Add a Dataview / Diff command

pyproject.toml

@@ -15,7 +15,7 @@ classifiers = [
         "Operating System :: OS Independent",
     ]
 dependencies = [
-    "textual >= 0.79",
+    "textual[syntax] >= 0.79",
     "rich",
     "platformdirs",
     "pyaml",

src/production_planner/DataView.tcss

@@ -0,0 +1,4 @@
+DataView > Horizontal {
+    width: auto;
+    height: auto;
+}

src/production_planner/__init__.py

@@ -82,6 +82,9 @@ def get_system_commands(self, screen: Screen) -> Iterable[SystemCommand]:
         yield planner_command("Save As", "Save the currently active file with a new filename", self._save_as)
         yield planner_command("Load", "Load a new file in the currently active table", self._load)
         yield planner_command("Delete", "Delete a file from the filesystem", self._delete)
+        # 3, because the command-palette is the second screen
+        if len(self.screen_stack) < 3:
+            yield planner_command("Dataview", "Shows the corresponding yaml source of the open file", self._dataview)
 
     def _save_as(self):
         if not self.focused_table:
@@ -99,6 +102,11 @@ def _delete(self):
             return
         self.call_next(self.focused_table.action_delete)
 
+    def _dataview(self):
+        if not self.focused_table or len(self.screen_stack) > 2:
+            return
+        self.call_next(self.focused_table.action_dataview)
+
     def is_table_shown(self, table: PlannerTable) -> bool:
         raise NotImplemented
 

src/production_planner/datatable.py

@@ -34,6 +34,8 @@
     SaveDataFile
 )
 
+from .dataview import DataView
+
 import os
 from dataclasses import dataclass
 from pathlib import Path
@@ -164,6 +166,9 @@ def on_mount(self) -> None:
     def on_focus(self):
         self.app.focused_table = self
 
+    def action_dataview(self):
+        self.app.push_screen(DataView(self))
+
     def save_data(self, subpath=None) -> Optional[Tuple[DataFile]]:
         result = self.sink.sink_commit(subpath)
         self.app.title = self.sink.title

src/production_planner/dataview.py

@@ -0,0 +1,60 @@
+#! /bin/env python
+# -*- coding:utf-8 -*-
+#  This Source Code Form is subject to the terms of the Mozilla Public
+#  License, v. 2.0. If a copy of the MPL was not distributed with this
+#  file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+from io import StringIO
+from difflib import unified_diff
+
+from textual.screen import Screen
+from textual.containers import Horizontal, Vertical
+from textual.widgets import (
+    TextArea,
+    Label,
+    Footer,
+)
+from textual.app import ComposeResult
+
+import yaml
+
+
+class YamlEditor(TextArea):
+    ...
+
+
+class DiffEditor(TextArea):
+    ...
+
+
+class DataView(Screen):
+    BINDINGS = [
+        ("escape", "cancel", "Cancel"),
+    ]
+    CSS_PATH = "DataView.tcss"
+
+    def __init__(self, table, *args, **kwargs):
+        self.table = table
+        super().__init__(*args, **kwargs)
+
+    def compose(self) -> ComposeResult:
+        with Horizontal():
+            with Vertical():
+                yield Label("File in session")
+                # FIXME: when `editor.read_only == False` then the `escape` > `action_cancel` binding doesn't work anymore
+                new = yaml.dump(self.table.nodetree)
+                yield YamlEditor.code_editor(new, language="yaml", read_only=True)
+
+            with Vertical():
+                old = yaml.dump(self.table.sink.sink._data)
+                diff = StringIO()
+                diff.writelines(unified_diff(old.splitlines(keepends=True),
+                                             new.splitlines(keepends=True),
+                                             fromfile="sink.yaml",
+                                             tofile="staging.yaml"))
+                yield Label("Difference to saved file")
+                yield DiffEditor.code_editor(diff.getvalue(), language="yaml", read_only=True)
+        yield Footer()
+
+    def action_cancel(self):
+        self.dismiss("")