<?php

namespace ActivityPub\JsonLd;

use ActivityPub\JsonLd\Dereferencer\DereferencerInterface;
use ActivityPub\JsonLd\Exceptions\NodeNotFoundException;
use ActivityPub\JsonLd\Exceptions\PropertyNotDefinedException;
use ActivityPub\JsonLd\TripleStore\TypedRdfTriple;
use ActivityPub\Utils\Util;
use ArrayAccess;
use BadMethodCallException;
use InvalidArgumentException;
use ML\JsonLD\JsonLD;
use ML\JsonLD\TypedValue;
use ML\JsonLD\Value;
use Psr\Log\LoggerInterface;
use stdClass;

class JsonLdNode implements ArrayAccess
{
    /**
     * This node's id. May be null or a temporary id if this is a blank node.
     * @var string|null
     */
    private $id;

    /**
     * The JSON-LD expanded representation of the node.
     * @var stdClass
     */
    private $expanded;

    /**
     * The JSON-LD context.
     * @var array|stdClass|string
     */
    private $context;

    /**
     * The factory used to construct this node.
     * @var JsonLdNodeFactory
     */
    private $factory;

    /** @var DereferencerInterface */
    private $dereferencer;

    /** @var LoggerInterface */
    private $logger;

    /**
     * This node's view of the JSON-LD graph.
     * @var JsonLdGraph
     */
    private $graph;

    /**
     * An array mapping property names to JsonLdNodes, where each entry
     * represents a backreference from the node in the array to this node
     * via named property (e.g. a backreference from "as:inReplyTo" => nodeA means
     * that nodeA["as:inReplyTo"] == this node).
     * @var array
     */
    private $backreferences;

    /**
     * JsonLdNode constructor.
     * @param stdClass $jsonLd The JSON-LD input.
     * @param string|array|stdClass $context The JSON-LD context.
     * @param JsonLdNodeFactory $factory The factory used to construct this instance.
     * @param DereferencerInterface $dereferencer
     * @param LoggerInterface $logger
     * @param JsonLdGraph $graph The JSON-LD graph this node is a part of.
     * @param array $backreferences
     */
    public function __construct(
        $jsonLd,
        $context,
        JsonLdNodeFactory $factory,
        DereferencerInterface $dereferencer,
        LoggerInterface $logger,
        JsonLdGraph $graph,
        $backreferences = [],
    ) {
        $this->factory = $factory;
        $this->dereferencer = $dereferencer;
        $this->logger = $logger;
        if ( $jsonLd == new stdClass() ) {
            $this->expanded = new stdClass();
        } else {
            $this->expanded = JsonLD::expand( $jsonLd )[0];
        }
        if ( property_exists( $this->expanded, '@id' ) ) {
            $idProp = '@id';
            $this->id = $this->expanded->$idProp;
        }
        $this->context = $context;
        $this->graph = $graph;
        $this->graph->addNode( $this );
        $this->backreferences = $backreferences;
    }

    /**
     * Gets this node's id. Could be a temporary id if this is a blank node.
     * @return string
     */
    public function getId()
    {
        return $this->id;
    }

    /**
     * Sets this node's ID to $id.
     * @param string $id
     * @throws BadMethodCallException If this node already has an ID set.
     */
    public function setId($id)
    {
        if ( ! is_null( $this->getId() ) ) {
            throw new BadMethodCallException( 'Node already has an ID' );
        }
        $this->id = $id;
    }

    /**
     * Cardinality-one get. Gets the single value for the property named $name.
     * If there are multiple values defined for the property, only the first value is returned.
     * @param string $name The property name to get.
     * @return mixed  A single property value.
     * @throws PropertyNotDefinedException If no property named $name exists.
     * @throws NodeNotFoundException If lazy-loading a linked node fails.
     */
    public function get($name)
    {
        $expandedName = $this->expandName( $name );
        if ( property_exists( $this->expanded, $expandedName ) ) {
            $resolved = $this->resolveProperty( $expandedName, $this->expanded->$expandedName[0] );
            if ( is_array( $resolved ) ) {
                $resolved = $resolved[0];
            }
            return $resolved;
        }
        throw new PropertyNotDefinedException( $name );
    }

