System

function preload() {
  // Setup simple oscillators for sound effects
  // These will be replaced with actual sound files if you have them
  airplaneEngineSound = new p5.Oscillator('sine');
  airplaneEngineSound.freq(220); // Low hum
  airplaneEngineSound.amp(0.1);
  airplaneEngineSound.stop(); // Stop initially

  dropSound = new p5.Oscillator('triangle');
  dropSound.freq(440); // Beep
  dropSound.amp(0.2);
  dropSound.stop(); // Stop initially

  collectSound = new p5.Oscillator('square');
  collectSound.freq(880); // Higher beep
  collectSound.amp(0.3);
  collectSound.stop(); // Stop initially
}

function setup() {
  createCanvas(windowWidth, windowHeight);
  airplane = new Airplane();
  foodCount = 0;

  // Start audio on user gesture (mandatory for browsers)
  // Audio will start playing after the first click/touch on the canvas
  userStartAudio();
  airplaneEngineSound.start();
  // airplaneEngineSound.loop(); // REMOVED: Oscillators are continuous by default

  // Initialize particles array (particles will be emitted by the airplane)
  particles = [];
}

function draw() {
  // Draw background with some transparency to create a trailing effect
  background(20, 20, 30, 25);

  // --- Airplane Logic ---
  airplane.update();
  airplane.display();

  // Emit particles from the airplane's rear as a trail
  if (frameCount % 5 === 0) { // Emit a particle every 5 frames
    let particlePos = createVector(airplane.pos.x - airplane.size * 0.8, airplane.pos.y + airplane.size * 0.1);
    particles.push(new Particle(particlePos.x, particlePos.y));
  }

  // Drop supply logic: Check if it's time to drop a new supply
  if (millis() - lastDropTime > dropInterval) {
    supplyDrops.push(new SupplyDrop(airplane.pos.x, airplane.pos.y));
    
    // Play drop sound with a quick fade-in and fade-out
    dropSound.start();
    dropSound.amp(0.2, 0.05); // Fade in to 0.2 amplitude in 0.05 seconds
    dropSound.amp(0, 0.5);   // Fade out to 0 amplitude in 0.5 seconds
    
    lastDropTime = millis();
  }

  // --- Supply Drops Logic ---
  // Loop through supply drops backwards to allow safe removal
  for (let i = supplyDrops.length - 1; i >= 0; i--) {
    let drop = supplyDrops[i];
    drop.update();
    drop.display();

    // Remove collected drops or drops that have fallen off-screen
    if (drop.state === 'collected' || drop.pos.y > height + drop.size) {
      supplyDrops.splice(i, 1);
    }
  }

  // --- Particle System Logic (Airplane Trail) ---
  // Loop through particles backwards to allow safe removal
  for (let i = particles.length - 1; i >= 0; i--) {
    let p = particles[i];
    p.update();
    p.display();
    if (!p.isAlive) {
      particles.splice(i, 1); // Remove dead particles
    }
  }

  // --- Food Counter Display ---
  fill(255); // White color for text
  textSize(24);
  textAlign(LEFT, TOP);
  text(`Food: ${foodCount}`, 10, 10);
}

function mousePressed() {
  handleTouchOrClick();
}

function touchStarted() {
  handleTouchOrClick();
  return false; // Prevent default touch behavior (like scrolling)
}

function handleTouchOrClick() {
  for (let drop of supplyDrops) {
    // Check if the drop is currently falling and if the mouse/touch is over it
    if (drop.state === 'falling' && drop.isCollected(mouseX, mouseY)) {
      drop.state = 'collected'; // Mark as collected
      foodCount++;             // Increment food count
      
