import {type Connection, type Edge, getConnectedEdges, getIncomers, getOutgoers, type Node} from '@xyflow/react'
import {clone, find, findIdx, isEqual, lpad, toStr, uuid} from 'licia'

export class CheckError extends Error {
  readonly id: string

  constructor(
    id: number,
    message: string,
  ) {
    super(message)
    this.id = `E${lpad(toStr(id), 6, '0')}`
  }

  public toString(): string {
    return `${this.id}: ${this.message}`
  }
}

export const multiStartNodeError = () => new CheckError(100, '只能存在1个开始节点')
export const multiEndNodeError = () => new CheckError(101, '只能存在1个结束节点')

const getNodeById = (id: string, nodes: Node[]) => find(nodes, (n: Node) => isEqual(n.id, id))

// @ts-ignore
export const checkAddNode: (type: string, nodes: Node[], edges: Edge[]) => void = (type, nodes, edges) => {
  if (isEqual(type, 'start-node') && findIdx(nodes, (node: Node) => isEqual(type, node.type)) > -1) {
    throw multiStartNodeError()
  }
  if (isEqual(type, 'end-node') && findIdx(nodes, (node: Node) => isEqual(type, node.type)) > -1) {
    throw multiEndNodeError()
  }
}

export const sourceNodeNotFoundError = () => new CheckError(200, '连线起始节点未找到')
export const targetNodeNotFoundError = () => new CheckError(201, '连线目标节点未找到')
export const startNodeToEndNodeError = () => new CheckError(202, '开始节点不能直连结束节点')
export const nodeToSelfError = () => new CheckError(203, '节点不能直连自身')
export const hasCycleError = () => new CheckError(204, '禁止流程循环')
export const nodeNotOnlyToEndNode = () => new CheckError(206, '直连结束节点的节点不允许连接其他节点')
export const hasRedundantEdgeError = () => new CheckError(207, '禁止出现冗余边')

const hasCycle = (sourceNode: Node, targetNode: Node, nodes: Node[], edges: Edge[], visited = new Set<string>()) => {
  if (visited.has(targetNode.id)) return false
  visited.add(targetNode.id)
  for (const outgoer of getOutgoers(targetNode, nodes, edges)) {
    if (isEqual(outgoer.id, sourceNode.id)) return true
    if (hasCycle(sourceNode, outgoer, nodes, edges, visited)) return true
  }
}

/* 摘自Dify的流程合法性判断 */

type ParallelInfoItem = {
  parallelNodeId: string
  depth: number
  isBranch?: boolean
}

type NodeParallelInfo = {
  parallelNodeId: string
  edgeHandleId: string
  depth: number
}

type NodeHandle = {
  node: Node
  handle: string
}

type NodeStreamInfo = {
  upstreamNodes: Set<string>
  downstreamEdges: Set<string>
}

const groupBy = (array: Record<string, any>[], iteratee: string) => {
  const result: Record<string, any[]> = {}
  for (const item of array) {
    // 获取属性值并转换为字符串键
    const key = item[iteratee]
    if (!result[key]) {
      result[key] = []
    }
    result[key].push(item)
  }
  return result
}

// @ts-ignore
export const getParallelInfo = (nodes: Node[], edges: Edge[], parentNodeId?: string) => {
  // 等到有子图的时候再考虑
  /*if (parentNodeId) {
    const parentNode = nodes.find(node => node.id === parentNodeId)
    if (!parentNode)
      throw new Error('Parent node not found')

    startNode = nodes.find(node => node.id === (parentNode.data as (IterationNodeType | LoopNodeType)).start_node_id)
  }
  else {
    startNode = nodes.find(node => isEqual(node.type, 'start_node'))
  }*/
  let startNode = nodes.find(node => isEqual(node.type, 'start-node'))
  if (!startNode)
    throw new Error('Start node not found')

  const parallelList = [] as ParallelInfoItem[]
  const nextNodeHandles = [{node: startNode, handle: 'source'}]
  let hasAbnormalEdges = false

  const traverse = (firstNodeHandle: NodeHandle) => {
    const nodeEdgesSet = {} as Record<string, Set<string>>
    const totalEdgesSet = new Set<string>()
    const nextHandles = [firstNodeHandle]
    const streamInfo = {} as Record<string, NodeStreamInfo>
    const parallelListItem = {
      parallelNodeId: '',
      depth: 0,
    } as ParallelInfoItem
    const nodeParallelInfoMap = {} as Record<string, NodeParallelInfo>
    nodeParallelInfoMap[firstNodeHandle.node.id] = {
      parallelNodeId: '',
      edgeHandleId: '',
      depth: 0,
    }

    while (nextHandles.length) {
      const currentNodeHandle = nextHandles.shift()!
      const {node: currentNode, handle: currentHandle = 'source'} = currentNodeHandle
      const currentNodeHandleKey = currentNode.id
      const connectedEdges = edges.filter(edge => edge.source === currentNode.id && edge.sourceHandle === currentHandle)
      const connectedEdgesLength = connectedEdges.length
      const outgoers = nodes.filter(node => connectedEdges.some(edge => edge.target === node.id))
      const incomers = getIncomers(currentNode, nodes, edges)

      if (!streamInfo[currentNodeHandleKey]) {
        streamInfo[currentNodeHandleKey] = {
          upstreamNodes: new Set<string>(),
          downstreamEdges: new Set<string>(),
        }
      }

