# AGENTS — react-virtual-aggridautomat

## What
PureComponent wrapper: AG Grid infinite-scroll + react-automat state. Library in `src/lib/`, demo in `src/demo/`.

## Exports (`src/lib/index.ts`)
- `AutomatGrid` — PureComponent. Props: `automat` (required), `columnDefs` (required), `rowIdField` (default `'id'`), `cacheBlockSize`, `rowBuffer`, `height`, `width`, `onGridApiReady`, plus standard AG Grid overrides.
- `createGridAutomat(options)` — Factory returning `Automat<GridAutomatState, GridAutomatActions>`.

## createGridAutomat
```ts
createGridAutomat({ fetchRows, name?, blockSize? })
```
- `fetchRows: ({startRow, endRow, sortModel, filterModel}) => Promise<{rows, lastRow?}>` — the only required option.
- State: `ready`, `loading`, `totalRows`, `sortModel`, `filterModel`, `revision`, `error`.
- Actions: `reload()`, `setSort(model)`, `setFilter(model)`.

## AutomatGrid internals
- Uses `InfiniteRowModelModule` (community, no enterprise needed).
- Constructor: sync read `automat.state`. Mount: `automat.subscribe(this, selector)`. Unmount: `unsub()`.
- On `revision` change (via `componentDidUpdate`): rebuilds `IDatasource` and calls `api.setGridOption('datasource', ds)`.
- `onSortChanged`/`onFilterChanged` → `automat.actions.setSort/setFilter` → bumps revision → datasource reset.
- `getRowId` uses `props.rowIdField` (default `'id'`) from row data.

## Patterns
```tsx
// 1. Create automat (module scope)
const grid = createGridAutomat({ fetchRows: myFetcher });
// 2. Render
<AutomatGrid automat={grid} columnDefs={cols} rowIdField="id" />
// 3. Reload externally
grid.actions.reload();
// 4. Subscribe from another component
this.unsub = grid.subscribe(this, s => ({ loading: s.loading }));
```

## Rules
- Never use hooks — PureComponent only.
- Subscribe in `componentDidMount`, unsubscribe in `componentWillUnmount`.
- Read `automat.state` in constructor for zero-flash initial render.
- `fetchRows` must return `{ rows, lastRow? }`. Set `lastRow` to total count to stop infinite scrolling.
- AG Grid modules: only `InfiniteRowModelModule` is registered by `AutomatGrid`.

## Commands
```
npm run dev      # Vite dev server
npm run build    # tsc + vite build
```