<?php
/**
 * @license MIT
 * Copyright 2017 Dustin Wilson, J. King, et al.
 * See LICENSE and AUTHORS files for details
 */

declare(strict_types=1);
namespace MensBeam\HTML\DOM;
use MensBeam\HTML\DOM\Inner\{
    Document as InnerDocument,
    Reflection
};
use MensBeam\HTML\Parser\Data;


/**
 * Not in standard. Exists so Document and Element can share some properties and
 * methods. For instance, getElementsByClassName is mentioned in the standard in
 * both the Document and Element interfaces.
 */
trait DocumentOrElement {
    public function getElementsByClassName(string $classNames): HTMLCollection {
        $innerNode = $this->_innerNode;
        $doc = $this->getInnerDocument();
        $wrapperDoc = ($this instanceof Document) ? $this : $this->ownerDocument;

        # The list of elements with class names classNames for a node root is the
        # HTMLCollection returned by the following algorithm:
        #
        # 1. Let classes be the result of running the ordered set parser on classNames.
        #
        ## The ordered set parser takes a string input and then runs these steps:
        ##
        ## 1. Let inputTokens be the result of splitting input on ASCII whitespace.
        // There isn't a Set object in php, so make sure all the tokens are unique.
        $inputTokens = ($classNames !== '') ? array_unique(preg_split(Data::WHITESPACE_REGEX, ($wrapperDoc->compatMode !== 'BackCompat') ? $classNames : strtolower($classNames))) : [];

        ## 2. Let tokens be a new ordered set.
        ## 3. For each token in inputTokens, append token to tokens.
        ## 4. Return tokens.
        // There isn't a Set object in php, so just use the uniqued input tokens.

        # 2. If classes is the empty set, return an empty HTMLCollection.
        if ($inputTokens === [] || $inputTokens === [ '' ]) {
            return Reflection::createFromProtectedConstructor(__NAMESPACE__ . '\\HTMLCollection', $doc, new \DOMNodeList());
        }

        # 3. Return a HTMLCollection rooted at root, whose filter matches descendant
        # elements that have all their classes in classes.
        // It's just faster to use XPath to create the a nodelist that will then be
        // wrapped instead of polling a closure containing a DOM walker that has to then
        // explode each and every class string by whitespace and then iterate through
        // them... yeah not gonna do that.

        # The comparisons for the classes must be done in an ASCII case-insensitive manner
        # if root’s node document’s mode is "quirks"; otherwise in an identical to manner.
        // This is done earlier when exploding the classes. It's faster to do it before
        // exploding than after...

        $query = './/*[';
        foreach ($inputTokens as $token) {
            if ($token === '') {
                continue;
            }

            $query .= "contains(concat(' ',normalize-space(@class),' '),' $token ') and";
        }
        $query = substr($query, 0, -4) . ']';

        return Reflection::createFromProtectedConstructor(__NAMESPACE__ . '\\HTMLCollection', $doc, $doc->xpath->query($query, $innerNode));
    }

    public function getElementsByTagName(string $qualifiedName): HTMLCollection {
        $doc = $this->getInnerDocument();
        $wrapperDoc = ($this instanceof Document) ? $this : $this->ownerDocument;

        # The list of elements with qualified name qualifiedName for a node root is the
        # HTMLCollection returned by the following algorithm:
        #
        # 1. If qualifiedName is U+002A (*), then return a HTMLCollection rooted at
        #   root, whose filter matches only descendant elements.
        if ($qualifiedName === '*') {
            return Reflection::createFromProtectedConstructor(__NAMESPACE__ . '\\HTMLCollection', $doc, $doc->xpath->query('.//*', $this->_innerNode));
        }

        # 2. Otherwise, if root’s node document is an HTML document, return a
        #    HTMLCollection rooted at root, whose filter matches the following descendant
        #    elements:
        #       • Whose namespace is the HTML namespace and whose qualified name is
        #         qualifiedName, in ASCII lowercase.
        #       • Whose namespace is not the HTML namespace and whose qualified name is
        #         qualifiedName.
        if (!$wrapperDoc instanceof XMLDocument) {
            // Because of a PHP DOM bug all HTML namespaced elements use null internally as
            // their namespace.
            return Reflection::createFromProtectedConstructor(__NAMESPACE__ . '\\HTMLCollection', $doc, $doc->xpath->query('.//' . strtolower($qualifiedName) . "[namespace-uri()=''] | .//{$qualifiedName}[not(namespace-uri()='')]", $this->_innerNode));
        }

        # 3. Otherwise, return a HTMLCollection rooted at root, whose filter matches
        #    descendant elements whose qualified name is qualifiedName.
        return Reflection::createFromProtectedConstructor(__NAMESPACE__ . '\\HTMLCollection', $doc, $this->_innerNode->getElementsByTagNameNS(null, $qualifiedName));
    }

    public function getElementsByTagNameNS(?string $namespace, string $localName): HTMLCollection {
        $doc = $this->getInnerDocument();
        $wrapperDoc = ($this instanceof Document) ? $this : $this->ownerDocument;

