feat: per-session diff viewer

apps/tui/package.json

@@ -14,6 +14,7 @@
 	},
 	"devDependencies": {
 		"@types/bun": "latest",
+		"@types/diff": "^8.0.0",
 		"@types/react": "^19.2.4"
 	},
 	"peerDependencies": {
@@ -27,6 +28,7 @@
 		"@techatnyu/ralphd": "workspace:*",
 		"@opentui/core": "^0.1.77",
 		"@opentui/react": "^0.1.77",
+		"diff": "^9.0.0",
 		"react": "^19.2.4"
 	}
 }

apps/tui/src/components/chat.tsx

@@ -6,6 +6,7 @@ import { daemon } from "@techatnyu/ralphd";
 import { useCallback, useEffect, useMemo, useRef, useState } from "react";
 import { createPromptTask } from "../lib/prompt-task";
 import { ralphStore } from "../lib/store";
+import { DiffViewer } from "./diff-viewer";
 
 type Role = "user" | "assistant" | "system";
 
@@ -99,6 +100,7 @@ export function Chat({
 	const [errorMessage, setErrorMessage] = useState<string | null>(null);
 	const [sessionId, setSessionId] = useState<string | null>(initialSessionId);
 	const [hydrated, setHydrated] = useState(false);
+	const [tab, setTab] = useState<"chat" | "diffs">("chat");
 	const [pendingQuestion, setPendingQuestion] =
 		useState<PendingQuestion | null>(null);
 	const sendLockRef = useRef(false);
@@ -309,6 +311,19 @@ export function Chat({
 	);
 
 	useKeyboard((event) => {
+		if (event.ctrl && event.name === "r") {
+			if (tab === "chat" && sessionId) {
+				setTab("diffs");
+			} else if (tab === "diffs") {
+				setTab("chat");
+			}
+			return;
+		}
+
+		if (tab !== "chat") {
+			return;
+		}
+
 		if (event.ctrl && event.name === "c") {
 			onQuit();
 		}
@@ -487,14 +502,26 @@ export function Chat({
 	const activeAnswers =
 		pendingQuestion?.answers[pendingQuestion.currentIndex] ?? [];
 
+	if (tab === "diffs" && sessionId) {
+		return (
+			<DiffViewer
+				instanceId={instanceId}
+				sessionId={sessionId}
+				onBack={() => setTab("chat")}
+				onQuit={onQuit}
+			/>
+		);
+	}
+
 	return (
 		<box flexDirection="column" flexGrow={1} width="100%">
 			<box flexShrink={0} height={1} width="100%">
 				<text attributes={TextAttributes.DIM}>
 					Ralph Chat · {instanceName}
 					{sessionId ? ` · session: ${sessionId.slice(0, 8)}` : ""}
 					{errorMessage ? ` · error: ${errorMessage}` : ""} · PgUp/PgDn or
-					Ctrl+U/Ctrl+D scroll · esc back · ctrl+c quit
+					Ctrl+U/Ctrl+D scroll{sessionId ? " · ctrl+r diffs" : ""} · esc back ·
+					ctrl+c quit
 				</text>
 			</box>
 

