import { CpNode } from "../cp-node.js";


/**
 * Returns the first `CpNode` (from this one by successively applying 
 * .nextOnCircle) that exits the circle.
 */
function getFirstExit(cpNode: CpNode) {
    // const startNode = this as CpNode;
    const startNode = cpNode;
    let cpNode_ = startNode;

    while (cpNode_.next === cpNode_.prevOnCircle) {
        cpNode_ = cpNode_.next;

        if (cpNode_ === startNode) {
            // The very special case the MAT is a single point.
            return undefined; 
        }
    }

    return cpNode_;
}


export { getFirstExit }