/**
 * Bipartite graph generation function
 */

import { Edge,Graph, Node } from "../types";

/**
 * Create a bipartite graph with two sets of nodes
 * @param n1 - Number of nodes in first set
 * @param n2 - Number of nodes in second set
 * @param p - Probability of edge between nodes in different sets
 * @param seed - Random seed for reproducibility
 * @returns Graph object with bipartite structure and setA/setB properties
 */
export function bipartiteGraph(
    n1: number,
    n2: number,
    p: number,
    seed?: number,
): Graph & { setA: Node[]; setB: Node[] } {
    const setA: Node[] = Array.from({ length: n1 }, (_, i) => `A${i}`);
    const setB: Node[] = Array.from({ length: n2 }, (_, i) => `B${i}`);
    const nodes = [...setA, ...setB];
    const edges: Edge[] = [];

    // Simple deterministic pseudo-random if seed provided
    let currentSeed = seed;
    const random =
        seed !== undefined
            ? () => {
                  currentSeed = ((currentSeed as number) * 9301 + 49297) % 233280;
                  return currentSeed / 233280;
              }
            : Math.random;

    // Only connect nodes between sets
    for (const a of setA) {
        for (const b of setB) {
            if (random() < p) {
                edges.push([a, b]);
            }
        }
    }

    return {
        nodes: () => nodes,
        edges: () => edges,
        setA,
        setB,
    };
}