widget: Add find_widget_type method.

Added find_widget_type to identify the type of widget present in the message
(e.g., polls, todo, etc.).

Added test.

Author: rsashank

docs/developer-file-overview.md

@@ -17,6 +17,7 @@ Zulip Terminal uses [Zulip's API](https://zulip.com/api/) to store and retrieve
 |                        | unicode_emojis.py   | Unicode emoji data, synchronized semi-regularly with the server source                  |
 |                        | urwid_types.py      | Types from the urwid API, to improve type checking                                      |
 |                        | version.py          | Keeps track of the version of the current code                                          |
+|                        | widget.py           | Process widgets (submessages) like polls, todo lists, etc.                              |
 |                        |                     |                                                                                         |
 | zulipterminal/cli      | run.py              | Marks the entry point into the application                                              |
 |                        |                     |                                                                                         |

tests/widget/test_widget.py

@@ -0,0 +1,60 @@
+from typing import Any
+
+import pytest
+from pytest import param as case
+
+from zulipterminal.widget import find_widget_type
+
+
+@pytest.mark.parametrize(
+    "submessage, expected_widget_type",
+    [
+        case(
+            [
+                {
+                    "id": 11897,
+                    "message_id": 1954461,
+                    "sender_id": 27294,
+                    "msg_type": "widget",
+                    "content": '{"widget_type": "poll", "extra_data": '
+                    '{"question": "Sample Question?", "options": ["Yes", "No"]}}',
+                },
+                {
+                    "id": 11898,
+                    "message_id": 1954461,
+                    "sender_id": 27294,
+                    "msg_type": "widget",
+                    "content": '{"type":"new_option","idx":1,"option":"Maybe"}',
+                },
+            ],
+            "poll",
+        ),
+        case(
+            [
+                {
+                    "id": 11899,
+                    "message_id": 1954463,
+                    "sender_id": 27294,
+                    "msg_type": "widget",
+                    "content": '{"widget_type": "todo", "extra_data": '
+                    '{"task_list_title": "Today\'s Tasks", "tasks": [{"task": '
+                    '"Write code", "desc": ""}, {"task": "Sleep", "desc": ""}]}}',
+                },
+                {
+                    "id": 11900,
+                    "message_id": 1954463,
+                    "sender_id": 27294,
+                    "msg_type": "widget",
+                    "content": '{"type":"new_task","key":2,"task":"Eat","desc":"",'
+                    '"completed":false}',
+                },
+            ],
+            "todo",
+        ),
+        case([{}], "unknown"),
+    ],
+)
+def test_find_widget_type(submessage: Any, expected_widget_type: str) -> None:
+    widget_type = find_widget_type(submessage)
+
+    assert widget_type == expected_widget_type

zulipterminal/widget.py

@@ -0,0 +1,17 @@
+"""
+Process widgets (submessages) like polls, todo lists, etc.
+"""
+
+import json
+from typing import Any
+
+
+def find_widget_type(submessage: Any) -> str:
+    if submessage and isinstance(submessage, list) and "content" in submessage[0]:
+        try:
+            content = json.loads(submessage[0]["content"])
+            return content.get("widget_type", "unknown")
+        except (json.JSONDecodeError, KeyError):
+            return "unknown"
+    else:
+        return "unknown"