chess

function enterSquare(i,j)
  a = setmetatable({},square)
  a.x = i
  a.y = j
  a.moved = false
  if math.floor(i/2) ~= i/2 and math.floor(j/2) ~= j/2 or math.floor(i/2) == i/2 and math.floor(j/2) == j/2 then
    a.color = "brown"
  else
    a.color = "yellow"
  end
  if j == 2 then
    a.piece = 'P'
    a.pc = 'white'
  elseif j == 7 then
    a.piece = 'P'
    a.pc = 'black'
  elseif j == 1 then
    if i == 1 or i == 8 then
      a.piece = 'R'
      a.pc = 'white'
    elseif i == 2 or i == 7 then
      a.piece = 'H'
      a.pc = 'white'
    elseif i == 3 or i == 6 then
      a.piece = 'B'
      a.pc = 'white'
    elseif i == 4 then
      a.piece = 'Q'
      a.pc = 'white'
    elseif i == 5 then
      a.piece = 'K'
      a.pc = 'white'
    end
  elseif j == 8 then
    if i == 1 or i == 8 then
      a.piece = 'R'
      a.pc = 'black'
    elseif i == 2 or i == 7 then
      a.piece = 'H'
      a.pc = 'black'
    elseif i == 3 or i == 6 then
      a.piece = 'B'
      a.pc = 'black'
    elseif i == 4 then
      a.piece = 'Q'
      a.pc = 'black'
    elseif i == 5 then
      a.piece = 'K'
      a.pc = 'black'
    end
  else
    a.pc = 'neutral'
    a.piece = " "
  end
  squares[#squares+1] = a
end

function ini()
  m = peripheral.wrap('right')
  m.setBackgroundColor(32768)
  m.clear()
  m.setTextScale(5)
  square = {}
  squares = {}
  square.__index = square
  availMovesX = {}
  availMovesY = {}
  showMoves = false
  blackCheck = false
  whiteCheck = false
  blackCheckMate = false
  whiteCheckMate = false
  playerTurn = 'White'
  for i = 1,8 do
    for j = 1,8 do
      enterSquare(i,j)
    end
  end
end

function drawBoard()
  m.setBackgroundColor(32768)
  m.clear()
  for i = 1,#squares do
    bleet = squares[i]
    m.setCursorPos(bleet.x,bleet.y)
    if bleet.color == 'brown' then
      m.setBackgroundColor(4096)
    else
      m.setBackgroundColor(16)
    end
    if showMoves then
      if available(bleet.x,bleet.y) then
        if bleet.color == 'brown' then
            m.setBackgroundColor(8192)
        else
            m.setBackgroundColor(32)
        end
      end
    end
    if bleet.pc == 'white' then
      m.setTextColor(1)
    else
      m.setTextColor(32768)
    end
    if whiteCheck and bleet.piece == 'K' and bleet.pc == 'white' then
      m.setBackgroundColor(16384)
    end
    if blackCheck and bleet.piece == 'K' and bleet.pc == 'black' then
      m.setBackgroundColor(16384)
    end
    m.write(bleet.piece)
  end
  m.setCursorPos(1,9)
  m.setBackgroundColor(32768)
  m.setTextColor(1)
  m.write(playerTurn.."'s turn!")
  if whiteCheck or blackCheck then
    m.setCursorPos(1,10)
    m.setBackgroundColor(32768)
    m.setTextColor(16384)
    m.write('Check!')
  end
  if whiteCheckMate or blackCheckMate then
    m.setCursorPos(1,10)
    m.setBackgroundColor(32768)
    m.setTextColor(16384)
    m.write('Checkmate!')
  end
end

function available(x,y)
  for i = 1,#availMovesX do
    if x == availMovesX[i] and y == availMovesY[i] then
      return true
    end
  end
end

function getPiece(x,y)
  for i = 1,#squares do
    deet = squares[i]
    if deet.x == x then
      if deet.y == y then
        return deet,i
      end
    end
  end
end

