Restore the markdown_view as an original_view

See the top of MarkdownLivePreview.py for terminology

Doesn't work well for unsaved files, as pre_close is triggered after the
confirmation dialog

MarkdownLivePreview.py

@@ -6,6 +6,14 @@ from .utils import *
 def plugin_loaded():
     pass
 
+SETTING_MDLP = "markdown_live_preview"
+
+# original_view: the view in the regular editor, without it's own window
+# markdown_view: the markdown view, in the special window
+# preview_view: the preview view, in the special window
+# original_window: the regular window
+# preview_window: the window with the markdown file and the preview
+
 class MdlpInsertCommand(sublime_plugin.TextCommand):
 
     def run(self, edit, point, string):
@@ -20,10 +28,12 @@ class OpenMarkdownPreviewCommand(sublime_plugin.TextCommand):
         a dialog) and re-insert it into a new view into a new window """
 
         original_view = self.view
+        original_window_id = original_view.window().id()
         file_name = original_view.file_name()
 
         syntax_file = original_view.settings().get('syntax')
 
+
         if file_name is None:
 
             # the file isn't saved, we need to restore the content manually
@@ -39,22 +49,25 @@ class OpenMarkdownPreviewCommand(sublime_plugin.TextCommand):
             original_view.close()
 
         sublime.run_command('new_window')
-        window = sublime.active_window()
+        preview_window = sublime.active_window()
 
-        window.run_command('set_layout', {
+        preview_window.run_command('set_layout', {
             'cols': [0.0, 0.5, 1.0],
             'rows': [0.0, 1.0],
             'cells': [[0, 0, 1, 1], [1, 0, 2, 1]]
         })
 
-        window.focus_group(0)
+        preview_window.focus_group(0)
         if file_name:
-            new_view = window.open_file(file_name)
+            markdown_view = preview_window.open_file(file_name)
         else:
-            new_view = window.new_file()
+            markdown_view = preview_window.new_file()
-            new_view.run_command('mdlp_insert', {'point': 0, 'string': content})
+            markdown_view.run_command('mdlp_insert', {'point': 0, 'string': content})
 
-        new_view.set_syntax_file(syntax_file)
+        markdown_view.set_syntax_file(syntax_file)
+        markdown_view.settings().set(SETTING_MDLP, {
+            "original_window_id": original_window_id
+        })
 
     def is_enabled(self):
         # FIXME: is this the best way there is to check if the current syntax is markdown?
@@ -62,3 +75,51 @@ class OpenMarkdownPreviewCommand(sublime_plugin.TextCommand):
         #        what about "md"?
         return 'markdown' in self.view.settings().get('syntax').lower()
 
+class MarkdownLivePreviewListener(sublime_plugin.EventListener):
+
+    def on_pre_close(self, markdown_view):
+        """ Close the view in the preview window, and store information for the on_close
+        listener (see doc there)
+        """
+        print('pre close')
+
+        if not markdown_view.settings().get(SETTING_MDLP):
+            return
+
+        self.markdown_view = markdown_view
+        self.preview_window = markdown_view.window()
+        self.file_name = markdown_view.file_name()
+
+        if self.file_name is None:
+            # FIXME: this is duplicated code. How should it be generalized?
+            total_region = sublime.Region(0, markdown_view.size())
+            self.content = markdown_view.substr(total_region)
+            markdown_view.erase(edit, total_region)
+        else:
+            self.content = None
+
+    def on_close(self, markdown_view):
+        """ Use the information saved to restore the markdown_view as an original_view
+        """
+        infos = markdown_view.settings().get(SETTING_MDLP)
+        if not infos:
+            return
+
+        assert markdown_view.id() == self.markdown_view.id(), \
+        "pre_close view.id() != close view.id()"
+
+        self.preview_window.run_command('close_window')
+
+        # find the window with the right id
+        original_window = next(window for window in sublime.windows() \
+                               if window.id() == infos['original_window_id'])
+        print(original_window.id(), self.preview_window.id(), infos)
+        if self.file_name:
+            original_window.open_file(self.file_name)
+        else:
+            # note here that this is called original_view, because it's what semantically
+            # makes sense, but this original_view.id() will be different than the one
+            # that we closed first to reopen in the preview window
+            # shouldn't cause any trouble though
+            original_view = original_window.new_file()
+            original_view.run_command('mdlp_insert', {'point': 0, 'string': self.content})