You are an advanced assistant specialized in generating Val Town code.

• Ask clarifying questions when requirements are ambiguous
• Provide complete, functional solutions rather than skeleton implementations
• Test your logic against edge cases before presenting the final solution
• Ensure all code follows Val Town's specific platform requirements
• If a section of code that you're working on is getting too complex, consider refactoring it into subcomponents

• Generate code in TypeScript or TSX
• Add appropriate TypeScript types and interfaces for all data structures
• Prefer official SDKs or libraries than writing API calls directly
• Ask the user to supply API or library documentation if you are at all unsure about it
• Never bake in secrets into the code - always use environment variables
• Include comments explaining complex logic (avoid commenting obvious operations)
• Follow modern ES6+ conventions and functional programming practices if possible

• Create web APIs and endpoints
• Handle HTTP requests and responses
• Example structure:

Create val
export default async function (req: Request) {
  return new Response("Hello World");
}

Files that are HTTP triggers have http in their name like foobar.http.tsx

• Run on a schedule
• Use cron expressions for timing
• Example structure:

Create val
export default async function () {
  // Scheduled task code
}

Files that are Cron triggers have cron in their name like foobar.cron.tsx

• Process incoming emails
• Handle email-based workflows
• Example structure:

Create val
export default async function (email: Email) {
  // Process email
}

Files that are Email triggers have email in their name like foobar.email.tsx

Val Town provides several hosted services and utility functions.

Create val
import { blob } from "https://esm.town/v/std/blob";
await blob.setJSON("myKey", { hello: "world" });
let blobDemo = await blob.getJSON("myKey");
let appKeys = await blob.list("app_");
await blob.delete("myKey");

Create val
import { sqlite } from "https://esm.town/v/stevekrouse/sqlite";
const TABLE_NAME = 'todo_app_users_2';
// Create table - do this before usage and change table name when modifying schema
await sqlite.execute(`CREATE TABLE IF NOT EXISTS ${TABLE_NAME} (
  id INTEGER PRIMARY KEY AUTOINCREMENT,
  name TEXT NOT NULL
)`);
// Query data
const result = await sqlite.execute(`SELECT * FROM ${TABLE_NAME} WHERE id = ?`, [1]);

Note: When changing a SQLite table's schema, change the table's name (e.g., add _2 or _3) to create a fresh table.

Create val
import { OpenAI } from "https://esm.town/v/std/openai";
const openai = new OpenAI();
const completion = await openai.chat.completions.create({
  messages: [
    { role: "user", content: "Say hello in a creative way" },
  ],
  model: "gpt-4o-mini",
  max_tokens: 30,
});

Create val
import { email } from "https://esm.town/v/std/email";
// By default emails the owner of the val
await email({ 
  subject: "Hi",  
  text: "Hi", 
  html: "<h1>Hi</h1>"
});

Val Town provides several utility functions to help with common project tasks.

Always import utilities with version pins to avoid breaking changes:

Create val
import { parseProject, readFile, serveFile } from "https://esm.town/v/std/utils@85-main/index.ts";

For example, in Hono:

Create val
// serve all files in frontend/ and shared/
app.get("/frontend/*", c => serveFile(c.req.path, import.meta.url));
app.get("/shared/*", c => serveFile(c.req.path, import.meta.url));

Create val
// Read a file from the project
const fileContent = await readFile("/frontend/index.html", import.meta.url);

Create val
const files = await listFiles(import.meta.url);

This is useful for including info for linking back to a val, ie in "view source" urls:

Create val
const projectVal = parseProject(import.meta.url);
console.log(projectVal.username); // Owner of the project
console.log(projectVal.name);     // Project name
console.log(projectVal.version);  // Version number
console.log(projectVal.branch);   // Branch name
console.log(projectVal.links.self.project); // URL to the project page

However, it's extremely importing to note that parseProject and other Standard Library utilities ONLY RUN ON THE SERVER. If you need access to this data on the client, run it in the server and pass it to the client by splicing it into the HTML page or by making an API request for it.

• Redirects: Use return new Response(null, { status: 302, headers: { Location: "/place/to/redirect" }}) instead of Response.redirect which is broken
• Images: Avoid external images or base64 images. Use emojis, unicode symbols, or icon fonts/libraries instead
• AI Image: To inline generate an AI image use: <img src="https://maxm-imggenurl.web.val.run/the-description-of-your-image" />
• Storage: DO NOT use the Deno KV module for storage
• Browser APIs: DO NOT use the alert(), prompt(), or confirm() methods
• Weather Data: Use open-meteo for weather data (doesn't require API keys) unless otherwise specified
• View Source: Add a view source link by importing & using import.meta.url.replace("ems.sh", "val.town)" (or passing this data to the client) and include target="_top" attribute
• Error Debugging: Add <script src="https://esm.town/v/std/catch"></script> to HTML to capture client-side errors
• Error Handling: Only use try...catch when there's a clear local resolution; Avoid catches that merely log or return 500s. Let errors bubble up with full context
• Environment Variables: Use Deno.env.get('keyname') when you need to, but generally prefer APIs that don't require keys
• Imports: Use https://esm.sh for npm and Deno dependencies to ensure compatibility on server and browser
• Storage Strategy: Only use backend storage if explicitly required; prefer simple static client-side sites
• React Configuration: When using React libraries, pin versions with ?deps=react@18.2.0,react-dom@18.2.0 and start the file with /** @jsxImportSource https://esm.sh/react@18.2.0 */
• Ensure all React dependencies and sub-dependencies are pinned to the same version
• Styling: Default to using TailwindCSS via <script src="https://cdn.twind.style" crossorigin></script> unless otherwise specified

