Reorganize conflict intake UI and expandable summaries (#96)

- Extract shared merge-conflict logic into reusable helpers
- Add expandable summary preview sheets for long guidance text
- Refresh intake layout with tooltip help and improved workspace display

Author: BunsDev

apps/web/src/components/merge-conflicts/ExpandableSummary.test.tsx

@@ -0,0 +1,59 @@
+import { renderToStaticMarkup } from "react-dom/server";
+import { describe, expect, it } from "vitest";
+
+import { ExpandableSummary } from "./ExpandableSummary";
+
+describe("ExpandableSummary", () => {
+  it("renders inline text by default when no children are provided", () => {
+    const html = renderToStaticMarkup(
+      <ExpandableSummary text="This is an AI summary that is long enough to be expandable and interesting." />,
+    );
+    expect(html).toContain(
+      "This is an AI summary that is long enough to be expandable and interesting.",
+    );
+  });
+
+  it("renders custom children when provided", () => {
+    const html = renderToStaticMarkup(
+      <ExpandableSummary text="Raw text here">
+        <span className="custom">Custom inline render</span>
+      </ExpandableSummary>,
+    );
+    expect(html).toContain("Custom inline render");
+    expect(html).toContain("custom");
+  });
+
+  it("shows the expand button for text longer than 40 characters", () => {
+    const html = renderToStaticMarkup(
+      <ExpandableSummary text="This is definitely long enough to warrant an expand button for the user." />,
+    );
+    expect(html).toContain("Expand summary");
+  });
+
+  it("hides the expand button for very short text", () => {
+    const html = renderToStaticMarkup(<ExpandableSummary text="Short." />);
+    expect(html).not.toContain("Expand summary");
+  });
+
+  it("hides the expand button for whitespace-only text", () => {
+    const html = renderToStaticMarkup(<ExpandableSummary text="                              " />);
+    expect(html).not.toContain("Expand summary");
+  });
+
+  it("applies the group/expand class for hover interaction", () => {
+    const html = renderToStaticMarkup(
+      <ExpandableSummary text="A sufficiently long expandable AI response summary text." />,
+    );
+    expect(html).toContain("group/expand");
+  });
+
+  it("passes className to the wrapper div", () => {
+    const html = renderToStaticMarkup(
+      <ExpandableSummary
+        className="mt-3"
+        text="Another long expandable text for testing className."
+      />,
+    );
+    expect(html).toContain("mt-3");
+  });
+});

apps/web/src/components/merge-conflicts/ExpandableSummary.tsx

@@ -0,0 +1,89 @@
+import { MaximizeIcon } from "lucide-react";
+import { memo, useState } from "react";
+import ReactMarkdown from "react-markdown";
+import remarkGfm from "remark-gfm";
+
+import { cn } from "~/lib/utils";
+import { Sheet, SheetPopup, SheetPanel } from "~/components/ui/sheet";
+
+/**
+ * Wraps plain-text or markdown AI summaries with an expand button
+ * that opens a clean, Notion-like full-height preview sheet.
+ *
+ * Usage:
+ *   <ExpandableSummary text={recommendation.detail} title="Resolution guidance" />
+ *
+ * The inline render is plain text (default children or the `text` prop).
+ * The expanded view renders the text as GitHub-flavored Markdown in a
+ * minimal, readable layout.
+ */
+
+interface ExpandableSummaryProps {
+  /** The raw text / markdown content to render */
+  text: string;
+  /** Title shown at the top of the expanded sheet */
+  title?: string;
+  /** Optional subtitle / context line below the title */
+  subtitle?: string;
+  /** Additional className for the inline wrapper */
+  className?: string;
+  /** Inline text element — defaults to rendering `text` in a <p> */
+  children?: React.ReactNode;
+}
+
+export const ExpandableSummary = memo(function ExpandableSummary({
+  text,
+  title,
+  subtitle,
+  className,
+  children,
+}: ExpandableSummaryProps) {
+  const [open, setOpen] = useState(false);
+
+  // Don't render the expand affordance for very short text
+  const isExpandable = text.trim().length > 40;
+
+  return (
+    <>
+      <div className={cn("group/expand relative", className)}>
+        {children ?? <p className="text-sm opacity-85">{text}</p>}
+
+        {isExpandable ? (
+          <button
+            aria-label="Expand summary"
+            className="absolute -top-1 -end-1 flex size-6 items-center justify-center rounded-md bg-background/80 text-muted-foreground/50 opacity-0 backdrop-blur-sm transition-all duration-150 hover:bg-muted hover:text-foreground group-hover/expand:opacity-100"
+            onClick={() => setOpen(true)}
+            type="button"
+          >
+            <MaximizeIcon className="size-3" />
+          </button>
+        ) : null}
+      </div>
+
+      {isExpandable ? (
+        <Sheet onOpenChange={setOpen} open={open}>
+          <SheetPopup className="max-w-2xl" showCloseButton side="right" variant="inset">
+            <SheetPanel scrollFade>
+              <article className="summary-preview mx-auto max-w-prose px-2 py-6">
+                {title ? (
+                  <header className="mb-8 border-b border-border/50 pb-6">
+                    <h1 className="font-heading text-xl font-semibold leading-tight text-foreground">
+                      {title}
+                    </h1>
+                    {subtitle ? (
+                      <p className="mt-2 text-sm text-muted-foreground">{subtitle}</p>
+                    ) : null}
+                  </header>
+                ) : null}
+
+                <div className="summary-preview-body text-[15px] leading-relaxed text-foreground/88">
+                  <ReactMarkdown remarkPlugins={[remarkGfm]}>{text}</ReactMarkdown>
+                </div>
+              </article>
+            </SheetPanel>
+          </SheetPopup>
+        </Sheet>
+      ) : null}
+    </>
+  );
+});

