%this code is ugly, please wear safety goggles
setscreen ("graphics:600:600")
setscreen ("offscreenonly")

const PADDLE_H := 100
const PADDLE_W := 12
const PADDLE_LEFT_X := 25
const PADDLE_RIGHT_X := maxx - (25 + PADDLE_W)
const PADDLE_VCAP := 16
const PADDLE_STARTY := (maxy div 2) - (PADDLE_H div 2)
const PADDLE_FRIC := 1 %rate at which velocity of paddle decreases when idle
const PADDLE_V_STEP := 1 %rate at which velicity increases per stroke (the ai is dumb because this puts it in the hole)
const PADDLE_COLOR := green
const BALL_R := 6 %this is actually the diameter; i'm too lazy to rename it
const BALL_HR := BALL_R div 2
const BALL_V := 5
const BALL_COLOR := blue
const K_UP := chr (200)
const K_DOWN := chr (208)
const DUMB_AMOUNT := 7 %10=god, 1=fence post
const FPS := 1000 div 60 %millisec/sec

type BALL :
    record
        x, y : int
        vx, vy : int
    end record

type PADDLE : %if i was supercool and making this correctly, i wouldn't exempt the x and vx.  4 player pong anyone?
    record
        y : int
        vy : int
    end record

var ball : BALL
var p_paddle : PADDLE
var ai_paddle : PADDLE
var startpos := 0 %0=player 1=ai
var done := false
var chars : array char of boolean

fcn get_paddle_x (left : boolean) : int
    if (left) then
        result PADDLE_LEFT_X
    else
        result PADDLE_RIGHT_X
    end if
end get_paddle_x
proc approach (var value : int, target, step : int)
    var nv : int
    if (value > target) then
        nv := value - step
        if (nv < target) then
            value := target
        else
            value := nv
        end if
    elsif (value < target) then
        nv := value + step
        if (nv > target) then
            value := target
        else
            value := nv
        end if
    end if
end approach

proc reset_ball
    if (startpos = 0) then
        ball.x := PADDLE_LEFT_X + PADDLE_W + BALL_HR + 1
        ball.y := p_paddle.y + (PADDLE_H div 2) - BALL_R
    else
        ball.x := PADDLE_RIGHT_X - PADDLE_W - BALL_HR - 1
        ball.y := ai_paddle.y + (PADDLE_H div 2) - BALL_R
    end if
    ball.vx := 0
    ball.vy := 0
end reset_ball
proc reset_paddles
    p_paddle.y := PADDLE_STARTY
    p_paddle.vy := 0
    ai_paddle.y := PADDLE_STARTY
    ai_paddle.vy := 0
end reset_paddles
proc launch_ball
    var q := Rand.Int (0, 1)
    if (startpos = 0) then %so it doesn't instantly bounce back
        ball.vx := BALL_V
    else
        ball.vx := -BALL_V
    end if
    if (q = 0) then
        ball.vy := -BALL_V
    else
        ball.vy := BALL_V
    end if
end launch_ball
proc newgame
    reset_paddles
    reset_ball
    launch_ball
end newgame
proc win (left : boolean)
    if (left) then %player
        put "player wins"
        startpos := 0
    else %ai
        put "ai wins"
        startpos := 1
    end if

    put "play again? (y/n) " ..
    View.Update
    loop
        var c : string (1)
        getch (c)
        if (c = "y") then
            newgame
            exit
        elsif (c = "n") then
            done := true
            exit
        end if
    end loop
end win
fcn collide_with_paddle (var p : PADDLE, x, y : int, left : boolean) : boolean
    %vertexes
    var px := get_paddle_x (left)
    var x1 := px
    var x2 := px + PADDLE_W
    var y1 := p.y
    var y2 := p.y + PADDLE_H

    if (x < x2 and x > x1 and y > y1 and y < y2 and left) then
        result true
    elsif (x > x1 and x < x2 and y > y1 and y < y2 and (not left)) then
        result true
    end if
    result false
end collide_with_paddle
fcn collide_ball : boolean %true if game is done
    var new_x := ball.vx + ball.x
    var new_y := ball.vy + ball.y
    var changed := 0

