widget: Add find_widget_type function.

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 +1,68 @@
+from typing import List
+
+import pytest
+from pytest import param as case
+
+from zulipterminal.widget import Submessage, find_widget_type
+
+
+@pytest.mark.parametrize(
+    "submessages, 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(
+    submessages: List[Submessage], expected_widget_type: str
+) -> None:
+    widget_type = find_widget_type(submessages)
+
+    assert widget_type == expected_widget_type

zulipterminal/widget.py

@@ -0,0 +1,25 @@
+"""
+Process widgets (submessages) like polls, todo lists, etc.
+"""
+
+import json
+from typing import Dict, List, Union
+
+
+Submessage = Dict[str, Union[int, str]]
+
+
+def find_widget_type(submessages: List[Submessage]) -> str:
+    if submessages and "content" in submessages[0]:
+        content = submessages[0]["content"]
+
+        if isinstance(content, str):
+            try:
+                loaded_content = json.loads(content)
+                return loaded_content.get("widget_type", "unknown")
+            except json.JSONDecodeError:
+                return "unknown"
+        else:
+            return "unknown"
+    else:
+        return "unknown"