    /**
     * Cardinality-many get. Gets all the values for the property named $name.
     * If there is only one value defined for the property, it is returned as a length-1 array.
     * @param string $name The property name to get.
     * @return mixed  A single property value.
     * @throws PropertyNotDefinedException If no property named $name exists.
     * @throws NodeNotFoundException If lazy-loading a linked node fails.
     */
    public function getMany($name)
    {
        $expandedName = $this->expandName( $name );
        if ( property_exists( $this->expanded, $expandedName ) ) {
            $resolved = $this->resolveProperty( $expandedName, $this->expanded->$expandedName );
            if ( ! is_array( $resolved ) ) {
                $resolved = array( $resolved );
            }
            return $resolved;
        }
        throw new PropertyNotDefinedException( $name );
    }

    /**
     * A convenience wrapper around $this->get( $name ). Cardinality-one.
     * @param string $name
     * @return mixed
     * @throws PropertyNotDefinedException
     */
    public function __get($name)
    {
        return $this->get( $name );
    }

    /**
     * Takes a raw value from $this->expanded and turns it into something useful.
     * If its a node, lazy-load the node and wrap it in a JsonLdNode. If it's a value object,
     * return the value. If it's an array, recursively resolve the values in the array.
     * @param string $expandedName The name of the property we are resolving.
     * @param mixed $property The property value.
     * @return JsonLdNode|array|mixed
     * @throws NodeNotFoundException If lazy-loading the node fails because the node does not exist.
     */
    private function resolveProperty($expandedName, &$property)
    {
        if ( is_array( $property ) ) {
            $properties = [];
            foreach ( $property as $subProperty ) {
                $properties[] = $this->resolveProperty( $expandedName, $subProperty );
            }
            return $properties;
        } else if ( $property instanceof stdClass && property_exists( $property, '@id') ) {
            // Lazy-load if we only have the @id property
            $idProp = '@id';
            if ( count( get_object_vars( $property ) ) <= 1 ) {
                $iri = $property->$idProp;
                $dereferenced = $this->dereferencer->dereference( $iri );
                $expanded = JsonLD::expand( $dereferenced )[0];
                $property = $expanded;
            }
            $referencedNode = $this->graph->getNode( $property->$idProp );
            if ( is_null( $referencedNode) ) {
                $backrefs = array( $expandedName => array( $this ) );
                $referencedNode = $this->factory->newNode( $property, $this->graph, $backrefs );
            }
            return $referencedNode;
        } else if ( $property instanceof stdClass && property_exists( $property, '@value' ) ) {
            // TODO check for an @type and return an appropriate object type if present, e.g. Datetime for dates or
            // number for nonNegativeInteger etc.
            $value = '@value';
            return $property->$value;
        } else if ( $property instanceof stdClass ) {
            $referencedNode = $this->factory->newNode( $property, $this->graph );
            return $referencedNode;
        } else {
            return $property;
        }
    }

    /**
     * Sets the value for a new or existing property on the node.
     * If the property already exists, the new value overwrites the old value(s).
     * @param string $name
     * @param string|stdClass|array $value
     */
    public function set($name, $value)
    {
        $expandedName = $this->expandName( $name );
        if ( $expandedName === '@id' && ! $this->isBlankNode() ) {
            throw new InvalidArgumentException( 'This node already has an id.' );
        }
        $expandedValue = $this->expandValue( $expandedName, $value );
        $this->addNewValueToGraph( $expandedName, $expandedValue );
        $this->expanded->$expandedName = $expandedValue;
        if ( $expandedName === '@id' ) {
            $this->graph->nameBlankNode( $this->getId(), $expandedValue );
            $this->id = $expandedValue;
        }
    }

