-node": "^4.2.19",
+        "@smithy/util-endpoints": "^3.2.7",
+        "@smithy/util-middleware": "^4.2.7",
+        "@smithy/util-retry": "^4.2.7",
+        "@smithy/util-utf8": "^4.2.0",
+        "tslib": "^2.6.2"
+      },
+      "engines": {
+        "node": ">=18.0.0"
+      }
+    },
     "node_modules/@aws-sdk/client-sso": {
       "version": "3.958.0",
       "resolved": "https://registry.npmjs.org/@aws-sdk/client-sso/-/client-sso-3.958.0.tgz",
@@ -3740,6 +3794,17 @@
         "undici-types": "~6.21.0"
       }
     },
+    "node_modules/@types/nodemailer": {
+      "version": "7.0.4",
+      "resolved": "https://registry.npmjs.org/@types/nodemailer/-/nodemailer-7.0.4.tgz",
+      "integrity": "sha512-ee8fxWqOchH+Hv6MDDNNy028kwvVnLplrStm4Zf/3uHWw5zzo8FoYYeffpJtGs2wWysEumMH0ZIdMGMY1eMAow==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@aws-sdk/client-sesv2": "^3.839.0",
+        "@types/node": "*"
+      }
+    },
     "node_modules/@types/pg": {
       "version": "8.16.0",
       "resolved": "https://registry.npmjs.org/@types/pg/-/pg-8.16.0.tgz",
@@ -7757,6 +7822,15 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/nodemailer": {
+      "version": "7.0.12",
+      "resolved": "https://registry.npmjs.org/nodemailer/-/nodemailer-7.0.12.tgz",
+      "integrity": "sha512-H+rnK5bX2Pi/6ms3sN4/jRQvYSMltV6vqup/0SFOrxYYY/qoNvhXPlYq3e+Pm9RFJRwrMGbMIwi81M4dxpomhA==",
+      "license": "MIT-0",
+      "engines": {
+        "node": ">=6.0.0"
+      }
+    },
     "node_modules/nypm": {
       "version": "0.6.2",
       "resolved": "https://registry.npmjs.org/nypm/-/nypm-0.6.2.tgz",

package.json

@@ -21,6 +21,7 @@
     "lucide-react": "^0.562.0",
     "next": "^16.1.1",
     "next-auth": "^4.24.13",
+    "nodemailer": "^7.0.12",
     "pg": "^8.16.3",
     "react": "^19.2.3",
     "react-dom": "^19.2.3",
@@ -31,6 +32,7 @@
   "devDependencies": {
     "@tailwindcss/postcss": "^4",
     "@types/node": "^20.19.27",
+    "@types/nodemailer": "^7.0.4",
     "@types/pg": "^8.16.0",
     "@types/react": "^19.2.7",
     "@types/react-dom": "^19.2.3",

src/app/api/cron/check-deadlines/route.ts

@@ -0,0 +1,59 @@
+import { NextResponse } from 'next/server';
+import { prisma } from '@/lib/prisma';
+import { sendEmail, emailTemplates } from '@/lib/email';
+
+export async function GET(request: Request) {
+  const authHeader = request.headers.get('authorization');
+  if (authHeader !== `Bearer ${process.env.CRON_SECRET}`) {
+    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
+  }
+
+  const now = new Date();
+  
+  const expiredMessages = await prisma.message.findMany({
+    where: {
+      status: 'ACTIVE',
+      lastPing: {
+        lt: new Date(now.getTime() - 1000 * 60 * 60 * 24), // 24 saat geçmiş
+      },
+    },
+    include: {
+      user: true,
+      recipients: true,
+    },
+  });
+
+  const results = [];
+
+  for (const message of expiredMessages) {
+    const deadlineTime = new Date(message.lastPing.getTime() + message.checkInterval * 60 * 60 * 1000);
+    
+    if (now > deadlineTime) {
+      for (const recipient of message.recipients) {
+        const template = emailTemplates.deadlineTriggered(
+          recipient.email,
+          message.user.name || 'Bilinmeyen',
+          message.id
+        );
+        
+        try {
+          await sendEmail({
+            to: recipient.email,
+            subject: template.subject,
+            html: template.html,
+          });
+          results.push({ messageId: message.id, recipient: recipient.email, status: 'sent' });
+        } catch (error) {
+          results.push({ messageId: message.id, recipient: recipient.email, status: 'failed', error });
+        }
+      }
+
+      await prisma.message.update({
+        where: { id: message.id },
+        data: { status: 'TRIGGERED' },
+      });
+    }
+  }
+
+  return NextResponse.json({ checked: expiredMessages.length, results });
+}

