Task Scheduler

This assignment is a PHP-based task management system w# Task Scheduler This assignment is a PHP-based task management system where users can add tasks to a common list and subscribe to receive hourly email reminders for pending tasks.

---

📌 Features to Implement

1️⃣ Task Management

• Add new tasks to the common list
• Duplicate tasks should not be added.
• Mark tasks as complete/incomplete
• Delete tasks
• Store tasks in tasks.txt

2️⃣ Email Subscription System

• Users can subscribe with their email
• Email verification process:
  • System generates a unique 6-digit verification code
  • Sends verification email with activation link
  • Link contains email and verification code
  • User clicks link to verify subscription
  • System moves email from pending to verified subscribers
• Store subscribers in subscribers.txt
• Store pending verifications in pending_subscriptions.txt

3️⃣ Reminder System

• CRON job runs every hour
• Sends emails to verified subscribers
• Only includes pending tasks in reminders
• Includes unsubscribe link in emails
• Unsubscribe process:
  • Every email includes an unsubscribe link
  • Link contains encoded email address
  • One-click unsubscribe removes email from subscribers

---

📜 File Details & Function Stubs

You must implement the following functions in functions.php:

function addTask($task_name) {
    // Add a new task to the list
}

function getAllTasks() {
    // Get all tasks from tasks.txt
}

function markTaskAsCompleted($task_id, $is_completed) {
    // Mark/unmark a task as complete
}

function deleteTask($task_id) {
    // Delete a task from the list
}

function generateVerificationCode() {
    // Generate a 6-digit verification code
}

function subscribeEmail($email) {
    // Add email to pending subscriptions and send verification
}

function verifySubscription($email, $code) {
    // Verify email subscription
}

function unsubscribeEmail($email) {
    // Remove email from subscribers list
}

function sendTaskReminders() {
    // Sends task reminders to all subscribers
 	// Internally calls  sendTaskEmail() for each subscriber
}

function sendTaskEmail( $email, $pending_tasks ) {
	// Sends a task reminder email to a subscriber with pending tasks.
}

📁 File Structure

• functions.php (Core functions)
• index.php (Main interface)
• verify.php (Email verification handler)
• unsubscribe.php (Unsubscribe handler)
• cron.php (Reminder sender)
• setup_cron.sh (CRON job setup)
• tasks.txt (Task storage)
• subscribers.txt (Verified subscribers)
• pending_subscriptions.txt (Pending verifications)

🔄 CRON Job Implementation

📌 You must implement a CRON job that runs cron.php every 1 hour.
📌 Do not just write instructions—provide an actual setup_cron.sh script inside src/.
📌 Your script should automatically configure the CRON job on execution.

---

🛠 Required Files

• setup_cron.sh (Must configure the CRON job)
• cron.php (Must handle sending GitHub updates via email)

---

🚀 How It Should Work

• The setup_cron.sh script should register a CRON job that executes cron.php every 1 hour.
• The CRON job must be automatically added when the script runs.
• The cron.php file should actually fetch pending tasks and send emails to subscribed users.

---

📩 Email Handling

✅ The email content must be in HTML format (not JSON).
✅ Use PHP's mail() function for sending emails.
✅ Each email should include an unsubscribe link.
✅ Store subscribers email in subscribers.txt (Do not use a database). ✅ Store pending verifications in pending_subscriptions.txt (Do not use a database). ✅ Each email should include an unsubscribe link.

---

❌ Disqualification Criteria

🚫 Hardcoding verification codes.
🚫 Using a database (use subscribers.txt).
🚫 Modifying anything outside the src/ directory.
🚫 Changing function names.
🚫 Not implementing a working CRON job.
🚫 Not formatting emails as HTML. 🚫 Using 3rd party libraries, only pure PHP is allowed.

---

📌 Input & Button Formatting Guidelines

📝 Task Management Inputs & Button:

• Add task input must have name="task-name" and id="task-name"
• Add task button must have id="add-task"

✅ Example:

<input type="text" name="task-name" id="task-name" placeholder="Enter new task" required>
<button type="submit" id="add-task">Add Task</button>

• Task list must have class="task-list".
• Task item in that list must have class="task-item
• Task item must have have a checkbox <input type="checkbox" class="task-status" > so user can mark it done.
• Once task item is completed add class completed. <li class="task-item completed">
• Task item should have a delete action with class="delete-task".

✅ Example:

<ul class="tasks-list">
	<li class="task-item">
		<input type="checkbox" class="task-status">
		<button class="delete-task">Delete</button>
	</li>	
</ul>

📧 Email Input & Submission Button:

• The email input field must have name="email".
• The submit button must have id="submit-email".

✅ Example:

<input type="email" name="email" required />
<button id="submit-email">Submit</button>

---

📩 Email Content Guidelines

✅ Verification Email:

• Subject: Verify subscription to Task Planner
• Body Format:

<p>Click the link below to verify your subscription to Task Planner:</p>
';
<p><a id="verification-link" href="{verification_link}">Verify Subscription</a></p>

• Sender: no-reply@example.com

---

📩 Email Content Guidelines

⚠️ Note: The Subject and Body of the email must strictly follow the formats below, including the exact HTML structure.

✅ Task Reminder Email:

• Subject: Task Planner - Pending Tasks Reminder
• Body Format:

<h2>Pending Tasks Reminder</h2>
<p>Here are the current pending tasks:</p>
<ul>
	<li>Task 1</li>
	<li>Task 2</li>
</ul>
<p><a id="unsubscribe-link" href="{unsubscribe_link}">Unsubscribe from notifications</a></p>

---

here users can add tasks to a common list and subscribe to receive hourly email reminders for pending tasks.

