# Core-v2 integration patterns

## Contents

1. [Install and bootstrap](#install-and-bootstrap)
2. [Mental model](#mental-model)
3. [Actions and retained history](#actions-and-retained-history)
4. [Gesture builder](#gesture-builder)
5. [Custom choreography](#custom-choreography)
6. [Connected partial presentations](#connected-partial-presentations)
7. [Nested scenes](#nested-scenes)
8. [Constraints and verification](#constraints-and-verification)

## Install and bootstrap

Install the Git package. Pin a commit or tag for reproducible applications:

```bash
npm install "git+https://git.harvmaster.com/Harvmaster/Native-Router-Vue.git#<commit-or-tag>"
```

The unpinned default-branch form is useful during active development:

```bash
npm install git+https://git.harvmaster.com/Harvmaster/Native-Router-Vue.git
```

The installed package name is `@native-vue-router/core-v2`. It has one peer
dependency: Vue `^3.5.0`. It does not depend on Vue Router.

Create the scene:

```ts
// src/scene.ts
import { createOriginScene, originView } from "@native-vue-router/core-v2";
import HomeView from "./views/HomeView.vue";

export const scene = createOriginScene({
  initial: originView(
    HomeView,
    { accountId: "42" },
    { key: "home", name: "Home" },
  ),
});
```

Render it:

```vue
<script setup lang="ts">
import { OriginScene } from "@native-vue-router/core-v2";
import "@native-vue-router/core-v2/style.css";
import { scene } from "./scene";
</script>

<template>
  <main class="app-shell">
    <OriginScene :scene="scene" />
  </main>
</template>

<style>
html,
body,
#app,
.app-shell {
  width: 100%;
  height: 100%;
  margin: 0;
}
</style>
```

The scene needs a definite width and height. Its view hosts are stable,
absolutely positioned siblings.

## Mental model

- `OriginView`: immutable recipe containing a Vue component, props, and
  optional diagnostic key/name.
- Scene node: one mounted instance created from a recipe.
- Operation edge: temporary source→target relationship with progress,
  velocity, choreography, and commit/cancel outcome.
- Origin: the mounted component that handled the event. There is no global
  current view.
- Retained history: linked mounted instances, independent of URLs.

A newly created target can originate another operation while its incoming
operation settles. Visual transforms compose by origin frame:

```text
visual(Y) = X→Y.target × Y→Z.source
visual(Z) = X→Y.target × Y→Z.target
```

## Actions and retained history

Helpers are overloaded:

- Without choreography they return `OriginNavigationIntent` for a gesture
  builder.
- With choreography they return a complete `OriginAction` for `begin()` or
  `perform()`.

### Forward

```ts
const profileView = () =>
  originView(
    ProfileView,
    { userId: "7" },
    { key: "profile-7", name: "Profile" },
  );

await origin.perform(forward(profileView(), slideLeft));
```

Commit parks but retains the origin. Back later restores that exact instance,
including local state and DOM scroll position.

### Back

```ts
if (origin.context.value.canGoBack) {
  await origin.perform(back(slideRight));
}
```

Back has no target recipe. It resolves `previousNodeKey`, animates the retained
instance, and unmounts the current entry only on commit.

Useful context:

```ts
const origin = useOrigin();

origin.nodeKey;
origin.context.value.view;
origin.context.value.previous;
origin.context.value.history;
origin.context.value.canGoBack;
```

### Replace

```ts
await origin.perform(
  replace(
    originView(
      OrderConfirmationView,
      { orderId: "NVO-2048" },
      { key: "confirmation", name: "Confirmation" },
    ),
    slideLeft,
  ),
);
```

Replace creates a target linked to the current origin's predecessor. Commit
unmounts the current entry; cancellation removes the proposed replacement and
restores the current entry. Back from the replacement skips the removed view.

### Placement

`above()` and `under()` select stacking, not direction or history:

```ts
above(originView(DialogView), fade);
under(originView(BackdropView), reveal);
```

Prefer `forward`, `back`, and `replace` when expressing history semantics.

## Gesture builder

Declare an anywhere forward gesture and responsive edge Back:

```vue
<script setup lang="ts">
import {
  OriginGestureSurface,
  back,
  forward,
  gesture,
  originView,
  slideLeft,
  slideRight,
  useOrigin,
} from "@native-vue-router/core-v2";
import DetailsView from "./DetailsView.vue";

const origin = useOrigin();
const detailsView = () =>
  originView(DetailsView, undefined, {
    key: "details",
    name: "Details",
  });

const openDetails = gesture.to
  .left()
  .navigate(() => forward(detailsView()))
  .animate(slideLeft);

const goBack = gesture.from
  .left("clamp(24px, 8%, 64px)")
  .to.right()
  .navigate((context) => (context.canGoBack ? back() : null))
  .animate(slideRight);

const gestures = [openDetails, goBack] as const;
</script>

<template>
  <OriginGestureSurface as="main" :gestures="gestures">
    <button
      type="button"
      data-origin-gesture="ignore"
      @click="origin.perform(forward(detailsView(), slideLeft))"
    >
      Open details
    </button>
  </OriginGestureSurface>
</template>
```

Builder stages:

1. Optional `.from`: pointer-down eligibility.
2. `.to`: direction recognition and axis lock.
3. Optional `.complete`: release policy.
4. `.navigate`: destination/history intent.
5. `.animate`: visual choreography.