function getAvail(x,y)
  availMovesX = {}
  availMovesY = {}
  for i = 1,8 do
    for j = 1,8 do
      if checkMove2(x,y,i,j) then
        availMovesX[#availMovesX+1] = i
        availMovesY[#availMovesY+1] = j
      end
    end
  end
end

function getSudoAvail(x,y)
  sudoAvailX = {}
  sudoAvailY = {}
  sheet = getPiece(x,y)
  if sheet.piece == 'B' or sheet.piece == 'Q' then
    for i = 1,4 do
      for j = 1,8 do
        if i == 1 then
          sudox = sheet.x + j
          sudoy = sheet.y + j
          if sudoy < 9 and sudox < 9 then
            beat = getPiece(sudox,sudoy)
            if beat.piece ~= ' ' then
              if beat.pc ~= sheet.pc then
                sudoAvailX[#sudoAvailX+1] = sudox
                sudoAvailY[#sudoAvailY+1] = sudoy
              end
              break
            else
              sudoAvailX[#sudoAvailX+1] = sudox
              sudoAvailY[#sudoAvailY+1] = sudoy
            end
          end
        elseif i == 2 then
          sudox = sheet.x - j
          sudoy = sheet.y + j
          if sudoy < 9 and sudox > 0 then
            beat = getPiece(sudox,sudoy)
            if beat.piece ~= ' ' then
              if beat.pc ~= sheet.pc then
                sudoAvailX[#sudoAvailX+1] = sudox
                sudoAvailY[#sudoAvailY+1] = sudoy
              end
              break
            else
              sudoAvailX[#sudoAvailX+1] = sudox
              sudoAvailY[#sudoAvailY+1] = sudoy
            end
          end
        elseif i == 3 then
          sudox = sheet.x + j
          sudoy = sheet.y - j
          if sudox < 9 and sudoy > 0 then
            beat = getPiece(sudox,sudoy)
            if beat.piece ~= ' ' then
              if beat.pc ~= sheet.pc then
                sudoAvailX[#sudoAvailX+1] = sudox
                sudoAvailY[#sudoAvailY+1] = sudoy
              end
              break
            else
              sudoAvailX[#sudoAvailX+1] = sudox
              sudoAvailY[#sudoAvailY+1] = sudoy
            end
          end
        else
          sudox = sheet.x - j
          sudoy = sheet.y - j
          if sudoy > 0 and sudox > 0 then
            beat = getPiece(sudox,sudoy)
            if beat.piece ~= ' ' then
              if beat.pc ~= sheet.pc then
                sudoAvailX[#sudoAvailX+1] = sudox
                sudoAvailY[#sudoAvailY+1] = sudoy
              end
              break
            else
              sudoAvailX[#sudoAvailX+1] = sudox
              sudoAvailY[#sudoAvailY+1] = sudoy
            end
          end
        end
      end
    end
  end
  if sheet.piece == 'R' or sheet.piece == 'Q' then
    for i = 1,4 do
      for j = 1,8 do
        if i == 1 then
          sudox = sheet.x + j
          sudoy = sheet.y
          if sudox < 9 then
            beat = getPiece(sudox,sudoy)
            if beat.piece ~= ' ' then
              if beat.pc ~= sheet.pc then
                sudoAvailX[#sudoAvailX+1] = sudox
                sudoAvailY[#sudoAvailY+1] = sudoy
              end
              break
            else
              sudoAvailX[#sudoAvailX+1] = sudox
              sudoAvailY[#sudoAvailY+1] = sudoy
            end
          end
        elseif i == 2 then
          sudox = sheet.x - j
          sudoy = sheet.y
          if sudox > 0 then
            beat = getPiece(sudox,sudoy)
            if beat.piece ~= ' ' then
              if beat.pc ~= sheet.pc then
                sudoAvailX[#sudoAvailX+1] = sudox
                sudoAvailY[#sudoAvailY+1] = sudoy
              end
              break
            else
              sudoAvailX[#sudoAvailX+1] = sudox
              sudoAvailY[#sudoAvailY+1] = sudoy
            end
          end
        elseif i == 3 then
          sudox = sheet.x
          sudoy = sheet.y + j
          if sudoy < 9 then
            beat = getPiece(sudox,sudoy)
            if beat.piece ~= ' ' then
              if beat.pc ~= sheet.pc then
                sudoAvailX[#sudoAvailX+1] = sudox
                sudoAvailY[#sudoAvailY+1] = sudoy
              end
              break
            else
              sudoAvailX[#sudoAvailX+1] = sudox
              sudoAvailY[#sudoAvailY+1] = sudoy
            end
          end
        else
          sudox = sheet.x
          sudoy = sheet.y - j
          if sudoy > 0 then
            beat = getPiece(sudox,sudoy)
            if beat.piece ~= ' ' then
              if beat.pc ~= sheet.pc then
                sudoAvailX[#sudoAvailX+1] = sudox
                sudoAvailY[#sudoAvailY+1] = sudoy
              end
              break
            else
              sudoAvailX[#sudoAvailX+1] = sudox
              sudoAvailY[#sudoAvailY+1] = sudoy
            end
          end
        end
      end
    end
  end
  return sudoAvailX,sudoAvailY
end

