Refactor Progression Comparison Logic and Enhance UI Components

- Introduced new utility functions for comparing slot differences, including `compareDiffKind`, `annotateCompareDiffKinds`, and various filtering functions to streamline the comparison process.
- Updated `ProgressionGraphEditor` to utilize the new comparison logic, improving the handling of slot differences and user notifications.
- Enhanced `ProgressionOptimizeCompareModal` to better manage proposed path suggestions, including clearer messaging and improved selection handling for optional replacements.
- Adjusted frontend components to reflect changes in comparison logic, ensuring a more intuitive user experience in managing progression paths.

frontend/src/components/ProgressionGraphEditor.jsx

@@ -28,36 +28,37 @@ import {
   applyEvaluateResponseToDraft,
   applyGapOfferToDraft,
   applySelectedCompareSteps,
-  buildProgressionComparePayload,
-  compareSlotDiffs,
-  collectGapOffersFromApiResponse,
-  dedupeGapOffersBySlot,
-  filterGapOffersForUnfilledSlots,
-  mergeGapOffersForDraft,
-  pathQaQualityPercent,
   applyResolvedStructuredToDraft,
   buildPlanningArtifactFromDraft,
+  buildProgressionComparePayload,
+  collectGapOffersFromApiResponse,
+  compareSlotDiffs,
+  dedupeGapOffersBySlot,
+  draftHasLibrarySlotAssignments,
+  draftRetrievalBoostExerciseIds,
+  EMPTY_PLANNING_CATALOG_CONTEXT,
+  filterGapOffersForUnfilledSlots,
   hydrateProgressionGraphDraft,
-  SLOT_MIN,
   insertSlotInDraft,
   librarySlotExercise,
   majorStepsToOverridePayload,
+  mergeGapOffersForDraft,
   moveSlotInDraft,
   patchSlotInDraft,
+  pathQaQualityPercent,
+  planningCatalogContextToApi,
+  recommendedCompareDiffs,
   removeSlotFromDraft,
   saveProgressionGraphDraft,
+  setCatalogSelectItems,
   setSlotPrimaryLibrary,
   SLOT_MAX,
+  SLOT_MIN,
   slotsAsPathStepRows,
   slotsToEvaluateSteps,
-  draftRetrievalBoostExerciseIds,
-  draftHasLibrarySlotAssignments,
   slotsToSlotAssignments,
   syncProgressionRoadmapFromSlots,
   syncSlotPhasesFromRoadmap,
-  EMPTY_PLANNING_CATALOG_CONTEXT,
-  planningCatalogContextToApi,
-  setCatalogSelectItems,
 } from '../utils/progressionGraphDraft'
 
 function roadmapStructuredPayload(startSituation, targetState, roadmapNotes) {
@@ -523,13 +524,22 @@ export default function ProgressionGraphEditor({ graphId, embedded = false, onSa
     const baselineQa = res?.baseline_path_qa || null
     const proposedQa = res?.proposed_path_qa || res?.path_qa || null
     const diffCount =
-      res?.slot_diff_count ?? compareSlotDiffs(res, { actionableOnly: true }).length
+      res?.slot_diff_count_recommended
+      ?? recommendedCompareDiffs(res).length
+      ?? res?.slot_diff_count
+      ?? compareSlotDiffs(res, { actionableOnly: true }).length
+    const replaceCount = (res?.slot_diffs || []).filter(
+      (d) => d?.diff_kind === 'replace',
+    ).length
     const bPct = pathQaQualityPercent(baselineQa)
     const pPct = pathQaQualityPercent(proposedQa)
     let notice =
       diffCount > 0
-        ? `Match: ${diffCount} Slot-Vorschlag/Vorschläge — bitte im Dialog prüfen und auswählen.`
-        : 'Match: Keine abweichenden Bibliotheks-Slots — Dialog zur Kontrolle geöffnet.'
+        ? `Match: ${diffCount} Lückenfüllung(en) im Dialog — nur diese sind vorausgewählt.`
+        : 'Match: Keine Bibliotheks-Lückenfüllungen — Dialog zur Kontrolle geöffnet.'
+    if (replaceCount > 0) {
+      notice += ` ${replaceCount} optionale Ersetzung(en) bestehender Slots — standardmäßig abgewählt.`
+    }
     const gapCount = collectGapOffersFromApiResponse(res).length
     if (gapCount > 0) {
       notice += ` ${gapCount} KI-Angebot(e) für leere Slots im Panel „Graph-Bewertung“.`

