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


/**
 * @internal
 * 
 * Traverses the shape from the given `CpNode` going around the shortest path
 * so that only a piece of the shape is traversed and returns the visited 
 * `CpNode`s (starting from the given `CpNode`).
 * 
 * @param cpStart The `CpNode` from where to start the traversal.
 */
function traverseCp(
        cpStart: CpNode) {

    let cpNode = cpStart;

    if (isTerminating(cpNode)) {
        return [cpNode];  // one-sharp corner
    }

    const visitedCps: CpNode[] = [];
    do {
        visitedCps.push(cpNode);
    
        const next = cpNode.next.prevOnCircle;
        cpNode = cpNode === next
                ? cpNode = cpNode.next.next // Terminal vertex
                : cpNode = next             // Take last exit
    
    } while (cpNode !== cpStart); 
    
    return visitedCps;
}


export { traverseCp }