function checkMove(x1,y1,x2,y2)
  local yeet = getPiece(x1,y1)
  local neet = getPiece(x2,y2)
  if yeet.piece == ' ' then
    return false
  end
  if yeet.pc == neet.pc and neet.piece ~= ' ' then
    return false
  end
  if x1 == x2 and y2 == y1 then
    return false
  end
  if x2 > 8 or x2 <1 or y2 > 8 or y2 < 1 then
    return false
  end
  if yeet.piece == 'B' or yeet.piece == 'R' or yeet.piece == 'Q' then
    tabx,taby = getSudoAvail(x1,y1)
    for i = 1,#tabx do
      if x2 == tabx[i] and y2 == taby[i] then
        return true
      end
    end
    return false
  end
  if yeet.piece == 'H' then
    if x2 == x1 + 2 then
      if y2 == y1 + 1 or y2 == y1 - 1 then
        return true
      end
    elseif x2 == x1 - 2 then
      if y2 == y1 + 1 or y2 == y1 - 1 then
        return true
      end
    elseif y2 == y1 + 2 then
      if x2 == x1 + 1 or x2 == x1 - 1 then
        return true
      end
    elseif y2 == y1 - 2 then
      if x2 == x1 + 1 or x2 == x1 - 1 then
        return true
      end
    end
  end
  if yeet.piece == 'K' then
    if y2 == y1 + 1 and x1 == x2 or y2 == y1 - 1 and x1 == x2 or x2 == x1 + 1 and y1 == y2 or x2 == x1 - 1 and y1 == y2 or x1 + 1 == x2 and y1 + 1 == y2 or x1 - 1 == x2 and y1 + 1 == y2 or x1 + 1 == x2 and y1 - 1 == y2 or x1 - 1 == x2 and y1 - 1 == y2 then
      return true
    elseif x2 == x1 + 2 and y2 == y1 or x2 == x1 - 2 and y2 == y1 then
        if yeet.moved then
            return false
        end
        if yeet.pc == 'white' then
            if checkWhite then
                return false
            end
            if x2 == x1 + 2 and y2 == y1 then
                temp1 = getPiece(7,1)
                temp2 = getPiece(6,1)
                if temp1.piece ~= ' ' then
                    return false
                end
                if temp2.piece ~= ' ' then
                    return false
                end
                rook = getPiece(8,1)
                if rook.piece == 'R' and not rook.moved then
                    castleTopRight = true
                    return true
                end
            elseif x2 == x1 - 2 and y2 == y1 then
                temp1 = getPiece(4,1)
                temp2 = getPiece(3,1)
                temp3 = getPiece(2,1)
                if temp1.piece ~= ' ' then
                    return false
                end
                if temp2.piece ~= ' ' then
                    return false
                end
                if temp3.piece ~= ' ' then
                    return false
                end
                rook = getPiece (1,1)
                if rook.piece == 'R' and not rook.moved then
                    castleTopLeft = true
                    return true
                end
            end
        elseif yeet.pc == 'black' then
            if checkBlack then
                return false
            end
            if x2 == x1 + 2 and y2 == y1 then
                temp1 = getPiece(7,8)
                temp2 = getPiece(6,8)
                if temp1.piece ~= ' ' then
                    return false
                end
                if temp2.piece ~= ' ' then
                    return false
                end
                rook = getPiece(8,8)
                if rook.piece == 'R' and not rook.moved then
                    castleBottomRight = true
                    return true
                end
            elseif x2 == x1 - 2 and y2 == y1 then
                temp1 = getPiece(4,8)
                temp2 = getPiece(3,8)
                temp3 = getPiece(2,8)
                if temp1.piece ~= ' ' then
                    return false
                end
                if temp2.piece ~= ' ' then
                    return false
                end
                if temp3.piece ~= ' ' then
                    return false
                end
                rook = getPiece (1,8)
                if rook.piece == 'R' and not rook.moved then
                    castleBottomLeft = true
                    return true
                end
            end
        end
    end
  end
  if yeet.piece == 'P' and yeet.pc == 'white' then
    leet = getPiece(x1,y1+1)
    if y2 == y1 + 1 and neet.piece == ' ' and x2 == x1  then
      return true
    elseif y2 == y1 + 2 and neet.piece == ' ' and leet.piece == ' ' and not yeet.moved and x2 == x1 then
      return true
    elseif y2 == y1 + 1 and x2 == x1 + 1 and neet.piece ~= ' ' then
      return true
    elseif y2 == y1 + 1 and x2 == x1 - 1 and neet.piece ~= ' ' then
      return true
    end
  end
  if yeet.piece == 'P' and yeet.pc == 'black' then
    leet = getPiece(x1,y1-1)
    if y2 == y1 - 1 and neet.piece == ' ' and x2 == x1 then
      return true
    elseif y2 == y1 - 2 and neet.piece == ' ' and leet.piece == ' ' and not yeet.moved and x2 == x1 then
      return true
    elseif y2 == y1 - 1 and x2 == x1 + 1 and neet.piece ~= ' ' then
      return true
    elseif y2 == y1 - 1 and x2 == x1 - 1 and neet.piece ~= ' ' then
      return true
    end
  end