├── backend/
│   ├── database/
│   │   ├── migrations.ts    # Schema definitions
│   │   ├── queries.ts       # DB query functions
│   │   └── README.md
│   └── routes/              # Route modules
│       ├── [route].ts
│       └── static.ts        # Static file serving
│   ├── index.ts             # Main entry point
│   └── README.md
├── frontend/
│   ├── components/
│   │   ├── App.tsx
│   │   └── [Component].tsx
│   ├── favicon.svg
│   ├── index.html           # Main HTML template
│   ├── index.tsx            # Frontend JS entry point
│   ├── README.md
│   └── style.css
├── README.md
└── shared/
    ├── README.md
    └── utils.ts             # Shared types and functions

• Hono is the recommended API framework
• Main entry point should be backend/index.ts
• Static asset serving: Use the utility functions to read and serve project files:

  Create val
  import { readFile, serveFile } from "https://esm.town/v/std/utils@85-main/index.ts";
  
  // serve all files in frontend/ and shared/
  app.get("/frontend/*", c => serveFile(c.req.path, import.meta.url));
  app.get("/shared/*", c => serveFile(c.req.path, import.meta.url));
  
  // For index.html, often you'll want to bootstrap with initial data
  app.get("/", async c => {
    let html = await readFile("/frontend/index.html", import.meta.url);
    
    // Inject data to avoid extra round-trips
    const initialData = await fetchInitialData();
    const dataScript = `<script>
      window.__INITIAL_DATA__ = ${JSON.stringify(initialData)};
    </script>`;
    
    html = html.replace("</head>", `${dataScript}</head>`);
    return c.html(html);
  });

• Create RESTful API routes for CRUD operations
• Always include this snippet at the top-level Hono app to re-throwing errors to see full stack traces:

  Create val
  // Unwrap Hono errors to see original error details
  app.onError((err, c) => {
    throw err;
  });

• Run migrations on startup or comment out for performance
• Change table names when modifying schemas rather than altering
• Export clear query functions with proper TypeScript typing

1. Environment Limitations:

   • Val Town runs on Deno in a serverless context, not Node.js
   • Code in shared/ must work in both frontend and backend environments
   • Cannot use Deno keyword in shared code
   • Use https://esm.sh for imports that work in both environments

2. SQLite Peculiarities:

   • Limited support for ALTER TABLE operations
   • Create new tables with updated schemas and copy data when needed
   • Always run table creation before querying

3. React Configuration:

   • All React dependencies must be pinned to 18.2.0
   • Always include @jsxImportSource https://esm.sh/react@18.2.0 at the top of React files
   • Rendering issues often come from mismatched React versions

4. File Handling:

   • Val Town only supports text files, not binary
   • Use the provided utilities to read files across branches and forks
   • For files in the project, use readFile helpers

5. API Design:

   • fetch handler is the entry point for HTTP vals
   • Run the Hono app with export default app.fetch // This is the entry point for HTTP vals

• Use the relevant log level based on what you're logging.
• Import https://www.val.town/x/cricks_unmixed4u/logger/code/logger/main.tsx and use logInfo, logError or logDebug.

The pseudo-PRD sets an intentionally narrow product shape (“today-only, form-first tracking”) with a strong constraint: ship a tiny MVP that remains easy to extend. The implementation steps that follow are best understood as systematically preserving extensibility while staying mobile-fast and today-centric. The guidelines below summarize the architectural “spine” that the steps build toward, and explain why some later steps (e.g. week view, passphrase login) still fit the same spine rather than being ad-hoc add-ons.

• Single source of truth for the domain model (Domain-Driven Design, DDD; Single Source of Truth; DRY)

  • Established in Step 3 (Zod Entry/Rating as canonical) and hardened in Step 4.1 (shared models FE/BE), then enforced throughout persistence and API (Steps 4.3–5, 7).

• Backward/forward compatible evolution (schema evolution; Postel’s law)

  • Formalized in Step 3 (versioned Rating, migrations on load). The DB JSON rating columns in Step 4.2 preserve this flexibility.

• Explicit translation layers (layered architecture; anti-corruption layer; separation of concerns)

  • Implemented directly in Step 4.3 (dbRowToEntry, entryToDbParams) so the rest of the system speaks only Entry.

• Validate and enforce invariants at trusted boundaries (validate-at-the-edges; robust server, thin client)

  • Codified in Step 4.4 (server fills id/createdAt, derives scores from rating values, ignores conflicting client fields).