frontend/src/components/ProgressionOptimizeCompareModal.jsx

@@ -2,7 +2,14 @@
  * Gegenüberstellung: bestehender Pfad vs. optimierter Match-Vorschlag.
  */
 import React, { useMemo, useState } from 'react'
-import { compareSlotDiffs, pathQaQualityPercent } from '../utils/progressionGraphDraft'
+import {
+  compareDiffsForDialog,
+  defaultSelectedCompareDiffs,
+  gapOnlyCompareDiffs,
+  optionalReplaceCompareDiffs,
+  pathQaQualityPercent,
+  recommendedCompareDiffs,
+} from '../utils/progressionGraphDraft'
 
 function qaLabel(pathQa) {
   const pct = pathQaQualityPercent(pathQa)
@@ -11,6 +18,66 @@ function qaLabel(pathQa) {
   return ok ? 'OK' : 'Hinweise'
 }
 
+function DiffRow({ diff, checked, onToggle, applying, tone = 'neutral' }) {
+  const midx = Number(diff.roadmap_major_step_index)
+  const border =
+    tone === 'warn'
+      ? '1px solid color-mix(in srgb, var(--danger) 35%, var(--border))'
+      : '1px solid var(--border)'
+  const bg = checked
+    ? tone === 'warn'
+      ? 'color-mix(in srgb, var(--danger) 6%, var(--surface2))'
+      : 'var(--surface2)'
+    : 'var(--surface)'
+
+  return (
+    <li
+      style={{
+        padding: '10px 12px',
+        borderRadius: '8px',
+        border,
+        background: bg,
+        fontSize: '12px',
+      }}
+    >
+      <label style={{ display: 'flex', gap: '8px', alignItems: 'flex-start', cursor: 'pointer' }}>
+        <input
+          type="checkbox"
+          checked={checked}
+          onChange={() => onToggle(midx)}
+          disabled={applying}
+          style={{ marginTop: '3px' }}
+        />
+        <span style={{ flex: 1 }}>
+          <strong>Slot {midx + 1}</strong>
+          {tone === 'warn' ? (
+            <span style={{ marginLeft: '6px', fontSize: '10px', color: 'var(--danger)' }}>
+              Ersetzt deine Zuordnung
+            </span>
+          ) : null}
+          <div
+            style={{
+              display: 'grid',
+              gridTemplateColumns: '1fr 1fr',
+              gap: '8px',
+              marginTop: '6px',
+            }}
+          >
+            <span style={{ color: 'var(--text2)' }}>
+              Bisher: {diff.baseline_title || '— leer —'}
+              {diff.baseline_exercise_id != null ? ` (#${diff.baseline_exercise_id})` : ''}
+            </span>
+            <span style={{ color: tone === 'warn' ? 'var(--danger)' : 'var(--accent-dark)' }}>
+              Neu: {diff.proposed_title || '— leer —'}
+              {diff.proposed_exercise_id != null ? ` (#${diff.proposed_exercise_id})` : ''}
+            </span>
+          </div>
+        </span>
+      </label>
+    </li>
+  )
+}
+
 export default function ProgressionOptimizeCompareModal({
   open,
   comparison,
@@ -19,37 +86,43 @@ export default function ProgressionOptimizeCompareModal({
   onApplySelected,
   applying = false,
 }) {
-  const slotDiffs = compareSlotDiffs(comparison, { actionableOnly: true })
-  const trivialDiffs = (comparison?.slot_diffs || []).filter((d) => d?.trivial_id_swap)
-  const [selected, setSelected] = useState(() => new Set())
-
-  const allKeys = useMemo(
-    () => slotDiffs.map((d) => Number(d.roadmap_major_step_index)),
-    [slotDiffs],
+  const recommended = useMemo(
+    () => recommendedCompareDiffs(comparison),
+    [comparison],
   )
+  const optionalReplace = useMemo(
+    () => optionalReplaceCompareDiffs(comparison),
+    [comparison],
+  )
+  const gapOnly = useMemo(() => gapOnlyCompareDiffs(comparison), [comparison])
+  const dialogDiffs = useMemo(() => compareDiffsForDialog(comparison), [comparison])
+  const defaultSelected = useMemo(
+    () => defaultSelectedCompareDiffs(comparison),
+    [comparison],
+  )
+
+  const [selected, setSelected] = useState(() => new Set())
 