end

function checkMove2(x1,y1,x2,y2)
  heat = getPiece(x1,y1)
  backupBoard()
  if checkMove(x1,y1,x2,y2) then
    moveHandler(x1,y1,x2,y2)
    heat = getPiece(x2,y2)
    if heat.pc == 'white' then
      if checkCheckWhite() then
        recoverBoard()
        return false
      else
        recoverBoard()
      end
    else
      if checkCheckBlack() then
        recoverBoard()
        return false
      else
        recoverBoard()
      end
    end
  else
    return false
  end
  return true
end

function checkCheckWhite()
  for i = 1,#squares do
    if squares[i].piece == 'K' and squares[i].pc == 'white' then
      king = squares[i]
      break
    end
  end
  xt = king.x
  yt = king.y
  for i = 1,#squares do
    if checkMove(squares[i].x,squares[i].y,xt,yt) then
      return true
    end
  end
end

function checkCheckMateWhite()
  backupBoard()
  for i = 1,#squares do
    feet = squares[i]
    if feet.pc == 'white' then
      for x = 1,8 do
        for y = 1,8 do
          if checkMove(feet.x,feet.y,x,y) then
            moveHandler(feet.x,feet.y,x,y)
            if not checkCheckWhite() then
              recoverBoard()
              return false
            end
            recoverBoard()
          end
        end
      end
    end
  end
  return true
end

