setscreen ("graphics:320;350,nooffscreenonly,nobuttonbar")

type snakeCoords :
    record
        x : int
        y : int
    end record

type snakeData :
    record
        dx : int
        dy : int
        speed : int
        clr : int
    end record

type gridData :
    record
        size : int
        width : int
        clr : int
    end record

const foodClr := RGB.AddColor (0.9, 0.1, 0.1)

var grdData : gridData
grdData.size := 30
grdData.width := 10
grdData.clr := RGB.AddColor (0.2, 0.9, 0.2)

var grid : array 1 .. grdData.size, 1 .. grdData.size of int
var snake : flexible array 1 .. 5 of snakeCoords
var snkData : snakeData
var keysDown : array char of boolean
var score, highScore, scoreInc : int := 0
var foodx, foody : int
snkData.clr := RGB.AddColor (0.3, 0.7, 0.3)


proc resetData
    cls
    var temp : int
    score := 0

    snkData.dx := 0
    snkData.dy := -1

    setscreen ("graphics:320;350,nooffscreenonly,nobuttonbar")
    put "what is the difficulty? (1-5)"
    get temp
    cls
    locate (maxrow div 2, maxcol div 2)
    put "3"
    delay (1000)
    cls
    locate (maxrow div 2, maxcol div 2)
    put "2"
    delay (1000)
    cls
    locate (maxrow div 2, maxcol div 2)
    put "1"
    delay (1000)
    cls
    setscreen ("graphics:320;350,offscreenonly,nobuttonbar")
    cls

    if temp > 5 then
        temp := 5
    elsif temp < 1 then
        temp := 1
    end if

    scoreInc := temp ** 2

    snkData.speed := (6 - temp) * 10 + 10

    new snake, 5

    for i : 1 .. upper (snake)
        snake (i).x := grdData.size div 2
        snake (i).y := grdData.size
    end for
end resetData

proc moveFood
    var done : boolean
    loop
        done := true
        foodx := Rand.Int (1, grdData.size)
        foody := Rand.Int (1, grdData.size)
        for i : 1 .. upper (snake)
            if snake (i).x = foodx and snake (i).y = foody then
                done := false
            end if
        end for
        exit when done = true
    end loop
end moveFood

proc moveSnake
    var tempx, tempy : int
    if snake (1).x = foodx and snake (1).y = foody then
        score += scoreInc
        moveFood
        new snake, upper (snake) + 1
    end if
    tempx := snake (1).x
    tempy := snake (1).y
    for decreasing i : upper (snake) .. 2
        snake (i).x := snake (i - 1).x
        snake (i).y := snake (i - 1).y
    end for
    snake (1).x := tempx + snkData.dx
    snake (1).y := tempy + snkData.dy
end moveSnake

proc updateSnakeData
    Input.KeyDown (keysDown)
    if keysDown (KEY_RIGHT_ARROW) and snkData.dx not= -1 then
        snkData.dx := 1
        snkData.dy := 0
    elsif keysDown (KEY_LEFT_ARROW) and snkData.dx not= 1 then
        snkData.dx := -1
        snkData.dy := 0
    elsif keysDown (KEY_UP_ARROW) and snkData.dy not= -1 then
        snkData.dx := 0
        snkData.dy := 1
    elsif keysDown (KEY_DOWN_ARROW) and snkData.dy not= 1 then
        snkData.dx := 0
        snkData.dy := -1
    end if
end updateSnakeData

proc drawGrid
    drawfillbox (grdData.width, grdData.width, grdData.size * grdData.width + grdData.width, grdData.size * grdData.width + grdData.width, grdData.clr)
    drawfillbox (foodx * grdData.width, foody * grdData.width, foodx * grdData.width + grdData.width, foody * grdData.width + grdData.width, foodClr)
    for i : 1 .. upper (snake)
        drawfillbox (snake (i).x * grdData.width, snake (i).y * grdData.width, snake (i).x * grdData.width + grdData.width, snake (i).y * grdData.width + grdData.width, snkData.clr)
    end for
end drawGrid

proc checkIfDead
    for i : 2 .. upper (snake)
        if (snake (1).x = snake (i).x and snake (1).y = snake (i).y) or snake (1).x < 1 or snake (1).x > grdData.size or snake (1).y < 1 or snake (1).y > grdData.size then
            if score > highScore then
                highScore := score
            end if
            resetData
            moveFood
            return
        end if
    end for
end checkIfDead

resetData
moveFood
loop
    updateSnakeData
    moveSnake
    drawGrid
    checkIfDead
    locate (1, 1)
    put "HIGH:  ", highScore
    put "SCORE: ", score
    View.Update
    delay (snkData.speed)
    cls
end loop