refactor(webui): deduplicate _extract_checkbox (3 copies → 1)

Extracted extract_checkbox from settings.py, form.py (x2) into
webui/routes/utils/common.py. Moved coerce_bool from settings.py
to common.py to break circular import.

Fixed bug in second form.py copy (was missing __contains__ check).
1006 tests pass.

abogen/webui/routes/settings.py

@@ -19,6 +19,7 @@ from abogen.webui.routes.utils.settings import (
     _NORMALIZATION_STRING_KEYS,
     _DEFAULT_ANALYSIS_THRESHOLD,
 )
+from abogen.webui.routes.utils.common import extract_checkbox
 from abogen.webui.routes.utils.voice import template_options
 from abogen.webui.debug_tts_runner import run_debug_tts_wavs
 from abogen.debug_tts_samples import DEBUG_TTS_SAMPLES
@@ -93,17 +94,9 @@ def update_settings() -> ResponseReturnValue:
         maximum=25,
     )
 
-    def _extract_checkbox(name: str, default: bool) -> bool:
-        values = form.getlist(name) if hasattr(form, "getlist") else []
-        if values:
-            return coerce_bool(values[-1], default)
-        if hasattr(form, "__contains__") and name in form:
-            return False
-        return default
-
     # Normalization settings
     for key in _NORMALIZATION_BOOLEAN_KEYS:
-        current[key] = _extract_checkbox(key, bool(current.get(key, True)))
+        current[key] = extract_checkbox(form, key, bool(current.get(key, True)))
     for key in _NORMALIZATION_STRING_KEYS:
         if hasattr(form, "__contains__") and key in form:
             current[key] = (form.get(key) or "").strip()

abogen/webui/routes/utils/common.py

@@ -1,6 +1,17 @@
-from typing import Any, Optional, Tuple, Iterable, List
+from typing import Any, Optional, Tuple, Iterable, List, Mapping
 from pathlib import Path
 
+
+def coerce_bool(value: Any, default: bool) -> bool:
+    if isinstance(value, bool):
+        return value
+    if isinstance(value, str):
+        return value.lower() in {"true", "1", "yes", "on"}
+    if value is None:
+        return default
+    return bool(value)
+
+
 def split_profile_spec(value: Any) -> Tuple[str, Optional[str]]:
     text = str(value or "").strip()
     if not text:
@@ -18,7 +29,31 @@ def split_speaker_spec(value: Any) -> Tuple[str, Optional[str]]:
 
     return split_profile_spec(value)
 
+
 def existing_paths(paths: Optional[Iterable[Path]]) -> List[Path]:
     if not paths:
         return []
     return [p for p in paths if p.exists()]
+
+
+def extract_checkbox(form: Mapping[str, Any], name: str, default: bool) -> bool:
+    """Extract a boolean checkbox value from a form-like mapping.
+
+    Handles both multi-value forms (Flask's `getlist`) and simple mappings.
+    If the checkbox name is present but has no value, it means unchecked (False).
+    """
+    values: List[str] = []
+    getter = getattr(form, "getlist", None)
+    if callable(getter):
+        raw_values = getter(name)
+        if raw_values:
+            values = list(raw_values)
+    else:
+        raw_flag = form.get(name)
+        if raw_flag is not None:
+            values = [raw_flag]
+    if values:
+        return coerce_bool(values[-1], default)
+    if name in form:
+        return False
+    return default

abogen/webui/routes/utils/form.py

@@ -29,7 +29,7 @@ from abogen.webui.routes.utils.voice import (
 )
 from abogen.webui.routes.utils.entity import sync_pronunciation_overrides
 from abogen.webui.routes.utils.epub import job_download_flags
-from abogen.webui.routes.utils.common import split_profile_spec
+from abogen.webui.routes.utils.common import split_profile_spec, extract_checkbox
 from abogen.utils import calculate_text_length
 from abogen.voice_profiles import serialize_profiles, normalize_profile_entry
 from abogen.chunking import ChunkLevel, build_chunks_for_chapters
@@ -537,28 +537,11 @@ def apply_book_step_form(
     else:
         pending.normalize_chapter_opening_caps = caps_default
 
-    def _extract_checkbox(name: str, default: bool) -> bool:
-        values: List[str] = []
-        getter = getattr(form, "getlist", None)
-        if callable(getter):
-            raw_values = getter(name)
-            if raw_values:
-                values = list(cast(Iterable[str], raw_values))
-        else:
-            raw_flag = form.get(name)
-            if raw_flag is not None:
-                values = [raw_flag]
-        if values:
-            return coerce_bool(values[-1], default)
-        if hasattr(form, "__contains__") and name in form:
-            return False
-        return default
-
     overrides_existing = getattr(pending, "normalization_overrides", None)
     overrides: Dict[str, Any] = dict(overrides_existing or {})
     for key in _NORMALIZATION_BOOLEAN_KEYS:
         default_toggle = overrides.get(key, bool(settings.get(key, True)))
-        overrides[key] = _extract_checkbox(key, default_toggle)
+        overrides[key] = extract_checkbox(form, key, default_toggle)
     for key in _NORMALIZATION_STRING_KEYS:
         default_val = overrides.get(key, str(settings.get(key, "")))
         val = form.get(key)
@@ -886,25 +869,10 @@ def build_pending_job_from_extraction(
         apply_config=bool(speaker_config_payload),
     )
 
-    def _extract_checkbox(name: str, default: bool) -> bool:
-        values: List[str] = []
-        getter = getattr(form, "getlist", None)
-        if callable(getter):
-            raw_values = getter(name)
-            if raw_values:
-                values = list(cast(Iterable[str], raw_values))
-        else:
-            raw_flag = form.get(name)
-            if raw_flag is not None:
-                values = [raw_flag]
-        if values:
-            return coerce_bool(values[-1], default)
-        return default
-
     normalization_overrides = {}
     for key in _NORMALIZATION_BOOLEAN_KEYS:
         default_val = bool(settings.get(key, True))
-        normalization_overrides[key] = _extract_checkbox(key, default_val)
+        normalization_overrides[key] = extract_checkbox(form, key, default_val)
 
     for key in _NORMALIZATION_STRING_KEYS:
         default_val = str(settings.get(key, ""))

abogen/webui/routes/utils/settings.py

@@ -15,7 +15,7 @@ from abogen.normalization_settings import (
 from abogen.utils import load_config, save_config
 from abogen.integrations.calibre_opds import CalibreOPDSClient
 from abogen.integrations.audiobookshelf import AudiobookshelfConfig
-from abogen.webui.routes.utils.common import split_profile_spec
+from abogen.webui.routes.utils.common import split_profile_spec, coerce_bool
 
 SAVE_MODE_LABELS = {
     "save_next_to_input": "Save next to input file",
@@ -245,16 +245,6 @@ def render_prompt_template(template: str, context: Mapping[str, str]) -> str:
     return _PROMPT_TOKEN_RE.sub(_replace, template)
 
 
-def coerce_bool(value: Any, default: bool) -> bool:
-    if isinstance(value, bool):
-        return value
-    if isinstance(value, str):
-        return value.lower() in {"true", "1", "yes", "on"}
-    if value is None:
-        return default
-    return bool(value)
-
-
 def coerce_float(value: Any, default: float) -> float:
     try:
         return max(0.0, float(value))