   React.useEffect(() => {
     if (!open) return
-    setSelected(new Set(allKeys))
-  }, [open, allKeys])
+    setSelected(new Set(defaultSelected))
+  }, [open, defaultSelected])
 
   if (!open || !comparison) return null
 
   const baselineQa = comparison.baseline_path_qa
-  const proposedQa = comparison.proposed_path_qa || comparison.path_qa
+  const pipelineQa = comparison.proposed_path_qa_pipeline
   const baselinePct = pathQaQualityPercent(baselineQa)
-  const proposedPct = pathQaQualityPercent(proposedQa)
-  const pipelinePct = pathQaQualityPercent(comparison?.proposed_path_qa_pipeline)
-  const rematchRounds = comparison?.proposed_path_qa_pipeline?.rematch_rounds
-    ?? proposedQa?.rematch_rounds
-  const pipelineQa = comparison?.proposed_path_qa_pipeline
+  const pipelinePct = pathQaQualityPercent(pipelineQa)
+  const rematchRounds = pipelineQa?.rematch_rounds
   const rematchCount = Array.isArray(pipelineQa?.rematch_log) ? pipelineQa.rematch_log.length : 0
   const refineCount = Array.isArray(pipelineQa?.refine_log) ? pipelineQa.refine_log.length : 0
   const hintCount = Number(pipelineQa?.optimization_hint_count || 0)
   const tierCount = Array.isArray(pipelineQa?.qa_tiers) ? pipelineQa.qa_tiers.length : 0
-  const noMeaningfulDiffs = slotDiffs.length === 0
-  const proposedNotBetter =
-    proposedPct != null && baselinePct != null && proposedPct <= baselinePct
+
+  const selectedReplaceCount = optionalReplace.filter((d) =>
+    selected.has(Number(d.roadmap_major_step_index)),
+  ).length
 
   const toggle = (midx) => {
     setSelected((prev) => {
@@ -60,8 +133,16 @@ export default function ProgressionOptimizeCompareModal({
     })
   }
 
-  const toggleAll = (on) => {
-    setSelected(on ? new Set(allKeys) : new Set())
+  const toggleGroup = (diffs, on) => {
+    setSelected((prev) => {
+      const next = new Set(prev)
+      for (const d of diffs) {
+        const midx = Number(d.roadmap_major_step_index)
+        if (on) next.add(midx)
+        else next.delete(midx)
+      }
+      return next
+    })
   }
 
   const title =
@@ -87,41 +168,30 @@ export default function ProgressionOptimizeCompareModal({
           {title}
         </h3>
         <p style={{ fontSize: '12px', color: 'var(--text3)', marginTop: 0, lineHeight: 1.45 }}>
-          KI matcht alle Lernziel-Slots neu (auch bereits belegte). Du wählst im Dialog, welche
-          Vorschläge übernommen werden — der Graph ändert sich erst nach „Auswahl übernehmen“.
+          Übernimm nur, was deinen Pfad verbessert. Leere Slots mit Bibliotheks-Treffer sind
+          vorausgewählt; Ersetzungen bestehender Übungen sind optional und oft schlechter.
+          KI-Entwürfe ohne Bibliotheks-ID gehören ins Panel „KI-Angebote“, nicht hierher.
         </p>
 
