Function splitVertical

frontend/layout/lib/layoutTree.ts:497–534

(layoutState: LayoutTreeState, action: LayoutTreeSplitVerticalAction)

// ─── SPLIT VERTICAL ─────────────────────────────────────────────────────────────

export function splitVertical(layoutState: LayoutTreeState, action: LayoutTreeSplitVerticalAction) {
    const { targetNodeId, newNode, position } = action;
    const targetNode = findNode(layoutState.rootNode, targetNodeId);
    if (!targetNode) {
        console.error("splitVertical: Target node not found", targetNodeId);
        return;
    }

    const parent = findParent(layoutState.rootNode, targetNodeId);
    if (parent && parent.flexDirection === FlexDirection.Column) {
        const index = parent.children.findIndex((child) => child.id === targetNodeId);
        if (index === -1) {
            console.error("splitVertical: Target node not found in parent's children", targetNodeId);
            return;
        }
        const insertIndex = position === "before" ? index : index + 1;
        // For vertical splits in an already vertical parent, splice directly.
        parent.children.splice(insertIndex, 0, newNode);
    } else {
        // Wrap target node in a new vertical group.
        // Create group node with an initial children array so that validation passes.
        const groupNode = newLayoutNode(FlexDirection.Column, targetNode.size, [targetNode], undefined);
        groupNode.children = position === "before" ? [newNode, targetNode] : [targetNode, newNode];
        if (parent) {
            const index = parent.children.findIndex((child) => child.id === targetNodeId);
            if (index === -1) {
                console.error("splitVertical (wrap): Target node not found in parent's children", targetNodeId);
                return;
            }
            parent.children[index] = groupNode;
        } else {
            layoutState.rootNode = groupNode;
        }
    }
    if (action.focused) {
        layoutState.focusedNodeId = newNode.id;
    }
}