Improve the sorting of e-mails when creating/editing a group

Http/Controllers/CustomersGroupsController.php

@@ -51,19 +51,50 @@ class CustomersGroupsController extends Controller {
 		// Get a list of Emails from the list of Customers.
 		$emails = $customers
 			->pluck('emails')
-			->flatten()
-			->sortBy('email');
-		// Group Emails by their first character.
+			->flatten();
+
+		// Group Emails by the first character of the Customer name.
 		// This is used to display them in collapsible groups.
 		$emails = $emails->mapToGroups(function ($email) {
-			$first_character = substr($email->email, $offset = 0, $length = 1);
+			$name = $email->customer->last_name ?
+				$email->customer->last_name :
+				$email->customer->first_name;
+			$first_character = strtoupper(substr(
+				$name ? $name : '?',
+				$offset = 0,
+				$length = 1,
+			));
+			// Group all Emails without a Customer name starting with a letter together.
+			if ( ! preg_match($pattern = '/[A-Z]/', $string = $first_character) )
+				$first_character = '?';
 			return [ $first_character => $email ];
 		});
+		// Sort the groups of Emails.
+		$emails = $emails->all();
+		ksort($emails);
+		// Sort the Emails inside each group.
+		$emails_sorted = [];
+		foreach ( $emails as $first_character => $emails_group ) {
+			$emails_sorted[$first_character] = $emails_group->sortBy(function ($email) {
+				if ( $email->customer->last_name ) {
+					$sort_string = $email->customer->last_name .' '. $email->customer->first_name .' '. $email->email;
+				} else if ( $email->customer->first_name ) {
+					$sort_string = $email->customer->first_name .' '. $email->email;
+				} else {
+					$sort_string = $email->email;
+				}
+				// Do an case-insensitive sort.
+				$sort_string = strtolower($sort_string);
+				// Convert diacritics to ASCII characters.
+				$sort_string = iconv('UTF-8', 'ASCII//TRANSLIT', $sort_string);
+				return $sort_string;
+			});
+		}
 
 		return view('mmfcustomersgroups::groups/edit', [
 			'mailboxes' => $mailboxes,
 			'customers' => $customers,
-			'emails'    => $emails,
+			'emails'    => $emails_sorted,
 			'group'     => $group,
 		]);
 	}

Resources/views/groups/partials/edit_form.blade.php

@@ -108,7 +108,9 @@
 															checked="checked"
 														@endif
 													>
-													{{ $email->email }}
+													{{ $email->customer->last_name }}
+													{{ $email->customer->first_name }}
+													<{{ $email->email }}>
 												</label>
 											</div>
 										</div>