thread: add basic support for folding long quoted blocks

1 files changed, 93 insertions, 7 deletions

diff --git a/alot/widgets/thread.py b/alot/widgets/thread.py
index b410ff14..dd179ed9 100644
--- a/alot/widgets/thread.py
+++ b/alot/widgets/thread.py
@@ -75,10 +75,30 @@ class _MIMEPartWidget(urwid.WidgetWrap):
     # when not None, a list of child _MIMEPartWidget subclasses
     _children = None
 
+    _fold_level = None
+
     def __init__(self, body_wgt, children = None):
         self._children   = children
+        self._fold_level = 0
         super().__init__(body_wgt)
 
+    @property
+    def foldlevel(self):
+        return self._fold_level
+    @foldlevel.setter
+    def foldlevel(self, val):
+        if self._children is None:
+            return
+
+        val_in  = max(0, val)
+        val_out = 0
+
+        for ch in self._children:
+            ch.foldlevel = val_in
+            val_out = max(val_out, ch.foldlevel)
+
+        self._fold_level = val_out
+
 class _CryptPartWidget(_MIMEPartWidget):
     def __init__(self, mime_tree, alternative_pref):
         children = None
@@ -132,17 +152,53 @@ class _AltMixedPart(_MIMEPartWidget):
     def __init__(self, children):
         super().__init__(urwid.Pile(children), children)
 
+class _TextBlock(urwid.WidgetWrap):
+
+    _level = None
+
+    _switch_wgt = None
+    _text_wgt   = None
+    _folded_wgt = None
+
+    def __init__(self, level, lines, attr, fold_context):
+        self._level    = level
+        self._text_wgt = urwid.Text((attr, '\n'.join(lines)))
+
+        context_start, context_end = fold_context
+        if level == 0 or len(lines) <= context_start + context_end + 1:
+            # block is too small for folding
+            self._folded_wgt = self._text_wgt
+        else:
+            folded_lines = lines[:context_start]
+            folded_lines.append('%s [...%d lines folded...]' %
+                ('> ' * level, len(lines) - context_start - context_end))
+            folded_lines.extend(lines[-context_end:])
+            self._folded_wgt = urwid.Text((attr, '\n'.join(folded_lines)))
+
+        self._switch_wgt = urwid.WidgetPlaceholder(self._text_wgt)
+
+        super().__init__(self._switch_wgt)
+
+    def set_foldlevel(self, level):
+        wgt = self._text_wgt if level >= self._level else self._folded_wgt
+        self._switch_wgt.original_widget = wgt
+
 class _TextPart(_MIMEPartWidget):
     _QUOTE_CHARS = '>|:}#'
     _QUOTE_REGEX = '(([ \t]*[{quote_chars}])+)'.format(quote_chars = _QUOTE_CHARS)
 
+    _max_level  = None
+    _block_wgts = None
+
     def __init__(self, text):
         attr_text   = settings.get_theming_attribute('thread', 'body')
         attrs_quote = settings.get_quote_theming()
+        fold_context = settings.get('thread_fold_context')
 
         lines = text.splitlines()
 
-        quote_levels = []
+        blocks    = []
+        max_level = 0
         for line in lines:
             level = 0
             m = re.match(self._QUOTE_REGEX, line)
@@ -151,18 +207,39 @@ class _TextPart(_MIMEPartWidget):
                 for c in self._QUOTE_CHARS:
                     level += g.count(c)
 
-            quote_levels.append(level)
+            max_level = max(max_level, level)
 
-        line_widgets = []
+            if len(blocks) > 0 and blocks[-1][0] == level:
+                blocks[-1][1].append(line)
+            else:
+                blocks.append((level, [line]))
 
-        for level, line in zip(quote_levels, lines):
+        block_wgts = []
+        for level, lines in blocks:
             if level == 0 or len(attrs_quote) < 1:
                 attr = attr_text
             else:
                 attr = attrs_quote[(level - 1) % len(attrs_quote)]
-            line_widgets.append(urwid.Text((attr, line)))
 
-        super().__init__(urwid.Pile(line_widgets))
+            wgt = _TextBlock(level, lines, attr, fold_context)
+            block_wgts.append(wgt)
+
+        self._block_wgts = block_wgts
+        self._max_level  = max_level
+
+        super().__init__(urwid.Pile(block_wgts))
+
+    @property
+    def foldlevel(self):
+        return self._fold_level
+    @foldlevel.setter
+    def foldlevel(self, val):
+        val = max(0, min(self._max_level, val))
+        logging.info('settting foldlevel to %d', val)
+
+        for b in self._block_wgts:
+            b.set_foldlevel(val)
+        self._fold_level = val
 
 class _EmptyMessageWidget(_MIMEPartWidget):
     def __init__(self):
@@ -201,7 +278,7 @@ def _render_mime_tree(mime_tree, alternative_pref):
         if mime_tree.is_alternative:
             return _handle_alternative(mime_tree, alternative_pref)
 
-        return _AltMixedPart(mime_tree, alternative_pref)
+        return _handle_mixed(mime_tree, alternative_pref)
 
     # no children - this is a leaf node
     # skip attachment parts
@@ -339,6 +416,8 @@ class MessageWidget(urwid.WidgetWrap):
         self.display_all_headers = False
         self.display_source      = False
 
+        self.foldlevel = settings.get('thread_fold_initial_level')
+
     def get_message(self):
         return self._message
 
@@ -425,6 +504,13 @@ class MessageWidget(urwid.WidgetWrap):
         self._reassemble(val)
         self._display_source = val
 
+    @property
+    def foldlevel(self):
+        return self._body_wgt.foldlevel
+    @foldlevel.setter
+    def foldlevel(self, val):
+        self._body_wgt.foldlevel = val
+
     def get_selected_attachment(self):
         """
         If an AttachmentWidget is currently focused, return it. Otherwise return