feat(ui): prompt to save view preferences on quit

.changeset/save-view-preferences-on-quit.md

@@ -0,0 +1,5 @@
+---
+"hunkdiff": minor
+---
+
+Offer to save changed view preferences to the user config on quit, including theme, layout, line numbers, wrapping, hunk headers, agent notes, and copy decorations.

src/core/config.test.ts

@@ -1,9 +1,9 @@
 import { afterEach, describe, expect, test } from "bun:test";
-import { mkdtempSync, mkdirSync, rmSync, writeFileSync } from "node:fs";
+import { mkdtempSync, mkdirSync, readFileSync, rmSync, writeFileSync } from "node:fs";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
 import type { CliInput } from "./types";
-import { resolveConfiguredCliInput } from "./config";
+import { resolveConfiguredCliInput, saveGlobalViewPreferences } from "./config";
 import { loadAppBootstrap } from "./loaders";
 
 const tempDirs: string[] = [];
@@ -46,6 +46,56 @@ afterEach(() => {
   cleanupTempDirs();
 });
 
+describe("config persistence", () => {
+  test("writes accepted view preferences to user config without disturbing tables", () => {
+    const home = createTempDir("hunk-save-config-home-");
+    const configPath = join(home, ".config", "hunk", "config.toml");
+    mkdirSync(join(home, ".config", "hunk"), { recursive: true });
+    writeFileSync(
+      configPath,
+      [
+        "# personal defaults",
+        'theme = "github-dark-default"',
+        "wrap_lines = false",
+        "",
+        "[custom_theme]",
+        'label = "Keep me"',
+      ].join("\n"),
+    );
+
+    const savedPath = saveGlobalViewPreferences(
+      {
+        mode: "split",
+        theme: "dracula",
+        showLineNumbers: false,
+        wrapLines: true,
+        showHunkHeaders: false,
+        showAgentNotes: true,
+        copyDecorations: true,
+      },
+      { env: { HOME: home } },
+    );
+
+    expect(savedPath).toBe(configPath);
+    expect(readFileSync(configPath, "utf8")).toBe(
+      [
+        "# personal defaults",
+        'theme = "dracula"',
+        "wrap_lines = true",
+        'mode = "split"',
+        "line_numbers = false",
+        "hunk_headers = false",
+        "agent_notes = true",
+        "copy_decorations = true",
+        "",
+        "[custom_theme]",
+        'label = "Keep me"',
+        "",
+      ].join("\n"),
+    );
+  });
+});
+
 describe("config resolution", () => {
   test("merges global, repo, pager, command, and CLI overrides in the right order", () => {
     const home = createTempDir("hunk-config-home-");
@@ -87,6 +137,7 @@ describe("config resolution", () => {
     });
 
     expect(resolved.repoConfigPath).toBe(join(repo, ".hunk", "config.toml"));
+    expect(resolved.viewPreferencesConfigPath).toBe(join(repo, ".hunk", "config.toml"));
     expect(resolved.input.options).toMatchObject({
       pager: true,
       mode: "stack",
@@ -271,6 +322,7 @@ describe("config resolution", () => {
     });
 
     expect(resolved.repoConfigPath).toBeUndefined();
+    expect(resolved.viewPreferencesConfigPath).toBe(join(home, ".config", "hunk", "config.toml"));
     expect(resolved.input.options.theme).toBe("github-dark-default");
   });
 

src/core/config.ts

@@ -1,5 +1,5 @@
 import fs from "node:fs";
-import { join } from "node:path";
+import { dirname, join } from "node:path";
 import { BUNDLED_SHIKI_THEME_IDS } from "../ui/lib/shikiThemes";
 import { normalizeBuiltInThemeId } from "../ui/themes";
 import { resolveGlobalConfigPath } from "./paths";
@@ -74,6 +74,19 @@ const DEFAULT_VIEW_PREFERENCES: PersistedViewPreferences = {
   copyDecorations: false,
 };
 
+const PERSISTED_VIEW_PREFERENCE_KEYS: Array<{
+  configKey: string;
+  value: (preferences: PersistedViewPreferences) => string | boolean | undefined;
+}> = [
+  { configKey: "theme", value: (preferences) => preferences.theme },
+  { configKey: "mode", value: (preferences) => preferences.mode },
+  { configKey: "line_numbers", value: (preferences) => preferences.showLineNumbers },
+  { configKey: "wrap_lines", value: (preferences) => preferences.wrapLines },
+  { configKey: "hunk_headers", value: (preferences) => preferences.showHunkHeaders },
+  { configKey: "agent_notes", value: (preferences) => preferences.showAgentNotes },
+  { configKey: "copy_decorations", value: (preferences) => preferences.copyDecorations },
+];
+
 interface ConfigResolutionOptions {
   cwd?: string;
   env?: NodeJS.ProcessEnv;
@@ -84,12 +97,54 @@ interface HunkConfigResolution {
   customTheme?: CustomThemeConfig;
   globalConfigPath?: string;
   repoConfigPath?: string;
+  viewPreferencesConfigPath?: string;
 }
 
 function isRecord(value: unknown): value is Record<string, unknown> {
   return typeof value === "object" && value !== null && !Array.isArray(value);
 }
 