      // Play collect sound with a quick fade-in and fade-out
      collectSound.start();
      collectSound.amp(0.3, 0.05); // Fade in to 0.3 amplitude in 0.05 seconds
      collectSound.amp(0, 0.5);    // Fade out to 0 amplitude in 0.5 seconds
      
      break; // Only collect one drop per click/touch
    }
  }
}

function windowResized() {
  resizeCanvas(windowWidth, windowHeight);
  // Reset airplane position on resize to ensure it starts properly
  airplane.pos.x = -airplane.size;
  airplane.pos.y = height * 0.2;
}

class Airplane {
  constructor() {
    this.size = 60; // Size reference for drawing
    // Start off-screen left, flying at 20% of screen height
    this.pos = createVector(-this.size, height * 0.2);
    this.vel = createVector(3, 0); // Constant speed flying right
    this.color = color(150, 150, 150); // Gray plane
  }

  update() {
    this.pos.add(this.vel);
    // Wrap around screen: if plane goes off right, reset to off-screen left
    if (this.pos.x > width + this.size) {
      this.pos.x = -this.size;
      this.pos.y = height * random(0.1, 0.4); // Vary flight height slightly
    }
  }

  display() {
    push();
    translate(this.pos.x, this.pos.y);

    // Body
    fill(this.color);
    noStroke();
    ellipse(0, 0, this.size, this.size * 0.4);

    // Tail fin
    triangle(-this.size * 0.4, 0, -this.size * 0.6, -this.size * 0.3, -this.size * 0.8, 0);

    // Wings
    rectMode(CENTER);
    rect(0, 0, this.size * 1.5, this.size * 0.2);

    // Cockpit
    fill(100, 100, 100);
    ellipse(this.size * 0.3, -this.size * 0.1, this.size * 0.3, this.size * 0.2);

    pop();
  }
}

class SupplyDrop {
  constructor(x, y) {
    this.pos = createVector(x, y);
    this.vel = createVector(0, 0);
    this.gravity = createVector(0, 0.1); // Simple downward gravity
    this.size = 30; // Size of the box
    this.state = 'falling'; // States: 'falling', 'collected'
    this.parachuteColor = color(255, 100, 100); // Red parachute
    this.boxColor = color(150, 100, 50);   // Brown box
  }

  update() {
    if (this.state === 'falling') {
      this.vel.add(this.gravity);
      this.pos.add(this.vel);

      // Limit velocity to prevent drops from falling too fast (simulating air resistance)
      this.vel.limit(5);
    }
  }

  display() {
    if (this.state === 'falling') {
      push();
      translate(this.pos.x, this.pos.y);

      // Parachute
      fill(this.parachuteColor);
      noStroke();
      arc(0, -this.size * 0.8, this.size * 2, this.size * 1.5, PI, TWO_PI); // Semi-circle

      // Strings connecting parachute to box
      stroke(0);
      strokeWeight(1);
      line(-this.size * 0.5, -this.size * 0.8, -this.size * 0.5, 0);
      line(this.size * 0.5, -this.size * 0.8, this.size * 0.5, 0);

      // Box
      fill(this.boxColor);
      noStroke();
      rectMode(CENTER);
      rect(0, 0, this.size, this.size);

      // "FOOD" label on the box
      fill(255);
      textSize(this.size * 0.4);
      textAlign(CENTER, CENTER);
      text("FOOD", 0, 0);

      pop();
    }
  }

  isCollected(mx, my) {
    // Check if the given mouse/touch coordinates are within the box
    return mx > this.pos.x - this.size / 2 &&
           mx < this.pos.x + this.size / 2 &&
           my > this.pos.y - this.size / 2 &&
           my < this.pos.y + this.size / 2;
  }
}

class Particle {
  constructor(x, y) {
    this.pos = createVector(x, y);
    // Particles move slightly backward and downward relative to the plane
    this.vel = createVector(random(-1, 0), random(-1, 1));
    this.size = random(2, 5);
    this.color = color(200, 200, 200); // Light gray for smoke/trail
    this.lifespan = 255; // Initial alpha value, decreases over time
    this.isAlive = true;
  }

  update() {
    this.pos.add(this.vel);
    this.lifespan -= random(3, 7); // Fade faster
    if (this.lifespan <= 0) {
      this.isAlive = false; // Mark particle for removal
    }
  }

  display() {
    if (this.isAlive) {
      noStroke();
      // Apply lifespan as alpha value
      fill(red(this.color), green(this.color), blue(this.color), this.lifespan);
      ellipse(this.pos.x, this.pos.y, this.size);
    }
  }
}