Tetris

shape = {}
shape[1] = {{0,0,0,0,0},
            {0,0,1,0,0},
            {0,0,1,0,0},
            {0,0,1,0,0},
            {0,0,1,0,0}}

shape[2] = {{0,0,0,0,0},
            {0,0,1,0,0},
            {0,0,1,0,0},
            {0,0,1,0,0},
            {0,1,1,0,0}}

shape[3] = {{0,0,0,0,0},
            {0,0,1,0,0},
            {0,0,1,0,0},
            {0,0,1,0,0},
            {0,0,1,1,0}}

shape[4] = {{0,0,0,0,0},
            {0,0,0,0,0},
            {0,0,1,1,0},
            {0,1,1,0,0},
            {0,0,0,0,0}}

shape[5] = {{0,0,0,0,0},
            {0,0,0,0,0},
            {0,1,1,0,0},
            {0,0,1,1,0},
            {0,0,0,0,0}}

shape[6] = {{0,0,0,0,0},
            {0,0,0,0,0},
            {0,0,1,0,0},
            {0,1,1,1,0},
            {0,0,0,0,0}}

shape[7] = {{0,0,0,0,0},
            {0,0,0,0,0},
            {0,1,1,0,0},
            {0,1,1,0,0},
            {0,0,0,0,0}}

local xMin = 2
local yMin = 1

local yL   = 4

local xMax = 23
local yMax = 18

local field = {}

function createField()
  for y = yMin,yMax do
    field[y] = {}
    for x = xMin,xMax do
      val = colors.black
      if y == yMax or x == xMin or x == xMax then
        val = colors.gray
      end
      field[y][x] = val
    end
  end
end

function printField()
  for y = yMin,yMax do
    for x = xMin,xMax do
      term.setBackgroundColor(field[y][x])
      term.setCursorPos(x,y)
      term.write(" ")
    end
  end
end

function checkCollision(num,dir,xP,yP)
  for y = 1,#shape[num] do
    for x = 1,#shape[num][y] do
      if dir == 1 then
        val = shape[num][y][x]
      elseif dir == 2 then
        val = shape[num][x][y]
      elseif dir == 3 then
        val = shape[num][#shape[num]+1-y][#shape[num][y]+1-x]
      elseif dir == 4 then
        val = shape[num][#shape[num][y]+1-x][#shape[num]+1-y]
      end
      if val == 1 then
        if field[yMin+y+yP-2][xMin+x+xP-2] ~= colors.black then
          return true
        end
      end
    end
  end
end

function displayShape(num,dir,xP,yP)
  for y = 1,#shape[num] do
    for x = 1,#shape[num][y] do
      if dir == 1 then
        val = shape[num][y][x]
      elseif dir == 2 then
        val = shape[num][x][y]
      elseif dir == 3 then
        val = shape[num][#shape[num]+1-y][#shape[num][y]+1-x]
      elseif dir == 4 then
        val = shape[num][#shape[num][y]+1-x][#shape[num]+1-y]
      end
      if val == 1 then
        if field[yMin+y+yP-2][xMin+x+xP-2] == colors.black then
          field[yMin+y+yP-2][xMin+x+xP-2] = colors.blue
        end
      end
    end
  end
end

function clearShape()
  for yP = yMin,yMax do
    for xP = xMin,xMax do
      if field[yP][xP] == colors.blue then
        field[yP][xP] = colors.black
      end
    end
  end
end

function moveArray()
  for yP = yMin,yMax do
    for xP = xMin,xMax do
      if field[yP][xP] == colors.blue then
        if yP <= yMin+yL then
          return true
        else
          field[yP][xP] = colors.red
        end
      end
    end
  end
end

function checkLine()
  for yP = yMin,yMax do
    stat = true
    for xP = xMin+1,xMax-1 do
      if field[yP][xP] ~= colors.red then
        stat = false
      end
    end
    if stat == true then
      for y = yP,yMin+1,-1 do
        for xP = xMin+1,xMax-1 do
          field[y][xP] = field[y-1][xP]
        end
      end
      for xP = xMin+1,xMax+1 do
        field[yMin][xP] = colors.black
      end
    end
  end
end

function printyL()
  term.setBackgroundColor(colors.lime)
  for xP = xMin+1,xMax-1 do
    term.setCursorPos(xP,yL+yMin)
    term.write(" ")
  end
end

createField()

local xP  = math.floor(xMax/2)
local yP  = yMin
local dir = 1
local s = math.random(1,7)

while true do
  event,key = os.pullEvent()
  clearShape()
  if key == keys.q then
    dir = dir+1
    if dir > 4 then
      dir = 1
    end
    if checkCollision(s,dir,xP,yP) then
      dir = dir-1
      if dir < 1 then
        dir = 4
      end
    end
  elseif key == keys.left then
    xP = xP-1
    if checkCollision(s,dir,xP,yP) then
      xP = xP+1
    end
  elseif key == keys.right then
    xP = xP+1
    if checkCollision(s,dir,xP,yP) then
      xP = xP-1
    end
  else
    yP = yP+1
    if checkCollision(s,dir,xP,yP) then
      displayShape(s,dir,xP,yP-1)
      if moveArray() then
        break
      end
      checkLine()
      s = math.random(1,7)
      yP = yMin
      xP = math.floor(xMax/2)
    end
  end
  displayShape(s,dir,xP,yP)
  printField()
  printyL()
end