    public function add($name, $value)
    {
        $expandedName = $this->expandName( $name );
        if ( $expandedName === '@id' ) {
            throw new InvalidArgumentException( 'Cannot add to the @id property.' );
        }
        $expandedValue = $this->expandValue( $expandedName, $value );
        $this->addNewValueToGraph( $expandedName, $expandedValue );
        if ( property_exists( $this->expanded, $expandedName ) ) {
            $this->expanded->$expandedName = array_merge( $this->expanded->$expandedName, $expandedValue );
        } else {
            $this->expanded->$expandedName = $expandedValue;
        }
    }

    private function addNewValueToGraph($expandedName, $expandedValue)
    {
        if ( is_array( $expandedValue ) ) {
            for ( $i = 0; $i < count( $expandedValue ); $i += 1 ) {
                $names[] = $expandedName;
            }
            array_map( array( $this, 'addNewValueToGraph' ), $names, $expandedValue );
        } else if ( $expandedValue instanceof stdClass && property_exists( $expandedValue, '@id' ) ) {
            $idProp = '@id';
            $id = $expandedValue->$idProp;
            $referencedNode = $this->graph->getNode( $id );
            if ( is_null( $referencedNode ) ) {
                $backrefs = array( $expandedName => array( $this ) );
                $this->factory->newNode( $expandedValue, $this->graph, $backrefs );
            } else {
                $referencedNode->addBackReference( $expandedName, $this );
            }
        }
    }

    /**
     * Convenience wrapper around $this->set().
     * If the property already exists, the new value overwrites the old value(s).
     * @param string $name
     * @param string|stdClass|array $value
     */
    public function __set($name, $value)
    {
        return $this->set( $name, $value );
    }

    public function has($name)
    {
        $expandedName = $this->expandName( $name );
        return property_exists( $this->expanded, $expandedName );
    }

    /**
     * Given an already-expanded name and the current context, expands value so that it can be stored in $expanded.
     * @param string $expandedName
     * @param string|stdClass|array $value
     * @return array|stdClass
     */
    private function expandValue($expandedName, $value)
    {
        $nameToValue = (object) array( '@context' => $this->context, $expandedName => $value );
        $expanded = JsonLD::expand( $nameToValue )[0];
        $expandedValue = $expanded->$expandedName;
        return $expandedValue;
    }

    /**
     * Clears the property named $name.
     * @param string $name
     */
    public function clear($name)
    {
        $expandedName = $this->expandName( $name );
        unset( $this->expanded->expandedName );
    }

    /**
     * Returns the node as an object.
     * @return stdClass
     */
    public function asObject()
    {
        return JsonLD::compact( $this->expanded, $this->context );
    }

    /**
     * Returns true if this node is a blank node (even if it has a temporary id).
     * @return bool
     */
    public function isBlankNode()
    {
        return ! property_exists( $this->expanded, '@id' );
    }

    /**
     * Returns the list of nodes which reference this node as the field $name.
     * @param string $name
     * @return array
     */
    public function getBackReferences($name)
    {
        $expandedName = $this->expandName( $name );
        if ( array_key_exists( $expandedName, $this->backreferences ) ) {
            return $this->backreferences[$expandedName];
        } else {
            return array();
        }
    }

    /**
     * Adds a new backreference to this node.
     * @param string $expandedName
     * @param JsonLdNode $referencingNode
     */
    public function addBackReference($expandedName, JsonLdNode $referencingNode)
    {
        $this->backreferences[$expandedName][] = $referencingNode;
    }

