<?php
namespace YTKNS;

class HtmlTag implements HtmlTypeInterface {
    private string $tagName = 'div';
    private array $attributes = [];
    private array $children = [];
    private bool $selfClosing = false;

    public function __construct(string $tagName, array $attributes = [], $children = null) {
        $this->tagName = $tagName;

        foreach($attributes as $key => $val)
            $this->setAttribute($key, $val);

        if(is_bool($children))
            $this->selfClosing = $children;
        elseif(is_array($children)) {
            foreach($children as $child)
                if($child !== null && $child instanceof HtmlTypeInterface)
                    $this->appendChild($child);
        }
    }

    public function getTagName(): string {
        return $this->tagName;
    }

    public function getAttribute(string $name): ?string {
        return $this->attributes[$name] ?? null;
    }
    public function setAttribute(string $name, $value): void {
        if($value === null) {
            $this->removeAttribute($name);
            return;
        }

        $this->attributes[$name] = $value;
    }
    public function removeAttribute(string $name): void {
        unset($this->attributes[$name]);
    }

    public function appendChild(HtmlTypeInterface $child): HtmlTypeInterface {
        return $this->children[] = $child;
    }
    public function removeChild(HtmlTypeInterface $target): void {
        $remove = [];
        
        foreach($this->children as $child)
            if($child === $target)
                $remove[] = $child;
 
        $this->children = array_diff($this->children, $remove);
    }

    public function setTextContent(string $textContent): void {
        $this->children = [new HtmlText($textContent)];
    }

    public function getElementsByTagName(string $tagName): array {
        $tagName = mb_strtolower($tagName);
        $elements = [];

        foreach($this->children as $child) {
            if($child instanceof HtmlTag) {
                $elements = array_merge($elements, $child->getElementsByTagName($tagName));

                if(mb_strtolower($child->getTagName()) === $tagName)
                    $elements[] = $child;
            }
        }

        return $elements;
    }
    public function getElementsByClassName(string $className): array {
        $elements = [];

        foreach($this->children as $child) {
            if($child instanceof HtmlTag) {
                $elements = array_merge($elements, $child->getElementsByClassName($className));

                $classList = explode(' ', $child->getAttribute('class') ?? '');
                if(in_array($className, $classList))
                    $elements[] = $child;
            }
        }

        return $elements;
    }
    public function getElementById(string $idString): ?HtmlTag {
        foreach($this->children as $child) {
            if($child instanceof HtmlTag) {
                if($child->getAttribute('id') == $idString)
                    return $child;

                $element = $child->getElementById($idString);

                if($element !== null)
                    return $element;
            }
        }

        return null;
    }

    public function asHTML(): string {
        $attrs = '';
        $children = '';

        foreach($this->attributes as $key => $val) {
            $attrs .= sprintf(' %s', $key);

            if($key !== $val)
                $attrs .= sprintf('="%s"', htmlspecialchars($val));
        }

        if($this->selfClosing)
            return sprintf('<%s%s/>', $this->getTagName(), $attrs);

        foreach($this->children as $child)
            $children .= $child->asHTML();

        return sprintf('<%1$s%2$s>%3$s</%1$s>', $this->getTagName(), $attrs, $children);
    }
}