import * as CF from '@efforting.tech/data/field-configuration-factories';


export const Indention_Mode = new CF.symbol_set({
	AUTO: 'Automatic detection of indention mode',
	SPACES: 'Indention is based on spaces',
	TABULATORS: 'Indention is based on tabulators',
}, 'Indention mode');


// BUG: Current implementation of CF.symbol_set doesn't support default value
export const Text_Settings = new CF.Schema({
	indention_mode: Indention_Mode,
	indention_tabulator_width: CF.cardinal_value(4, 'Width of a tabulator in spaces'),
	first_line: CF.natural_value(1, 'First line number'),
}, 'Text settings');


export function string_has_contents(str) {
	return /\S/.test(str);
}


export function *indented_line_iterator(settings, text) {
	let line_no = settings.first_line;
	let index = 0;
	const { indention_tabulator_width } = settings;

	switch (settings.indention_mode) {
		case Indention_Mode.symbols.TABULATORS: {
			for (const line of text.matchAll(/^(\t*)(.*)$/gm)) {
				const [raw, tabs, remaining] = line;
				yield { raw, indent: tabs.length, line: remaining, line_no: line_no++, index: index++};
			}
			break;
		}
		case Indention_Mode.symbols.SPACES: {
			for (const line of text.matchAll(/^([ ]*)(.*)$/gm)) {
				const [raw, spaces, remaining] = line;

				if ((spaces.length % indention_tabulator_width) !== 0) {
					throw new Error('Unaligned indention');	//TODO - proper error
				}
				yield { raw, indent: Math.floor(spaces.length / indention_tabulator_width), line: remaining, line_no: line_no++, index: index++};
			}
			break;
		}
		default:
			throw new Error(`Unsupported indention mode: ${settings.indention_mode}`);	//TODO - proper error
	}
}