import Rx, { Observable } from 'rxjs';
import Grid from './grid';
import Particle from './particle';
import Controls from './controls';
import { CONTROLS, ENTITIES } from './enums';

function Animation() {

    // TODO remove bottom padding from Disqus
    // TODO fix "hangup" small radius evade bug
    // TODO don't load simulation until requested
    // TODO sort out particle nextframe

    // TODO ANIM1ab free movement

    // TODO ANIM3a streamline updateLeader
    // TODO ANIM3b separation
    // TODO ANIM3c alignment
};

Animation.prototype.destroy = function() {

}

Animation.prototype.subscriber = function({ key, value }) {
    switch(key) {
        case CONTROLS.ANIMATING: this.updateAnimating(value); break;
        case CONTROLS.COUNT: this.updateCount(value); break;
        case CONTROLS.SPEED: this.updateSpeed(value); break;
    }
}

Animation.prototype.nextFrame = function() {
    this.particles.forEach(p => {
        const prevX = p.arc.endX;
        const prevY = p.arc.endY;

        p.nextFrame();

        this.grid.deletePoint({ x: prevX, y: prevY, type: ENTITIES.PARTICLE });
        this.grid.setPoint({ x: p.arc.endX, y: p.arc.endY, type: ENTITIES.PARTICLE }, p);
    });
}

Animation.prototype.updateAnimating = function(isAnimating) {
    this.options.animating = isAnimating;

    if (isAnimating) {
        const fps$ = Rx.Observable.interval(1000 / 32)
            .takeWhile(_ => this.options.animating);

        fps$.subscribe(this.nextFrame.bind(this));
    }
}

Animation.prototype.updateCount = function(count) {
    const bounds = this.container.getBoundingClientRect();

    while (this.particles.length > count) {
        const p = this.particles.pop();
        this.grid.deletePoint({ x: p.arc.endX, y: p.arc.endY, type: ENTITIES.PARTICLE });
        p.remove();
    }

    while (this.particles.length < count) {
        const p = new Particle(this.container, bounds, this.options, this.grid);
        this.grid.setPoint({ x: p.arc.endX, y: p.arc.endY, type: ENTITIES.PARTICLE }, p);
        this.particles.push(p);
    }
}

Animation.prototype.updateSpeed = function(value) {
    this.options.speed = value;
    this.particles.forEach(p => p.updateConfig({ speed: value }));
}

export default Animation;