Prevent the setting of an e-mail from a Customer from "stealing" it from other Customers

src/Customer.php

@@ -6,7 +6,6 @@
 
 namespace MillionsMissingFrance\FreescoutRestrictedCustomers;
 
-use App\Email;
 use App\CustomerChannel;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Support\Facades\Hash;
@@ -105,4 +104,80 @@ class Customer extends BaseCustomer {
 			$this->save();
 		}
 	}
+
+	/**
+	 * Set customer emails.
+	 *
+	 * @param array $emails
+	 */
+	public function syncEmails($emails) {
+		if (is_array($emails)) {
+			$deleted_emails = [];
+			foreach ($this->emails as $email) {
+				foreach ($emails as $email_address) {
+					if (Email::sanitizeEmail($email->email) == Email::sanitizeEmail($email_address)) {
+						continue 2;
+					}
+				}
+				$deleted_emails[] = $email;
+			}
+			$mailbox = $this->mailbox;
+			foreach ($emails as $email_address) {
+				$email_address = Email::sanitizeEmail($email_address);
+				if (!$email_address) {
+					continue;
+				}
+				$email = Email
+					::whereInMailbox($mailbox)
+					->where('email', $email_address)
+					->first();
+				$new_emails = [];
+				if ($email) {
+					// Assign email to current customer
+					if ($email->customer_id != $this->id) {
+						$email->customer()->associate($this);
+						$email->save();
+					}
+				} else {
+					$new_emails[] = new Email(['email' => $email_address]);
+				}
+				if ($new_emails) {
+					$this->emails()->saveMany($new_emails);
+				}
+			}
+
+			foreach ($deleted_emails as $email) {
+				if (Conversation::where('customer_email', $email->email)->exists()) {
+					// Create customers for deleted emails
+					// if there is a conversation with 'customer_email'.
+					$customer = new self();
+					$customer->save();
+					$email->customer()->associate($customer);
+					$email->save();
+				} else {
+					// Simply delete an email.
+					$email->delete();
+				}
+			}
+		}
+	}
+
+	/**
+	 * Add new email to customer.
+	 */
+	public function addEmail($email_address, $check_if_exists = false) {
+		// Check if email already exists and belongs to another customer.
+		if ($check_if_exists) {
+			$mailbox = $this->mailbox;
+			$email = Email
+				::whereInMailbox($mailbox)
+				->where('email', $email_address)
+				->first();
+			if ($email && !empty($email->customer_id)) {
+				return false;
+			}
+		}
+		$new_email = new Email(['email' => $email_address]);
+		$this->emails()->save($new_email);
+	}
 }

src/Email.php

@@ -28,4 +28,19 @@ class Email extends BaseEmail {
 			->count();
 		return ( $emails_count != 0 );
 	}
+
+	/**
+	 * Return a query limited to a specific Mailbox
+	 *
+	 * @param Mailbox $mailbox
+	 *
+	 * @return QueryBuilder
+	 */
+	public static function whereInMailbox($mailbox) {
+		$query = self
+			::whereHas('customer', function($query) use($mailbox) {
+				$query->where('mailbox_id', '=', $mailbox->id);
+			});
+		return $query;
+	}
 }