// @flow

import type Options from '../options';
import { createCell } from '../utils';

/*
 * Ensure each row has the same number of columns.
 */
function validateNode(opts: Options) {
    const isRow = node => node.type === opts.typeRow;
    const isCell = node => node.type === opts.typeCell;
    const countCells = row => row.nodes.count(isCell);

    return node => {
        if (node.type !== opts.typeTable) {
            return undefined;
        }

        const rows = node.nodes.filter(isRow);
        const maxColumns = Math.max(
            // Minimum 1 column
            1,
            rows.map(countCells).max()
        );
        const rowsMissingColumns = rows.filter(
            row => countCells(row) < maxColumns
        );

        if (rowsMissingColumns.isEmpty()) {
            return undefined;
        }

        return change => {
            rowsMissingColumns.forEach(row => {
                const numberOfCellsToAdd = maxColumns - row.nodes.size;
                const cells = Array.from({ length: numberOfCellsToAdd }).map(
                    () => createCell(opts)
                );
                cells.forEach(cell =>
                    change.insertNodeByKey(row.key, row.nodes.size, cell, {
                        normalize: false
                    })
                );
            });
        };
    };
}

export default validateNode;