<?php

namespace CorpusParole\Helpers;

use EasyRdf\Resource;

use EasyRdf\Literal;

use EasyRdf\RdfNamespace;

use EasyRdf\Serialiser\Turtle;

/**

 * Globally Inspired by EasyRdf\Serialiser\Turtle::serialiseResource

 */

class RdfHelper {

    private $prefixes = [];

    public function getPrefixes() {

        return $this->prefixes;

    }

    /**

     * Keep track of the prefixes used while serialising

     * @ignore

     */

    public function addPrefix($qname)

    {

        list ($prefix) = explode(':', $qname);

        $this->prefixes[$prefix] = true;

        return $prefix;

    }

    /**

     * Given a IRI string, escape and enclose in angle brackets.

     *

     * @param  string $resourceIri

     *

     * @return string

     */

    public function escapeIri($resourceIri) {

        $escapedIri = str_replace('>', '\\>', $resourceIri);

        return "<span class=\"corpus-rdf-resource\"><span class=\"corpus-rdf-resource-delimiter\">&lt;</span><a class=\"corpus-rdf-resource-link\" href=\"$resourceIri\" target=\"_blank\">".htmlentities($escapedIri)."</a><span class=\"corpus-rdf-resource-delimiter\">&gt;</span></span>";

    }

    /**

     * Insprired by EasyRdf\Serialiser\Turtle::serialiseLiteral

     * Given a string, enclose in quotes and escape any quotes in the string.

     * Strings containing tabs, linefeeds or carriage returns will be

     * enclosed in three double quotes (""").

     *

     * @param  string $value

     *

     * @return string

     */

    public function serialiseLiteral($literal)

    {

        $value = strval($literal);

        $quoted = Turtle::quotedString($value);

        if ($datatype = $literal->getDatatypeUri()) {

            if ($datatype == 'http://www.w3.org/2001/XMLSchema#integer') {

                return sprintf('<span class="corpus-rdf-literal corpus-rdf-literal-value">%d</span>', $value);

            } elseif ($datatype == 'http://www.w3.org/2001/XMLSchema#decimal') {

                return sprintf('<span class="corpus-rdf-literal corpus-rdf-literal-value">%s</span>', $value);

            } elseif ($datatype == 'http://www.w3.org/2001/XMLSchema#double') {

                return sprintf('<span class="corpus-rdf-literal corpus-rdf-literal-value">%e</span>', $value);

            } elseif ($datatype == 'http://www.w3.org/2001/XMLSchema#boolean') {

                return sprintf('<span class="corpus-rdf-literal corpus-rdf-literal-value">%s</span>', $value);

            } else {

                $escaped = $this->serialiseResource($datatype, false);

                return sprintf('<span class="corpus-rdf-literal"><span class="corpus-rdf-literal-value corpus-rdf-literal-value-str">%s</span><span class="corpus-rdf-literal-type-separator">^^</span><span class="corpus-rdf-literal-type">%s</span></span>', $quoted, $escaped);

            }

        } elseif ($lang = $literal->getLang()) {

            return sprintf('<span class="corpus-rdf-literal"><span class="corpus-rdf-literal-value corpus-rdf-literal-value-str">%s</span><span class="corpus-rdf-literal-lang-separator">@</span><span class="corpus-rdf-literal-lang">%s</span></span>',$quoted, $lang);

        } else {

            return "<span class=\"corpus-rdf-literal corpus-rdf-literal-value\">$quoted</span>";

        }

    }

    /**

     * Given a an EasyRdf\Resource or URI, convert it into a string, suitable to

     * be written to a Turtle document. URIs will be shortened into CURIES

     * where possible.

     *

     * @param  Resource|string $resource The resource to convert to a Turtle string

     * @param  boolean $createNamespace  If true, a new namespace may be created

     *

     * @return string

     */

    public function serialiseResource($resource, $createNamespace = false)

    {

        if (is_object($resource)) {

            if ($resource->isBNode()) {

                $uri = preg_replace("/^_\:/", "", $resource->getUri(), 1);

                return "<span class=\"corpus-rdf-blank-node\"><span class=\"corpus-rdf-blank-node-prefix\">_:</span>".htmlentities($uri)."</span>";

            }

            $resource = $resource->getUri();

        }

        $short = RdfNamespace::shorten($resource, $createNamespace);

        if ($short) {

            $prefix = $this->addPrefix($short);

            $shortVal = substr($short, strlen($prefix)+1);

            $namespaceVal = RdfNamespace::namespaces()[$prefix];

            return "<span class=\"corpus-rdf-resource\"><span class=\"corpus-rdf-resource-prefix\" title=\"$namespaceVal\">$prefix</span><span class=\"corpus-rdf-resource-short-separator\">:</span><a class=\"corpus-rdf-resource-link\" href=\"$resource\" target=\"_blank\" title=\"$resource\">".htmlentities($shortVal)."</a></span>";

        }

        return $this->escapeIri($resource);

    }

    public function serialiseValue($val) {

        if($val instanceof Resource) {

            return $this->serialiseResource($val, false);

        } elseif($val instanceof Literal) {

            return $this->serialiseLiteral($val);

        } else {

            throw new \InvalidArgumentException(

                "serialiseObject() requires \$object to be ".

                'of type EasyRdf\Resource or EasyRdf\Literal'

            );

        }

    }

}