function shuffleArray(array) {
  for (let i = array.length - 1; i > 0; i--) {
    const j = Math.floor(Math.random() * (i + 1))
    ;[array[i], array[j]] = [array[j], array[i]]
  }
}

// generate a list of all possible edges, excluding duplicates and self-references
function generatePossibleEdges(nodes) {
  const possibleEdges = []

  for (const sourceNode of nodes) {
    for (const targetNode of nodes) {
      if (sourceNode.id !== targetNode.id) {
        const edgeId = `e${sourceNode.id}-${targetNode.id}`
        possibleEdges.push({ id: edgeId, source: sourceNode.id, target: targetNode.id, type: 'animation', animated: true })
      }
    }
  }

  return possibleEdges
}

/**
 * Composable that returns a function to shuffle the edges of a graph
 *
 * @returns {Function} A function that takes a list of nodes and returns a list of edges
 */
export function useShuffle() {
  return (nodes) => {
    const possibleEdges = generatePossibleEdges(nodes)
    shuffleArray(possibleEdges)

    const usedNodes = new Set()
    const newEdges = []

    // ensure every node is used, maintaining a single starting node and no duplicate connections
    for (const edge of possibleEdges) {
      if (!usedNodes.has(edge.target) && (usedNodes.size === 0 || usedNodes.has(edge.source))) {
        newEdges.push(edge)
        usedNodes.add(edge.source)
        usedNodes.add(edge.target)
      }
    }

    return newEdges
  }
}