import ClusterElement from "./ClusterElement";

export default class TreeNode {
    private _leftChild: TreeNode | null;
    private _rightChild: TreeNode | null;
    private _parent: TreeNode | null;
    public readonly values: ClusterElement[];
    public readonly height: number;

    // Keep track of which ID's are already assigned to TreeNode's.
    public static currentID = 0;
    // ID used for constructing graphs.
    public readonly id: number;

    constructor(parent: TreeNode | null, leftChild: TreeNode | null, rightChild: TreeNode | null, values: ClusterElement[], height: number) {
        this._parent = parent;
        this._leftChild = leftChild;
        this._rightChild = rightChild;
        this.values = values;
        this.height = height;
        this.id = TreeNode.currentID;
        TreeNode.currentID++;
    }

    get parent(): TreeNode | null {
        return this._parent;
    }

    set parent(value: TreeNode | null) {
        this._parent = value;
    }

    get leftChild(): TreeNode | null {
        return this._leftChild;
    }

    set leftChild(value: TreeNode | null) {
        this._leftChild = value;
    }

    get rightChild(): TreeNode | null {
        return this._rightChild;
    }

    set rightChild(value: TreeNode | null) {
        this._rightChild = value;
    }

    /**
     * Convert this tree and all of it's children to the Newic-format.
     *
     * @param: idExtractor Function that extract's the name from a given node's id.
     */
    public toNewick(nameExtractor: (id: number) => string): string {
        let output: string = "";

        if (!this.leftChild && !this.rightChild) {
            return nameExtractor(this.values[0].id) + ":" + this.height;
        }

        output += "(";

        if (this.leftChild) {
            output += this.leftChild.toNewick(nameExtractor) + ",";
        }

        if (this.rightChild) {
            output += this.rightChild.toNewick(nameExtractor);
        }

        output += ")" + this.id + ":" + this.height;

        return output;
    }

    /**
     * Convert this tree and all of it's children to the dot GraphViz-format.
     */
    public toGraphViz(nameExtractor: (id: number) => string): string {
        let root: TreeNode | undefined = this;

        let output = "digraph dendrogram {\n";
        let labels = "";
        let edges = "";

        let toCheck: TreeNode[] = [root];
        while (toCheck.length > 0) {
            root = toCheck.shift();

            if (!root) {
                break;
            }

            if (!root.leftChild && !root.rightChild) {
                labels += `    ${root.id} [label="${nameExtractor(root.values[0].id)}"];\n`;
            } else {
                labels += `    ${root.id} [label="${root.id}"];\n`;
            }


            if (root.leftChild) {
                edges += `    ${root.id} -> ${root.leftChild.id};\n`;
                toCheck.push(root.leftChild);
            }

            if (root.rightChild) {
                edges += `    ${root.id} -> ${root.rightChild.id};\n`;
                toCheck.push(root.rightChild);
            }
        }
        output += labels + edges + "}";
        return output;
    }
}