-        {noMeaningfulDiffs || proposedNotBetter ? (
-          <div
-            style={{
-              marginBottom: '12px',
-              padding: '10px 12px',
-              borderRadius: '8px',
-              border: '1px solid color-mix(in srgb, var(--danger) 35%, var(--border))',
-              background: 'color-mix(in srgb, var(--danger) 8%, var(--surface2))',
-              fontSize: '12px',
-              lineHeight: 1.45,
-            }}
-          >
-            {noMeaningfulDiffs ? (
-              <strong>Keine inhaltlichen Slot-Änderungen</strong>
-            ) : (
-              <strong>Vorschlag nicht besser als dein Pfad</strong>
-            )}
-            {noMeaningfulDiffs ? (
-              <p style={{ margin: '6px 0 0', color: 'var(--text2)' }}>
-                Rematch hat höchstens dieselben Übungen unter anderen IDs getroffen — kein Grund zur
-                Übernahme. Bitte abbrechen.
-              </p>
-            ) : (
-              <p style={{ margin: '6px 0 0', color: 'var(--text2)' }}>
-                Fair bewertet liefert der Vorschlag keinen höheren Pfad-QS-Wert. Die frühere niedrigere
-                Pipeline-Zahl{pipelinePct != null ? ` (${pipelinePct} %)` : ''} stammte aus dem
-                Rematch-Lauf, nicht aus dem sichtbaren End-Pfad.
-              </p>
-            )}
-          </div>
-        ) : null}
+        <div
+          style={{
+            marginBottom: '12px',
+            padding: '10px 12px',
+            borderRadius: '8px',
+            border: '1px solid color-mix(in srgb, var(--accent) 30%, var(--border))',
+            background: 'color-mix(in srgb, var(--accent) 6%, var(--surface2))',
+            fontSize: '12px',
+            lineHeight: 1.45,
+          }}
+        >
+          <strong>Warum nicht einfach alles übernehmen?</strong>
+          <p style={{ margin: '6px 0 0', color: 'var(--text2)' }}>
+            Der Match-Lauf optimiert den <em>gesamten</em> Pfad neu (inkl. Rematch). Das kann
+            bereits gute Slots verschlechtern. Die Prozentzahl rechts bezieht sich auf diesen
+            Ganzpfad — nicht darauf, dass deine Auswahl besser ist. Nimm deshalb standardmäßig
+            nur Lückenfüllungen an.
+          </p>
+        </div>
 
         <div
           style={{
@@ -140,7 +210,7 @@ export default function ProgressionOptimizeCompareModal({
               fontSize: '12px',
             }}
           >
-            <strong>Aktuell</strong>
+            <strong>Dein Pfad (bewertet)</strong>
             <div style={{ marginTop: '6px' }}>{qaLabel(baselineQa)}</div>
             {baselineQa?.topic_coverage ? (
               <p style={{ margin: '6px 0 0', color: 'var(--text2)' }}>{baselineQa.topic_coverage}</p>
@@ -150,117 +220,158 @@ export default function ProgressionOptimizeCompareModal({
             style={{
               padding: '10px 12px',
               borderRadius: '8px',
-              border: '1px solid color-mix(in srgb, var(--accent) 35%, var(--border))',
-              background: 'color-mix(in srgb, var(--accent) 8%, var(--surface2))',
+              border: '1px solid color-mix(in srgb, var(--text3) 35%, var(--border))',
+              background: 'var(--surface2)',
               fontSize: '12px',
             }}
           >
-            <strong>Vorschlag (Match + Optimierung)</strong>
-            <div style={{ marginTop: '6px' }}>{qaLabel(proposedQa)}</div>
-            {proposedPct != null && baselinePct != null && proposedPct !== baselinePct ? (
-              <p style={{ margin: '6px 0 0', color: 'var(--text2)' }}>
-                Δ {proposedPct - baselinePct > 0 ? '+' : ''}
-                {proposedPct - baselinePct} Prozentpunkte
-              </p>
-            ) : null}
-            {proposedQa?.topic_coverage ? (
-              <p style={{ margin: '6px 0 0', color: 'var(--text2)' }}>{proposedQa.topic_coverage}</p>
-            ) : null}
+            <strong>Match-Ganzpfad (nur Info)</strong>
+            <div style={{ marginTop: '6px', color: 'var(--text2)' }}>
+              {pipelineQa ? qaLabel(pipelineQa) : '—'}
+            </div>
+            <p style={{ margin: '6px 0 0', fontSize: '11px', color: 'var(--text3)' }}>
+              Rematch-Prozess — kein Versprechen für deine Checkbox-Auswahl.
+              {pipelinePct != null && baselinePct != null && pipelinePct < baselinePct
+                ? ` (${pipelinePct} % < ${baselinePct} % bei voller Übernahme).`
+                : ''}
+            </p>
           </div>
         </div>
 
