-- Define the game board size
local ROWS = 20
local COLUMNS = 10

-- Define the Tetris shapes and their rotations
local SHAPES = {
    {{1, 1, 1, 1}},
    {{1, 1}, {1, 1}},
    {{1, 1, 1}, {0, 1, 0}},
    {{1, 1, 1}, {1, 0, 0}},
    {{1, 1, 1}, {0, 0, 1}},
    {{1, 1, 0}, {0, 1, 1}},
    {{0, 1, 1}, {1, 1, 0}}
}

-- Initialize the game board
local gameBoard = {}
for i = 1, ROWS do
    gameBoard[i] = {}
    for j = 1, COLUMNS do
        gameBoard[i][j] = 0
    end
end

-- Define the current Tetrimino
local currentShape, currentRow, currentCol

-- Function to generate a random Tetrimino
local function getRandomShape()
    local randomIndex = math.random(1, #SHAPES)
    return SHAPES[randomIndex]
end

-- Function to check if a move is valid
local function isValidMove(shape, row, col)
    for r = 1, #shape do
        for c = 1, #shape[r] do
            if shape[r][c] == 1 then
                local newRow = row + r
                local newCol = col + c
                if newRow < 1 or newRow > ROWS or newCol < 1 or newCol > COLUMNS or gameBoard[newRow][newCol] == 1 then
                    return false
                end
            end
        end
    end
    return true
end

-- Function to place the current Tetrimino on the board
local function placeShapeOnBoard()
    for r = 1, #currentShape do
        for c = 1, #currentShape[r] do
            if currentShape[r][c] == 1 then
                local row = currentRow + r
                local col = currentCol + c
                gameBoard[row][col] = 1
            end
        end
    end
end

-- Function to clear completed rows
local function clearRows()
    local row = ROWS
    while row >= 1 do
        local isComplete = true
        for col = 1, COLUMNS do
            if gameBoard[row][col] == 0 then
                isComplete = false
                break
            end
        end
        if isComplete then
            table.remove(gameBoard, row)
            table.insert(gameBoard, 1, {})
            for i = 1, COLUMNS do
                table.insert(gameBoard[1], 0)
            end
        else
            row = row - 1
        end
    end
end

-- Function to update the game
local function update()
    if isValidMove(currentShape, currentRow + 1, currentCol) then
        currentRow = currentRow + 1
    else
        placeShapeOnBoard()
        clearRows()
        currentShape = getRandomShape()
        currentRow = 1
        currentCol = math.floor(COLUMNS / 2)
    end
end

-- Initialize the game loop
math.randomseed(os.time())
currentShape = getRandomShape()
currentRow = 1
currentCol = math.floor(COLUMNS / 2)

-- You would need to implement rendering and input handling to make this a playable game.

-- Example of rendering the game board (in a console)
for row = 1, ROWS do
    local rowStr = ""
    for col = 1, COLUMNS do
        rowStr = rowStr .. (gameBoard[row][col] == 1 and "#" or ".")
    end
    print(rowStr)
end

-- Example of a game loop
while true do
    update()
    -- Render the game board
    -- Handle user input
    -- Implement game logic
    -- Sleep to control the game speed
    os.execute("sleep 0.5")
end