script.js

const addBtns = document.querySelectorAll(".add-btn:not(.solid)");
const saveItemBtns = document.querySelectorAll(".solid");
const addItemContainers = document.querySelectorAll(".add-container");
const addItems = document.querySelectorAll(".add-item");
// Item Lists
const listColumns = document.querySelectorAll(".drag-item-list");
const backlogList = document.getElementById("backlog-list");
const progressList = document.getElementById("progress-list");
const completeList = document.getElementById("complete-list");
const onHoldList = document.getElementById("on-hold-list");

// Items
let updatedOnLoad = false;

// Initialize Arrays
let backlogListArray = [];
let progressListArray = [];
let completeListArray = [];
let onHoldListArray = [];
let listArrays = []; // this array holds all above arrays

// Drag Functionality
let draggedItem;
let currentColumn;
let dragging = false;

// Get Arrays from localStorage if available, set default values if not
function getSavedColumns() {
  if (localStorage.getItem("backlogItems")) {
    backlogListArray = JSON.parse(localStorage.backlogItems);
    progressListArray = JSON.parse(localStorage.progressItems);
    completeListArray = JSON.parse(localStorage.completeItems);
    onHoldListArray = JSON.parse(localStorage.onHoldItems);
  } else {
    backlogListArray = [];
    progressListArray = [];
    completeListArray = [];
    onHoldListArray = [];
  }
}

// Set localStorage Arrays
function updateSavedColumns() {
  listArrays = [
    backlogListArray,
    progressListArray,
    completeListArray,
    onHoldListArray,
  ];
  const arrayNames = ["backlog", "progress", "complete", "onHold"];
  arrayNames.forEach((arrayName, index) => {
    localStorage.setItem(
      `${arrayName}Items`,
      JSON.stringify(listArrays[index])
    );
  });
}

// Filter Arrays to remove empty items
function filterArray(array) {
  const filteredArray = array.filter((item) => item !== null);
  return filteredArray;
}

// Create DOM Elements for each list item
function createItemEl(columnEl, column, item, index) {
  // List Item
  const listEl = document.createElement("li");
  listEl.classList.add("drag-item");
  listEl.textContent = item;
  listEl.draggable = true;
  listEl.setAttribute("ondragstart", "drag(event)");
  listEl.contentEditable = true;
  listEl.id = index;
  listEl.setAttribute("onfocusout", `updateItem(${index}, ${column})`);
  // Append
  columnEl.appendChild(listEl);
}

// Update Columns in DOM - Reset HTML, Filter Array, Update localStorage

function updateDOM() {
  // Check localStorage once
  if (!updatedOnLoad) {
    getSavedColumns();
  }
  // Backlog Column
  backlogList.textContent = "";
  backlogListArray.forEach((backlogItem, index) => {
    createItemEl(backlogList, 0, backlogItem, index);
  });
  backlogListArray = filterArray(backlogListArray);
  // Progress Column
  progressList.textContent = "";
  progressListArray.forEach((progressItem, index) => {
    createItemEl(progressList, 1, progressItem, index);
  });
  progressListArray = filterArray(progressListArray);
  // Complete Column
  completeList.textContent = "";
  completeListArray.forEach((completeItem, index) => {
    createItemEl(completeList, 2, completeItem, index);
  });
  completeListArray = filterArray(completeListArray);
  // On Hold Column
  onHoldList.textContent = "";
  onHoldListArray.forEach((onHoldItem, index) => {
    createItemEl(onHoldList, 3, onHoldItem, index);
  });
  onHoldListArray = filterArray(onHoldListArray);
  // to update only once
  updatedOnLoad = true;
  updateSavedColumns();
}

// Update Item - Delete if necessary, or update Array value
function updateItem(id, column) {
  const selectedArray = listArrays[column];
  const selectedColumnEl = listColumns[column].children;
  if (!dragging) {
    if (!selectedColumnEl[id].textContent) {
      delete selectedArray[id];
    } else {
      selectedArray[id] = selectedColumnEl[id].textContent;
    }
    updateDOM();
  }
}

//Add to column list,  Reset textbox
function addToColumn(column) {
  const itemText = addItems[column].textContent;
  const selectedArray = listArrays[column];
  selectedArray.push(itemText);
  addItems[column].textContent = "";
  updateDOM();
}

// Show Add Item input box
function showInputBox(column) {
  addBtns[column].style.visibility = "hidden";
  saveItemBtns[column].style.display = "flex";
  addItemContainers[column].style.display = "flex";
}

//Hide item input box
function hideInputBox(column) {
  addBtns[column].style.visibility = "visible";
  saveItemBtns[column].style.display = "none";
  addItemContainers[column].style.display = "none";
  addToColumn(column);
}

//Allow arrays to reflect Drag and drop items
function rebuildArrays() {
  backlogListArray = Array.from(backlogList.children).map((i) => i.textContent);
  progressListArray = Array.from(progressList.children).map(
    (i) => i.textContent
  );
  completeListArray = Array.from(completeList.children).map(
    (i) => i.textContent
  );
  onHoldListArray = Array.from(onHoldList.children).map((i) => i.textContent);
  updateDOM();
}

// When item start dragging
function drag(e) {
  draggedItem = e.target;
  dragging = true;
}
// when the item enters the column area
function dragEnter(column) {
  listColumns[column].classList.add("over");
  currentColumn = column;
}
// Colum allows of item to drop
function allowDrop(e) {
  e.preventDefault();
}
// Dropping item in column
function drop(e) {
  e.preventDefault();
  // remove background color / padding
  listColumns.forEach((column) => {
    column.classList.remove("over");
  });
  // Add item to the column
  const parent = listColumns[currentColumn];
  parent.appendChild(draggedItem);
  // dragging complete
  dragging = false;
  rebuildArrays();
}

//On load
updateDOM();