         {tierCount > 0 || rematchCount > 0 || refineCount > 0 || hintCount > 0 ? (
           <p style={{ fontSize: '11px', color: 'var(--text2)', margin: '0 0 14px', lineHeight: 1.45 }}>
-            3-Stufen-Optimierung im Vorschlag
+            Rematch-Protokoll
             {tierCount > 0 ? ` · ${tierCount} QS-Stufen` : ''}
             {rematchCount > 0
-              ? ` · Auto-Rematch ${rematchRounds != null ? `(${rematchRounds} Runde(n))` : ''}: ${rematchCount} Anpassung(en)`
+              ? ` · ${rematchRounds != null ? `${rematchRounds} Runde(n)` : ''}: ${rematchCount} Anpassung(en)`
               : ''}
             {refineCount > 0 ? ` · ${refineCount} Stufen-Spec verfeinert` : ''}
             {hintCount > 0 ? ` · ${hintCount} Handlungshinweis(e)` : ''}
-            . Nur Prozessinfo — nicht für die Prozentzahl links/rechts.
           </p>
         ) : null}
 
-        {trivialDiffs.length > 0 ? (
-          <p style={{ fontSize: '11px', color: 'var(--text3)', margin: '0 0 14px', lineHeight: 1.45 }}>
-            {trivialDiffs.length} reine ID-Tausche (gleicher Titel) — nicht übernehmbar, daher nicht gelistet.
+        {gapOnly.length > 0 ? (
+          <p style={{ fontSize: '11px', color: 'var(--text2)', margin: '0 0 14px', lineHeight: 1.45 }}>
+            Slot{gapOnly.length > 1 ? 's' : ''}{' '}
+            {gapOnly.map((d) => Number(d.roadmap_major_step_index) + 1).join(', ')}: kein
+            Bibliotheks-Treffer — bitte „KI-Angebote“ im Panel nutzen (eigenständig pro Slot).
           </p>
         ) : null}
 