---

📌 Features to Implement

1️⃣ Task Management

• Add new tasks to the common list
• Duplicate tasks should not be added.
• Mark tasks as complete/incomplete
• Delete tasks
• Store tasks in tasks.txt

2️⃣ Email Subscription System

• Users can subscribe with their email
• Email verification process:
  • System generates a unique 6-digit verification code
  • Sends verification email with activation link
  • Link contains email and verification code
  • User clicks link to verify subscription
  • System moves email from pending to verified subscribers
• Store subscribers in subscribers.txt
• Store pending verifications in pending_subscriptions.txt

3️⃣ Reminder System

• CRON job runs every hour
• Sends emails to verified subscribers
• Only includes pending tasks in reminders
• Includes unsubscribe link in emails
• Unsubscribe process:
  • Every email includes an unsubscribe link
  • Link contains encoded email address
  • One-click unsubscribe removes email from subscribers

---

📜 File Details & Function Stubs

You must implement the following functions in functions.php:

function addTask($task_name) {
    // Add a new task to the list
}

function getAllTasks() {
    // Get all tasks from tasks.txt
}

function markTaskAsCompleted($task_id, $is_completed) {
    // Mark/unmark a task as complete
}

function deleteTask($task_id) {
    // Delete a task from the list
}

function generateVerificationCode() {
    // Generate a 6-digit verification code
}

function subscribeEmail($email) {
    // Add email to pending subscriptions and send verification
}

function verifySubscription($email, $code) {
    // Verify email subscription
}

function unsubscribeEmail($email) {
    // Remove email from subscribers list
}

function sendTaskReminders() {
    // Sends task reminders to all subscribers
 	// Internally calls  sendTaskEmail() for each subscriber
}

function sendTaskEmail( $email, $pending_tasks ) {
	// Sends a task reminder email to a subscriber with pending tasks.
}

📁 File Structure

• functions.php (Core functions)
• index.php (Main interface)
• verify.php (Email verification handler)
• unsubscribe.php (Unsubscribe handler)
• cron.php (Reminder sender)
• setup_cron.sh (CRON job setup)
• tasks.txt (Task storage)
• subscribers.txt (Verified subscribers)
• pending_subscriptions.txt (Pending verifications)

🔄 CRON Job Implementation

📌 You must implement a CRON job that runs cron.php every 1 hour.
📌 Do not just write instructions—provide an actual setup_cron.sh script inside src/.
📌 Your script should automatically configure the CRON job on execution.

---

🛠 Required Files

• setup_cron.sh (Must configure the CRON job)
• cron.php (Must handle sending GitHub updates via email)

---

🚀 How It Should Work

• The setup_cron.sh script should register a CRON job that executes cron.php every 1 hour.
• The CRON job must be automatically added when the script runs.
• The cron.php file should actually fetch pending tasks and send emails to subscribed users.

---

📩 Email Handling

✅ The email content must be in HTML format (not JSON).
✅ Use PHP's mail() function for sending emails.
✅ Each email should include an unsubscribe link.
✅ Store subscribers email in subscribers.txt (Do not use a database). ✅ Store pending verifications in pending_subscriptions.txt (Do not use a database). ✅ Each email should include an unsubscribe link.

---

❌ Disqualification Criteria

🚫 Hardcoding verification codes.
🚫 Using a database (use subscribers.txt).
🚫 Modifying anything outside the src/ directory.
🚫 Changing function names.
🚫 Not implementing a working CRON job.
🚫 Not formatting emails as HTML. 🚫 Using 3rd party libraries, only pure PHP is allowed.

---

📌 Input & Button Formatting Guidelines

📝 Task Management Inputs & Button:

• Add task input must have name="task-name" and id="task-name"
• Add task button must have id="add-task"

✅ Example:

<input type="text" name="task-name" id="task-name" placeholder="Enter new task" required>
<button type="submit" id="add-task">Add Task</button>

• Task list must have class="task-list".
• Task item in that list must have class="task-item
• Task item must have have a checkbox <input type="checkbox" class="task-status" > so user can mark it done.
• Once task item is completed add class completed. <li class="task-item completed">
• Task item should have a delete action with class="delete-task".

✅ Example:

<ul class="tasks-list">
	<li class="task-item">
		<input type="checkbox" class="task-status">
		<button class="delete-task">Delete</button>
	</li>	
</ul>

📧 Email Input & Submission Button:

• The email input field must have name="email".
• The submit button must have id="submit-email".

✅ Example:

<input type="email" name="email" required />
<button id="submit-email">Submit</button>

---

📩 Email Content Guidelines

✅ Verification Email:

• Subject: Verify subscription to Task Planner
• Body Format:

<p>Click the link below to verify your subscription to Task Planner:</p>
';
<p><a id="verification-link" href="{verification_link}">Verify Subscription</a></p>

• Sender: no-reply@example.com

---

📩 Email Content Guidelines

⚠️ Note: The Subject and Body of the email must strictly follow the formats below, including the exact HTML structure.

✅ Task Reminder Email:

• Subject: Task Planner - Pending Tasks Reminder
• Body Format:

<h2>Pending Tasks Reminder</h2>
<p>Here are the current pending tasks:</p>
<ul>
	<li>Task 1</li>
	<li>Task 2</li>
</ul>
<p><a id="unsubscribe-link" href="{unsubscribe_link}">Unsubscribe from notifications</a></p>

---