import { tabs_to_spaces } from '@efforting.tech/text/text-utilities';

const raster_table_pattern = /^((?:[^\S\n]|[\w-])+)\n((?:[^\S\n]|-)+)\n(.+)/ms;
const column_pattern = /\s*(.+?)(?=\s{2,}|$)/gd;
const row_pattern = /^(.+)$/mg

// If loader is null we return a raw representation
export function load_raster_table(raster, loader=null, tab_width=4, null_padding=true) {
	if (raster.match(/\t/g)) {
		raster = tabs_to_spaces(raster, tab_width);
	}

	if (null_padding) {	//TODO - this is just experimental proof of concept
		raster = raster.replace(/〃/g, '\0〃');
	}


	const m = raster.match(raster_table_pattern);
	const column_matches = [...m[1].matchAll(column_pattern)];
	const column_positions = [...column_matches.map(cm => cm.indices[1][0])]
	const column_names = [...column_matches.map(cm => cm[1])]
	const rows = [];

	for (const row of m[3].matchAll(row_pattern)) {

		const pending_row = [];
		for (let ci=0; ci<column_positions.length; ci++) {
			const cell = row[1].slice(column_positions[ci], column_positions[ci+1]);
			if (null_padding) {
				pending_row.push(cell.replace(/\0/, ''));
			} else {
				pending_row.push(cell);
			}
		}
		rows.push(pending_row);
	}

	if (loader) {
		return new loader({ rows, column_names });
	} else {
		return {column_names, column_positions, rows};
	}
}


//TODO: load_ditto_raster_table