app.js

document.addEventListener('DOMContentLoaded', () => {
    const grid = document.querySelector('.grid')
    const scoreDisplay = document.getElementById('score')
    const width = 8
    const squares = []
    let score = 0
    
    
    const candyColors = [
        'url(images/red-candy.png)',
        'url(images/yellow-candy.png)',
        'url(images/orange-candy.png)',
        'url(images/purple-candy.png)',
        'url(images/green-candy.png)',
        'url(images/blue-candy.png)'
      ]
    
    
    //create your board
    function createBoard() {
      for (let i = 0; i < width*width; i++) {
        const square = document.createElement('div')
        square.setAttribute('draggable', true)
        square.setAttribute('id', i)
        let randomColor = Math.floor(Math.random() * candyColors.length)
        square.style.backgroundImage = candyColors[randomColor]
        grid.appendChild(square)
        squares.push(square)
      }
    }
    createBoard()
    
    // Dragging the Candy
    let colorBeingDragged
    let colorBeingReplaced
    let squareIdBeingDragged
    let squareIdBeingReplaced
    
    squares.forEach(square => square.addEventListener('dragstart', dragStart))
    squares.forEach(square => square.addEventListener('dragend', dragEnd))
    squares.forEach(square => square.addEventListener('dragover', dragOver))
    squares.forEach(square => square.addEventListener('dragenter', dragEnter))
    squares.forEach(square => square.addEventListener('drageleave', dragLeave))
    squares.forEach(square => square.addEventListener('drop', dragDrop))
    
    function dragStart(){
        colorBeingDragged = this.style.backgroundImage
        squareIdBeingDragged = parseInt(this.id)
        // this.style.backgroundImage = ''
    }
    
    function dragOver(e) {
        e.preventDefault()
    }
    
    function dragEnter(e) {
        e.preventDefault()
    }
    
    function dragLeave() {
        this.style.backgroundImage = ''
    }
    
    function dragDrop() {
        colorBeingReplaced = this.style.backgroundImage
        squareIdBeingReplaced = parseInt(this.id)
        this.style.backgroundImage = colorBeingDragged
        squares[squareIdBeingDragged].style.backgroundImage = colorBeingReplaced
    }
    
    function dragEnd() {
        //What is a valid move?
        let validMoves = [squareIdBeingDragged -1 , squareIdBeingDragged -width, squareIdBeingDragged +1, squareIdBeingDragged +width]
        let validMove = validMoves.includes(squareIdBeingReplaced)
    
        if (squareIdBeingReplaced && validMove) {
            squareIdBeingReplaced = null
        }  else if (squareIdBeingReplaced && !validMove) {
           squares[squareIdBeingReplaced].style.backgroundImage = colorBeingReplaced
           squares[squareIdBeingDragged].style.backgroundImage = colorBeingDragged
        } else  squares[squareIdBeingDragged].style.backgroundImage = colorBeingDragged
    }
    
    //drop candies once some have been cleared
    function moveIntoSquareBelow() {
        for (i = 0; i < 55; i ++) {
            if(squares[i + width].style.backgroundImage === '') {
                squares[i + width].style.backgroundImage = squares[i].style.backgroundImage
                squares[i].style.backgroundImage = ''
                const firstRow = [0, 1, 2, 3, 4, 5, 6, 7]
                const isFirstRow = firstRow.includes(i)
                if (isFirstRow && (squares[i].style.backgroundImage === '')) {
                  let randomColor = Math.floor(Math.random() * candyColors.length)
                  squares[i].style.backgroundImage = candyColors[randomColor]
                }
            }
        }
    }
    
    
    ///Checking for Matches
    //for row of Four
      function checkRowForFour() {
        for (i = 0; i < 60; i ++) {
          let rowOfFour = [i, i+1, i+2, i+3]
          let decidedColor = squares[i].style.backgroundImage
          const isBlank = squares[i].style.backgroundImage === ''
    
          const notValid = [5, 6, 7, 13, 14, 15, 21, 22, 23, 29, 30, 31, 37, 38, 39, 45, 46, 47, 53, 54, 55]
          if (notValid.includes(i)) continue
    
          if(rowOfFour.every(index => squares[index].style.backgroundImage === decidedColor && !isBlank)) {
            score += 4
            scoreDisplay.innerHTML = score
            rowOfFour.forEach(index => {
            squares[index].style.backgroundImage = ''
            })
          }
        }
      }
      checkRowForFour()
    
    //for column of Four
      function checkColumnForFour() {
        for (i = 0; i < 39; i ++) {
          let columnOfFour = [i, i+width, i+width*2, i+width*3]
          let decidedColor = squares[i].style.backgroundImage
          const isBlank = squares[i].style.backgroundImage === ''
    
          if(columnOfFour.every(index => squares[index].style.backgroundImage === decidedColor && !isBlank)) {
            score += 4
            scoreDisplay.innerHTML = score
            columnOfFour.forEach(index => {
            squares[index].style.backgroundImage = ''
            })
          }
        }
      }
    checkColumnForFour()
    
      //for row of Three
      function checkRowForThree() {
        for (i = 0; i < 61; i ++) {
          let rowOfThree = [i, i+1, i+2]
          let decidedColor = squares[i].style.backgroundImage
          const isBlank = squares[i].style.backgroundImage === ''
    
          const notValid = [6, 7, 14, 15, 22, 23, 30, 31, 38, 39, 46, 47, 54, 55]
          if (notValid.includes(i)) continue
    
          if(rowOfThree.every(index => squares[index].style.backgroundImage === decidedColor && !isBlank)) {
            score += 3
            scoreDisplay.innerHTML = score
            rowOfThree.forEach(index => {
            squares[index].style.backgroundImage = ''
            })
          }
        }
      }
      checkRowForThree()
    
    //for column of Three
      function checkColumnForThree() {
        for (i = 0; i < 47; i ++) {
          let columnOfThree = [i, i+width, i+width*2]
          let decidedColor = squares[i].style.backgroundImage
          const isBlank = squares[i].style.backgroundImage === ''
    
          if(columnOfThree.every(index => squares[index].style.backgroundImage === decidedColor && !isBlank)) {
            score += 3
            scoreDisplay.innerHTML = score
            columnOfThree.forEach(index => {
            squares[index].style.backgroundImage = ''
            })
          }
        }
      }
    checkColumnForThree()
    
    // Checks carried out indefintely - Add Butotn to clear interval for best practise
    window.setInterval(function(){
        checkRowForFour()
        checkColumnForFour()
        checkRowForThree()
        checkColumnForThree()
        moveIntoSquareBelow()
      }, 100);
    })