class Walker {
    constructor(
        position,
        speed,
        topSpeed,
        trailSize,
        color,
        accelerationType,
        headSize
    ) {
        this.t = random(1000000)
        this.position = position
        this.velocity = createVector(0, 0)
        this.acceleration = createVector(0, 0)

        this.trail = []
        this.trailSize = trailSize

        this.speed = speed
        this.topSpeed = topSpeed
        this.color = color
        this.accelerationType = accelerationType
        this.headSize = headSize
    }

    step(dt) {
        let dx = this.acceleration.x
        let dy = this.acceleration.y
        if (this.accelerationType == "noise") {
            dx = map(noise(this.t), 0, 1, -1, 1)
            dy = map(noise(this.t + 10000), 0, 1, -1, 1)
        } else if (this.accelerationType == "random") {
            if (random(0, 1) < 0.15) {
                dx = random(-1, 1)
                dy = random(-1, 1)
            }
        }

        this.acceleration = createVector(dx, dy).normalize()
        this.acceleration.setMag(this.speed)

        this.velocity.add(p5.Vector.mult(this.acceleration, dt))
        this.velocity.limit(this.topSpeed)
        this.position.add(p5.Vector.mult(this.velocity, dt))
        this.t += dt/2

        this.position.x = (this.position.x + width) % width
        this.position.y = (this.position.y + height) % height

        this.trail.push(this.position.copy())
        if (this.trail.length > this.trailSize) {
            this.trail.splice(0, 1)
        }
    }

    draw() {
        stroke(this.color)
        for (var p of this.trail) {
            point(p)
        }
        circle(this.position.x, this.position.y, this.headSize)
        // line(this.position.x, this.position.y, this.position.x+this.velocity.x, this.position.y+this.velocity.y)
    }
}

let speedUp = 0
let creatures = []

let speedUpSlider

function setup() {
    createCanvas(640, 240)
    background(255)

    for (let i = 0; i < 20; i++) {
        creatures.push(new Walker(
            createVector(random(0, width), random(0, height)),
            10,
            10,
            200,
            color(20, 200, 20),
            "noise",
            3
        ))
    }

    for (let i = 0; i < 50; i++) {
        creatures.push(new Walker(
            createVector(random(0, width), random(0, height)),
            400,
            50,
            10,
            color(20, 20, 20),
            "random",
            1
        ))
    }

    speedUpSlider = createSlider(0, 10, 0)
    speedUpSlider.changed(() => {
        speedUp = speedUpSlider.value()
    })
}

function draw() {
    background(255)

    // let fps = frameRate();
    // text(Math.round(fps), 50, 50);

    let dt = deltaTime / 1000
    for (let i = 0; i < speedUp + 1; i++) {
        for (var creature of creatures) {
            creature.step(dt)
            creature.draw()
        }
    }
}