# Troubleshooting Guide - Admin Panel Issues

## Common Issues and Solutions

### Issue 1: Admin Panel Not Loading / Blank Page

**Possible Causes:**
1. Database not created
2. Database connection failed
3. Missing files
4. PHP errors

**Solutions:**

1. **Check Database:**
   - Open phpMyAdmin (http://localhost/phpmyadmin)
   - Check if database `lancet_exam_system` exists
   - If not, import `sql/database.sql`

2. **Check Database Credentials:**
   - Open `config/database.php`
   - Verify:
     - DB_HOST: `localhost`
     - DB_USER: `root` (or your MySQL username)
     - DB_PASS: `` (or your MySQL password)
     - DB_NAME: `lancet_exam_system`

3. **Run Diagnostic Test:**
   - Access: `http://localhost/Lancetclasses/admin/test.php`
   - This will show what's wrong

4. **Check PHP Errors:**
   - Open `config/config.php`
   - Ensure `error_reporting(E_ALL);` and `ini_set('display_errors', 1);` are enabled
   - Check browser console for JavaScript errors

### Issue 2: Cannot Login to Admin Panel

**Possible Causes:**
1. Admin account not created
2. Wrong password
3. Database not imported

**Solutions:**

1. **Check Admin Account:**
   ```sql
   SELECT * FROM admins;
   ```
   - Should show at least one admin with username `admin`
   - If empty, import `sql/database.sql` again

2. **Default Credentials:**
   - Username: `admin`
   - Password: `admin123`

3. **Reset Admin Password (if needed):**
   ```sql
   UPDATE admins SET password = '$2y$10$92IXUNpkjO0rOQ5byMi.Ye4oKoEa3Ro9llC/.og/at2.uheWG/igi' WHERE username = 'admin';
   ```
   (This sets password to `admin123`)

### Issue 3: Database Connection Error

**Error Message:** "Database connection failed"

**Solutions:**

1. **Check MySQL Service:**
   - Open XAMPP Control Panel
   - Ensure MySQL is running (green)

2. **Check Database Name:**
   - Database must be named exactly: `lancet_exam_system`
   - Case-sensitive on Linux/Mac

3. **Check User Permissions:**
   - Ensure MySQL user has CREATE, SELECT, INSERT, UPDATE, DELETE permissions

4. **Test Connection Manually:**
   ```php
   <?php
   try {
       $pdo = new PDO('mysql:host=localhost;dbname=lancet_exam_system', 'root', '');
       echo "Connected successfully";
   } catch(PDOException $e) {
       echo "Connection failed: " . $e->getMessage();
   }
   ?>
   ```

### Issue 4: Session Errors

**Error:** "Session ini settings cannot be changed"

**Solution:**
- Already fixed in `config/config.php`
- Session settings are now set before session_start()

### Issue 5: Page Shows "Access Denied" or Redirects

**Possible Causes:**
1. Not logged in
2. Session expired
3. CSRF token mismatch

**Solutions:**

1. **Clear Browser Cookies:**
   - Clear cookies for localhost
   - Try again

2. **Check Session:**
   - Ensure cookies are enabled in browser
   - Check if session files are being created in `C:\xampp\tmp\` (Windows)

3. **Check File Permissions:**
   - Ensure PHP can write to temp directory

### Issue 6: CSS/JavaScript Not Loading

**Symptoms:**
- Page loads but looks unstyled
- Buttons/icons not showing

**Solutions:**

1. **Check SITE_URL:**
   - Open `config/config.php`
   - Ensure `SITE_URL` matches your actual URL:
     ```php
     define('SITE_URL', 'http://localhost/Lancetclasses');
     ```

2. **Check File Paths:**
   - Verify `assets/css/custom.css` exists
   - Verify `assets/js/custom.js` exists

3. **Check Browser Console:**
   - Press F12
   - Check Console tab for 404 errors
   - Fix paths accordingly

### Issue 7: File Upload Not Working

**Solutions:**

1. **Check Upload Directory:**
   - Ensure `uploads/` folder exists
   - Ensure subfolders exist: `uploads/photos/`, `uploads/materials/`, `uploads/marksheets/`

2. **Check Permissions:**
   - On Windows: Usually not an issue
   - On Linux: `chmod 755 uploads` and subfolders

3. **Check PHP Settings:**
   - `upload_max_filesize` in php.ini
   - `post_max_size` in php.ini
   - Should be at least 10M

### Quick Diagnostic Steps

1. **Access Diagnostic Page:**
   ```
   http://localhost/Lancetclasses/admin/test.php
   ```

2. **Check Error Logs:**
   - XAMPP: `C:\xampp\apache\logs\error.log`
   - PHP: `C:\xampp\php\logs\php_error_log`

3. **Verify Installation:**
   - Database imported: ✓
   - Config files exist: ✓
   - Upload folders exist: ✓
   - Admin account exists: ✓

### Still Having Issues?

1. **Enable Full Error Display:**
   ```php
   // In config/config.php
   error_reporting(E_ALL);
   ini_set('display_errors', 1);
   ```

2. **Check PHP Version:**
   - Required: PHP 7.4 or higher
   - Check: `<?php phpinfo(); ?>`

3. **Check Required Extensions:**
   - PDO
   - PDO_MySQL
   - GD (for image handling)
   - mbstring

4. **Test Basic PHP:**
   - Create `test.php` in root:
   ```php
   <?php phpinfo(); ?>
   ```
   - If this doesn't work, PHP is not configured correctly

---

## Contact Support

If issues persist:
1. Run diagnostic test: `admin/test.php`
2. Check error logs
3. Note exact error messages
4. Check browser console for JavaScript errors