apps/tui/src/components/diff-viewer.tsx

@@ -0,0 +1,235 @@
+import type { ScrollBoxRenderable } from "@opentui/core";
+import { TextAttributes } from "@opentui/core";
+import { useKeyboard } from "@opentui/react";
+import type { FileDiff } from "@techatnyu/ralphd";
+import { daemon } from "@techatnyu/ralphd";
+import { useEffect, useRef, useState } from "react";
+
+const DIFFS_POLL_INTERVAL_MS = 500;
+
+interface DiffViewerProps {
+	instanceId: string;
+	sessionId: string;
+	onBack(): void;
+	onQuit(): void;
+}
+
+function statusGlyph(status: FileDiff["status"]): string {
+	switch (status) {
+		case "added":
+			return "A";
+		case "deleted":
+			return "D";
+		case "modified":
+			return "M";
+		default:
+			return " ";
+	}
+}
+
+function extensionOf(file: string): string {
+	const dot = file.lastIndexOf(".");
+	if (dot < 0 || dot === file.length - 1) {
+		return "";
+	}
+	return file.slice(dot + 1);
+}
+
+interface FileRowProps {
+	diff: FileDiff;
+	focused: boolean;
+	expanded: boolean;
+}
+
+function FileRow({ diff, focused, expanded }: FileRowProps) {
+	return (
+		<box flexDirection="column" marginBottom={1}>
+			<box flexDirection="row">
+				<text attributes={focused ? TextAttributes.BOLD : TextAttributes.NONE}>
+					{`${focused ? "> " : "  "}${statusGlyph(diff.status)}  ${diff.file}  `}
+				</text>
+				<text fg="#5fff87">{`+${diff.additions}`}</text>
+				<text>{"  "}</text>
+				<text fg="#ff5f5f">{`-${diff.deletions}`}</text>
+			</box>
+			{expanded ? (
+				<box marginLeft={2} marginTop={1}>
+					<diff
+						diff={diff.patch}
+						view="unified"
+						filetype={extensionOf(diff.file)}
+						showLineNumbers={true}
+						wrapMode="none"
+					/>
+				</box>
+			) : null}
+		</box>
+	);
+}
+
+export function DiffViewer({
+	instanceId,
+	sessionId,
+	onBack,
+	onQuit,
+}: DiffViewerProps) {
+	const [diffs, setDiffs] = useState<FileDiff[]>([]);
+	const [error, setError] = useState<string | null>(null);
+	const [selectedIndex, setSelectedIndex] = useState(0);
+	const [expanded, setExpanded] = useState<Set<string>>(() => new Set());
+	const scrollRef = useRef<ScrollBoxRenderable | null>(null);
+
+	useEffect(() => {
+		let cancelled = false;
+		let inFlight = false;
+
+		const fetchDiffs = async () => {
+			if (inFlight || cancelled) {
+				return;
+			}
+			inFlight = true;
+			try {
+				const result = await daemon.sessionDiffs({ instanceId, sessionId });
+				if (!cancelled) {
+					setDiffs(result.diffs);
+					setError(null);
+				}
+			} catch (err) {
+				if (!cancelled) {
+					setError(err instanceof Error ? err.message : String(err));
+				}
+			} finally {
+				inFlight = false;
+			}
+		};
+
+		void fetchDiffs();
+		const handle = setInterval(() => {
+			void fetchDiffs();
+		}, DIFFS_POLL_INTERVAL_MS);
+		return () => {
+			cancelled = true;
+			clearInterval(handle);
+		};
+	}, [instanceId, sessionId]);
+
+	useKeyboard((event) => {
+		if (event.ctrl && event.name === "c") {
+			onQuit();
+			return;
+		}
+
+		if (event.name === "escape") {
+			onBack();
+			return;
+		}
+
+		if (event.name === "pageup") {
+			scrollRef.current?.scrollBy(-1, "viewport");
+			return;
+		}
+
+		if (event.name === "pagedown") {
+			scrollRef.current?.scrollBy(1, "viewport");
+			return;
+		}
+
+		if (event.ctrl && event.name === "u") {
+			scrollRef.current?.scrollBy(-0.5, "viewport");
+			return;
+		}
+
+		if (event.ctrl && event.name === "d") {
+			scrollRef.current?.scrollBy(0.5, "viewport");
+			return;
+		}
+
+		if (event.name === "down" || event.name === "j") {
+			setSelectedIndex((prev) =>
+				Math.max(0, Math.min(prev + 1, diffs.length - 1)),
+			);
+			return;
+		}
+
+		if (event.name === "up" || event.name === "k") {
+			setSelectedIndex((prev) =>
+				Math.max(0, Math.min(prev - 1, diffs.length - 1)),
+			);
+			return;
+		}
+
+		if (event.name === "return" || event.name === "space") {
+			const current = diffs[selectedIndex];
+			if (!current) {
+				return;
+			}
+			setExpanded((prev) => {
+				const next = new Set(prev);
+				if (next.has(current.file)) {
+					next.delete(current.file);
+				} else {
+					next.add(current.file);
+				}
+				return next;
+			});
+			return;
+		}
+
+		if (event.name === "e") {
+			setExpanded((prev) => {
+				if (prev.size < diffs.length) {
+					return new Set(diffs.map((d) => d.file));
+				}
+				return new Set();
+			});
+			return;
+		}
+	});
+
+	let additions = 0;
+	let deletions = 0;
+	for (const d of diffs) {
+		additions += d.additions;
+		deletions += d.deletions;
+	}
+
+	return (
+		<box flexDirection="column" flexGrow={1} width="100%">
+			<box flexShrink={0} height={1} width="100%">
+				<text attributes={TextAttributes.DIM}>
+					{`Diffs · ${diffs.length} file${diffs.length === 1 ? "" : "s"} · +${additions}/-${deletions} · j/k nav · enter expand · e all · esc back · ctrl+c quit`}
+				</text>
+			</box>
+
+			<scrollbox
+				ref={scrollRef}
+				flexGrow={1}
+				flexShrink={1}
+				minHeight={0}
+				width="100%"
+				border={true}
+				padding={0}
+				stickyScroll={false}
+			>
+				{diffs.length === 0 ? (
+					<text attributes={TextAttributes.DIM}>No changes yet.</text>
+				) : (
+					diffs.map((d, i) => (
+						<FileRow
+							key={d.file}
+							diff={d}
+							focused={i === selectedIndex}
+							expanded={expanded.has(d.file)}
+						/>
+					))
+				)}
+			</scrollbox>
+
+			{error ? (
+				<box flexShrink={0} height={1} width="100%">
+					<text fg="#ff5f5f">{`Error: ${error}`}</text>
+				</box>
+			) : null}
+		</box>
+	);
+}