import { promises as fs } from 'fs';
import { parse as parse_yaml } from 'yaml';
import { resolve as resolve_path, dirname } from 'path';

export async function read_config(file: string) {
	const path = resolve_path(process.cwd(), file);
	const yaml = await fs.readFile(path, 'utf8');
	const config = parse_yaml(yaml);
	validate_config(config);
	resolve_paths(path, config);
	return config;
}

export interface Config {
	input: {
		root: string;
		raw?: string[];
		text?: string[];
		markdown?: string[];
		'schema+json'?: string[];
		'schema+yaml'?: string[];
		'openapi+json'?: string[];
		'openapi+yaml'?: string[];
		// ...
	};
	templates?: {
		layouts?: string;
		partials?: string;
		env?: string[];
	};
	output: {
		root: string;
	};
	markdown?: {
		// 
	};
	schema?: {
		// 
	};
	openapi?: {
		// ;
	}
	// ...
}

function validate_config(config: unknown) : asserts config is Config {
	// todo: validate config
}

function resolve_paths(file_path: string, config: Config) {
	const base_path = dirname(file_path);
	config.input.root = resolve_path(base_path, config.input.root);
	config.output.root = resolve_path(base_path, config.output.root);

	if (config.templates?.layouts) {
		config.templates.layouts = resolve_path(base_path, config.templates.layouts);
	}

	if (config.templates?.partials) {
		config.templates.partials = resolve_path(base_path, config.templates.partials);
	}
}