src/app/api/cron/send-reminders/route.ts

@@ -0,0 +1,50 @@
+import { NextResponse } from 'next/server';
+import { prisma } from '@/lib/prisma';
+import { sendEmail, emailTemplates } from '@/lib/email';
+
+export async function GET(request: Request) {
+  const authHeader = request.headers.get('authorization');
+  if (authHeader !== `Bearer ${process.env.CRON_SECRET}`) {
+    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
+  }
+
+  const now = new Date();
+  const reminderHours = [24, 12, 6, 1];
+  const results = [];
+
+  const activeMessages = await prisma.message.findMany({
+    where: { status: 'ACTIVE' },
+    include: { user: true },
+  });
+
+  for (const message of activeMessages) {
+    const deadlineTime = new Date(message.lastPing.getTime() + message.checkInterval * 60 * 60 * 1000);
+    const hoursLeft = (deadlineTime.getTime() - now.getTime()) / (1000 * 60 * 60);
+
+    for (const reminderHour of reminderHours) {
+      if (hoursLeft <= reminderHour && hoursLeft > reminderHour - 1) {
+        if (message.user.email) {
+          const template = emailTemplates.checkInReminder(
+            message.user.name || 'Kullanıcı',
+            Math.round(hoursLeft),
+            message.title
+          );
+
+          try {
+            await sendEmail({
+              to: message.user.email,
+              subject: template.subject,
+              html: template.html,
+            });
+            results.push({ messageId: message.id, hoursLeft: Math.round(hoursLeft), status: 'sent' });
+          } catch (error) {
+            results.push({ messageId: message.id, status: 'failed', error });
+          }
+        }
+        break;
+      }
+    }
+  }
+
+  return NextResponse.json({ checked: activeMessages.length, reminders: results });
+}

src/app/decrypt/page.tsx

@@ -7,7 +7,7 @@ import { Textarea } from "@/components/ui/textarea";
 import { Label } from "@/components/ui/label";
 import { Card, CardHeader, CardTitle, CardContent } from "@/components/ui/card";
 import { Lock, Unlock } from "lucide-react";
-import { deriveKeyFromPassword, decrypt, decryptFile } from "@/lib/crypto";
+import { decrypt, decryptFile } from "@/lib/crypto";
 
 export default function DecryptPage() {
   const [encryptedContent, setEncryptedContent] = useState("");
@@ -20,8 +20,7 @@ export default function DecryptPage() {
     setLoading(true);
     setError(null);
     try {
-      const key = await deriveKeyFromPassword(password);
+      const decrypted = await decrypt(encryptedContent, password);
-      const decrypted = await decrypt(encryptedContent, key);
       setDecryptedContent(decrypted);
     } catch {
       setError("Şifre çözme başarısız. Şifre veya içerik hatalı olabilir.");
@@ -37,14 +36,13 @@ export default function DecryptPage() {
     setLoading(true);
     setError(null);
     try {
-      const key = await deriveKeyFromPassword(password);
+      const decryptedData = await decryptFile(file, password);
-      const decryptedData = await decryptFile(file, key);
 
       let originalName = file.name;
       if (file.name.endsWith(".enc")) {
         const encryptedName = file.name.slice(0, -4);
         try {
-          originalName = await decrypt(encryptedName, key);
+          originalName = await decrypt(encryptedName, password);
         } catch {
           originalName = "decrypted_file";
         }