    %top & bottom walls
    if (new_y < 0 or new_y > maxy) then
        ball.vy := -ball.vy
        changed := 1
    end if

    %game loser
    if (new_x < 0) then
        win (false)
        result true
    elsif (new_x > maxx) then
        win (true)
        result true
    end if

    %paddles
    if (collide_with_paddle (p_paddle, new_x, new_y, true)) then
        ball.vx := -ball.vx
    elsif (collide_with_paddle (ai_paddle, new_x, new_y, false)) then
        ball.vx := -ball.vx
    end if

    result false
end collide_ball
proc move_ball
    ball.x := ball.vx + ball.x
    ball.y := ball.vy + ball.y
end move_ball
proc do_player
    Input.KeyDown (chars)

    if (chars (K_UP)) then
        p_paddle.vy := min (p_paddle.vy + PADDLE_V_STEP, PADDLE_VCAP)
    elsif (chars (K_DOWN)) then
        p_paddle.vy := max (p_paddle.vy - PADDLE_V_STEP, -PADDLE_VCAP)
    else
        approach (p_paddle.vy, 0, PADDLE_FRIC)
    end if
    if (p_paddle.vy > 1) then
        p_paddle.y := min (p_paddle.y + p_paddle.vy, maxy - PADDLE_H)
        if (p_paddle.y = maxy - PADDLE_H) then
            p_paddle.vy := 0
        end if
    else
        p_paddle.y := max (p_paddle.y + p_paddle.vy, 0)
        if (p_paddle.y = 0) then
            p_paddle.vy := 0
        end if
    end if
end do_player
proc do_ai_think
    if (ball.vx < 0) then %looks more realistic if it idles when player is moving
        return
    end if
    var projected_y := ball.y + ball.vy
    var current_path := ai_paddle.y + ai_paddle.vy + (PADDLE_H div 2)

    if (projected_y > current_path) then
        ai_paddle.vy := min (ai_paddle.vy + PADDLE_V_STEP, round ((PADDLE_VCAP / 2) / (DUMB_AMOUNT / 10))) %makes it look dumb
    elsif (projected_y < current_path) then
        ai_paddle.vy := max (ai_paddle.vy - PADDLE_V_STEP, round ((-PADDLE_VCAP / 2) / (DUMB_AMOUNT / 10))) %and lose occasionally
    else
        approach (ai_paddle.vy, 0, PADDLE_FRIC)
    end if

    if (ai_paddle.vy > 1) then
        ai_paddle.y := min (ai_paddle.y + ai_paddle.vy, maxy - PADDLE_H)
    else
        ai_paddle.y := max (ai_paddle.y + ai_paddle.vy, 0)
    end if
end do_ai_think

proc drawball
    drawfilloval (ball.x, ball.y, BALL_HR, BALL_HR, BALL_COLOR)
end drawball
proc drawplayer
    drawfillbox (PADDLE_LEFT_X, p_paddle.y, PADDLE_LEFT_X + PADDLE_W, p_paddle.y + PADDLE_H, PADDLE_COLOR)
end drawplayer
proc drawai
    drawfillbox (PADDLE_RIGHT_X, ai_paddle.y, PADDLE_RIGHT_X + PADDLE_W, ai_paddle.y + PADDLE_H, PADDLE_COLOR)
end drawai
proc drawgui
    %hahahahaha
end drawgui

%divide by zero lol
if (DUMB_AMOUNT < 1 or DUMB_AMOUNT > 10) then
    put "DUMB_AMOUNT = ", DUMB_AMOUNT, "\nWHY WOULD YOU DO THIS D:<\n0 < DUMB_AMOUNT < 11\nPLEASE THANKS."
    return
end if
loop
    newgame
    loop
        cls
        drawball
        drawplayer
        drawai
        drawgui
        View.Update

        exit when (collide_ball)
        move_ball
        do_player
        do_ai_think

        Time.DelaySinceLast (FPS)
    end loop
    exit when done
end loop