apps/web/src/components/merge-conflicts/MergeConflictShell.logic.test.ts

@@ -7,6 +7,8 @@ import {
   groupConflictCandidatesByFile,
   humanizeConflictError,
   pickRecommendedConflictCandidate,
+  pullRequestStateBadgeClassName,
+  workspaceModeLabel,
 } from "./MergeConflictShell.logic";
 
 describe("pickRecommendedConflictCandidate", () => {
@@ -211,3 +213,54 @@ describe("buildConflictFeedbackPreview", () => {
     ).toContain("Operator note: Keep the API signature from the incoming branch.");
   });
 });
+
+describe("workspaceModeLabel", () => {
+  it('returns "Repo scan" when no workspace is prepared', () => {
+    expect(workspaceModeLabel(null)).toBe("Repo scan");
+  });
+
+  it('returns "Prepared in repo" for local mode', () => {
+    expect(
+      workspaceModeLabel({
+        branch: "feature/auth",
+        cwd: "/Users/val/project",
+        mode: "local",
+        worktreePath: null,
+      }),
+    ).toBe("Prepared in repo");
+  });
+
+  it('returns "Dedicated worktree" for worktree mode', () => {
+    expect(
+      workspaceModeLabel({
+        branch: "feature/auth",
+        cwd: "/Users/val/.git/worktrees/auth",
+        mode: "worktree",
+        worktreePath: "/Users/val/.git/worktrees/auth",
+      }),
+    ).toBe("Dedicated worktree");
+  });
+});
+
+describe("pullRequestStateBadgeClassName", () => {
+  it("returns emerald styling for open PRs", () => {
+    const result = pullRequestStateBadgeClassName("open");
+    expect(result).toContain("emerald");
+    expect(result).not.toContain("muted");
+  });
+
+  it("returns muted styling for merged PRs", () => {
+    const result = pullRequestStateBadgeClassName("merged");
+    expect(result).toContain("muted");
+    expect(result).not.toContain("emerald");
+  });
+
+  it("returns muted styling for closed PRs", () => {
+    const result = pullRequestStateBadgeClassName("closed");
+    expect(result).toContain("muted");
+  });
+
+  it("returns identical styling for merged and closed states", () => {
+    expect(pullRequestStateBadgeClassName("merged")).toBe(pullRequestStateBadgeClassName("closed"));
+  });
+});

apps/web/src/components/merge-conflicts/MergeConflictShell.logic.ts

@@ -224,3 +224,25 @@ export function computeActiveStepIndex(
   const index = steps.findIndex((step) => step.status !== "done");
   return index === -1 ? steps.length : index;
 }
+
+export interface PreparedWorkspace {
+  branch: string;
+  cwd: string;
+  mode: "local" | "worktree";
+  worktreePath: string | null;
+}
+
+export function workspaceModeLabel(workspace: PreparedWorkspace | null): string {
+  if (!workspace) return "Repo scan";
+  return workspace.mode === "worktree" ? "Dedicated worktree" : "Prepared in repo";
+}
+
+export function pullRequestStateBadgeClassName(state: GitResolvedPullRequest["state"]): string {
+  switch (state) {
+    case "open":
+      return "border-emerald-500/30 bg-emerald-500/12 text-emerald-700 dark:text-emerald-300";
+    case "merged":
+    case "closed":
+      return "border-border bg-muted/70 text-foreground";
+  }
+}