<?php
namespace YTKNS;

use InvalidArgumentException;

final class Gradient {
    private int $direction = 0;
    private array $points = [];

    public function getArray(): array {
        $arr = [
            'd' => $this->getDirection(),
            'p' => [],
        ];

        foreach($this->getPoints() as $point)
            $arr['p'][] = $point->getArray();

        return $arr;
    }

    public static function fromArray($array): ?self {
        $gradient = new static;

        if(!empty($array)) {
            if(is_string($array))
                $array = json_decode($array);
            if(is_object($array))
                $array = (array)$array;
            if(is_array($array)) {
                if(isset($array['d']) && is_int($array['d']))
                    $gradient->setDirection($array['d']);

                if(isset($array['p']) && is_array($array['p'])) {
                    $gradient->resetPoints();

                    foreach($array['p'] as $point)
                        $gradient->addPoint(GradientPoint::fromArray($point));
                }
            }
        }

        if(count($gradient->points) < 2)
            return null;

        return $gradient;
    }        

    public function getCSS(): string {
        $points = [];

        foreach($this->points as $point)
            $points[] = $point->getCSS();

        return sprintf('linear-gradient(%ddeg, %s)', $this->getDirection(), implode(', ', $points));
    }

    public function getDirection(): int {
        return $this->direction;
    }
    public function setDirection(int $dir): self {
        if($dir < 0 || $dir > 359)
            throw new InvalidArgumentException('dir must be between 0 and 359.');
        $this->direction = $dir;
        return $this;
    }

    public function getPoints(): array {
        return $this->points;
    }

    public function addPoint(GradientPoint $point): self {
        if(!in_array($point, $this->points))
            $this->points[] = $point;
        return $this;
    }
    public function removePoint(GradientPoint $point): self {
        $index = array_search($point, $this->points);
        if($index !== null)
            unset($this->points[$index]);
        return $this;
    }
    public function resetPoints(): self {
        $this->points = [];
        return $this;
    }
}