boxes/helper: Add support for rendering tables.

Added a helper function, render_table, to process a table and
return its content as a list of strings which can then be rendered
in the MessageBox.

Tests amended.

tests/ui/test_ui_tools.py

@@ -1332,7 +1332,17 @@ def test_private_message_to_self(self, mocker):
         ('<hr/>', ['[RULER NOT RENDERED]']),
         ('<img>', ['[IMAGE NOT RENDERED]']),
         ('<img/>', ['[IMAGE NOT RENDERED]']),
-        ('<table>stuff</table>', ['[TABLE NOT RENDERED]']),
+        ('<table><thead><tr><th>Firstname</th><th>Lastname</th></tr></thead>'
+         '<tbody><tr><td>John</td><td>Doe</td></tr><tr><td>Mary</td><td>Moe'
+         '</td></tr></tbody></table>', [
+             ('bold', '------------------------\n'),
+             ('bold', '| Firstname | Lastname |\n'),
+             ('bold', '------------------------\n'),
+             '| John      | Doe      |\n',
+             '------------------------\n',
+             '| Mary      | Moe      |\n',
+             '------------------------',
+            ]),
         ('<span class="katex-display">some-math</span>', ['some-math']),
         ('<span class="katex">some-math</span>', ['some-math']),
         ('<ul><li>text</li></ul>', ['', '  * ', '', 'text']),

zulipterminal/helper.py

@@ -485,3 +485,43 @@ def notify(title: str, html_text: str) -> None:
     if command:
         res = subprocess.run(shlex.split(command), stdout=subprocess.DEVNULL,
                              stderr=subprocess.STDOUT)
+
+
+def render_table(element: Any) -> List[Union[str, Tuple[str, str]]]:
+    """
+    Renders table to be displayed in the MessageBox.
+    """
+    # Header.
+    headers = element.find('thead').findChild().findChildren()
+    # Cells store data column-wise.
+    cells = [[] for _ in headers]  # type: List[List[str]]
+    for index, header in enumerate(headers):
+        cells[index].append(' ' + header.text + ' ')
+
+    # Body.
+    rows = element.find('tbody').find_all('tr')
+    for row in rows:
+        for index, data in enumerate(row.findChildren()):
+            cells[index].append(' ' + data.text + ' ')
+
+    # Rendering.
+    col_width = [len(max(column, key=lambda s: len(s))) for column in cells]
+    dashes = ('-' * (sum(col_width) + len(headers) + 1)) + '\n'
+    contents = []  # type: List[Union[str, Tuple[str, str]]]
+    contents.append(('bold', dashes))
+    rows_count = len(rows) + 1  # +1 to include header.
+    for index in range(rows_count):
+        row = '|' + '|'.join(col[index].ljust(col_width[col_index])
+                             for col_index, col in enumerate(cells)) + '|\n'
+        if index == 0:
+            # Make the headers bold.
+            contents.append(('bold', row))
+            contents.append(('bold', dashes))
+        else:
+            contents.append(row)
+            if index == rows_count - 1:
+                # Remove '\n' for the last row.
+                contents.append(dashes[:-1])
+            else:
+                contents.append(dashes)
+    return contents

zulipterminal/ui_tools/boxes.py

@@ -13,7 +13,7 @@
 
 from zulipterminal.config.keys import is_command_key, keys_for_command
 from zulipterminal.helper import (
-    Message, match_groups, match_stream, match_user,
+    Message, match_groups, match_stream, match_user, render_table,
 )
 from zulipterminal.urwid_types import urwid_Size
 
@@ -386,7 +386,6 @@ def soup2markup(self, soup: Any) -> List[Any]:
             'br': '',  # No indicator of absence
             'hr': 'RULER',
             'img': 'IMAGE',
-            'table': 'TABLE'
         }
         unrendered_div_classes = {  # In pairs of 'div_class': 'text'
             # TODO: Support embedded content & twitter preview?
@@ -482,6 +481,8 @@ def soup2markup(self, soup: Any) -> List[Any]:
                 # TODO: Support nested lists
                 markup.append('  * ')
                 markup.extend(self.soup2markup(element))
+            elif element.name == 'table':
+                markup.extend(render_table(element))
             else:
                 markup.extend(self.soup2markup(element))
         return markup