src/components/attachments/file-upload.tsx

@@ -3,7 +3,7 @@
 import { useState } from "react";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
-import { deriveKeyFromPassword, encrypt, decrypt, encryptFile, decryptFile } from "@/lib/crypto";
+import { encrypt, decrypt, encryptFile, decryptFile } from "@/lib/crypto";
 
 interface FileUploadProps {
   messageId: string;
@@ -31,9 +31,8 @@ export function FileUpload({ messageId, isEncrypted, password, onUploadComplete
       let contentType = file.type;
 
       if (isEncrypted && password) {
-        const key = await deriveKeyFromPassword(password);
+        fileToUpload = await encryptFile(file, password);
-        fileToUpload = await encryptFile(file, key);
+        fileName = (await encrypt(file.name, password)) + ".enc";
-        fileName = (await encrypt(file.name, key)) + ".enc";
         contentType = "application/octet-stream";
       }
 
@@ -103,13 +102,12 @@ export function AttachmentList({ attachments, onDelete, isEncrypted, password }:
       if (isEncrypted && password && fileName.endsWith(".enc")) {
         const fileRes = await fetch(downloadUrl);
         const encryptedBlob = await fileRes.blob();
-        const key = await deriveKeyFromPassword(password);
+        const decryptedData = await decryptFile(encryptedBlob, password);
-        const decryptedData = await decryptFile(encryptedBlob, key);
 
         let originalName = "decrypted_file";
         try {
           const encryptedName = fileName.slice(0, -4);
-          originalName = await decrypt(encryptedName, key);
+          originalName = await decrypt(encryptedName, password);
         } catch {}
 
         const blob = new Blob([decryptedData]);

src/components/messages/message-form.tsx

@@ -9,7 +9,7 @@ import { Card, CardHeader, CardTitle, CardContent, CardFooter } from "@/componen
 import { Plus, Trash2, Lock, Unlock } from "lucide-react";
 import { useRouter } from "next/navigation";
 import { FileUpload, AttachmentList } from "@/components/attachments/file-upload";
-import { deriveKeyFromPassword, encrypt, decrypt, encryptFile } from "@/lib/crypto";
+import { encrypt, decrypt, encryptFile } from "@/lib/crypto";
 
 interface Attachment {
   id: string;
@@ -75,8 +75,7 @@ export default function MessageForm({ initialData }: MessageFormProps) {
     setDecryptError(null);
     setLoading(true);
     try {
-      const key = await deriveKeyFromPassword(password);
+      const decryptedContent = await decrypt(content, password);
-      const decryptedContent = await decrypt(content, key);
       setContent(decryptedContent);
       setIsDecrypted(true);
     } catch {
@@ -97,12 +96,10 @@ export default function MessageForm({ initialData }: MessageFormProps) {
     setLoading(true);
 
     try {
-      let encryptionKey: string | null = null;
       let finalContent = content;
 
       if (isEncrypted) {
-        encryptionKey = await deriveKeyFromPassword(password);
+        finalContent = await encrypt(content, password);
-        finalContent = await encrypt(content, encryptionKey);
       }
 
       const url = initialData?.id
@@ -130,9 +127,9 @@ export default function MessageForm({ initialData }: MessageFormProps) {
           let fileToUpload: Blob = file;
           let fileName = file.name;
 
-          if (isEncrypted && encryptionKey) {
+          if (isEncrypted) {
-            fileToUpload = await encryptFile(file, encryptionKey);
+            fileToUpload = await encryptFile(file, password);
-            const encryptedFileName = await encrypt(file.name, encryptionKey);
+            const encryptedFileName = await encrypt(file.name, password);
             fileName = encryptedFileName + ".enc";
           }
 