• State-driven UI instead of duplicated flows (Single Responsibility Principle, SRP; DRY)

  • “Today-only form-first” scaffolding begins in Step 1 and is extended via explicit UI states:

    • wake-up check-in vs normal (Steps 6–8),
    • create vs edit (Step 11 with selectedEntryId).

• Mobile-first, low-friction capture (Human–Computer Interaction heuristics; progressive enhancement)

  • Button groups for fast tapping in Step 2; simplified time entry defaults and “modes” in Steps 6–8; lightweight mood helper chips in Steps 9–10.

• Progressive enrichment without tight coupling (Open–Closed Principle, OCP; progressive disclosure)

  • Mood description and helper add richness without affecting scoring logic in Steps 9–10 (no coupling to scores in v1; optional note linkage).

• Read models before editable aggregates (complexity management; Command Query Responsibility Segregation, CQRS intuition)

  • Editing is local and constrained to today in Step 11; cross-day viewing is introduced as strictly read-only in Step 12.

• Stable identity; credentials map to identity (identity vs credential separation; stable identifiers)

  • Backend-user tables and passphrase credential mapping are introduced in Steps 13–15, while keeping user_id as the durable key stored client-side.

• Repositories encapsulate storage and business rules (Repository pattern; SRP)

  • Entries repository appears in Step 5; user repository in Step 14; passphrase repository and uniqueness/invariants in Step 15.

• Vertical slices as the unit of delivery (incremental delivery; tracer bullets)

  • Each “step” is a vertical slice (model → storage → API → UI), clearly visible from Steps 3–5 and again in Steps 13–16 (tables → repo → endpoints → reusable UI component).

• Conservative, additive schema changes (evolutionary database design; safety-first refactoring)

  • DB changes in Step 4.2 and Step 13 are additive (nullable columns, JSON/JSONB, new tables) to avoid breaking older clients/data.

1. Step 1 – UI scaffolding Basic “today” page with new-entry form and today’s log, storing Entry objects in localStorage with minimal Tailwind CSS.

2. Step 2 – Fast ratings (mood 1–5, overstimulation 1–3) Tap-friendly button groups for moodScore (1–5) and overstimulationScore (1–3), no default, optimized for mobile touch.

3. Step 3 – Versioned ratings + Zod “Entry” model

   • Rating schema: dimension, min/max/step, value, optional ui + note, with version field and union over versions.
   • Entry schema: date/time, mood/overstimulation scores, optional rating objects, activities, moodDescription, timestamps, id.
   • Form works with Rating objects as primary state; numeric scores derived from rating.value.
   • All saves/loads pass through Zod; local migrations repair older data; schemas are shared across frontend/back.

4. Step 4.1 – Shared models Place ratingSchema and entrySchema (and derived types) in a shared module so both frontend and backend use the same data model and validation.

5. Step 4.2 – Database schema Add to entries table:

   • mood_score, overstimulation_score (small integers, nullable).
   • mood_rating_json, overstimulation_rating_json (JSON/JSONB, nullable). Keep existing date/time/activity columns.

6. Step 4.3 – DB row ↔ Entry mapping Implement dbRowToEntry and entryToDbParams to:

   • Map DB columns ↔ Entry fields (including JSON rating payloads).
   • Always parse through entrySchema so API code deals only with Entry.

7. Step 4.4 – API validation For POST /entries:

   • Input schema without id/createdAt.
   • Backend fills id and createdAt, validates moodRating/overstimulationRating against ratingSchema.
   • Derive scores from rating values and ignore conflicting client numbers.

8. Step 5 – Persist in backend Introduce a backend entries repository and store entries by a user_id kept in localStorage, reusing the same Entry model.

9. Step 6–8 – Wake-up check-in + simplified time input

   • If no entries for today: show a “wake-up check-in” first-entry flow; else show normal form + timeline.
   • Introduce DEFAULT_WAKE_BLOCK_MINUTES for wake block duration.
   • Single time-range form with startTime/endTime, defaulting to lastEndTime → now, with implicit “modes” based on edits.

10. Step 9–10 – Mood description + helper (v1)

    • Entry.moodDescription field persisted and displayed; also flows into moodRating.note.
    • Add moodWords.ts with four small word lists: highEnergyPleasant, highEnergyUnpleasant, lowEnergyPleasant, lowEnergyUnpleasant.
    • “Help me describe this” link opens a compact 2×2 helper (High/Low energy × Pleasant/Unpleasant) showing chips from those lists.
    • Chip behavior: first tap sets moodDescription; further taps append ", <word>"; helper stays open until user taps “Done/Close”.
    • Visually light, touch-friendly chips; no behavior coupling to scores in v1.

