refactor: boxes/model: Validate PM recipients more thoroughly.

This commit refactors the `get_invalid_recipients_emails()` method
of the model to `check_recipient_validity()` which checks if the
recipient's name and email match.

This commit adds logic in WriteBox, to tidy and validate recipients,
following this strategy:
* Ensures that the email and the name are of the same user.
* Removes extra text after the email.

The recipients information is tidied for all the valid recipients,
by formatting the information to fit the `name <email>` format.

The call to this method from boxes.py is also updated accordingly.

Tests added.

Author: prah23

tests/ui_tools/test_boxes.py

@@ -718,7 +718,6 @@ def focus_val(x: str) -> int:
         if write_box.focus_position == write_box.FOCUS_CONTAINER_HEADER:
             write_box.header_write_box.focus_col = (focus_val(
                                                     initial_focus_col_name))
-        write_box.model.get_invalid_recipient_emails.return_value = []
         write_box.model.user_dict = mocker.MagicMock()
 
         write_box.keypress(size, tab_key)
@@ -732,6 +731,99 @@ def focus_val(x: str) -> int:
             assert (write_box.FOCUS_MESSAGE_BOX_BODY
                     == focus_val(expected_focus_col_name))
 
+    @pytest.mark.parametrize(['raw_recipients', 'tidied_recipients'], [
+        ('Human 1 [email protected]', 'Human 1 <[email protected]>'),
+        ('Human 2 [email protected] random text',
+         'Human 2 <[email protected]>'),
+        ('Human Myself [email protected] random, Human 1 <[email protected]>',
+         'Human Myself <[email protected]>, Human 1 <[email protected]>'),
+        ('Human Myself <[email protected]>, Human 1 [email protected] random',
+         'Human Myself <[email protected]>, Human 1 <[email protected]>'),
+        ('Human Myself [email protected] random,'
+         'Human 1 [email protected] random',
+         'Human Myself <[email protected]>, Human 1 <[email protected]>'),
+        ('Human Myself [email protected] random, Human 1 [email protected] '
+         'random, Human 2 [email protected] random',
+         'Human Myself <[email protected]>, Human 1 <[email protected]>, '
+         'Human 2 <[email protected]>'),
+        ('Human Myself [email protected], Human 1 [email protected] random, '
+         'Human2 [email protected]',
+         'Human Myself <[email protected]>, Human 1 <[email protected]>, '
+         'Human2 <[email protected]>')
+    ], ids=[
+        'untidy_with_improper_formatting',
+        'untidy_with_extra_text',
+        'untidy_first_recipient_out_of_two',
+        'untidy_second_recipient_out_of_two',
+        'two_untidy_recipients',
+        'three_untidy_recipients',
+        'untidy_middle_recipient_out_of_three'
+    ])
+    @pytest.mark.parametrize("tab_key",
+                             keys_for_command("CYCLE_COMPOSE_FOCUS"))
+    def test_tidying_recipients_on_cycling_out(self, write_box, widget_size,
+                                               mocker, raw_recipients,
+                                               tidied_recipients, tab_key):
+        write_box.private_box_view()
+        write_box.focus_position = write_box.FOCUS_CONTAINER_HEADER
+        write_box.header_write_box.focus_col = (
+            write_box.FOCUS_HEADER_BOX_RECIPIENT
+        )
+
+        write_box.to_write_box.set_edit_text(raw_recipients)
+        write_box.to_write_box.set_edit_pos(len(raw_recipients))
+
+        size = widget_size(write_box)
+        write_box.keypress(size, tab_key)
+
+        assert write_box.to_write_box.edit_text == tidied_recipients
+
+    @pytest.mark.parametrize(['raw_recipients', 'invalid_recipients'], [
+        ('Human 1 <[email protected]>', 'Human 1 <[email protected]>'),
+        ('[email protected]', '[email protected]'),
+        ('Human 1', 'Human 1')
+    ], ids=[
+        'name_email_mismatch',
+        'no_name_specified',
+        'no_email_specified'
+    ])
+    @pytest.mark.parametrize("tab_key",
+                             keys_for_command("CYCLE_COMPOSE_FOCUS"))
+    def test_footer_notification_on_invalid_recipients(self, write_box,
+                                                       tab_key, mocker,
+                                                       widget_size,
+                                                       raw_recipients,
+                                                       invalid_recipients):
+
+        write_box.model.check_recipient_validity = mocker.Mock(
+            return_value=False
+        )
+
+        write_box.private_box_view()
+        write_box.focus_position = write_box.FOCUS_CONTAINER_HEADER
+        write_box.header_write_box.focus_col = (
+            write_box.FOCUS_HEADER_BOX_RECIPIENT
+        )
+
+        write_box.to_write_box.edit_text = raw_recipients
+        write_box.to_write_box.set_edit_pos(len(raw_recipients))
+        size = widget_size(write_box)
+        write_box.keypress(size, tab_key)
+
+        expected_lines = [
+            'Invalid recipient(s) - ' + invalid_recipients, ' - Use ',
+            ('code', primary_key_for_command('AUTOCOMPLETE')), ' or ',
+            ('code', primary_key_for_command('AUTOCOMPLETE_REVERSE')),
+            ' to autocomplete.'
+        ]
+
+        self.view.set_footer_text.assert_called_once_with(expected_lines, 3)
+        # If there are invalid recipients, we expect the focus
+        # to remain in the to_write_box.
+        assert write_box.focus_position == write_box.FOCUS_CONTAINER_HEADER
+        assert (write_box.header_write_box.focus_col
+                == write_box.FOCUS_HEADER_BOX_RECIPIENT)
+
     @pytest.mark.parametrize(["msg_type", "expected_box_size"], [
         ('private',     1),
         ('stream',      4),