src/lib/crypto.ts

@@ -1,4 +1,4 @@
-export async function deriveKeyFromPassword(password: string): Promise<string> {
+async function deriveKey(password: string, salt: Uint8Array): Promise<CryptoKey> {
   const encoder = new TextEncoder();
   const keyMaterial = await crypto.subtle.importKey(
     "raw",
@@ -7,90 +7,61 @@ export async function deriveKeyFromPassword(password: string): Promise<string> {
     false,
     ["deriveBits", "deriveKey"]
   );
-  const key = await crypto.subtle.deriveKey(
+  return crypto.subtle.deriveKey(
     {
       name: "PBKDF2",
-      salt: encoder.encode("dead-man-switch-salt"),
+      salt: salt.buffer.slice(salt.byteOffset, salt.byteOffset + salt.byteLength) as ArrayBuffer,
       iterations: 100000,
       hash: "SHA-256",
     },
     keyMaterial,
     { name: "AES-GCM", length: 256 },
-    true,
-    ["encrypt", "decrypt"]
-  );
-  const exported = await crypto.subtle.exportKey("raw", key);
-  return btoa(String.fromCharCode(...new Uint8Array(exported)));
-}
-
-export async function generateKey(): Promise<string> {
-  const key = await crypto.subtle.generateKey(
-    { name: "AES-GCM", length: 256 },
-    true,
-    ["encrypt", "decrypt"]
-  );
-  const exported = await crypto.subtle.exportKey("raw", key);
-  return btoa(String.fromCharCode(...new Uint8Array(exported)));
-}
-
-export async function importKey(keyString: string): Promise<CryptoKey> {
-  const keyData = Uint8Array.from(atob(keyString), (c) => c.charCodeAt(0));
-  return crypto.subtle.importKey(
-    "raw",
-    keyData,
-    { name: "AES-GCM", length: 256 },
     false,
     ["encrypt", "decrypt"]
   );
 }
 
-export async function encrypt(data: string, keyString: string): Promise<string> {
+export async function encrypt(data: string, password: string): Promise<string> {
-  const key = await importKey(keyString);
+  const salt = crypto.getRandomValues(new Uint8Array(16));
   const iv = crypto.getRandomValues(new Uint8Array(12));
+  const key = await deriveKey(password, salt);
   const encoded = new TextEncoder().encode(data);
-  const encrypted = await crypto.subtle.encrypt(
+  const encrypted = await crypto.subtle.encrypt({ name: "AES-GCM", iv }, key, encoded);
-    { name: "AES-GCM", iv },
+  const combined = new Uint8Array(16 + 12 + encrypted.byteLength);
-    key,
+  combined.set(salt);
-    encoded
+  combined.set(iv, 16);
-  );
+  combined.set(new Uint8Array(encrypted), 28);
-  const combined = new Uint8Array(iv.length + encrypted.byteLength);
-  combined.set(iv);
-  combined.set(new Uint8Array(encrypted), iv.length);
   return btoa(String.fromCharCode(...combined));
 }
 
-export async function decrypt(encryptedData: string, keyString: string): Promise<string> {
+export async function decrypt(encryptedData: string, password: string): Promise<string> {
-  const key = await importKey(keyString);
   const combined = Uint8Array.from(atob(encryptedData), (c) => c.charCodeAt(0));
-  const iv = combined.slice(0, 12);
+  const salt = combined.slice(0, 16);
-  const data = combined.slice(12);
+  const iv = combined.slice(16, 28);
-  const decrypted = await crypto.subtle.decrypt(
+  const data = combined.slice(28);
-    { name: "AES-GCM", iv },
+  const key = await deriveKey(password, salt);
-    key,
+  const decrypted = await crypto.subtle.decrypt({ name: "AES-GCM", iv }, key, data);
-    data
-  );
   return new TextDecoder().decode(decrypted);
 }
 
-export async function encryptFile(file: File, keyString: string): Promise<Blob> {
+export async function encryptFile(file: File, password: string): Promise<Blob> {
-  const key = await importKey(keyString);
+  const salt = crypto.getRandomValues(new Uint8Array(16));
   const iv = crypto.getRandomValues(new Uint8Array(12));
+  const key = await deriveKey(password, salt);
   const arrayBuffer = await file.arrayBuffer();
-  const encrypted = await crypto.subtle.encrypt(
+  const encrypted = await crypto.subtle.encrypt({ name: "AES-GCM", iv }, key, arrayBuffer);
-    { name: "AES-GCM", iv },
+  const combined = new Uint8Array(16 + 12 + encrypted.byteLength);
-    key,
+  combined.set(salt);
-    arrayBuffer
+  combined.set(iv, 16);
-  );
+  combined.set(new Uint8Array(encrypted), 28);
-  const combined = new Uint8Array(iv.length + encrypted.byteLength);
-  combined.set(iv);
-  combined.set(new Uint8Array(encrypted), iv.length);
   return new Blob([combined], { type: "application/octet-stream" });
 }
 