-        {slotDiffs.length === 0 ? (
+        {dialogDiffs.length === 0 ? (
           <p style={{ fontSize: '12px', color: 'var(--text2)' }}>
-            Keine inhaltlichen Abweichungen — der End-Stand entspricht deinem Pfad.
+            Keine übernehmbaren Bibliotheks-Änderungen. Leere Slots ggf. über KI-Angebote im Panel
+            befüllen — nichts am Pfad ändern ist oft die richtige Wahl.
           </p>
         ) : (
           <>
-            <div style={{ display: 'flex', gap: '8px', marginBottom: '8px', flexWrap: 'wrap' }}>
-              <button type="button" className="btn btn-secondary" style={{ fontSize: '11px' }} onClick={() => toggleAll(true)}>
-                Alle wählen
-              </button>
-              <button type="button" className="btn btn-secondary" style={{ fontSize: '11px' }} onClick={() => toggleAll(false)}>
-                Keine
-              </button>
-            </div>
-            <ul style={{ listStyle: 'none', padding: 0, margin: 0, display: 'flex', flexDirection: 'column', gap: '8px' }}>
-              {slotDiffs.map((diff) => {
-                const midx = Number(diff.roadmap_major_step_index)
-                const checked = selected.has(midx)
-                return (
-                  <li
-                    key={`diff-${midx}`}
-                    style={{
-                      padding: '10px 12px',
-                      borderRadius: '8px',
-                      border: '1px solid var(--border)',
-                      background: checked ? 'var(--surface2)' : 'var(--surface)',
-                      fontSize: '12px',
-                    }}
+            {recommended.length > 0 ? (
+              <>
+                <h4 style={{ margin: '0 0 8px', fontSize: '0.9rem' }}>
+                  Lücken füllen (empfohlen)
+                </h4>
+                <div style={{ display: 'flex', gap: '8px', marginBottom: '8px', flexWrap: 'wrap' }}>
+                  <button
+                    type="button"
+                    className="btn btn-secondary"
+                    style={{ fontSize: '11px' }}
+                    onClick={() => toggleGroup(recommended, true)}
                   >
-                    <label style={{ display: 'flex', gap: '8px', alignItems: 'flex-start', cursor: 'pointer' }}>
-                      <input
-                        type="checkbox"
-                        checked={checked}
-                        onChange={() => toggle(midx)}
-                        disabled={applying}
-                        style={{ marginTop: '3px' }}
-                      />
-                      <span style={{ flex: 1 }}>
-                        <strong>Slot {midx + 1}</strong>
-                        <div
-                          style={{
-                            display: 'grid',
-                            gridTemplateColumns: '1fr 1fr',
-                            gap: '8px',
-                            marginTop: '6px',
-                          }}
-                        >
-                          <span style={{ color: 'var(--text2)' }}>
-                            Bisher: {diff.baseline_title || '— leer —'}
-                            {diff.baseline_exercise_id != null ? ` (#${diff.baseline_exercise_id})` : ''}
-                          </span>
-                          <span style={{ color: 'var(--accent-dark)' }}>
-                            Neu: {diff.proposed_title || '— leer —'}
-                            {diff.proposed_exercise_id != null ? ` (#${diff.proposed_exercise_id})` : ''}
-                          </span>
-                        </div>
-                      </span>
-                    </label>
-                  </li>
-                )
-              })}
-            </ul>
+                    Alle Lücken wählen
+                  </button>
+                  <button
+                    type="button"
+                    className="btn btn-secondary"
+                    style={{ fontSize: '11px' }}
+                    onClick={() => toggleGroup(recommended, false)}
+                  >
+                    Keine
+                  </button>
+                </div>
+                <ul
+                  style={{
+                    listStyle: 'none',
+                    padding: 0,
+                    margin: '0 0 16px',
+                    display: 'flex',
+                    flexDirection: 'column',
+                    gap: '8px',
+                  }}
+                >
+                  {recommended.map((diff) => (
+                    <DiffRow
+                      key={`fill-${diff.roadmap_major_step_index}`}
+                      diff={diff}
+                      checked={selected.has(Number(diff.roadmap_major_step_index))}
+                      onToggle={toggle}
+                      applying={applying}
+                    />
+                  ))}
+                </ul>
+              </>
+            ) : null}
+
+            {optionalReplace.length > 0 ? (
+              <>
+                <h4 style={{ margin: '0 0 8px', fontSize: '0.9rem', color: 'var(--danger)' }}>
+                  Bestehende Slots ersetzen (optional — oft Verschlechterung)
+                </h4>
+                <p style={{ fontSize: '11px', color: 'var(--text2)', margin: '0 0 8px' }}>
+                  Standard: abgewählt. Nur aktivieren, wenn du die konkrete Übung bewusst tauschen
+                  willst.
+                </p>
+                <ul
+                  style={{
+                    listStyle: 'none',
+                    padding: 0,
+                    margin: 0,
+                    display: 'flex',
+                    flexDirection: 'column',
+                    gap: '8px',
+                  }}
+                >
+                  {optionalReplace.map((diff) => (
+                    <DiffRow
+                      key={`replace-${diff.roadmap_major_step_index}`}
+                      diff={diff}
+                      checked={selected.has(Number(diff.roadmap_major_step_index))}
+                      onToggle={toggle}
+                      applying={applying}
+                      tone="warn"
+                    />
+                  ))}
+                </ul>
+              </>
+            ) : null}
           </>
         )}
 
-        <div style={{ display: 'flex', flexWrap: 'wrap', gap: '8px', marginTop: '16px', justifyContent: 'flex-end' }}>
+        {selectedReplaceCount > 0 ? (
+          <p
+            className="form-error"
+            style={{ marginTop: '12px', fontSize: '11px' }}
+          >
+            {selectedReplaceCount} Ersetzung(en) gewählt — kann Pfad-QS senken. Lückenfüllungen
+            sind unkritischer.
+          </p>
+        ) : null}
+
+        <div
+          style={{
+            display: 'flex',
+            flexWrap: 'wrap',
+            gap: '8px',
+            marginTop: '16px',
+            justifyContent: 'flex-end',
+          }}
+        >
           <button type="button" className="btn btn-secondary" disabled={applying} onClick={onClose}>
             Abbrechen
           </button>
           <button
             type="button"
             className="btn btn-primary"
-            disabled={applying || selected.size === 0 || slotDiffs.length === 0 || proposedNotBetter}
+            disabled={applying || selected.size === 0 || dialogDiffs.length === 0}
             onClick={() => onApplySelected([...selected])}
           >
             {applying ? 'Übernehmen …' : `Auswahl übernehmen (${selected.size})`}

frontend/src/utils/progressionGraphDraft.js

@@ -985,6 +985,51 @@ function actionableCompareSlotDiffs(diffs) {
   return (diffs || []).filter((d) => !d.trivial_id_swap)
 }
 