11. Step 11 – Edit today’s entries in-place

    • State: selectedEntryId: string | null, mode derived as "create" vs "edit".
    • Rows in “Today’s log” are tappable; tap sets selectedEntryId and (optionally) scrolls to form.
    • In edit mode, prefill all editable fields from the selected Entry and disable default time logic.
    • Labels/buttons switch to “Edit entry” / “Save changes” + “Cancel editing”.
    • Save in edit mode: validate, rebuild Entry (keep id, createdAt, date), replace in today list, persist, re-sort, then reset to create mode.
    • Cancel: clear selection, reset form, reapply default times and clear selection states.
    • Selected row is highlighted; wake-up entry edits behave like any other row; edits restricted to today’s entries.

12. Step 12 – Week overview (read-only, Monday–Sunday)

    • Date utilities: WEEK_START_DAY = "monday", getWeekStart, getWeekEnd, formatDate.
    • New WeekOverview view, navigated via “View this week” / “Back to today”.
    • loadEntriesForDateRange(startDate, endDate) loads and filters entries; groupEntriesByDate groups them.
    • For each day Monday–Sunday: show header and either “No entries” or a simple list of time, mood (score + description), overstimulation, must/pleasant activities.
    • View is strictly read-only.

13. Step 13 – User data tables

    • Add activity_log_users_v1 with id, created_at, last_seen_at.
    • Add activity_log_passphrase_credentials_v1 with id, user_id (FK), passphrase_hash, created_at, plus unique constraint on passphrase_hash.

14. Step 14 – User repository Implement backend functions:

    • createActivityLogUserV1() (new id, insert, return row).
    • getActivityLogUserV1ById(id) → user or null.
    • touchActivityLogUserV1LastSeen(id) → update last_seen_at = now (no-op if missing).
    • Optional ensureActivityLogUserV1(id) and small tests covering create/get/touch.

15. Step 15 – Map existing user_id to passphrase

    • Clarify that activity_log_entries_v* .user_id equals activity_log_users_v1.id, and is generated once then stored in localStorage["activity_log_user_id"].
    • Add createActivityLogUserV1WithId(id) and ensureActivityLogUserV1ForId(id).
    • Passphrase repo: createPassphraseCredentialV1(userId, hash) and findPassphraseCredentialByHashV1(hash).
    • POST /api/activity-log/passphrase/set: validate body, hash passphrase, enforce uniqueness (409 if used by other user), ensure user row exists for userId, then create credential if new.
    • POST /api/activity-log/passphrase/login: hash passphrase, look up credential, return userId or 401.
    • Frontend: keep existing activity_log_user_id generation; “Set passphrase” binds current userId to passphrase; “Login with passphrase” on new device sets activity_log_user_id from backend response and reloads data; entries model/queries unchanged, always filter by user_id.

16. Step 16 – Reusable “log in with passphrase” component (in progress)

    • Create PassphraseLoginSection with props onLoginSuccess(userId).
    • Move passphrase input + submit logic into this component (passphrase, isLoading, errorMessage state; calls login endpoint).
    • Use it on main page and wake-up check-in, reusing a shared handleLoginSuccess (stores userId, updates state, reloads data).
    • Show component only when currentUserId === null; hide automatically after login.
    • Include warnings about passphrase sensitivity; optionally reuse Bitwarden link markup via the component.
17. • Step 17 – Passphrase sync warning

• Track hasPassphrase: boolean in app state, persisted in localStorage["activity_log_has_passphrase"].
• Initialise it from localStorage on app startup.
• When /passphrase/set or /passphrase/login succeeds, set hasPassphrase = true and persist it.
• In App.tsx, show a small warning card (“data only on this device, set a passphrase to sync”) only when !hasPassphrase, with actions to set or use an existing passphrase; hide it once hasPassphrase is true.

18. • Step 18 – Shared UI components

• Identify repeated UI between the main entry form and WakeUpCheckIn (card, labels, buttons, errors, mood/overstimulation controls, mood description).
• Extract layout primitives: ActivityCard, FieldLabel, TimeInputField, PrimaryButton, ErrorText.
• Extract basic mood/overstimulation/mood-description components: MoodRatingButtons, OverstimulationRatingButtons, MoodDescriptionField.
• Refactor both main form and WakeUpCheckIn to use these components so they share visuals and structure.

19. • Step 19 – V1 rating UI for mood + overstimulation

• Reuse existing Rating / RatingV1 schema.
• Implement RatingButtonsV1 that renders a scaled button group based on rating.scale and uses the Tailwind styling from WakeUpCheckIn.
• Implement MoodRatingField and OverstimulationRatingField as thin wrappers over RatingButtonsV1 for the two dimensions.
• Update WakeUpCheckIn and the main form to keep full RatingV1 state and render these fields instead of inline button groups.

20. • Step 20 – Use shared rating components in EntryForm.tsx

• In EntryForm.tsx, store mood and overstimulation as RatingV1 (or Rating | undefined) instead of plain numbers, initialised via createMoodRating / createOverstimulationRating for existing entries when needed.
• Replace inline rating JSX with <MoodRatingField> and <OverstimulationRatingField>.
• On submit, build EntryInput by passing both the rating objects and derived numeric scores (from .value), satisfying entryInputSchema.
• Ensure validation requires a mood selection (and optionally overstimulation) and that edit mode correctly preloads and updates ratings and scores.