Starting at `.to` permits pointer-down anywhere. Edge distances accept CSS
pixels, percentages, `calc()`, and `clamp()`. Use `.from.when(context => ...)`
for arbitrary shapes, safe areas, or exclusion regions.

Set explicit completion policy for product-specific velocity behavior:

```ts
const open = gesture.to
  .left()
  .complete(
    ({ progress, velocity }) =>
      progress >= 0.38 || (progress >= 0.06 && velocity >= 0.85),
  )
  .navigate(() => forward(detailsView()))
  .animate(slideLeft);
```

Use `OriginGesture` when only one definition owns the host:

```vue
<OriginGesture :gesture="goBack">
  <article>...</article>
</OriginGesture>
```

## Custom choreography

Effects are recomputed often. Keep them pure:

```ts
import { defineOriginChoreography } from "@native-vue-router/core-v2";

const percent = (value: number) => `${value * 100}%`;

export const focusCard = defineOriginChoreography({
  name: "focus-card",
  commitThreshold: 0.36,
  effects: ({ progress }) => ({
    frame: {
      transform: `translateY(${-Math.sin(progress * Math.PI) * 8}px)`,
    },
    source: {
      transform: `scale(${1 - progress * 0.08})`,
      opacity: 1 - progress * 0.45,
    },
    target: {
      transform: `translateY(${percent((1 - progress) * 0.1)}) scale(${
        0.82 + progress * 0.18
      })`,
      opacity: progress,
      style: {
        borderRadius: `${(1 - progress) * 28}px`,
      },
    },
  }),
});
```

`frame` affects both sides and descendants. Transforms concatenate, opacities
multiply, and other `style` properties use local-last precedence.

Choreography context includes progress, velocity, phase, intent, measured
origin/target rectangles, and scene viewport.

## Connected partial presentations

Normal forward commit removes its operation edge and parks the retained source.
Set `persistAtRest: true` when progress-1 effects must remain connected:

```ts
export const openDrawer = defineOriginChoreography({
  name: "open-two-thirds-drawer",
  persistAtRest: true,
  effects: ({ progress }) => ({
    source: {
      transform: `translateX(${progress * 66.6667}%)`,
    },
    target: {
      transform: `translateX(${(progress - 1) * 66.6667}%)`,
    },
  }),
});

export const closeDrawer = defineOriginChoreography({
  name: "close-two-thirds-drawer",
  effects: ({ progress }) => ({
    source: {
      transform: `translateX(${-progress * 66.6667}%)`,
    },
    target: {
      transform: `translateX(${(1 - progress) * 66.6667}%)`,
    },
  }),
});
```

Open with a retained push:

```ts
forward(originView(DrawerView), openDrawer);
```

The source becomes `exposed`: mounted and visible, but inert and
`aria-hidden`. The drawer is active. Back temporarily suspends the settled
opening edge and uses the close choreography. A cancelled Back restores the
opening relationship; committed Back removes the drawer.

Requirements:

- Use `persistAtRest` only with push history.
- Make close progress 0 visually identical to open progress 1.
- Put a transparent interactive region in the target if tapping the exposed
  source area should dismiss; the source itself is intentionally inert.
- Do not treat settled connected edges as live animations in diagnostics.

## Nested scenes

Create another scene when an embedded component needs independent history:

```ts
const carouselScene = createOriginScene({
  initial: originView(CarouselSlide, { index: 0 }),
});
```

Render `<OriginScene :scene="carouselScene" />` inside the parent view. The
nearest injected node scope owns `useOrigin()` and gestures.

Current parent/child ownership is selected at pointer-down. Give the child a
non-overlapping `.from` region when the parent must retain fallback behavior.
Do not assume a child can decline after capture and automatically hand the same
pointer sequence to its parent.

## Constraints and verification

- No URL, deep-link, route-param, or browser-history model is included. Model
  data as props/state and bridge host Back separately.
- No global active view exists. The component receiving the event is the
  origin.
- Pushed entries remain mounted until Back pops them. There is no eviction
  policy yet.
- Parked/exposed entries are inert, but their Vue watchers, timers, and effects
  continue running.
- One origin owns at most one outgoing operation; a target may originate the
  next operation once its incoming intent commits.
- Gesture recognition handles one primary pointer and one axis.
- Nested scenes have separate history and measurements.
- `KeepAlive` is not the scene cache and should not wrap scene navigation.
- Reduced-motion preference settles operations immediately.

Verify scene diagnostics and DOM behavior:

```ts
scene.nodes.value;
scene.operations.value;
scene.contextFor(nodeKey);
scene.styleForNode(nodeKey);
```

Test committed and cancelled operations, component mount/unmount counts,
retained DOM identity, scroll position, rapid chained operations, replace
history, connected presentation cancellation, responsive edge regions, focus,
inert/ARIA behavior, and production bundling.