import type { Snippet } from "svelte";
export type PanelStackShape = "split-primary" | "sticky-item";
/**
 * Bound ratified by the chat consumer lane: beyond 4 sections, stacking
 * collapsible regions in a pane capped at 640px makes scrolling unmanageable
 * and the single-owner rule becomes untenable. Enforced as a dev-time
 * `console.warn` in `register()` (this package's established convention —
 * see NavActionStack/WaterfallChart — is to warn and degrade, never throw
 * or silently truncate); exported here so the bound is also visible through
 * types/docs to a consumer reading `PanelStackProps`.
 */
export declare const PANEL_STACK_MAX_SECTIONS = 4;
/**
 * Default of `PanelStackProps.primaryMinHeight` (the primary section's
 * usable floor, in px) — exported so a consumer can reference the default
 * without hardcoding it. This is also the ONLY place the number is
 * hardcoded: PanelStack mirrors the live `primaryMinHeight` prop (which
 * defaults to this constant) onto the
 * `--st-component-panelStack-primaryMinBlockSize` custom property on its
 * own root, and the stylesheet's `min-block-size` reads that same
 * property — so the JS auto-collapse threshold and the CSS floor read the
 * same number and can no longer drift apart the way two independently
 * hardcoded copies could.
 */
export declare const PRIMARY_MIN_BLOCK_SIZE_PX = 160;
export type PanelStackProps = {
    /** "sticky-item" (default): one section expanded at a time, all headers stay visible.
        "split-primary": the `primary` section is always expanded and owns the scroll;
        the others are content-sized disclosures. */
    shape?: PanelStackShape;
    /** Accessible name for the stack region. */
    label?: string;
    /** sticky-item, controlled: id of the expanded section. */
    expanded?: string | null;
    /** sticky-item, uncontrolled seed. */
    defaultExpanded?: string | null;
    onExpandedChange?: (id: string | null) => void;
    /**
     * split-primary: id of the section that owns the scroll. Falls back to the
     * first EXPANDED section (DOM order) when unset or stale, and — if nothing
     * is expanded — to the first registered section, so the stack never
     * degrades to zero scroll owners.
     */
    primary?: string;
    /** Usable floor for the primary section, in px. While the primary sits above it the
        primary absorbs overflow; once it would drop below, a secondary auto-collapses
        instead of compressing the primary further. Default 160. */
    primaryMinHeight?: number;
    /**
     * At most {@link PANEL_STACK_MAX_SECTIONS} `PanelSection` children are
     * supported — see that constant's doc comment for why.
     */
    children?: Snippet;
    class?: string;
};
/**
 * Context contract shared with PanelSection. Every shape-dependent branch
 * (sticky-item vs split-primary) is decided HERE and only here — PanelSection
 * never reads `shape`, it only calls these four functions/callback. If the
 * consumer-lane contract for these two shapes changes, this is the one place
 * to touch.
 */
export declare const PANEL_STACK_KEY: unique symbol;
export type PanelStackContext = {
    /** Is this section the (non-collapsible) primary of a split-primary stack? */
    isPrimary: (id: string) => boolean;
    /** Is this section currently expanded (body visible, content-sized or scrolling)? */
    isExpanded: (id: string) => boolean;
    /** Is this section's body THE single scroll owner right now (flex:1 1 0, overflow:auto)? */
    isScrollOwner: (id: string) => boolean;
    /** Header was activated (click / Space / Enter on the disclosure button). */
    toggle: (id: string) => void;
    /**
     * Register a section's root AND header element, in mount/DOM order;
     * returns an unregister callback. NOT just bookkeeping — the stack falls
     * back to the first registered section as the scroll owner whenever
     * nothing else designates one (unset/stale `expanded` or `primary`), so
     * the invariant "exactly one scroll owner whenever the stack has ≥1
     * section" holds even for a misconfigured or dynamically-changing stack.
     * `headerEl` is used only by split-primary's auto-collapse measurement
     * (the header of whichever section is CURRENTLY primary is observed for
     * its height); sticky-item ignores it.
     */
    register: (id: string, rootEl: HTMLElement, headerEl: HTMLElement) => () => void;
};
declare const PanelStack: import("svelte").Component<PanelStackProps, {}, "">;
type PanelStack = ReturnType<typeof PanelStack>;
export default PanelStack;
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