-export async function decryptFile(encryptedBlob: Blob, keyString: string): Promise<ArrayBuffer> {
+export async function decryptFile(encryptedBlob: Blob, password: string): Promise<ArrayBuffer> {
-  const key = await importKey(keyString);
   const combined = new Uint8Array(await encryptedBlob.arrayBuffer());
-  const iv = combined.slice(0, 12);
+  const salt = combined.slice(0, 16);
-  const data = combined.slice(12);
+  const iv = combined.slice(16, 28);
+  const data = combined.slice(28);
+  const key = await deriveKey(password, salt);
   return crypto.subtle.decrypt({ name: "AES-GCM", iv }, key, data);
 }

src/lib/email.ts

@@ -0,0 +1,150 @@
+import nodemailer from 'nodemailer';
+
+const transporter = nodemailer.createTransport({
+  host: process.env.SMTP_HOST,
+  port: Number(process.env.SMTP_PORT) || 587,
+  secure: process.env.SMTP_SECURE === 'true',
+  auth: {
+    user: process.env.SMTP_USER,
+    pass: process.env.SMTP_PASS,
+  },
+});
+
+function escapeHtml(unsafe: string): string {
+  return unsafe
+    .replace(/&/g, '&')
+    .replace(/</g, '&lt;')
+    .replace(/>/g, '&gt;')
+    .replace(/"/g, '&quot;')
+    .replace(/'/g, '&#039;');
+}
+
+interface EmailOptions {
+  to: string;
+  subject: string;
+  html: string;
+}
+
+export async function sendEmail({ to, subject, html }: EmailOptions) {
+  return transporter.sendMail({
+    from: process.env.SMTP_FROM || 'Dead Man Switch <[email protected]>',
+    to,
+    subject,
+    html,
+  });
+}
+
+export const emailTemplates = {
+  deadlineTriggered: (recipientEmail: string, senderName: string, messageId: string) => ({
+    subject: `Önemli Mesaj: ${escapeHtml(senderName)} tarafından gönderildi`,
+    html: `
+      <!DOCTYPE html>
+      <html>
+      <head>
+        <meta charset="utf-8">
+        <style>
+          body { font-family: Arial, sans-serif; line-height: 1.6; color: #333; }
+          .container { max-width: 600px; margin: 0 auto; padding: 20px; }
+          .header { background: #dc2626; color: white; padding: 20px; border-radius: 8px 8px 0 0; }
+          .content { background: #f9fafb; padding: 20px; border: 1px solid #e5e7eb; }
+          .button { display: inline-block; background: #3b82f6; color: white; padding: 12px 24px; border-radius: 6px; text-decoration: none; margin-top: 15px; }
+          .footer { text-align: center; padding: 15px; color: #6b7280; font-size: 12px; }
+        </style>
+      </head>
+      <body>
+        <div class="container">
+          <div class="header">
+            <h1>Dead Man's Switch Tetiklendi</h1>
+          </div>
+          <div class="content">
+            <p>Merhaba,</p>
+            <p><strong>${escapeHtml(senderName)}</strong> tarafından size önceden hazırlanmış bir mesaj bırakıldı.</p>
+            <p>Bu mesaj, belirlenen süre içinde check-in yapılmadığı için otomatik olarak gönderilmiştir.</p>
+            <p>Mesajı görüntülemek için aşağıdaki bağlantıya tıklayın:</p>
+            <a href="${process.env.NEXT_PUBLIC_APP_URL}/decrypt/${messageId}" class="button">Mesajı Görüntüle</a>
+            <p style="margin-top: 20px; font-size: 14px; color: #6b7280;">Mesaj şifreli ise, gönderen tarafından size iletilen şifreyi girmeniz gerekecektir.</p>
+          </div>
+          <div class="footer">
+            <p>Dead Man's Switch Sistemi</p>
+          </div>
+        </div>
+      </body>