Follow Engineering Guidelines.

Proposed “first simple pass” for data entry. = infer a default mode from lastEndTime and now, and only change how we prefill and label the form. No separate screens yet.

Given:

• lastEnd = DateTime of last entry end (or null).
• now = current DateTime.
• RECENT_GAP_MINUTES = e.g. 90 (tunable).

Rules:

1. If !lastEnd → default to Backfill mode (user is probably logging what they just did).

2. Else compute gapMinutes = (now - lastEnd) in minutes (across days).

   • If gapMinutes <= RECENT_GAP_MINUTES → Forward mode (continue log).
   • If gapMinutes > RECENT_GAP_MINUTES → Backfill mode (user has been off the log).

Editing an existing entry is always Precision mode (no inference needed).

1. Define mode enum

   • Add type EntryCreationMode = "forward" | "backfill"; (precision is implicit, for edits only).
   • Rationale: Gives you a concrete handle in state and UI to branch on.

2. Implement gap-based inference function

   • Add inferEntryCreationMode(lastEnd: Date | null, now: Date): EntryCreationMode using rules above.
   • Introduce RECENT_GAP_MINUTES constant (e.g. 90) near this function so it is easy to tweak.
   • Rationale: Central place to adjust behavior without touching UI code.

3. Expose lastEnd as a real DateTime

   • Ensure you can derive lastEnd: Date | null from the stored entries (not only HH:MM).
   • If you currently only store HH:MM, standardize on full DateTime for the backend and derive lastEnd from the most recent entry for today/overall.
   • Rationale: You need a real time delta in minutes, not just a time-of-day string.

4. Determine mode when opening “New Entry”

   • In the “open new entry form” code path, compute:

     • const mode = inferEntryCreationMode(lastEnd, new Date()).

   • Store this in component state: const [creationMode, setCreationMode] = useState<EntryCreationMode | null>(…);

   • Rationale: Mode is decided once per form-open, not recomputed on every render.

5. Forward mode defaults (continue from last)

   • If creationMode === "forward":

     • Set startTime to formatted lastEnd (HH:MM).
     • Set endTime to getCurrentTimeString().

   • Make sure this only happens on first render / form-open, not every rerender (e.g. via useEffect with a guard).

   • Rationale: Common “I’ve just been doing this” flow becomes zero-picker, confirm-only.

6. Backfill mode defaults (log last X from now)

   • Introduce DEFAULT_BACKFILL_MINUTES (e.g. 30).

   • If creationMode === "backfill":

     • Let endTime = getCurrentTimeString().
     • Let startTime = format(addMinutes(now, -DEFAULT_BACKFILL_MINUTES)).
     • Reuse or slightly adapt the addMinutesToTimeString helper for this.

   • Rationale: In “I lost track” mode, user starts from “now” and only adjusts how far back, not absolute clock times.

7. Heading / helper text based on mode

   • For creationMode === "forward":

     • Change sublabel/description to something like: Continuing from your last entry at {lastEndTime}.

   • For creationMode === "backfill":

     • Show: Logging something you were doing until just now (default: last {DEFAULT_BACKFILL_MINUTES} minutes).

   • Rationale: Make the mental model visible to you (and later users) without new screens.

8. Keep existing time inputs unchanged for now

   • Do not yet add chips or step changes; just rely on better defaults and text.
   • Keep “Use last end (…)” and “Use now (…)” buttons as-is.
   • Rationale: Isolate the effect of mode inference and prefilling first; avoid multiple changes at once.

9. Log inferred mode for your own usage

   • Temporarily console.log or add a subtle debug badge with:

     • creationMode, gapMinutes, lastEnd, now.

   • Use your own real logging to see if RECENT_GAP_MINUTES and DEFAULT_BACKFILL_MINUTES feel right.

   • Rationale: Lets you calibrate thresholds based on your real behavior before building more UI on top.

Focusing only on interaction-driven refinement of EntryCreationMode.

• You already have EntryCreationMode = "forward" | "backfill".
• You already set creationMode once when opening the “New Entry” form, based on lastEnd and now.

Introduce a small internal type to represent the “evidence” from user actions:

Create val
type ModeSignal =
  | "used_last_end_for_start" // strong evidence: forward logger
  | "used_now_for_end";       // strong evidence: backfill logger

(You can extend this later with more subtle signals without touching the UI.)

Define a small function that takes the current mode and a signal and returns the new mode. Keep it near where you define EntryCreationMode, not in the component body.

Create val
type EntryCreationMode = "forward" | "backfill";

function updateModeFromSignal(
  current: EntryCreationMode,
  signal: ModeSignal
): EntryCreationMode {
  switch (signal) {
    case "used_last_end_for_start":
      // anchor = start, user manipulates end ⇒ forward
      return "forward";

    case "used_now_for_end":
      // anchor = end, user manipulates start ⇒ backfill
      return "backfill";

    default:
      return current;
  }
}

This is intentionally simple now; later you can make it more nuanced (e.g. respect “locked” modes, add hysteresis, etc.) in one place.

