const head = arr => (arr && arr.length ? arr[0] : undefined);

head([1, 2, 3]); // 1
head([]); // undefined
head(null); // undefined
head(undefined); // undefined

const levenshteinDistance = (s, t) => {
  if (!s.length) return t.length;
  if (!t.length) return s.length;
  const arr = [];
  for (let i = 0; i <= t.length; i++) {
    arr[i] = [i];
    for (let j = 1; j <= s.length; j++) {
      arr[i][j] =
        i === 0
          ? j
          : Math.min(
              arr[i - 1][j] + 1,
              arr[i][j - 1] + 1,
              arr[i - 1][j - 1] + (s[j - 1] === t[i - 1] ? 0 : 1)
            );
    }
  }
  return arr[t.length][s.length];
};

levenshteinDistance('duck', 'dark'); // 2

const celsiusToFahrenheit = (celsius) => celsius * 9/5 + 32;
const fahrenheitToCelsius = (fahrenheit) => (fahrenheit - 32) * 5/9;
// Examples
celsiusToFahrenheit(15);    // 59
celsiusToFahrenheit(0);     // 32
celsiusToFahrenheit(-20);   // -4
fahrenheitToCelsius(59);    // 15
fahrenheitToCelsius(32);    // 0

const union = (...arr) => [...new Set(arr.flat())];

// Example
union([1, 2], [2, 3], [3]);     // [1, 2, 3]

import { createSlice } from "@reduxjs/toolkit";

const alert = createSlice({
	name: "alert",
	initialState: {
	msg: "",
	status: "",
	},
	reducers: {
	set_alert: (state, action) => {
	return {
	...state,
	msg: action.payload.msg,
	status: action.payload.status,
	};
	},
	clear_alert: (state, action) => {
	return {
	...state,
	msg: "",
	status: "",
	};
	},
	},
});

export default alert.reducer;

const { set_alert, clear_alert } = alert.actions;

export const setAlert = (msg, status) => dispatch => {
	dispatch(set_alert({ msg, status }));
	setTimeout(() => dispatch(clear_alert()), 4000);
};

export const clearAlert = () => dispatch => {
	dispatch(clear_alert());
};

class TreeNode {
  constructor(data, depth) {
    this.data = data;
    this.children = [];
    this.depth = depth;
  }
}

function buildNaryTree(hosts) {
  const nodeMap = {};

  // Step 1: Create a map of nodes using fqdn as the key
  hosts.forEach((host) => {
    nodeMap[host.fqdn] = new TreeNode(host, 0); // Initialize depth to 0
  });

  // Step 2: Iterate through the array and add each node to its parent's list of children
  hosts.forEach((host) => {
    if (host.displayParent) {
      if (nodeMap[host.displayParent]) {
        const parent = nodeMap[host.displayParent];
        const node = nodeMap[host.fqdn];
        node.depth = parent.depth + 1; // Update the depth
        parent.children.push(node);
      } else {
        console.error(`Parent with fqdn ${host.displayParent} not found for ${host.fqdn}`);
      }
    }
  });

  // Find the root nodes (nodes with no parent)
  const rootNodes = hosts.filter((host) => !host.displayParent).map((host) => nodeMap[host.fqdn]);

  return rootNodes;
}

function treeToObjects(node) {
  const result = [];

  function inOrder(node) {
    if (!node) {
      return;
    }

    
    // Visit the current node and add it to the result
    result.push(node.data);

    // Visit children nodes first
    node.children.forEach((child) => {
      inOrder(child);
    });
  }

  inOrder(node);
  return result;
}

// Usage example
const hosts = [
  {
    fqdn: 'fqdn_1',
    display_name: 'Host 1',
  },
  {
    fqdn: 'fqdn_2',
    display_name: 'Host 2',
    displayParent: 'fqdn_1',
  },
  {
    fqdn: 'fqdn_3',
    display_name: 'Host 3'
  },
  {
    fqdn: 'fqdn_4',
    display_name: 'Host 4',
    displayParent: 'fqdn_3',
  },
  {
    fqdn: 'fqdn_5',
    display_name: 'Host 5',
    displayParent: 'fqdn_1',
  },
];

const tree = buildNaryTree(hosts);

// Function to convert the tree to an array of objects
function convertTreeToArray(nodes) {
  const result = [];
  nodes.forEach((node) => {
    result.push(...treeToObjects(node));
  });
  return result;
}

// Convert the tree back to an array of objects
const arrayFromTree = convertTreeToArray(tree);

console.log(arrayFromTree);