import { deepMerge } from '@aesthetic/utils';
import { DEPTHS } from './constants';
import { Theme } from './Theme';
import { DeepPartial, DesignTokens, ThemeOptions, ThemeTokens } from './types';

export class Design<Block extends object> {
	readonly name: string;

	readonly rootLineHeight: number;

	readonly rootTextSize: number;

	readonly spacingUnit: number;

	readonly tokens: DesignTokens;

	constructor(name: string, tokens: Omit<DesignTokens, 'depth'>) {
		this.name = name;
		this.tokens = { ...tokens, depth: DEPTHS };
		this.rootLineHeight = tokens.typography.rootLineHeight;
		this.rootTextSize = Number.parseFloat(tokens.typography.rootTextSize);

		// Pre-compiled for the chosen type, no need to calculate manually
		this.spacingUnit = tokens.spacing.unit;
	}

	/**
	 * Create a new theme with the defined theme tokens, while inheriting the shared design tokens.
	 */
	createTheme(options: ThemeOptions, tokens: ThemeTokens): Theme<Block> {
		return new Theme(options, tokens, this);
	}

	/**
	 * Extend and instantiate a new design instance with customized design tokens.
	 */
	extend(name: string, tokens: DeepPartial<DesignTokens>): Design<Block> {
		return new Design(name, deepMerge(this.tokens, tokens));
	}
}