+      </html>
+    `,
+  }),
+
+  checkInReminder: (userName: string, hoursLeft: number, switchTitle: string) => ({
+    subject: `Hatırlatma: ${escapeHtml(switchTitle)} için check-in gerekli`,
+    html: `
+      <!DOCTYPE html>
+      <html>
+      <head>
+        <meta charset="utf-8">
+        <style>
+          body { font-family: Arial, sans-serif; line-height: 1.6; color: #333; }
+          .container { max-width: 600px; margin: 0 auto; padding: 20px; }
+          .header { background: #f59e0b; color: white; padding: 20px; border-radius: 8px 8px 0 0; }
+          .content { background: #f9fafb; padding: 20px; border: 1px solid #e5e7eb; }
+          .warning { background: #fef3c7; padding: 15px; border-radius: 8px; margin: 15px 0; border-left: 4px solid #f59e0b; }
+          .button { display: inline-block; background: #3b82f6; color: white; padding: 12px 24px; border-radius: 6px; text-decoration: none; margin-top: 15px; }
+          .footer { text-align: center; padding: 15px; color: #6b7280; font-size: 12px; }
+        </style>
+      </head>
+      <body>
+        <div class="container">
+          <div class="header">
+            <h1>Check-in Hatırlatması</h1>
+          </div>
+          <div class="content">
+            <p>Merhaba ${escapeHtml(userName)},</p>
+            <div class="warning">
+              <strong>"${escapeHtml(switchTitle)}"</strong> için son <strong>${hoursLeft} saat</strong> kaldı!
+            </div>
+            <p>Mesajlarınızın gönderilmemesi için lütfen check-in yapın.</p>
+            <a href="${process.env.NEXT_PUBLIC_APP_URL}/dashboard" class="button">Şimdi Check-in Yap</a>
+          </div>
+          <div class="footer">
+            <p>Dead Man's Switch Sistemi</p>
+          </div>
+        </div>
+      </body>
+      </html>
+    `,
+  }),
+
+  welcomeEmail: (userName: string) => ({
+    subject: 'Dead Man\'s Switch\'e Hoş Geldiniz',
+    html: `
+      <!DOCTYPE html>
+      <html>
+      <head>
+        <meta charset="utf-8">
+        <style>
+          body { font-family: Arial, sans-serif; line-height: 1.6; color: #333; }
+          .container { max-width: 600px; margin: 0 auto; padding: 20px; }
+          .header { background: #3b82f6; color: white; padding: 20px; border-radius: 8px 8px 0 0; }
+          .content { background: #f9fafb; padding: 20px; border: 1px solid #e5e7eb; }
+          .button { display: inline-block; background: #3b82f6; color: white; padding: 12px 24px; border-radius: 6px; text-decoration: none; margin-top: 15px; }
+          .footer { text-align: center; padding: 15px; color: #6b7280; font-size: 12px; }
+        </style>
+      </head>
+      <body>
+        <div class="container">
+          <div class="header">
+            <h1>Hoş Geldiniz!</h1>
+          </div>
+          <div class="content">
+            <p>Merhaba ${escapeHtml(userName)},</p>
+            <p>Dead Man's Switch sistemine kayıt olduğunuz için teşekkür ederiz.</p>
+            <p>Artık önemli mesajlarınızı güvenle saklayabilir ve belirlediğiniz kişilere iletilmesini sağlayabilirsiniz.</p>
+            <a href="${process.env.NEXT_PUBLIC_APP_URL}/dashboard" class="button">Dashboard'a Git</a>
+          </div>
+          <div class="footer">
+            <p>Dead Man's Switch Sistemi</p>
+          </div>
+        </div>
+      </body>
+      </html>
+    `,
+  }),
+};