import type { GraphDocument2d } from './types';
import { copyExpressionPresentation } from '#lib/document/expression-presentation.js';

/**
 * Build the plain-data transfer object expected by Wasm and the render worker.
 * Svelte state can contain nested proxies, which the structured-clone algorithm
 * used by Worker.postMessage cannot clone.
 */
export function toTransferableDocument(document: GraphDocument2d): GraphDocument2d {
	const copy: GraphDocument2d = {
		viewport: { ...document.viewport },
		expressions: document.expressions.map((expression) => {
			const result: GraphDocument2d['expressions'][number] = {
				id: expression.id,
				input_mode: expression.input_mode,
				source: expression.source,
				...copyExpressionPresentation(expression),
				enabled: expression.enabled,
				color: expression.color
			};

			if (expression.slider !== undefined) {
				const slider: NonNullable<GraphDocument2d['expressions'][number]['slider']> = {};

				if (expression.slider.min !== undefined) {
					slider.min = expression.slider.min;
				}

				if (expression.slider.max !== undefined) {
					slider.max = expression.slider.max;
				}

				if (expression.slider.step !== undefined) {
					slider.step = expression.slider.step;
				}

				result.slider = slider;
			}

			return result;
		})
	};

	if (document.name !== undefined) {
		copy.name = document.name;
	}

	if (document.complex_mode !== undefined) {
		copy.complex_mode = document.complex_mode;
	}

	if (document.grid_cell_size !== undefined) {
		copy.grid_cell_size = document.grid_cell_size;
	}

	if (document.variable_overrides !== undefined) {
		copy.variable_overrides = { ...document.variable_overrides };
	}

	return copy;
}