Remove overlapping highlights when applying a new one

src/pyj/range_utils.pyj

@@ -60,6 +60,11 @@ def unwrap(node):
         p.normalize()
 
 
+def unwrap_crw(crw):
+    for node in document.querySelectorAll(f'span[data-calibre-range-wrapper="{crw}"]'):
+        unwrap(node)
+
+
 def create_wrapper_function(wrapper_elem, r):
     start_node = r.startContainer
     end_node = r.endContainer
@@ -109,3 +114,33 @@ def wrap_text_in_range(style, r):
 def reset_highlight_counter():
     nonlocal wrapper_counter
     wrapper_counter = 0
+
+
+def is_text_node(node):
+    return node.nodeType is Node.TEXT_NODE or node.nodeType is Node.CDATA_SECTION_NODE
+
+
+def range_wrappers_intersecting_selection(sel):
+    ans = {}
+    sel = sel or window.getSelection()
+    if not sel:
+        return ans
+    r = sel.getRangeAt(0)
+    if not r:
+        return ans
+    walker = document.createTreeWalker(r.commonAncestorContainer, NodeFilter.SHOW_ALL, None, False)
+    in_selection = False
+    while True:
+        node = walker.nextNode()
+        if not node:
+            break
+        if not in_selection and node is not r.startContainer:
+            continue
+        in_selection = True
+        if node.nodeType is Node.ELEMENT_NODE and node.dataset.calibreRangeWrapper:
+            ans[node.dataset.calibreRangeWrapper] = True
+        elif is_text_node(node) and node.parentNode.dataset.calibreRangeWrapper:
+            ans[node.parentNode.dataset.calibreRangeWrapper] = True
+        if node is r.endContainer:
+            break
+    return Object.keys(ans)

src/pyj/read_book/iframe.pyj

@@ -11,7 +11,10 @@ from select import (
 
 from fs_images import fix_fullscreen_svg_images
 from iframe_comm import IframeClient
-from range_utils import reset_highlight_counter, wrap_text_in_range
+from range_utils import (
+    range_wrappers_intersecting_selection, reset_highlight_counter, unwrap_crw,
+    wrap_text_in_range
+)
 from read_book.cfi import cfi_for_selection, scroll_to as scroll_to_cfi
 from read_book.extract import get_elements
 from read_book.find import reset_find_caches, select_search_result
@@ -646,12 +649,28 @@ class IframeBoss:
         elif data.type is 'set-highlight-style':
             set_selection_style(data.style)
         elif data.type is 'apply-highlight':
+            sel = window.getSelection()
+            text = ''
+            if sel:
+                text = sel.toString()
             bounds = cfi_for_selection()
+            intersecting_wrappers = range_wrappers_intersecting_selection()
             annot_id = wrap_text_in_range(data.style)
+            removed_highlights = {}
             if annot_id is not None:
-                window.getSelection().removeAllRanges()
+                sel.removeAllRanges()
                 self.annot_id_uuid_map[annot_id] = data.uuid
-            self.send_message('annotations', type='highlight-applied', uuid=data.uuid, ok=annot_id is not None, bounds=bounds)
+                for crw in intersecting_wrappers:
+                    unwrap_crw(crw)
+                    removed_highlights[self.annot_id_uuid_map[crw]] = True
+            self.send_message(
+                'annotations',
+                type='highlight-applied',
+                uuid=data.uuid, ok=annot_id is not None,
+                bounds=bounds,
+                removed_highlights=Object.keys(removed_highlights),
+                highlighted_text=text,
+            )
             reset_find_caches()
         else:
             console.log('Ignoring annotations message to iframe with unknown type: ' + data.type)