import { arrayEach } from '../../../../helpers/array.mjs';
import { collapseNode } from './collapse.mjs';
import { getFirstChildProperty, isNodeReflectsFirstChildColspan, traverseHiddenNodeColumnIndexes } from './utils/tree.mjs';
/**
 * Expanding a node is a process where the processing node is expanded to
 * its original colspan width. To restore an original state of all node
 * children on the right, the modified nodes are replaced with the cloned
 * nodes (they were cloned while collapsing).
 *
 * @param {TreeNode} nodeToProcess A tree node to process.
 * @returns {object} Returns an object with properties:
 *                    - rollbackModification: The function that rollbacks
 *                      the tree to the previous state.
 *                    - affectedColumns: The list of the visual column
 *                      indexes which are affected. That list is passed
 *                      to the hiddens column logic.
 *                    - colspanCompensation: The number of colspan by
 *                      which the processed node colspan was increased.
 */ export function expandNode(nodeToProcess) {
    const { data: nodeData, childs: nodeChilds } = nodeToProcess;
    if (!nodeData.isCollapsed || nodeData.isHidden || nodeData.origColspan <= 1) {
        return {
            rollbackModification: ()=>{},
            affectedColumns: [],
            colspanCompensation: 0
        };
    }
    const isNodeReflected = isNodeReflectsFirstChildColspan(nodeToProcess);
    if (isNodeReflected) {
        return expandNode(nodeChilds[0]);
    }
    nodeData.isCollapsed = false;
    const allLeavesExceptMostLeft = nodeChilds.slice(1);
    const affectedColumns = new Set();
    let colspanCompensation = 0;
    if (allLeavesExceptMostLeft.length > 0) {
        arrayEach(allLeavesExceptMostLeft, (node)=>{
            // Restore original state of the collapsed headers.
            node.replaceTreeWith(node.data.clonedTree);
            node.data.clonedTree = null;
            const leafData = node.data;
            // Calculate by how many colspan it needs to increase the headings to match them to
            // the colspan width of all its children.
            colspanCompensation += leafData.colspan;
            traverseHiddenNodeColumnIndexes(node, (gridColumnIndex)=>{
                affectedColumns.add(gridColumnIndex);
            });
        });
    } else {
        const { colspan, origColspan, columnIndex } = nodeData;
        // In a case when the node doesn't have any children restore the colspan width to
        // its original state.
        colspanCompensation = origColspan - colspan;
        // Add column to "affected" started from 1. The header without children can not be
        // collapsed so the first column is already visible and we shouldn't touch it.
        for(let i = 1; i < origColspan; i++){
            affectedColumns.add(columnIndex + i);
        }
    }
    nodeToProcess.walkUp((node)=>{
        const { data } = node;
        data.colspan += colspanCompensation;
        if (data.colspan >= data.origColspan) {
            data.colspan = data.origColspan;
            data.isCollapsed = false;
        } else if (isNodeReflectsFirstChildColspan(node)) {
            data.isCollapsed = getFirstChildProperty(node, 'isCollapsed');
        }
    });
    return {
        rollbackModification: ()=>collapseNode(nodeToProcess),
        affectedColumns: Array.from(affectedColumns),
        colspanCompensation
    };
}
