const express = require('express')
const app = express()

// Main function
function topoSort(){
  const dependencies = [
    [],
    [],
    [1],
    [0],
    [],
    [3],
    [2, 4, 5],
    [5, 6]
  ]


  let inDegrees = mapInDegrees(dependencies)
  let queue = generateQueue(inDegrees)
  let list = []

  for(let i = 0; i < inDegrees.length; i++){
    for(let row of dependencies){
      for(let item of row){
        if(item === queue[0]){
          inDegrees[dependencies.indexOf(row)]-=1
          if(inDegrees[dependencies.indexOf(row)] == 0){
            queue.push(dependencies.indexOf(row))
          }
          list.push(queue[0])
          queue.shift()
        }
      }
    }
  }

  //list.push(dependencies.length-1)
  return list

}

// Generates in-degrees
function mapInDegrees(dependencies){
  let inDegrees = []
  for(let i = 0; i < dependencies.length; i++){
    inDegrees.push(dependencies[i].length)
  }
  return inDegrees
}

// Generates queue
function generateQueue(inDegrees){
  let queue = []
  for(let i = 0; i < inDegrees.length; i++){
    if(inDegrees[i] === 0)
      queue.push(i)
  }
  return queue
}

console.log(topoSort())
app.listen(3000, () => {

})