      if (nodeEdgesSet[currentNodeHandleKey]?.size > 0 && incomers.length > 1) {
        const newSet = new Set<string>()
        for (const item of totalEdgesSet) {
          if (!streamInfo[currentNodeHandleKey].downstreamEdges.has(item))
            newSet.add(item)
        }
        if (isEqual(nodeEdgesSet[currentNodeHandleKey], newSet)) {
          parallelListItem.depth = nodeParallelInfoMap[currentNode.id].depth
          nextNodeHandles.push({node: currentNode, handle: currentHandle})
          break
        }
      }

      if (nodeParallelInfoMap[currentNode.id].depth > parallelListItem.depth)
        parallelListItem.depth = nodeParallelInfoMap[currentNode.id].depth

      outgoers.forEach((outgoer) => {
        const outgoerConnectedEdges = getConnectedEdges([outgoer], edges).filter(edge => edge.source === outgoer.id)
        const sourceEdgesGroup = groupBy(outgoerConnectedEdges, 'sourceHandle')
        const incomers = getIncomers(outgoer, nodes, edges)

        if (outgoers.length > 1 && incomers.length > 1)
          hasAbnormalEdges = true

        Object.keys(sourceEdgesGroup).forEach((sourceHandle) => {
          nextHandles.push({node: outgoer, handle: sourceHandle})
        })
        if (!outgoerConnectedEdges.length)
          nextHandles.push({node: outgoer, handle: 'source'})

        const outgoerKey = outgoer.id
        if (!nodeEdgesSet[outgoerKey])
          nodeEdgesSet[outgoerKey] = new Set<string>()

        if (nodeEdgesSet[currentNodeHandleKey]) {
          for (const item of nodeEdgesSet[currentNodeHandleKey])
            nodeEdgesSet[outgoerKey].add(item)
        }

        if (!streamInfo[outgoerKey]) {
          streamInfo[outgoerKey] = {
            upstreamNodes: new Set<string>(),
            downstreamEdges: new Set<string>(),
          }
        }

        if (!nodeParallelInfoMap[outgoer.id]) {
          nodeParallelInfoMap[outgoer.id] = {
            ...nodeParallelInfoMap[currentNode.id],
          }
        }

        if (connectedEdgesLength > 1) {
          const edge = connectedEdges.find(edge => edge.target === outgoer.id)!
          nodeEdgesSet[outgoerKey].add(edge.id)
          totalEdgesSet.add(edge.id)

          streamInfo[currentNodeHandleKey].downstreamEdges.add(edge.id)
          streamInfo[outgoerKey].upstreamNodes.add(currentNodeHandleKey)

          for (const item of streamInfo[currentNodeHandleKey].upstreamNodes)
            streamInfo[item].downstreamEdges.add(edge.id)

          if (!parallelListItem.parallelNodeId)
            parallelListItem.parallelNodeId = currentNode.id

          const prevDepth = nodeParallelInfoMap[currentNode.id].depth + 1
          const currentDepth = nodeParallelInfoMap[outgoer.id].depth

          nodeParallelInfoMap[outgoer.id].depth = Math.max(prevDepth, currentDepth)
        } else {
          for (const item of streamInfo[currentNodeHandleKey].upstreamNodes)
            streamInfo[outgoerKey].upstreamNodes.add(item)

          nodeParallelInfoMap[outgoer.id].depth = nodeParallelInfoMap[currentNode.id].depth
        }
      })
    }

    parallelList.push(parallelListItem)
  }

  while (nextNodeHandles.length) {
    const nodeHandle = nextNodeHandles.shift()!
    traverse(nodeHandle)
  }

  return {
    parallelList,
    hasAbnormalEdges,
  }
}

export const checkAddConnection: (connection: Connection, nodes: Node[], edges: Edge[]) => void = (connection, nodes, edges) => {
  let sourceNode = getNodeById(connection.source, nodes)
  if (!sourceNode) {
    throw sourceNodeNotFoundError()
  }
  let targetNode = getNodeById(connection.target, nodes)
  if (!targetNode) {
    throw targetNodeNotFoundError()
  }
  // 禁止短路整个流程
  if (isEqual('start-node', sourceNode.type) && isEqual('end-node', targetNode.type)) {
    throw startNodeToEndNodeError()
  }

  // 禁止流程出现环，必须是有向无环图
  if (isEqual(sourceNode.id, targetNode.id)) {
    throw nodeToSelfError()
  } else if (hasCycle(sourceNode, targetNode, nodes, edges)) {
    throw hasCycleError()
  }

  let newEdges = [...clone(edges), {...connection, id: uuid()}]
  let {hasAbnormalEdges} = getParallelInfo(nodes, newEdges)
  if (hasAbnormalEdges) {
    throw hasRedundantEdgeError()
  }
}

export const atLeastOneStartNodeError = () => new CheckError(300, '至少存在1个开始节点')
export const atLeastOneEndNodeError = () => new CheckError(301, '至少存在1个结束节点')

// @ts-ignore
export const checkSave: (nodes: Node[], edges: Edge[], data: any) => void = (nodes, edges, data) => {
  if (nodes.filter(n => isEqual('start-node', n.type)).length < 1) {
    throw atLeastOneStartNodeError()
  }
  if (nodes.filter(n => isEqual('end-node', n.type)).length < 1) {
    throw atLeastOneEndNodeError()
  }
}