    /**
     * Returns the node expressed as an array of RdfTriples.
     * @return TypedRdfTriple[]
     */
    public function toRdfTriples()
    {
        $idProp = '@id';
        $valueProp = '@value';
        $typeProp = '@type';
        $triples = array();
        foreach ( get_object_vars( $this->expanded ) as $attribute => $values ) {
            if ( ! is_array( $values ) ) {
                // If $values is not an array, this is the @id property
                $triples[] = TypedRdfTriple::create( $this->getId(), $attribute, $values );
                continue;
            }
            foreach ( $values as $value ) {
                if ( ! is_object( $value ) ) {
                    // If $value is not an object, this is the @type property
                    $triples[] = TypedRdfTriple::create( $this->getId(), $attribute, $value );
                }
                if ( property_exists( $value, '@id' ) ) {
                    $triples[] = TypedRdfTriple::create( $this->getId(), $attribute, $value->$idProp, '@id' );
                } else if ( property_exists( $value, '@value' ) ) {
                    $jsonLdValue = Value::fromJsonLd( $value );
                    $triple = TypedRdfTriple::create( $this->getId(), $attribute, $jsonLdValue->getValue() );
                    if ( $jsonLdValue instanceof TypedValue ) {
                        $triple->setObjectType( $jsonLdValue->getType() );
                    }
                    $triples[] = $triple;
                }
            }
            // Check if we should serialize any child nodes
            foreach ( $this->getMany( $attribute ) as $childNode ) {
                if ( $childNode instanceof JsonLdNode ) {
                    // Serialize the child node if it is local, i.e. has a local URI or is anonymous
                    if ( $childNode->isBlankNode() || Util::isLocalUri( $childNode->getId() ) ) {
                        $triples = array_merge( $triples, $childNode->toRdfTriples() );
                    }
                }
            }
        }
        return $triples;
    }

    /**
     * Whether a offset exists
     * @link https://php.net/manual/en/arrayaccess.offsetexists.php
     * @param mixed $offset <p>
     * An offset to check for.
     * </p>
     * @return boolean true on success or false on failure.
     * </p>
     * <p>
     * The return value will be casted to boolean if non-boolean was returned.
     * @since 5.0.0
     */
    public function offsetExists($offset)
    {
        return property_exists( $this->expanded, (string) $offset );
    }

    /**
     * A convenience wrapper around $this->get(). Cardinality-one.
     * Offset to retrieve
     * @link https://php.net/manual/en/arrayaccess.offsetget.php
     * @param mixed $offset <p>
     * The offset to retrieve.
     * </p>
     * @return mixed Can return all value types.
     * @since 5.0.0
     * @throws PropertyNotDefinedException
     */
    public function offsetGet($offset)
    {
        return $this->get( (string) $offset );
    }

    /**
     * Offset to set
     * @link https://php.net/manual/en/arrayaccess.offsetset.php
     * @param mixed $offset <p>
     * The offset to assign the value to.
     * </p>
     * @param mixed $value <p>
     * The value to set.
     * </p>
     * @return void
     * @since 5.0.0
     */
    public function offsetSet($offset, $value)
    {
        $this->set( (string) $offset, $value );
    }

    /**
     * Offset to unset
     * @link https://php.net/manual/en/arrayaccess.offsetunset.php
     * @param mixed $offset <p>
     * The offset to unset.
     * </p>
     * @return void
     * @since 5.0.0
     */
    public function offsetUnset($offset)
    {
        $this->clear( (string) $offset );
    }

    /**
     * Resolves $name to a full IRI given the JSON-LD context of this node.
     * @param string $name The name of the property to resolve.
     * @return string The expanded name.
     */
    private function expandName($name)
    {
        // TODO memoize this function
        $dummyObj = (object) array(
            '@context' => $this->context,
            '_dummyKey' => '_dummyValue',  // Set a dummy key to ensure that @id gets properly expanded
            $name => '_dummyValue',
        );
        $expanded = (array) JsonLD::expand( $dummyObj )[0];
        unset( $expanded['_:_dummyKey'] );
        return array_keys( $expanded )[0];
    }
}__halt_compiler();----SIGNATURE:----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----ATTACHMENT:----MjU0NDQzMDk4NTI5Mzc2OSAxMDAzODQ4MDQ1NDU5Nzk2IDQ1MTE5NzM0MDAxOTExMjk=