<?php

namespace App\View;

use JumPHP\Renderer\Renderer;

/** Small squares that fly, fall and fade: dust, sparks, splashes, confetti. Level coordinates. */
final class Particles
{
    private const MAX = 500;
    /** @var array<int, array{0:float,1:float,2:float,3:float,4:float,5:float,6:array,7:float,8:float}> x y vx vy life max colour size gravity */
    private array $list = [];

    public function clear(): void
    {
        $this->list = [];
    }

    /** @return array<int, array{0:float,1:float,2:float,3:float,4:float,5:float,6:array,7:float,8:float}> */
    public function all(): array
    {
        return $this->list;
    }

    public function count(): int
    {
        return count($this->list);
    }

    /** @param array<int, array|string> $colors */
    public function burst(float $x, float $y, int $count, array $colors, float $speed = 60, float $life = 0.6, float $gravity = 240,
                          float $size = 1, float $up = 0.5, float $spread = M_PI): void
    {
        for ($i = 0; $i < $count && count($this->list) < self::MAX; $i++) {
            $a = -M_PI / 2 + (mt_rand(-1000, 1000) / 1000) * $spread;
            $v = $speed * (0.35 + mt_rand(0, 650) / 1000);
            $c = \JumPHP\Util\Color::of($colors[array_rand($colors)]);
            $this->list[] = [$x, $y, cos($a) * $v, sin($a) * $v - $speed * $up * 0.3, $life * (0.6 + mt_rand(0, 400) / 1000), $life,
                [$c->r, $c->g, $c->b], $size + (mt_rand(0, 100) < 25 ? 1 : 0), $gravity];
        }
    }

    public function update(float $dt): void
    {
        foreach ($this->list as $i => &$p) {
            $p[4] -= $dt;
            if ($p[4] <= 0) {
                unset($this->list[$i]);
                continue;
            }
            $p[3] += $p[8] * $dt;
            $p[0] += $p[2] * $dt;
            $p[1] += $p[3] * $dt;
        }
        unset($p);
    }

    public function render(Renderer $r, float $camX, float $camY = 0): void
    {
        foreach ($this->list as $p) {
            $x = $p[0] - $camX;
            if ($x < -4 || $x > 484) {
                continue;
            }
            $k = $p[4] / $p[5];
            $c = $p[6];
            $c[3] = $k > 0.5 ? 255 : (int)(255 * $k * 2);
            $s = $p[7];
            $r->fillRect($x, $p[1] - $camY, $s, $s, $c);
        }
    }
}