Assume you already have:

Create val
const [creationMode, setCreationMode] = useState<EntryCreationMode>("forward");

Current button (simplified from your snippet):

Create val
{lastEndTime && (
  <button
    type="button"
    onClick={() => setStartTime(lastEndTime)}
    className="text-xs text-blue-500 hover:text-blue-700 mt-1"
  >
    Use last end ({lastEndTime})
  </button>
)}

Refactor handler to also update mode:

Create val
{lastEndTime && (
  <button
    type="button"
    onClick={() => {
      setStartTime(lastEndTime);
      setCreationMode((current) =>
        updateModeFromSignal(current, "used_last_end_for_start")
      );
    }}
    className="text-xs text-blue-500 hover:text-blue-700 mt-1"
  >
    Use last end ({lastEndTime})
  </button>
)}

Current button (simplified):

Create val
<button
  type="button"
  onClick={() => setEndTime(getCurrentTimeString())}
  className="text-xs text-blue-500 hover:text-blue-700 mt-1"
>
  Use now ({getCurrentTimeString()})
</button>

Refactor handler:

Create val
<button
  type="button"
  onClick={() => {
    const nowStr = getCurrentTimeString();
    setEndTime(nowStr);
    setCreationMode((current) =>
      updateModeFromSignal(current, "used_now_for_end")
    );
  }}
  className="text-xs text-blue-500 hover:text-blue-700 mt-1"
>
  Use now ({getCurrentTimeString()})
</button>

Now, every time you use one of these helpers, creationMode is updated to match the implied anchor.

This is not necessary, but if you want to inspect how often your inferred mode is “overruled” by real use:

Create val
type ModeSource = "initial_inference" | "interaction";

const [creationModeSource, setCreationModeSource] =
  useState<ModeSource>("initial_inference");

Then in handlers:

Create val
setCreationMode((current) =>
  updateModeFromSignal(current, "used_last_end_for_start")
);
setCreationModeSource("interaction");

and similarly for used_now_for_end.

This gives you a hook for debugging and later analytics.

Add a tiny debug label or console log to see the effect while you use the app:

Create val
{/* Debug-only, remove later */}
<div className="text-[10px] text-gray-400 mt-1">
  mode: {creationMode}
</div>

This lets you see mode flips in real time as you click “Use last end” / “Use now”, which you will need once you start showing different affordances per mode.

Core idea: keep one simple set of “+ / − X minutes” controls, but attach them to different sides of the block depending on EntryCreationMode.

Forward mode (anchor = start): user mostly adjusts end time.

Backfill mode (anchor = end): user mostly adjusts start time.

Same mental model, same buttons, just applied to the anchored side.

1. Decide the behavior and constants

   1.1. Confirm your mode semantics:

   • creationMode === "forward" ⇒ anchor = start, user mainly adjusts end.
   • creationMode === "backfill" ⇒ anchor = end, user mainly adjusts start.

   1.2. Choose your default nudge sizes:

   Create val
   const NUDGE_MINUTES = [-15, -5, +5, +15];

   1.3. Decide how nudges map to time changes:

   • Forward mode: endTime = endTime + deltaMinutes.
   • Backfill mode: startTime = startTime - deltaMinutes (so +5m means “5 minutes earlier start” → longer block).

2. Add / reuse a time-string nudge helper

   2.1. If you do not already have one, add:

   Create val
   function addMinutesToTimeString(timeStr: string, minutes: number): string {
     const [h, m] = timeStr.split(":").map(Number);
     const total = h * 60 + m + minutes;
   
     const minutesInDay = 24 * 60;
     const wrapped = ((total % minutesInDay) + minutesInDay) % minutesInDay;
   
     const nh = Math.floor(wrapped / 60);
     const nm = wrapped % 60;
   
     const hh = nh.toString().padStart(2, "0");
     const mm = nm.toString().padStart(2, "0");
   
     return `${hh}:${mm}`;
   }

   2.2. Keep all “+ / − minutes” behavior going through this helper.

3. Create a reusable BoundaryAdjuster component

   3.1. Add a small component next to your time-input code:

   Create val
   type Boundary = "start" | "end";
   
   const NUDGE_MINUTES = [-15, -5, +5, +15];
   
   function BoundaryAdjuster({
     boundary,
     onNudge,
   }: {
     boundary: Boundary;
     onNudge: (deltaMinutes: number) => void;
   }) {
     const label =
       boundary === "start" ? "Adjust start of block" : "Adjust end of block";
   
     return (
       <div className="mt-1">
         <div className="text-[10px] text-gray-500 mb-1">{label}</div>
         <div className="flex gap-1 flex-wrap">
           {NUDGE_MINUTES.map((delta) => (
             <button
               key={delta}
               type="button"
               onClick={() => onNudge(delta)}
               className="text-[11px] px-1.5 py-0.5 rounded text-blue-500 hover:text-blue-700"
             >
               {delta > 0 ? `+${delta}m` : `${delta}m`}
             </button>
           ))}
         </div>
       </div>
     );
   }

