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// Global Variables
float pad1y = 300;
float pad1x = 75;
float padWidth = 25;
float padHeight = 125;
float pad2y = 300;
float pad2x = 725;

// these variables control motion
boolean pad1Up = false;
boolean pad1Down = false;
boolean pad2Up = false;
boolean pad2Down = false;

// these variables store the puck's x and y position
float puckX;
float puckY;
float puckSize = 25;
// these variables determine the speed of the puck's motion
float yvel = -3;
float xvel = -1;

int p1score = 0;
int p2score = 0;

// 3. change the value of this variable based on the desired difficulty
//    1 is the easiest 
//    2 is medium
//    3 is the hardest
int difficulty = 1;
int paddleError; // gives the paddle a delay so it's not always moving towards the puck

void setup() {
    size(800, 600);
    rectMode(CENTER);
    textAlign(CENTER, CENTER);
    puckX = width/2;
    puckY = height/2;
    
    // set the value of paddleError based on the value of difficulty
    if (difficulty == 1) {
        paddleError = 20;
    }
    if (difficulty == 2) {
        paddleError = 12;
    }
    if (difficulty == 3) {
        paddleError = 5;
    }
}

void draw() {
    background(0);
    fill(255, 255, 255);
    pad1Controller();
    pad2Controller();
    puckController();
    checkScore();

    textSize(30);
    text(p1score, 200, height/6);
    text(p2score, 600, height/6);
}

void pad1Controller() {
    rect(pad1x, pad1y, padWidth, padHeight);
    
    if(pad1Up == true) {
        pad1y -= 5;
    }
    
    if (pad1Down == true) {
        pad1y += 5;
    }
    
    if (pad1y < padHeight/2) {
        pad1y = padHeight/2;
    }
    
    if (pad1y > height - (padHeight/2)) {
        pad1y = height - (padHeight/2);
    }
}

// paddle 2 will be the AI
void pad2Controller() {
    rect(pad2x, pad2y, padWidth, padHeight);
    if (pad2Up == true) {
        pad2y -= 5;
    }
    if (pad2Down == true) {
        pad2y += 5;
    }
    
    // 1. makes the paddle unbeatable
    // pad2y = puckY;
    
    // 2. the paddle moves all the time, 
    // but at a slower speed than the puck is moving
    // if (puckY > 0) {
    //     pad2y += yvel/2;
    // } else {
    //     pad2y -= yvel/2;
    // }
    
    // 3. use the paddleError variable to add a delay to the paddle
    if (pad2y + padHeight/2 + paddleError < puckY) {
        if (yvel > 0) {
            pad2y += yvel;
        }
    }
    
    if (pad2y - paddleError - padHeight/2> puckY ) {
        if (yvel < 0) {
            pad2y += yvel;
        }
    }
    
    
    // if (pad2y < padHeight/2) {
    //     pad2y = padHeight/2;
    // }
    
    // if (pad2y > height - (padHeight/2)) {
    //     pad2y = height - (padHeight/2);
    // }
}

void puckController() {
    ellipse(puckX, puckY, puckSize, puckSize);
    puckX += xvel;
    puckY += yvel;
    
    
    if(puckY > (height - puckSize/2) || puckY < puckSize/2){ 
        yvel = -yvel; 
    } 
    
    // 1. Add conditionals to check if the puck is touching each paddle.
    //    If it is, reverse vx.
    if(abs(puckX - pad2x) < (25 + padWidth)/2){ 
        if(abs(puckY - pad2y)<(25 + padHeight)/2){
            xvel = -xvel; 
            yvel = -yvel; 
        } 
    } 
    if(abs(puckX - pad1x) < (25 + padWidth)/2){ 
        if(abs(puckY - pad1y)<(25 + padHeight)/2){ 
            xvel = -xvel; 
            yvel = -yvel; 
        } 
    } 
}


void keyPressed() {
    if (key == 'w') {
        pad1Up = true;
    }
    if (key == 's') {
        pad1Down = true;
    }
    if (keyCode == UP) {
        pad2Up = true;
    }
    if (keyCode == DOWN) {
        pad2Down = true;
    }
}

void keyReleased() {
    if (key == 'w') {
        pad1Up = false;
    }
    if (key == 's') {
        pad1Down = false;
    }
    if (keyCode == UP) {
        pad2Up = false;
    }
    if (keyCode == DOWN) {
        pad2Down = false;
    }
}


void checkScore() {
    if(puckX < 0){ 
        p2score += 1; 
        respawnPuck();
    } 
    if(puckX > width){ 
        p1score += 1; 
        respawnPuck();
    } 
}

void respawnPuck() {
    puckX = width/2;
    puckY = height/2;
    xvel = random(-3, 3);
    yvel = random(-3, 3);
}