import { FlowBlock, Line } from '../../contracts/src/index.js';
/**
 * Shared, canvas-independent justify-adjustment calculation.
 *
 * Single source of truth for the per-line justify slack (word-spacing and
 * inter-character distribution) so painter measurement, caret/hit-test
 * geometry, and the editor-neutral segment-geometry substrate all agree on
 * the same numbers. Depends only on `@superdoc/contracts` line/run data —
 * no Canvas context — so it is safe to call from geometry producers that run
 * without a live DOM.
 */
/**
 * Represents the justify alignment adjustment applied to a line.
 *
 * When text is justified, the layout engine distributes extra space (slack)
 * evenly across all space characters in the line. This type captures both
 * the per-space adjustment amount and the total number of spaces, which are
 * used by text measurement functions to accurately calculate character
 * positions in justified text.
 *
 * @property extraPerSpace - Additional pixels to add after each space character (can be 0 for non-justified text)
 * @property totalSpaces - Total count of space characters in the line (used for validation and debugging)
 */
export type JustifyAdjustment = {
    extraPerSpace: number;
    totalSpaces: number;
    interCharacterSpacing: number;
    interCharacterBoundaries: readonly number[];
};
export type GetJustifyAdjustmentParams = {
    block: FlowBlock;
    line: Line;
    availableWidthOverride?: number;
    alignmentOverride?: string;
    isLastLineOfParagraph?: boolean;
    paragraphEndsWithLineBreak?: boolean;
    skipJustifyOverride?: boolean;
};
/**
 * Counts the number of space characters in a text string.
 *
 * Only counts spaces that participate in CSS word-spacing behavior (regular
 * space and non-breaking space). This is used for justify alignment
 * calculations where extra width needs to be distributed proportionally
 * across spaces.
 *
 * @param text - The text string to analyze
 * @returns The count of space characters (regular space U+0020 and non-breaking space U+00A0)
 *
 * @example
 * ```typescript
 * countSpaces("Hello World");  // Returns: 1
 * countSpaces("A B C");        // Returns: 2
 * countSpaces("No-spaces");    // Returns: 0
 * ```
 */
export declare const countSpaces: (text: string) => number;
/**
 * Computes the per-space expansion applied when a line is justified.
 *
 * Uses shared justify utilities to ensure consistency with the painter's
 * justify logic, which distributes slack (extra horizontal space) evenly
 * across all space characters using CSS word-spacing.
 *
 * Algorithm:
 * 1. Use shouldApplyJustify() to determine if justify should be applied (including last-line detection)
 * 2. Count all space characters (or use pre-computed line.spaceCount)
 * 3. Use calculateJustifySpacing() to compute per-space adjustment
 * 4. Support negative slack for compressed lines (naturalWidth > availableWidth)
 *
 * Edge Cases:
 * - Non-justify alignment: Returns zero adjustment
 * - Last line of paragraph: Returns zero adjustment (unless paragraph ends with soft break)
 * - No spaces: Returns zero adjustment (prevents division by zero)
 * - Lines with author-defined tab stops: Returns zero adjustment
 * - Compressed lines: Returns negative adjustment (naturalWidth used for slack calculation)
 * - Empty runs array: Returns zero adjustment
 *
 * @param params - Named parameters for justify adjustment.
 * @param params.block - The paragraph block containing the line
 * @param params.line - The line to compute justify adjustment for
 * @param params.availableWidthOverride - The available width for content (fragment width minus paragraph indents).
 *   Must match what the painter uses to ensure consistent justify spacing. If not provided,
 *   falls back to line.maxWidth or line.width.
 * @param params.alignmentOverride - Optional alignment override (defaults to block.attrs.alignment)
 * @param params.isLastLineOfParagraph - Whether this is the last line of the paragraph.
 *   If not provided, auto-derived from block/line: `line.toRun >= block.runs.length - 1`.
 *   Auto-derivation ensures measurement matches rendering. Returns false for empty runs arrays.
 * @param params.paragraphEndsWithLineBreak - Whether the paragraph ends with a soft break (Shift+Enter).
 *   If not provided, auto-derived: `lastRun?.kind === 'lineBreak'`.
 *   Auto-derivation ensures measurement matches rendering. Returns false for empty runs arrays.
 * @param params.skipJustifyOverride - Explicit override to skip justify
 * @returns Object containing extraPerSpace (pixels to add after each space) and totalSpaces
 *
 * @example
 * ```typescript
 * // Line with 200px width in 250px available space, 5 spaces
 * const adj = getJustifyAdjustment({ block, line, availableWidthOverride: 250, isLastLineOfParagraph: false });
 * // Returns: { extraPerSpace: 10, totalSpaces: 5 }  (50px slack / 5 spaces)
 *
 * // Last line of paragraph (no soft break)
 * const adj = getJustifyAdjustment({ block, line, availableWidthOverride: 250, isLastLineOfParagraph: true });
 * // Returns: { extraPerSpace: 0, totalSpaces: 5 }  (last line not justified)
 * ```
 */
export declare const getJustifyAdjustment: ({ block, line, availableWidthOverride, alignmentOverride, isLastLineOfParagraph, paragraphEndsWithLineBreak, skipJustifyOverride, }: GetJustifyAdjustmentParams) => JustifyAdjustment;