+/** Serialize one primitive TOML preference value. */
+function serializeTomlPreferenceValue(value: string | boolean) {
+  if (typeof value === "boolean") {
+    return value ? "true" : "false";
+  }
+
+  return JSON.stringify(value);
+}
+
+/** Update one top-level TOML key while preserving sections and unrelated comments. */
+function upsertTopLevelTomlValue(source: string, key: string, value: string | boolean) {
+  const lines = source.length > 0 ? source.split("\n") : [];
+  const serialized = serializeTomlPreferenceValue(value);
+  const assignment = `${key} = ${serialized}`;
+  let firstTableIndex = lines.findIndex((line) => /^\s*\[/.test(line));
+  if (firstTableIndex < 0) {
+    firstTableIndex = lines.length;
+  }
+
+  const keyPattern = new RegExp(`^\\s*${key.replace(/[.*+?^${}()|[\]\\]/g, "\\$&")}\\s*=`);
+  for (let index = 0; index < firstTableIndex; index += 1) {
+    if (keyPattern.test(lines[index] ?? "")) {
+      lines[index] = assignment;
+      return `${lines.join("\n").replace(/\n*$/, "")}\n`;
+    }
+  }
+
+  let insertAt = firstTableIndex;
+  const hasTableSpacer = insertAt > 0 && lines[insertAt - 1] === "";
+  if (hasTableSpacer) {
+    insertAt -= 1;
+  }
+  lines.splice(
+    insertAt,
+    0,
+    assignment,
+    ...(hasTableSpacer || insertAt === lines.length ? [] : [""]),
+  );
+  return `${lines.join("\n").replace(/\n*$/, "")}\n`;
+}
+
 /** Accept only the layout names Hunk already supports. */
 function normalizeLayoutMode(value: unknown): LayoutMode | undefined {
   return value === "auto" || value === "split" || value === "stack" ? value : undefined;
@@ -302,6 +357,37 @@ function readTomlRecord(path: string) {
   return parsed;
 }
 
+/** Persist accepted in-app view preferences to the selected Hunk config file. */
+export function saveGlobalViewPreferences(
+  preferences: PersistedViewPreferences,
+  {
+    configPath: configuredPath,
+    env = process.env,
+  }: Pick<ConfigResolutionOptions, "env"> & { configPath?: string } = {},
+) {
+  const configPath = configuredPath ?? resolveGlobalConfigPath(env);
+  if (!configPath) {
+    throw new Error("Could not resolve a config path because HOME/XDG_CONFIG_HOME is unset.");
+  }
+
+  let source = "";
+  if (fs.existsSync(configPath)) {
+    source = fs.readFileSync(configPath, "utf8");
+  }
+
+  let nextSource = source;
+  for (const key of PERSISTED_VIEW_PREFERENCE_KEYS) {
+    const value = key.value(preferences);
+    if (value !== undefined) {
+      nextSource = upsertTopLevelTomlValue(nextSource, key.configKey, value);
+    }
+  }
+
+  fs.mkdirSync(dirname(configPath), { recursive: true });
+  fs.writeFileSync(configPath, nextSource);
+  return configPath;
+}
+
 /** Resolve CLI input against global and repo-local config files. */
 export function resolveConfiguredCliInput(
   input: CliInput,
@@ -373,5 +459,9 @@ export function resolveConfiguredCliInput(
     customTheme: resolvedCustomTheme,
     globalConfigPath: userConfigPath,
     repoConfigPath,
+    // Persist in the repo config only when the repo already has one; otherwise keep personal view
+    // choices user-scoped so Hunk does not create project policy files from an interactive prompt.
+    viewPreferencesConfigPath:
+      repoConfigPath && fs.existsSync(repoConfigPath) ? repoConfigPath : userConfigPath,
   };
 }

src/core/startup.ts

@@ -232,6 +232,7 @@ export async function prepareStartupPlan(
   }
 
   bootstrap.initialThemeMode = initialThemeMode ?? bootstrap.initialThemeMode;
+  bootstrap.viewPreferencesConfigPath = configured.viewPreferencesConfigPath;
 
   controllingTerminal ??= usesPipedPatchInputImpl(cliInput) ? openControllingTerminalImpl() : null;
 

src/core/types.ts

@@ -366,4 +366,5 @@ export interface AppBootstrap {
   initialShowHunkHeaders?: boolean;
   initialShowAgentNotes?: boolean;
   initialCopyDecorations?: boolean;
+  viewPreferencesConfigPath?: string;
 }