answers: collapsing behavior fixed height

web/src/components/search/search-results-panel.tsx

@@ -1,6 +1,8 @@
+import { useEffect, useRef, useState } from "preact/hooks";
 import { Search } from "lucide-preact";
 import type { SearchDetail, SearchResultItem } from "@/lib/api";
 import { MarkdownContent } from "@/components/markdown/markdown-content";
+import { cn } from "@/lib/utils";
 
 function cleanResultText(input: string) {
   return input
@@ -50,6 +52,29 @@ type Props = {
 };
 
 export function SearchResultsPanel({ search, isLoading, isRunning, showPrompt = true, className }: Props) {
+  const ANSWER_COLLAPSED_HEIGHT_CLASS = "h-[3rem]";
+  const [isAnswerExpanded, setIsAnswerExpanded] = useState(false);
+  const [canExpandAnswer, setCanExpandAnswer] = useState(false);
+  const answerBodyRef = useRef<HTMLDivElement | null>(null);
+
+  useEffect(() => {
+    setIsAnswerExpanded(false);
+    setCanExpandAnswer(false);
+  }, [search?.id, search?.answerText]);
+
+  useEffect(() => {
+    const el = answerBodyRef.current;
+    if (!el || !search?.answerText) {
+      setCanExpandAnswer(false);
+      return;
+    }
+    if (isAnswerExpanded) {
+      setCanExpandAnswer(true);
+      return;
+    }
+    setCanExpandAnswer(el.scrollHeight - el.clientHeight > 1);
+  }, [search?.answerText, isAnswerExpanded]);
+
   const citationEntries = (search?.answerCitations ?? [])
     .map((citation, index) => {
       const href = citation.url || citation.id || "";
@@ -68,6 +93,11 @@ export function SearchResultsPanel({ search, isLoading, isRunning, showPrompt =
     return citationEntries.find((entry) => entry.normalizedHref === normalized)?.index;
   };
 
+  const hasAnswerText = !!search?.answerText;
+  const isAnswerLoading = isRunning && !hasAnswerText;
+  const hasCitations = citationEntries.length > 0;
+  const isExpandable = hasAnswerText && (canExpandAnswer || hasCitations);
+
   return (
     <div className={className ?? "mx-auto w-full max-w-4xl"}>
       {search?.query ? (
@@ -84,17 +114,47 @@ export function SearchResultsPanel({ search, isLoading, isRunning, showPrompt =
       {(isRunning || !!search?.answerText || !!search?.answerError) && (
         <section className="mb-6 rounded-xl border border-slate-600/60 bg-[#121a2e] p-4">
           <p className="text-xs font-semibold uppercase tracking-wide text-sky-300/90">Answer</p>
-          {isRunning && !search?.answerText ? <p className="mt-2 text-sm text-muted-foreground">Generating answer...</p> : null}
+          {(isAnswerLoading || hasAnswerText) ? (
-          {search?.answerText ? (
+            <div className="mt-2">
+              <div className="relative">
+                <div
+                  ref={answerBodyRef}
+                  className={cn(
+                    "overflow-hidden",
+                    !isAnswerExpanded && ANSWER_COLLAPSED_HEIGHT_CLASS
+                  )}
+                >
+                  {isAnswerLoading ? (
+                    <div className="text-sm text-muted-foreground">Generating answer...</div>
+                  ) : (
                     <MarkdownContent
-              markdown={search.answerText}
+                      markdown={search?.answerText ?? ""}
                       mode="citationTokens"
                       resolveCitationIndex={resolveCitationIndex}
-              className="mt-2 text-sm leading-6 text-slate-100"
+                      className="text-sm leading-6 text-slate-100"
                     />
+                  )}
+                </div>
+                {!isAnswerExpanded && (isExpandable || isAnswerLoading) ? (
+                  <div className="pointer-events-none absolute inset-x-0 bottom-0 h-7 bg-gradient-to-t from-[#121a2e] to-transparent" />
+                ) : null}
+              </div>
+              <div className="mt-2 h-5">
+                {isExpandable ? (
+                  <button
+                    type="button"
+                    className="inline-flex items-center gap-1 text-xs font-medium text-sky-200 hover:text-sky-100"
+                    onClick={() => setIsAnswerExpanded((current) => !current)}
+                  >
+                    <span className={cn("inline-block text-[11px] transition-transform", isAnswerExpanded && "rotate-180")}>▾</span>
+                    {isAnswerExpanded ? "Show less" : "Show more"}
+                  </button>
+                ) : null}
+              </div>
+            </div>
           ) : null}
           {search?.answerError ? <p className="mt-2 text-sm text-red-500">{search.answerError}</p> : null}
-          {!!citationEntries.length && (
+          {isAnswerExpanded && !!citationEntries.length && (
             <div className="mt-3 flex flex-wrap gap-2">
               {citationEntries.slice(0, 8).map((citation) => {
                 return (