   3.2. Keep it generic; it does not know about “forward/backfill”, only “start/end”.

4. Integrate with the Start Time column (backfill mode)

   4.1. In the JSX for your Start Time field, conditionally render BoundaryAdjuster only when creationMode === "backfill":

   Create val
   {/* Start Time column */}
   <div className="flex-1">
     <label className="block text-sm font-medium mb-1">Start Time</label>
     <input
       type="time"
       value={startTime}
       onChange={(e) => setStartTime(e.target.value)}
       className="w-full px-4 py-3 text-lg border-2 border-gray-200 rounded-lg focus:border-blue-400 focus:outline-none"
       required
     />
   
     {lastEndTime && (
       <button
         type="button"
         onClick={() => {
           setStartTime(lastEndTime);
           setCreationMode((current) =>
             updateModeFromSignal(current, "used_last_end_for_start")
           );
         }}
         className="text-xs text-blue-500 hover:text-blue-700 mt-1"
       >
         Use last end ({lastEndTime})
       </button>
     )}
   
     {creationMode === "backfill" && (
       <BoundaryAdjuster
         boundary="start"
         onNudge={(delta) => {
           // Backfill semantics:
           // +5m => start earlier => subtract delta from start.
           const newStart = addMinutesToTimeString(startTime, -delta);
           setStartTime(newStart);
         }}
       />
     )}
   </div>

5. Integrate with the End Time column (forward mode)

   5.1. In the JSX for your End Time field, render BoundaryAdjuster only when creationMode === "forward":

   Create val
   {/* End Time column */}
   <div className="flex-1">
     <label className="block text-sm font-medium mb-1">End Time</label>
     <input
       type="time"
       value={endTime}
       onChange={(e) => setEndTime(e.target.value)}
       className="w-full px-4 py-3 text-lg border-2 border-gray-200 rounded-lg focus:border-blue-400 focus:outline-none"
       required
     />
   
     <button
       type="button"
       onClick={() => {
         const nowStr = getCurrentTimeString();
         setEndTime(nowStr);
         setCreationMode((current) =>
           updateModeFromSignal(current, "used_now_for_end")
         );
       }}
       className="text-xs text-blue-500 hover:text-blue-700 mt-1"
     >
       Use now ({getCurrentTimeString()})
     </button>
   
     {creationMode === "forward" && (
       <BoundaryAdjuster
         boundary="end"
         onNudge={(delta) => {
           // Forward semantics:
           // +5m => end later => add delta to end.
           const newEnd = addMinutesToTimeString(endTime, delta);
           setEndTime(newEnd);
         }}
       />
     )}
   </div>

6. Keep basic controls and mode signals intact

   6.1. Do not remove or hide:

   • The raw time inputs for Start and End.
   • The “Use last end” and “Use now” buttons.

   6.2. Ensure those buttons still emit mode signals:

   • “Use last end” ⇒ updateModeFromSignal(current, "used_last_end_for_start").
   • “Use now” ⇒ updateModeFromSignal(current, "used_now_for_end").

   This lets users “correct” the mode just by using the helpers.

7. Handle edge cases carefully

   7.1. If startTime or endTime is empty:

   • Either disable the nudge buttons (e.g. disabled={!startTime} / !endTime).
   • Or initialize them first (e.g. treat missing as getCurrentTimeString()).

   7.2. If nudges cross midnight:

   • addMinutesToTimeString already wraps around; this is fine for “today-only” logging as long as you conceptually stay in the same day.
   • If you later support cross-day ranges, you will want full DateTime backing instead of HH:MM only.

8. Make the behavior legible (optional debug)

   8.1. Temporarily show the inferred mode in a subtle way:

   Create val
   <div className="text-[10px] text-gray-400 mt-1">
     mode: {creationMode}
   </div>

   8.2. Use the app for a few days and notice:

   • Does forward mode feel right when you are continuing from last entry?
   • Does backfill mode feel right when you are logging “what just happened”?

   Then you can tweak:

   • The threshold for initial inference.
   • The NUDGE_MINUTES set.
   • Whether to keep the debug label.

9. Clean up and prepare for future refinements

   9.1. Once the pattern feels right:

   • Remove debug labels.
   • Keep BoundaryAdjuster, EntryCreationMode, and updateModeFromSignal as core primitives.

   9.2. This sets you up to later:

   • Add duration chips or a “log last X minutes” helper using the same EntryCreationMode.
   • Introduce more subtle signals (e.g. repeated manual edits of just one side) without changing the basic affordance pattern.

The UI is a bit confusing when boundary === start in @EntryForm.tsx.

Namely, e.g. the "-15/5 m" buttons move the start time into the future, thereby actually acting like they're "+" buttons.

1.1. Keep RECENT_GAP_MINUTES as is Used for both:

• Initial forward/backfill inference.
• Threshold for when to avoid snapping (your “Threshold for Precision Mode”).

