feat(tui): add interactive extension service

packages/ui/tui/src/extension.ts

@@ -0,0 +1,165 @@
+/**
+ * Public interactive-extension contract for one mounted TUI front door.
+ *
+ * Plugins receive terminal-specific rendering primitives without access to
+ * the live pi-tui tree, focus controller, overlay handles, or terminal
+ * lifecycle. Registrations and open overlays remain owned by the calling
+ * Cordis fiber.
+ * @module @deepseek-ai/dsh-tui/extension
+ */
+
+/** Terminal component shape accepted from a trusted TUI extension. */
+export interface TuiComponent {
+  /**
+   * Render this component for the supplied viewport width.
+   * @param width - Available terminal columns.
+   * @returns terminal lines owned by this component.
+   */
+  render(width: number): string[]
+  /**
+   * Handle one terminal input sequence while this component owns focus.
+   * @param data - Raw terminal input sequence.
+   */
+  handleInput?(data: string): void
+  /** Receive key-release events instead of having them filtered by the host. */
+  wantsKeyRelease?: boolean
+  /** Drop cached rendering derived from theme, size, or component state. */
+  invalidate(): void
+}
+
+/** Optional focus state forwarded by the host to a component. */
+export interface TuiFocusable {
+  /** Whether the component currently owns terminal focus. */
+  focused: boolean
+}
+
+/** Read-only semantic color roles supplied by the mounted TUI. */
+export interface TuiTheme {
+  /** Render ordinary foreground text. */
+  readonly text: (value: string) => string
+  /** Render secondary information. */
+  readonly muted: (value: string) => string
+  /** Render low-emphasis hints. */
+  readonly dim: (value: string) => string
+  /** Render the active accent role. */
+  readonly accent: (value: string) => string
+  /** Render a successful outcome. */
+  readonly success: (value: string) => string
+  /** Render a warning. */
+  readonly warning: (value: string) => string
+  /** Render an error. */
+  readonly error: (value: string) => string
+  /** Apply the host's bold role. */
+  readonly bold: (value: string) => string
+}
+
+/** Current terminal viewport exposed without the mutable Terminal object. */
+export interface TuiViewport {
+  /** Terminal columns. */
+  readonly columns: number
+  /** Terminal rows. */
+  readonly rows: number
+}
+
+/** Supported overlay anchor points. */
+export type TuiOverlayAnchor =
+  | 'center'
+  | 'top-left'
+  | 'top-right'
+  | 'bottom-left'
+  | 'bottom-right'
+  | 'top-center'
+  | 'bottom-center'
+  | 'left-center'
+  | 'right-center'
+
+/** Terminal-edge spacing for an overlay. */
+export interface TuiOverlayMargin {
+  /** Rows reserved above the overlay. */
+  readonly top?: number
+  /** Columns reserved to the right of the overlay. */
+  readonly right?: number
+  /** Rows reserved below the overlay. */
+  readonly bottom?: number
+  /** Columns reserved to the left of the overlay. */
+  readonly left?: number
+}
+
+/** Position and size constraints retained under TUI host ownership. */
+export interface TuiOverlayOptions {
+  /** Width in columns or as a percentage of terminal width. */
+  readonly width?: number | `${number}%`
+  /** Minimum width in columns. */
+  readonly minWidth?: number
+  /** Maximum height in rows or as a percentage of terminal height. */
+  readonly maxHeight?: number | `${number}%`
+  /** Overlay anchor; defaults to the terminal center. */
+  readonly anchor?: TuiOverlayAnchor
+  /** Terminal-edge spacing. */
+  readonly margin?: number | TuiOverlayMargin
+}
+
+/** Capabilities available while an overlay component is queued or visible. */
+export interface TuiOverlayHost {
+  /**
+   * Aborts when the request, caller fiber, overlay session, or TUI closes.
+   * Extension work started for the overlay must cooperate with this signal.
+   */
+  readonly signal: AbortSignal
+  /** Current viewport; a fresh immutable value is returned on every read. */
+  readonly viewport: TuiViewport
+  /** Semantic styles that follow terminal color-scheme changes. */
+  readonly theme: TuiTheme
+  /**
+   * Escape control characters in untrusted display text.
+   * @param value - text crossing into terminal presentation.
+   * @returns a printable representation that cannot emit terminal controls.
+   */
+  display(value: string): string
+  /** Invalidate the component and schedule one contained terminal redraw. */
+  invalidate(): void
+  /** Close this overlay normally; repeated calls are no-ops. */
+  close(): void
+}
+
+/** One effect-owned request to create an interactive overlay. */
+export interface TuiOverlayRequest {
+  /**
+   * Construct the component when this request reaches the front of the modal
+   * queue. A throw closes the session with `reason: "error"`.
+   */
+  readonly create: (host: TuiOverlayHost) => TuiComponent & Partial<TuiFocusable>
+  /** Host-owned position and size constraints. */
+  readonly options?: TuiOverlayOptions
+  /** Optional request cancellation in addition to caller and TUI ownership. */
+  readonly signal?: AbortSignal
+}
+
+/** Stable reason an overlay stopped being queued or visible. */
+export type TuiOverlayCloseReason =
+  | 'closed'
+  | 'aborted'
+  | 'owner-disposed'
+  | 'tui-disposed'
+  | 'error'
+
+/** Settled overlay outcome; component failures retain their original value. */
+export type TuiOverlayOutcome =
+  | { readonly reason: Exclude<TuiOverlayCloseReason, 'error'> }
+  | { readonly reason: 'error'; readonly error: unknown }
+
+/** Live state of an overlay operation. */
+export type TuiOverlayState = 'queued' | 'active' | 'closed'
+
+/** Handle returned to the extension that opened an overlay. */
+export interface TuiOverlaySession {
+  /** Current queue/display state. */
+  readonly state: TuiOverlayState
+  /** Settles exactly once after the overlay leaves the queue or display. */
+  readonly closed: Promise<TuiOverlayOutcome>
+  /**
+   * Close the overlay normally and await its settled outcome.
+   * @returns the same immutable value exposed through {@link closed}.
+   */
+  close(): Promise<TuiOverlayOutcome>
+}