function love.load()
    snakeSegments = {
        {x = 3, y = 1},
        {x = 2, y = 1},
        {x = 1, y = 1},
    }

    timer = 0

    direction = 'right'
end

function love.update(dt)
    timer = timer + dt
    if timer >= 0.15 then
        timer = 0

        local nextXPosition = snakeSegments[1].x
        local nextYPosition = snakeSegments[1].y

        if direction == 'right' then
            nextXPosition = nextXPosition + 1
        elseif direction == 'left' then
            nextXPosition = nextXPosition - 1
        elseif direction == 'down' then
            nextYPosition = nextYPosition + 1
        elseif direction == 'up' then
            nextYPosition = nextYPosition - 1
        end

        table.insert(snakeSegments, 1, {
            x = nextXPosition, y = nextYPosition
        })
        table.remove(snakeSegments)
    end
end

function love.keypressed(key)
    if key == 'right'
    and direction ~= 'left' then
        direction = 'right'

    elseif key == 'left'
    and direction ~= 'right' then
        direction = 'left'

    elseif key == 'down'
    and direction ~= 'up' then
        direction = 'down'

    elseif key == 'up'
    and direction ~= 'down' then
        direction = 'up'
    end
end

function love.draw()
    local gridXCount = 20
    local gridYCount = 15
    local cellSize = 15

    love.graphics.setColor(.28, .28, .28)
    love.graphics.rectangle(
        'fill',
        0,
        0,
        gridXCount * cellSize,
        gridYCount * cellSize
    )

    for segmentIndex, segment in ipairs(snakeSegments) do
        love.graphics.setColor(.6, 1, .32)
        love.graphics.rectangle(
            'fill',
            (segment.x - 1) * cellSize,
            (segment.y - 1) * cellSize,
            cellSize - 1,
            cellSize - 1
        )
    end
end