function checkCheckBlack()
  for i = 1,#squares do
    if squares[i].piece == 'K' and squares[i].pc == 'black' then
      king = squares[i]
      break
    end
  end
  xt = king.x
  yt = king.y
  for i = 1,#squares do
    if checkMove(squares[i].x,squares[i].y,xt,yt) then
      return true
    end
  end
end

function checkCheckMateBlack()
  backupBoard()
  for i = 1,#squares do
    feet = squares[i]
    if feet.pc == 'black' then
      for x = 1,8 do
        for y = 1,8 do
          if checkMove(feet.x,feet.y,x,y) then
            moveHandler(feet.x,feet.y,x,y)
            if not checkCheckBlack() then
              recoverBoard()
              return false
            end
            recoverBoard()
          end
        end
      end
    end
  end
  return true
end

function backupBoard()
  bBoard = {}
  for i = 1,#squares do
    bBoard[i] = {}
    for k,v in pairs(squares[i]) do
      bBoard[i][k] = squares[i][k]
    end
  end
end

function recoverBoard()
  squares = {}
  for i = 1,#bBoard do
    squares[i] = {}
    for k,v in pairs(bBoard[i]) do
      squares[i][k] = bBoard[i][k]
    end
  end
end

function moveHandler(x1,y1,x2,y2)
  p1,num1 = getPiece(x1,y1)
  p2,num2 = getPiece(x2,y2)
  p2.pc = p1.pc
  p2.piece = p1.piece
  p2.moved = true
  p1.pc = 'neutral'
  p1.piece = ' '
  squares[num1].pc = p1.pc
  squares[num1].piece = p1.piece
  squares[num1].moved = p1.moved
  squares[num2].pc = p2.pc
  squares[num2].piece = p2.piece
  squares[num2].moved = p2.moved
end

function turnHandler(player)
  while true do
    event,key,x1,y1 = os.pullEvent('monitor_touch')
    jeet = getPiece(x1,y1)
    if jeet.pc == player then
      getAvail(x1,y1)
      showMoves = true
      drawBoard()
      while true do
        event,key,x2,y2 = os.pullEvent('monitor_touch')
        if checkMove2(x1,y1,x2,y2) then
          temp = getPiece(x1,y1)
          if temp.piece == 'K' and x2 == x1 + 2 and y2 == y1 or temp.piece == 'K' and x2 == x1 - 2 and y2 == y1 then
            if temp.pc == 'white' then
                if x2 == 7 and y2 == 1 and castleTopRight then
                    ctr = true
                elseif x2 == 3 and y2 == 1 and castleTopLeft then
                    moveHandler(1,1,4,1)
                end
            else
                if x2 == 7 and y2 == 8 and castleBottomRight then
                    cbr = true
                elseif x2 == 3 and y2 == 8 and castleBottomLeft then
                    moveHandler(1,8,4,8)
                end
            end
          end
          moveHandler(x1,y1,x2,y2)
          if ctr then
            moveHandler(8,1,6,1)
            ctr = false
          end
          if cbr then
            moveHandler(8,8,6,8)
            cbr = false
          end
          showMoves = false
          if player == 'white' then
            playerTurn = 'Black'
            return
          else
            playerTurn = 'White'
            return
          end
        else
          showMoves = false
          drawBoard()
          break
        end
      end
    end
  end
end

ini()

while true do
 drawBoard()
 if playerTurn == 'White' then
   turnHandler('white')
   if checkCheckBlack() then
    if checkCheckMateBlack() then
        blackCheckMate = true
        drawBoard()
        break
    else
        blackCheck = true
    end
 end
 whiteCheck = false
 else
   turnHandler('black')
   if checkCheckWhite() then
    if checkCheckMateWhite() then
        whiteCheckMate = true
        drawBoard()
        break
    else
        whiteCheck = true
    end
   end
   blackCheck = false
 end
end