zulipterminal/model.py

@@ -914,11 +914,14 @@ def _handle_typing_event(self, event: Event) -> None:
                 else:
                     raise RuntimeError("Unknown typing event operation")
 
-    def get_invalid_recipient_emails(self, recipient_emails: List[str]
-                                     ) -> List[str]:
-
-        return [email for email in recipient_emails
-                if email not in self.user_dict]
+    def check_recipient_validity(self, recipient_name: str,
+                                 recipient_email: str,
+                                 ) -> bool:
+        if recipient_email and recipient_email in self.user_dict:
+            verified_name = self.user_dict[recipient_email]['full_name']
+            if recipient_name == verified_name:
+                return True
+        return False
 
     def is_valid_stream(self, stream_name: str) -> bool:
         for stream in self.stream_dict.values():

zulipterminal/ui_tools/boxes.py

@@ -619,14 +619,50 @@ def keypress(self, size: urwid_Size, key: str) -> Optional[str]:
                         header.focus_col = self.FOCUS_HEADER_BOX_STREAM
                 else:
                     self.update_recipient_emails(self.to_write_box)
-                    invalid_emails = self.model.get_invalid_recipient_emails(
-                        self.recipient_emails
+                    tidy_recipients = []
+                    invalid_recipients = []
+                    recipients = [recipient.strip()
+                                  for recipient in
+                                  self.to_write_box.edit_text.split(',')
+                                  if recipient.strip()]
+
+                    for recipient in recipients:
+                        cleaned_recipient_list = re.findall(
+                            r"^(.*?)(?:\s*?<?([\w\.-]+@[\w\.-]+)>?(.*))?$",
+                            recipient
+                        )
+                        recipient_name, recipient_email, invalid_text = (
+                            cleaned_recipient_list[0]
+                        )
+                        valid = self.model.check_recipient_validity(
+                            recipient_name, recipient_email
+                        )
+
+                        if valid:
+                            tidy_recipients.append(
+                                f"{recipient_name} <{recipient_email}>"
+                            )
+                        else:
+                            invalid_recipients.append(recipient)
+                            tidy_recipients.append(recipient)
+
+                    self.to_write_box.edit_text = ", ".join(tidy_recipients)
+                    self.to_write_box.edit_pos = len(
+                        self.to_write_box.edit_text
                     )
-                    if invalid_emails:
-                        invalid_emails_error = ('Invalid recipient(s) - '
-                                                + ', '.join(invalid_emails))
-                        self.view.set_footer_text(invalid_emails_error, 3)
+                    if invalid_recipients:
+                        invalid_recipients_error = [
+                            'Invalid recipient(s) - '
+                            + ', '.join(invalid_recipients), ' - Use ',
+                            ('code', primary_key_for_command('AUTOCOMPLETE')),
+                            ' or ',
+                            ('code', primary_key_for_command('AUTOCOMPLETE'
+                                                             '_REVERSE')),
+                            ' to autocomplete.'
+                        ]
+                        self.view.set_footer_text(invalid_recipients_error, 3)
                         return key
+
                     users = self.model.user_dict
                     self.recipient_user_ids = [users[email]['user_id']
                                                for email in