Add live Markdown editing, colours and files in the tree

Client/Viewer.py

@@ -4,6 +4,9 @@ EditorView/ImageView idea, with SaraView's View/Edit/Save toolbar).
 - Markdown is rendered in View; the other text types are shown as
   highlighted code. Edit is a plain monospace field with an explicit Save
   (Ctrl+S). On a server, saving records line blame for you, like the web view.
+- With Markdown editing set to Live (Settings > General), Markdown opens in
+  LiveMarkdown instead: rendered, and click a block to edit it in place.
+  Edit/View becomes Source/Live there.
 - Images are shown fitted to the window.
 - Video and other files get their details and Open Externally (a server
   file is downloaded to ~/.cache/SaraView first). Flet has no built-in
@@ -16,7 +19,8 @@ from typing import Callable, Optional
 import flet as ft
 
 from App import App
-from Core import ChipButton, CodeStyleSheet, HumanSize, Palette
+from Core import ChipButton, CodeStyleSheet, HumanSize, MarkdownCodeTheme, MarkdownSheet, Palette
+from LiveMarkdown import LiveMarkdown
 from Sources import Entry, SourceError, TextFileTypes
 
 LanguageByExtension = {
@@ -56,6 +60,9 @@ class FileView(ft.Container):
         self.OnClose = OnClose
         self.OnFocusChange = OnFocusChange
         self.IsText = self.FileType in TextFileTypes
+        self.IsLive = (self.FileType == "markdown" and TheApp.Config.MarkdownEditing == "Live"
+                       and TheApp.Source.CanWrite)
+        self.Live: Optional[LiveMarkdown] = None
         self.IsEditing = False
         self.IsDirty = False
         self.Content = ""
@@ -63,6 +70,9 @@ class FileView(ft.Container):
 
         self.StatusText = ft.Text("", color=Palette.Overlay0, size=12)
         self.ToggleButton = ChipButton("Edit", self._ToggleEdit, Icon=ft.Icons.EDIT_OUTLINED)
+        if self.IsLive:
+            self.ToggleButton.content = "Source"
+            self.ToggleButton.icon = ft.Icons.CODE
         self.SaveButton = ChipButton("Save", lambda e: self.Save(), Icon=ft.Icons.SAVE_OUTLINED, Disabled=True)
         CanWrite = TheApp.Source.CanWrite
         if not CanWrite:
@@ -109,6 +119,10 @@ class FileView(ft.Container):
             if self.IsText:
                 self.Content = Source.ReadText(self.Root, self.RelativePath)
                 self.TextField.value = self.Content
+                if self.IsLive:
+                    self.Live = LiveMarkdown(self.Content, self.TheApp.Config.FontSize, self._OnTextChanged,
+                                             self.OnFocusChange, self._OnTapLink)
+                    return self.Live
                 return self._RenderedView()
             if self.FileType == "image":
                 return ft.Image(src=Source.ReadBytes(self.Root, self.RelativePath), fit=ft.BoxFit.CONTAIN, expand=True)
@@ -124,7 +138,8 @@ class FileView(ft.Container):
                 value=Text,
                 selectable=True,
                 extension_set=ft.MarkdownExtensionSet.GITHUB_FLAVORED,
-                code_theme=ft.MarkdownCodeTheme.ATOM_ONE_DARK,
+                md_style_sheet=MarkdownSheet(self.TheApp.Config.FontSize),
+                code_theme=MarkdownCodeTheme(),
                 code_style_sheet=CodeStyleSheet(),
                 on_tap_link=self._OnTapLink,
             )
@@ -134,7 +149,8 @@ class FileView(ft.Container):
                 value=FencedBlock(Text, LanguageByExtension.get(Extension, "")),
                 selectable=True,
                 extension_set=ft.MarkdownExtensionSet.GITHUB_FLAVORED,
-                code_theme=ft.MarkdownCodeTheme.ATOM_ONE_DARK,
+                md_style_sheet=MarkdownSheet(self.TheApp.Config.FontSize),
+                code_theme=MarkdownCodeTheme(),
                 code_style_sheet=CodeStyleSheet(),
             )
         else:
@@ -186,7 +202,7 @@ class FileView(ft.Container):
     def CanSave(self) -> bool:
         return self.IsText and self.IsDirty
 
-    def _OnTextChanged(self, e) -> None:
+    def _OnTextChanged(self, e=None) -> None:
         if not self.IsDirty:
             self.IsDirty = True
             self.SaveButton.disabled = False
@@ -194,7 +210,17 @@ class FileView(ft.Container):
             self.SaveButton.update()
             self.StatusText.update()
 
+    @property
+    def Text(self) -> str:
+        """What's being edited, in whichever view has it."""
+        if self.Live is not None and not self.IsEditing:
+            return self.Live.Text
+        return self.TextField.value or ""
+
     def _ToggleEdit(self, e=None) -> None:
+        if self.Live is not None:
+            self._ToggleSource()
+            return
         self.IsEditing = not self.IsEditing
         if self.IsEditing:
             self.Body.content = self.TextField
@@ -210,6 +236,32 @@ class FileView(ft.Container):
         self.Body.update()
         self.ToggleButton.update()
 
+    def _ToggleSource(self) -> None:
+        """Live mode's toggle: the whole file as plain text, and back."""
+        self.IsEditing = not self.IsEditing
+        if self.IsEditing:
+            self.TextField.value = self.Live.Text
+            self.Live.EditingIndex = None  # its open block's text is in the field now
+            self.Body.content = self.TextField
+            self.ToggleButton.content = "Live"
+            self.ToggleButton.icon = ft.Icons.VISIBILITY_OUTLINED
+            self.OnFocusChange(True)
+        else:
+            self.Live.SetText(self.TextField.value or "", Update=False)  # not on the page yet
+            self.Body.content = self.Live
+            self.ToggleButton.content = "Source"
+            self.ToggleButton.icon = ft.Icons.CODE
+            self.OnFocusChange(False)
+        self.Body.update()
+        self.ToggleButton.update()
+
+    def HandleEscape(self) -> bool:
+        """Esc first closes an open block in live mode; True if it did."""
+        if self.Live is not None and not self.IsEditing and self.Live.IsEditing:
+            self.Live.Commit()
+            return True
+        return False
+
     def ToggleEdit(self) -> None:
         if self.IsText and not self.ToggleButton.disabled:
             self._ToggleEdit()
@@ -218,11 +270,11 @@ class FileView(ft.Container):
         if not self.CanSave:
             return
         try:
-            self.TheApp.Source.WriteText(self.Root, self.RelativePath, self.TextField.value or "")
+            self.TheApp.Source.WriteText(self.Root, self.RelativePath, self.Text)
         except SourceError as Error:
             self.TheApp.HandleError(Error, f"Couldn't save {self.Item.Name}")
             return
-        self.Content = self.TextField.value or ""
+        self.Content = self.Text
         self.IsDirty = False
         self.SaveButton.disabled = True
         self.StatusText.value = "Saved."