# AGENT.md

This document provides an overview of the Next Explorer project, its structure, and its implementation details.

## Project Overview

Next Explorer is a web application for exploring the Spectrum Next ecosystem. It is built with Next.js (App Router), React, and TypeScript.

It has two main areas:
- Registers: parsed from `data/nextreg.txt`, browsable with real-time filtering and deep links.
- ZXDB Explorer: a deep, cross‑linked browser for ZXDB entries, labels, genres, languages, and machine types backed by MySQL using Drizzle ORM.

## Project Structure

The project is a Next.js application with the following structure:
```

next-explorer/
├── eslint.config.mjs
├── next.config.ts
├── package.json
├── pnpm-lock.yaml
├── tsconfig.json
├── data/
│   ├── nextreg.txt
│   ├── custom_parsers.txt
│   └── wikilinks.txt
├── node_modules/...
├── public/...
└── src/
├── middleware.js
├── app/
│   ├── layout.tsx
│   ├── page.module.css
│   ├── page.tsx
│   └── registers/
│       ├── page.tsx
│       ├── RegisterBrowser.tsx
│       ├── RegisterDetail.tsx
│       └── [hex]/
│           └── page.tsx
├── components/
│   ├── Navbar.tsx
│   └── ThemeDropdown.tsx
├── scss/
│   ├── _bootswatch.scss
│   ├── _explorer.scss
│   ├── _variables.scss
│   └── nbn.scss
├── services/
│   └── register.service.ts
└── utils/
├── register_parser.ts
└── register_parsers/
├── reg_default.ts
└── reg_f0.ts
```
- **`data/`**: Contains the raw input data for the Spectrum Next explorer.
  - `nextreg.txt`: Main register definition file.
  - `custom_parsers.txt`, `wikilinks.txt`: Auxiliary configuration/data used by the parser.
- **`src/app/`**: Next.js App Router entrypoint.
  - `layout.tsx`: Root layout for all routes.
  - `page.tsx`: Application home page.
  - `registers/`: Routes and components for the register explorer.
    - `page.tsx`: Server Component that loads and lists all registers.
    - `RegisterBrowser.tsx`: Client Component implementing search/filter and listing.
    - `RegisterDetail.tsx`: Client Component that renders a single register’s details, including modes, notes, and source modal.
    - `[hex]/page.tsx`: Dynamic route that renders details for a specific register by hex address.
- `src/app/zxdb/`: ZXDB Explorer routes and client components.
  - `page.tsx` + `ZxdbExplorer.tsx`: Search + filters with server-rendered initial content and ISR.
  - `entries/[id]/page.tsx` + `EntryDetail.tsx`: Entry details (SSR initial data).
  - `labels/page.tsx`, `labels/[id]/page.tsx` + client: Labels search and detail.
  - `genres/`, `languages/`, `machinetypes/`: Category hubs and detail pages.
- `src/app/api/zxdb/`: Zod‑validated API routes (Node runtime) for search and category browsing.
- `src/server/`:
  - `env.ts`: Zod env parsing/validation (t3.gg style). Validates `ZXDB_URL` (mysql://).
  - `server/db.ts`: Drizzle over `mysql2` singleton pool.
  - `server/schema/zxdb.ts`: Minimal Drizzle models (entries, labels, helper tables, lookups).
  - `server/repo/zxdb.ts`: Repository queries for search, details, categories, and facets.
- **`src/components/`**: Shared UI components such as `Navbar` and `ThemeDropdown`.
- **`src/services/register.service.ts`**: Service layer responsible for loading and caching parsed register data.
- **`src/utils/register_parser.ts` & `src/utils/register_parsers/`**: Parsing logic for `nextreg.txt`, including mode/bitfield handling and any register-specific parsing extensions.

## Implementation Details

Comment what the code does, not what the agent has done. The documentation's purpose is the state of the application today, not a log of actions taken.

### Data Parsing

- `getRegisters()` in `src/services/register.service.ts`:
  - Reads `data/nextreg.txt` from disk.
  - Uses `parseNextReg()` from `src/utils/register_parser.ts` to convert the raw text into an array of `Register` objects.
  - Returns the in-memory representation of all registers (and can be extended to cache results across calls).

- `parseNextReg()` and related helpers in `register_parser.ts`:
  - Parse the custom `nextreg.txt` format into structured data:
    - Register addresses (hex/dec).
    - Names, notes, and descriptive text.
    - Per-mode read/write/common bitfield views.
    - Optional source lines and external links (e.g. wiki URLs).
  - Delegate special-case parsing to functions in `src/utils/register_parsers/` (e.g. `reg_default.ts`, `reg_f0.ts`) when needed.

### React / Next.js Patterns

- **Server Components**:
  - `src/app/registers/page.tsx` and `src/app/registers/[hex]/page.tsx` are Server Components.
  - ZXDB pages under `/zxdb` server‑render initial content for fast first paint, with ISR (`export const revalidate = 3600`) on non‑search pages.
  - Server components call repository functions directly on the server and pass data to client components for presentation.

- **Client Components**:
  - `RegisterBrowser.tsx`:
    - Marked with `'use client'`.
    - Uses React state to manage search input and filtered results.
  - `RegisterDetail.tsx`:
    - Marked with `'use client'`.
    - Renders a single register with tabs for different access modes.
  - ZXDB client components (e.g., `ZxdbExplorer.tsx`, `EntryDetail.tsx`, `labels/*`) receive initial data from the server and keep interactions on the client without blocking the first paint.

- **Dynamic Routing**:
  - Pages and API routes must await dynamic params in Next.js 15:
    - Pages: `export default async function Page({ params }: { params: Promise<{ id: string }> }) { const { id } = await params; }`
    - API: `export async function GET(req, ctx: { params: Promise<{ id: string }> }) { const raw = await ctx.params; /* validate with Zod */ }`
  - `src/app/registers/[hex]/page.tsx` resolves the `[hex]` segment and calls `notFound()` if absent.

### ZXDB Integration

- Database connection via `mysql2` pool wrapped by Drizzle (`src/server/db.ts`).
- Env validation via Zod (`src/env.ts`) ensures `ZXDB_URL` is a valid `mysql://` URL.
- Minimal Drizzle schema models used for fast search and lookups (`src/server/schema/zxdb.ts`).
- Repository consolidates SQL with typed results (`src/server/repo/zxdb.ts`).
- API routes under `/api/zxdb/*` validate inputs with Zod and run on Node runtime.
- UI under `/zxdb` is deeply cross‑linked and server‑renders initial data for performance. Links use Next `Link` to enable prefetching.
  - Helper SQL `ZXDB/scripts/ZXDB_help_search.sql` must be run to create `search_by_*` tables for efficient searches.
  - Lookup tables use column `text` for display names; the Drizzle schema maps it as `name`.

### Working Patterns***

- git branching:
  - Do not create new branches
- git commits:
  - Create COMMIT_EDITMSG file, await any user edits, then commit using that 
    commit note, and then delete the COMMIT_EDITMSG file. Remember to keep
    the first line as the subject <50char
- git commit messages:
  - Use imperative mood (e.g., "Add feature X", "Fix bug Y").
  - Include relevant issue numbers if applicable.
  - Sign-off commit message as Junie@<hostname>

### References

- ZXDB setup and API usage: `docs/ZXDB.md`