+/** fill = leerer Slot + Bibliotheks-Treffer; replace = bestehende Übung tauschen; gap_only = nur KI-Angebot. */
+export function compareDiffKind(diff) {
+  if (!diff || diff.trivial_id_swap) return 'skip'
+  const hasBase = diff.baseline_exercise_id != null
+  const hasProp = diff.proposed_exercise_id != null
+  if (!hasBase && hasProp) return 'fill'
+  if (hasBase && hasProp) return 'replace'
+  if (!hasBase && !hasProp) return 'gap_only'
+  if (hasBase && !hasProp) return 'replace'
+  return 'skip'
+}
+
+export function annotateCompareDiffKinds(diffs) {
+  return (diffs || []).map((d) => ({
+    ...d,
+    diff_kind: compareDiffKind(d),
+  }))
+}
+
+/** Nur übernehmbare Bibliotheks-Diffs (kein reines Titel-/Gap-Geplänkel). */
+export function compareDiffsForDialog(comparison) {
+  const diffs = annotateCompareDiffKinds(
+    compareSlotDiffs(comparison, { actionableOnly: true }),
+  )
+  return diffs.filter((d) => d.diff_kind === 'fill' || d.diff_kind === 'replace')
+}
+
+export function recommendedCompareDiffs(comparison) {
+  return compareDiffsForDialog(comparison).filter((d) => d.diff_kind === 'fill')
+}
+
+export function optionalReplaceCompareDiffs(comparison) {
+  return compareDiffsForDialog(comparison).filter((d) => d.diff_kind === 'replace')
+}
+
+export function gapOnlyCompareDiffs(comparison) {
+  return annotateCompareDiffKinds(
+    compareSlotDiffs(comparison, { actionableOnly: true }),
+  ).filter((d) => d.diff_kind === 'gap_only')
+}
+
+export function defaultSelectedCompareDiffs(comparison) {
+  return recommendedCompareDiffs(comparison).map((d) => Number(d.roadmap_major_step_index))
+}
+
 function mergeGapFillOffersFromSteps(steps, offers) {
   const merged = (offers || []).map((o) => ({ ...o }))
   const seen = new Set(merged.map((o) => o.offer_id).filter(Boolean))
@@ -1006,10 +1051,16 @@ export function buildProgressionComparePayload(baselineRes, proposedRes) {
   const proposedSteps = Array.isArray(proposedRes?.steps) ? proposedRes.steps : []
   const baselineQa = baselineRes?.path_qa || null
   const pipelineQa = proposedRes?.path_qa || null
-  const slotDiffs = annotateCompareSlotDiffs(
-    buildProgressionSlotDiffs(baselineSteps, proposedSteps),
+  const slotDiffs = annotateCompareDiffKinds(
+    annotateCompareSlotDiffs(
+      buildProgressionSlotDiffs(baselineSteps, proposedSteps),
+    ),
   )
   const actionableDiffs = actionableCompareSlotDiffs(slotDiffs)
+  const dialogDiffs = actionableDiffs.filter(
+    (d) => d.diff_kind === 'fill' || d.diff_kind === 'replace',
+  )
+  const recommendedDiffs = dialogDiffs.filter((d) => d.diff_kind === 'fill')
   const gapFillOffers = mergeGapFillOffersFromSteps(
     proposedSteps,
     proposedRes?.gap_fill_offers || [],
@@ -1029,7 +1080,10 @@ export function buildProgressionComparePayload(baselineRes, proposedRes) {
     gap_fill_offers: gapFillOffers,
     slot_diffs: slotDiffs,
     slot_diffs_actionable: actionableDiffs,
-    slot_diff_count: actionableDiffs.length,
+    slot_diffs_dialog: dialogDiffs,
+    slot_diffs_recommended: recommendedDiffs,
+    slot_diff_count: dialogDiffs.length,
+    slot_diff_count_recommended: recommendedDiffs.length,
     slot_diff_count_including_trivial: slotDiffs.length,
     slot_diffs_source: 'steps',
     path_qa: proposedQa,