1.2. Add a default block length

Create val
const DEFAULT_AUTO_BLOCK_MINUTES = 30; // e.g. 30

1.3. Add a small helper to check the precision window

Create val
function isInPrecisionWindow(lastEnd: Date | null, now: Date): boolean {
  if (!lastEnd) return false;
  const gapMinutes = (now.getTime() - lastEnd.getTime()) / 60000;
  return gapMinutes <= RECENT_GAP_MINUTES;
}

1.4. Reuse addMinutesToTimeString as already discussed for time string arithmetic.

You already have:

• EntryCreationMode = "forward" | "backfill"
• updateModeFromSignal(current, signal)

Add a component-local helper that decides how to adjust times when the mode changes:

Create val
function snapTimesOnModeChange(
  newMode: EntryCreationMode,
  params: {
    lastEnd: Date | null;
    now: Date;
    startTime: string;
    endTime: string;
    setStartTime: (s: string) => void;
    setEndTime: (s: string) => void;
  }
) {
  const { lastEnd, now, startTime, endTime, setStartTime, setEndTime } = params;

  // 1) If we are in the precision window, do nothing.
  if (isInPrecisionWindow(lastEnd, now)) return;

  if (newMode === "forward") {
    // Anchor at start, create a reasonable block after it.
    // Assumes startTime is already meaningful (e.g. set to lastEnd).
    if (!startTime) return;

    const snappedEnd = addMinutesToTimeString(
      startTime,
      DEFAULT_AUTO_BLOCK_MINUTES
    );
    setEndTime(snappedEnd);
  }

  if (newMode === "backfill") {
    // Anchor at now, create a reasonable block before it.
    const endStr = formatTime(now); // "HH:MM"
    const startStr = addMinutesToTimeString(
      endStr,
      -DEFAULT_AUTO_BLOCK_MINUTES
    );

    setEndTime(endStr);
    setStartTime(startStr);
  }
}

Notes:

• This is exactly your “Switching to mode === forward sets end to 30 minutes after start; vice versa for backfill” rule.
• The “except when in precision mode” part is enforced by isInPrecisionWindow.

You already update mode when:

• “Use last end” is clicked → strong forward signal.
• “Use now” is clicked → strong backfill signal.

Adjust those handlers so that they:

1. Set the relevant time(s) as before.
2. Compute the new mode via updateModeFromSignal.
3. Apply snapTimesOnModeChange with that new mode.

Create val
{lastEndTime && (
  <button
    type="button"
    onClick={() => {
      // 1) Apply the direct effect
      setStartTime(lastEndTime);

      // 2) Compute new mode from signal
      const newMode = updateModeFromSignal(
        creationMode,
        "used_last_end_for_start"
      );

      // 3) Snap times if appropriate (outside precision window)
      snapTimesOnModeChange(newMode, {
        lastEnd,             // Date | null
        now: new Date(),
        startTime: lastEndTime, // we just set this
        endTime,
        setStartTime,
        setEndTime,
      });

      // 4) Commit the mode change
      setCreationMode(newMode);
    }}
    className="text-xs text-blue-500 hover:text-blue-700 mt-1"
  >
    Use last end ({lastEndTime})
  </button>
)}

Result:

• If now - lastEnd > RECENT_GAP_MINUTES:

  • Mode becomes forward.
  • endTime is reset to startTime + DEFAULT_AUTO_BLOCK_MINUTES.

• If now - lastEnd <= RECENT_GAP_MINUTES:

  • Mode becomes forward.
  • Times are left as-is (precision window).

Create val
<button
  type="button"
  onClick={() => {
    const now = new Date();
    const nowStr = formatTime(now); // "HH:MM"

    // 1) Apply the direct effect
    setEndTime(nowStr);

    // 2) Compute new mode from signal
    const newMode = updateModeFromSignal(
      creationMode,
      "used_now_for_end"
    );

    // 3) Snap times if appropriate (outside precision window)
    snapTimesOnModeChange(newMode, {
      lastEnd,
      now,
      startTime,
      endTime: nowStr,
      setStartTime,
      setEndTime,
    });

    // 4) Commit the mode change
    setCreationMode(newMode);
  }}
  className="text-xs text-blue-500 hover:text-blue-700 mt-1"
>
  Use now ({getCurrentTimeString()})
</button>

Result:

• If now - lastEnd > RECENT_GAP_MINUTES:

  • Mode becomes backfill.
  • endTime is set to now.
  • startTime is set to now - DEFAULT_AUTO_BLOCK_MINUTES.

• If now - lastEnd <= RECENT_GAP_MINUTES:

  • Mode becomes backfill.
  • Only endTime is set to now; startTime is untouched (precision).

• In forward mode, your “Adjust end of block” nudges are now anchored on a 30-minute block starting at startTime (outside the precision window).
• In backfill mode, your “Adjust start of block” nudges are anchored on a 30-minute block ending at now (outside the precision window).
• Inside the precision window (gap ≤ RECENT_GAP_MINUTES), switching modes does not resnap, so you keep your carefully chosen times and only get different nudges/affordances.

This keeps:

• RECENT_GAP_MINUTES as the single mental and code constant for “precision vs rough logging”.
• Default blocks simple and adjustable, via the same minimal “+ / − X minutes” affordance.