export class DepTree {
  constructor(obj) {
    this.order = { ...obj.order }
    this.byId = { ...obj.byId }
    this.allIds = [...obj.allIds]

    this.tree = {}
    for (let k in obj.tree) {
      this.tree[k] = { ...obj.tree[k] }
    }

  }

  addParent(id) {
    if (this.tree[id]) return
    this.tree[id] = {}
    this.order[id] = this.allIds.length
    this.allIds.push(id)
  }

  addChild(childId, ...parentIds) {
    for (let parentId of parentIds) {
      this.tree[parentId][childId] = true;
    }

    this.addParent(childId)
  }



  getDescendents(id) {
    const dfs = (id) => {
      visited.add(id)
      desc.push(id)
      for (let k in this.tree[id]) {
        if (!visited.has(k)) {
          dfs(k)
        }
      }
    }

    const visited = new Set()
    const desc = []

    dfs(id)

    return desc
  }



  deleteNode(id) {


    const nodesToDel = this.getDescendents(id)

    nodesToDel.sort((a, b) => this.order[b] - this.order[a])


    let spliceIdx;
    for (let id of nodesToDel) {
      spliceIdx = this.order[id]

      this.allIds.splice(spliceIdx, 1)

      const deletedObj = sc.obj3d.children.splice(spliceIdx + 1, 1)[0] // first 1 elements are non geom

      deletedObj.traverse((obj) => {
        if (obj.geometry) obj.geometry.dispose()
        if (obj.material) obj.material.dispose()
      })

      delete this.tree[id]
      delete this.byId[id]
      delete this.order[id]
    }

    for (let i = spliceIdx; i < this.allIds.length; i++) {
      this.order[this.allIds[i]] = i
    }

    const nodeToDelSet = new Set(nodesToDel)
    for (let k in this.tree) {
      for (let m in this.tree[k]) {
        if (nodeToDelSet.has(m)) {
          delete this.tree[k][m]
        }
      }
    }
    return this
  }



}




// const dt = new DepTree()
// dt.addParent('r1')
// dt.addParent('r2')
// dt.addChild('r3', 'r1', 'r2')s
// dt.addParent('r4')
// dt.addChild('r5', 'r4', 'r3')
// dt.addChild('r6', 'r1', 'r5')
// dt.addChild('r7', 'r3', 'r5')

// dt.addParent('r8')

// // console.log(dt)

// // const x = dt.deleteNode('r3')
// // console.log(x)
// // console.log(dt.allIds, dt.order)
// // [ 6, 5, 4, 2 ]
// // [ 'r1', 'r2', 'r4' ] { r1: 0, r2: 1, r4: 2 }


// const x = dt.deleteNode('r5')
// console.log(dt)
// DepTree {
//   tree: { r1: { r3: true }, r2: { r3: true }, r3: {}, r4: {}, r8: {} },
//   order: { r1: 0, r2: 1, r3: 2, r4: 3, r8: 4 },
//   allIds: [ 'r1', 'r2', 'r3', 'r4', 'r8' ]
// }