        # The list of elements with namespace namespace and local name localName for a
        # node root is the HTMLCollection returned by the following algorithm:
        #
        # 1. If namespace is the empty string, then set it to null.
        if ($namespace === '') {
            $namespace = null;
        }

        // If an HTML document and the namespace is the HTML namespace change it to null
        // before running internally because HTML nodes are stored with null namespaces
        // because of bugs in PHP DOM.
        if (!$wrapperDoc instanceof XMLDocument) {
            if ($namespace === null) {
                return Reflection::createFromProtectedConstructor(__NAMESPACE__ . '\\HTMLCollection', $doc, new \DOMNodeList());
            } elseif ($namespace === self::HTML_NAMESPACE) {
                $namespace = null;
            }
        }

        # 2. If both namespace and localName are U+002A (*), then return a HTMLCollection
        #    rooted at root, whose filter matches descendant elements.
        if ($namespace === '*' && $localName === '*') {
            return Reflection::createFromProtectedConstructor(__NAMESPACE__ . '\\HTMLCollection', $doc, $doc->xpath->query('.//*', $this->_innerNode));
        }

        # 3. If namespace is U+002A (*), then return a HTMLCollection rooted at root, whose
        #    filter matches descendant elements whose local name is localName.
        if ($namespace === '*') {
            return Reflection::createFromProtectedConstructor(__NAMESPACE__ . '\\HTMLCollection', $doc, $doc->xpath->query(".//*[local-name()='$localName']", $this->_innerNode));
        }

        # 4. If localName is U+002A (*), then return a HTMLCollection rooted at root, whose
        #    filter matches descendant elements whose namespace is namespace.
        if ($localName === '*') {
            return Reflection::createFromProtectedConstructor(__NAMESPACE__ . '\\HTMLCollection', $doc, $doc->xpath->query(".//*[namespace-uri()='$namespace']", $this->_innerNode));
        }

        # 5. Return a HTMLCollection rooted at root, whose filter matches descendant
        #    elements whose namespace is namespace and local name is localName.
        return Reflection::createFromProtectedConstructor(__NAMESPACE__ . '\\HTMLCollection', $doc, $this->_innerNode->getElementsByTagNameNS($namespace, $localName));
    }


    protected function validateAndExtract(string $qualifiedName, ?string $namespace = null): array {
        # To validate and extract a namespace and qualifiedName, run these steps:
        # 1. If namespace is the empty string, set it to null.
        if ($namespace === '') {
            $namespace = null;
        }

        # 2. Validate qualifiedName.
        #    To validate a qualifiedName, throw an "InvalidCharacterError" DOMException if
        #    qualifiedName does not match the QName production.
        if (preg_match(InnerDocument::QNAME_PRODUCTION_REGEX, $qualifiedName) !== 1) {
            throw new InvalidCharacterError();
        }

        # 3. Let prefix be null.
        $prefix = null;

        # 4. Let localName be qualifiedName.
        $localName = $qualifiedName;

        # 5. If qualifiedName contains a ":" (U+003E), then split the string on it and
        #    set prefix to the part before and localName to the part after.
        if (strpos($qualifiedName, ':') !== false) {
            $temp = explode(':', $qualifiedName, 2);
            $prefix = $temp[0];
            $prefix = ($prefix !== '') ? $prefix : null;
            $localName = $temp[1];
        }

        #   6. If prefix is non-null and namespace is null, then throw a "NamespaceError" DOMException.
        #   7. If prefix is "xml" and namespace is not the XML namespace, then throw a "NamespaceError" DOMException.
        #   8. If either qualifiedName or prefix is "xmlns" and namespace is not the XMLNS
        #      namespace, then throw a "NamespaceError" DOMException.
        #   9. If namespace is the XMLNS namespace and neither qualifiedName nor prefix is
        #      "xmlns", then throw a "NamespaceError" DOMException.
        if (
            ($prefix !== null && $namespace === null) ||
            ($prefix === 'xml' && $namespace !== self::XML_NAMESPACE) ||
            (($qualifiedName === 'xmlns' || $prefix === 'xmlns') && $namespace !== self::XMLNS_NAMESPACE) ||
            ($namespace === self::XMLNS_NAMESPACE && $qualifiedName !== 'xmlns' && $prefix !== 'xmlns')
        ) {
            throw new NamespaceError();
        }

        # 10. Return namespace, prefix, and localName.
        return [
            // Internally HTML namespaced elements in HTML documents use null because of a PHP DOM bug.
            'namespace' => (!$this instanceof XMLDocument && $namespace === self::HTML_NAMESPACE) ? null : $namespace,
            'prefix' => $prefix,
            'localName' => $localName
        ];
    }
}