Improve speaker mapping UX

src/mka/ui/streamlit_app.py

@@ -21,6 +21,7 @@ from mka.application.meeting_service import (
     MeetingProcessingService,
     ParticipantInput,
     ProcessingOptions,
+    SpeakerMappingReview,
     stable_id,
 )
 from mka.application.people_yaml import (
@@ -340,6 +341,73 @@ def _progress_callback(
     return update
 
 
+def _speaker_options(
+    participants: tuple[str, ...], mappings: dict[str, str | None], speaker_label: str
+) -> list[str | None]:
+    """Reserve other speakers' participants while retaining this speaker's mapping."""
+    current = mappings.get(speaker_label)
+    reserved = {value for label, value in mappings.items() if label != speaker_label}
+    options: list[str | None] = [None]
+    options.extend(person for person in participants if person == current or person not in reserved)
+    if current is not None and current not in options:
+        options.append(current)
+    return options
+
+
+def _mapping_counts(
+    speaker_labels: tuple[str, ...], mappings: dict[str, str | None]
+) -> tuple[int, int, int]:
+    """Count only detected speakers, including explicit cleared selections."""
+    detected = len(speaker_labels)
+    assigned = sum(mappings.get(label) is not None for label in speaker_labels)
+    return detected, assigned, detected - assigned
+
+
+def _render_speaker_mapping(review: SpeakerMappingReview, run_name: str) -> dict[str, str]:
+    st.subheader("Identify diarized speakers")
+    st.caption(
+        "Confirm identities explicitly. Unmapped speakers remain anonymous; "
+        "the diarized source transcript is not modified."
+    )
+    participant_names = dict(review.participants)
+    # Read every widget before rendering so later speakers also reserve their person.
+    keys = {
+        speaker.speaker_label: f"speaker_mapping_{run_name}_{speaker.speaker_label}"
+        for speaker in review.speakers
+    }
+    mappings = {
+        label: st.session_state.get(key, review.current_mappings.get(label))
+        for label, key in keys.items()
+    }
+    detected, assigned, unassigned = _mapping_counts(tuple(keys), mappings)
+    st.markdown(f"**{detected} speakers detected · {assigned} assigned · {unassigned} unassigned**")
+    if unassigned:
+        st.warning(
+            "Some detected speakers have no confirmed participant mapping. "
+            "Check whether a participant is missing or speaker assignment is incomplete. "
+            "You can still generate a protocol with anonymous speakers."
+        )
+    selections: dict[str, str] = {}
+    for speaker in review.speakers:
+        label = speaker.speaker_label
+        current = mappings[label]
+        options = _speaker_options(tuple(participant_names), mappings, label)
+        st.session_state[keys[label]] = current
+        selected = st.selectbox(
+            f"{label} — Unassigned" if current is None else label,
+            options=options,
+            format_func=lambda value, names=participant_names: (
+                "Unmapped / Unknown" if value is None else names.get(value, value)
+            ),
+            key=keys[label],
+        )
+        if selected is not None:
+            selections[label] = selected
+        for excerpt in speaker.excerpts:
+            st.caption(f"“{excerpt}”")
+    return selections
+
+
 def _render_result() -> None:
     outcome = st.session_state.outcome
     if outcome is None:
@@ -383,29 +451,7 @@ def _render_result() -> None:
     if review is None or not review.speakers:
         return
 
-    st.subheader("Identify diarized speakers")
-    st.caption(
-        "Confirm identities explicitly. Unmapped speakers remain anonymous; "
-        "the diarized source transcript is not modified."
-    )
-    participant_names = dict(review.participants)
-    options = [None, *participant_names]
-    selections: dict[str, str] = {}
-    for speaker in review.speakers:
-        current = review.current_mappings.get(speaker.speaker_label)
-        selected = st.selectbox(
-            speaker.speaker_label,
-            options=options,
-            index=options.index(current) if current in options else 0,
-            format_func=lambda value, names=participant_names: (
-                "Unmapped / Unknown" if value is None else names[value]
-            ),
-            key=f"speaker_mapping_{outcome.run_dir.name}_{speaker.speaker_label}",
-        )
-        if selected is not None:
-            selections[speaker.speaker_label] = selected
-        for excerpt in speaker.excerpts:
-            st.caption(f"“{excerpt}”")
+    selections = _render_speaker_mapping(review, outcome.run_dir.name)
 
     duplicate_assignments = len(selections.values()) != len(set(selections.values()))
     if duplicate_assignments: