import { GraphJSON, NodeJSON } from 'behave-graph'
import { Edge, Node } from 'reactflow'

import { getNodeSpecJSON } from '../util/getNodeSpecJSON'

const nodeSpecJSON = getNodeSpecJSON()

const isNullish = (value: any): value is null | undefined => value === undefined || value === null

export const flowToBehave = (nodes: Node[], edges: Edge[]): GraphJSON => {
  const graph: GraphJSON = { nodes: [], variables: [], customEvents: [] }

  nodes.forEach((node) => {
    if (node.type === undefined) return

    const nodeSpec = nodeSpecJSON.find((nodeSpec) => nodeSpec.type === node.type)

    if (nodeSpec === undefined) return

    const behaveNode: NodeJSON = {
      id: node.id,
      type: node.type,
      metadata: {
        positionX: String(node.position.x),
        positionY: String(node.position.y)
      }
    }

    Object.entries(node.data).forEach(([key, value]) => {
      if (behaveNode.parameters === undefined) {
        behaveNode.parameters = {}
      }
      behaveNode.parameters[key] = { value: value as string }
    })

    edges
      .filter((edge) => edge.target === node.id)
      .forEach((edge) => {
        const inputSpec = nodeSpec.inputs.find((input) => input.name === edge.targetHandle)
        if (inputSpec && inputSpec.valueType === 'flow') {
          // skip flows
          return
        }
        if (behaveNode.parameters === undefined) {
          behaveNode.parameters = {}
        }
        if (isNullish(edge.targetHandle)) return
        if (isNullish(edge.sourceHandle)) return

        // TODO: some of these are flow outputs, and should be saved differently.  -Ben, Oct 11, 2022
        behaveNode.parameters[edge.targetHandle] = {
          link: { nodeId: edge.source, socket: edge.sourceHandle }
        }
      })

    edges
      .filter((edge) => edge.source === node.id)
      .forEach((edge) => {
        const outputSpec = nodeSpec.outputs.find((output) => output.name === edge.sourceHandle)
        if (outputSpec && outputSpec.valueType !== 'flow') {
          return
        }
        if (behaveNode.flows === undefined) {
          behaveNode.flows = {}
        }
        if (isNullish(edge.targetHandle)) return
        if (isNullish(edge.sourceHandle)) return

        // TODO: some of these are flow outputs, and should be saved differently.  -Ben, Oct 11, 2022
        behaveNode.flows[edge.sourceHandle] = {
          nodeId: edge.target,
          socket: edge.targetHandle
        }
      })

    // TODO filter out any orphan nodes at this point, to avoid errors further down inside behave-graph

    graph.nodes?.push(behaveNode)
  })

  return graph
}