import {
  Component, ChangeDetectionStrategy, input, inject,
  ElementRef, afterNextRender, DestroyRef, signal,
} from '@angular/core';
import { ReducedMotionService } from '../../services/reduced-motion.service';
import { AnimationLoopService } from '../../services/animation-loop.service';

interface MeshPoint {
  x: number;
  y: number;
  vx: number;
  vy: number;
  color: string;
}

@Component({
  selector: 'fl-gradient-mesh',
  standalone: true,
  changeDetection: ChangeDetectionStrategy.OnPush,
  template: `
    @for (point of meshPoints(); track $index) {
      <div
        class="fl-gradient-mesh__blob"
        [style.left.%]="point.x"
        [style.top.%]="point.y"
        [style.background]="point.color"
        [style.filter]="'blur(' + blur() + 'px)'"
      ></div>
    }
  `,
  styleUrl: './fl-gradient-mesh.component.scss',
  host: {
    'class': 'fl-gradient-mesh',
  },
})
export class FlGradientMeshComponent {
  private el = inject(ElementRef);
  private reducedMotion = inject(ReducedMotionService);
  private animationLoop = inject(AnimationLoopService);
  private destroyRef = inject(DestroyRef);

  // Inputs
  readonly points = input(5);
  readonly colors = input<string[]>(['#3b82f6', '#8b5cf6', '#ec4899', '#f59e0b']);
  readonly speed = input(1);
  readonly blur = input(80);

  // Internal
  private meshPointsData: MeshPoint[] = [];
  private loopCleanup: (() => void) | null = null;

  // Signals
  readonly meshPoints = signal<Array<{ x: number; y: number; color: string }>>([]);

  constructor() {
    afterNextRender(() => {
      this.initializeMesh();

      if (this.reducedMotion.reduced()) {
        this.updateDisplay();
        return;
      }

      const id = `gradient-mesh-${Math.random().toString(36).slice(2)}`;
      this.loopCleanup = this.animationLoop.registerWithElement(id, this.el.nativeElement, (delta) => this.tick(delta));
    });

    this.destroyRef.onDestroy(() => {
      this.loopCleanup?.();
    });
  }

  private initializeMesh(): void {
    const count = this.points();
    const colors = this.colors();
    this.meshPointsData = [];

    for (let i = 0; i < count; i++) {
      this.meshPointsData.push({
        x: Math.random() * 100,
        y: Math.random() * 100,
        vx: (Math.random() - 0.5) * 10,
        vy: (Math.random() - 0.5) * 10,
        color: colors[i % colors.length],
      });
    }

    this.updateDisplay();
  }

  private tick(delta: number): void {
    const speed = this.speed() * delta * 10;

    for (const point of this.meshPointsData) {
      point.x += point.vx * speed;
      point.y += point.vy * speed;

      // Bounce off edges
      if (point.x < 0 || point.x > 100) {
        point.vx *= -1;
        point.x = Math.max(0, Math.min(100, point.x));
      }
      if (point.y < 0 || point.y > 100) {
        point.vy *= -1;
        point.y = Math.max(0, Math.min(100, point.y));
      }
    }

    this.updateDisplay();
  }

  private updateDisplay(): void {
    this.meshPoints.set(
      this.meshPointsData.map(p => ({
        x: p.x,
        y: p.y,
        color: p.color,
      }))
    );
  }
}