Enable conference registration

Change-Id: I5e973513d78c63a48e62ff1aa3a5d9a1621f4a4d
diff --git a/templates/email.php b/templates/email.php
index 58eb17f..c55c38e 100644
--- a/templates/email.php
+++ b/templates/email.php
@@ -8,10 +8,10 @@
 
 $WELCOME_TEMPLATE = (object)[
         "subject" => "[" . $SERVICE_ACRONYM . "] Thank you for your " . $SERVICE_ACRONYM . " registration",
-        "text"    => "Thank for registering at " . $SERVICE_ACRONYM . " .",
+        "text"    => "Thank for registering for " . $SERVICE_ACRONYM . " .",
         "html" => "<html><body>
                 <p>Dear {{full_name}},</p>
-                <p>Thank for registering at " . $SERVICE_ACRONYM . " .</p>"
+                <p>Thank for registering for " . $SERVICE_ACRONYM . " .</p>"
                 . $REGISTRATION_INFORMATION . "
                 <p>
                 <p>Best regards,</p>
diff --git a/templates/register.htm b/templates/register.htm
index 5e4df50..3ce7a33 100644
--- a/templates/register.htm
+++ b/templates/register.htm
@@ -507,7 +507,7 @@
         <div class="form-group form-check">
             <input type="checkbox" class="form-check-input" name="participation_confirmed" id="participate" required
                 <?php echo isset($_POST['participation_confirmed']) ? 'checked' : '' ?>
-                oninput="update_total_costs()"
+                oninput="update_total_due()"
                 value="participation_confirmed">
             <label class="form-check-label fs-4" for="participation_confirmed">I confirm that I will be attending the <?php echo $SERVICE_ACRONYM; ?> conference. 
                 <?php if(new DateTimeImmutable("now") <= new DateTimeImmutable($EARLYBIRD_DEADLINE." 23:59:59 HST")) {
@@ -529,7 +529,7 @@
         <div class="form-group form-check">
             <input type="checkbox" class="form-check-input" name="student" id="student"
                 <?php echo isset($_POST['student']) ? 'checked' : '' ?>
-                oninput="update_total_costs()"
+                oninput="update_total_due()"
                 value="student">
             <label class="form-check-label fs-4" for="student">I am student and will therefore benefit from student discount of <strong>€ <span id="student_discount"><?php echo $STUDENT_DISCOUNT; ?></span></strong>.
             </label>
@@ -541,7 +541,7 @@
         <div class="form-group form-check">
             <input type="checkbox" class="form-check-input" name="conference_dinner" id="conference_dinner"
                 <?php echo isset($_POST['conference_dinner']) ? 'checked' : '' ?>
-                oninput="update_total_costs()"
+                oninput="update_total_due()"
                 value="conference_dinner">
             <label class="form-check-label fs-4" for="conference_dinner">I will be attending the conference dinner on 20 July at 8pm at the Rheinterrassen for the price of <strong>€ <span id="conference_dinner_price"><?php echo $CONFERENCE_DINNER; ?></span></strong>.
             </label>
@@ -551,7 +551,7 @@
             <label class="form-label fw-bold" for="exampleInputAmount">Total Amount in Euro to be paid</label>
             <div class="input-group">
               <div class="input-group-text fs-3">€</div>
-              <input lang="en" name="total_costs" id="total_costs" class="form-control text-end fw-bold fs-3" readonly>
+              <input lang="en" name="total_due" id="total_due" class="form-control text-end fw-bold fs-3" readonly>
             </div>
             <div id="totalHelp" class="form-text fs-4">Only bank transfer is available as a payment method. After submitting the form, you will be asked to confirm your e-mail address. After you have confirmed it, you will receive an invoice with all bank details.</div>
     </div>
diff --git a/templates/strings.php b/templates/strings.php
index 557a60f..dc2f1a3 100644
--- a/templates/strings.php
+++ b/templates/strings.php
@@ -1,4 +1,6 @@
 <?php
+include_once 'config.php';
+
 $RUNTIME_ERROR = (object)[
         "not_found" => "<center><h2>This page does not exist!</h2></center>",
         "template_not_found" => "Either you did not create the folder '{{template}}' or strings.php is missing on it. Maybe you have set LANG_CC: '{{langcc}}' wrong on config.php?",
@@ -30,7 +32,7 @@
 ];
 
 $EMAIL_VALIDATION_ERROR = (object)[
-        "registered" => "This email is already belongs to an account. Did you <a href='{{link}}'>forget your password?</a><br>",
+        "registered" => "This email is already belongs to an account. It seems like you are already registered. Please check your mailbox." . ($CONFERENCE_REGISTRATION? "": "Or did you <a href='{{link}}'>forget your password?</a><br>"),
         "invalid" => "Invalid email format<br>",
         "blacklisted" => "This email service is not allowed<br>",
         "pending" => "This email is already pending approval, check your mailbox or try to register with a different email<br>",