<?php

namespace Ulmus;

use Ulmus\Repository,
    Ulmus\Query,
    Ulmus\Common\EntityResolver,
    Ulmus\Common\EntityField;

use Ulmus\Annotation\Classes\{ Method, Table, Collation, };
use Ulmus\Annotation\Property\{ Field, Relation, OrderBy, Where, Join, Virtual };
use Ulmus\Annotation\Property\Field\{ Id, ForeignKey, CreatedAt, UpdatedAt, };

trait EntityTrait {
    use EventTrait;
    
    /**
     * @Ignore
     */
    protected bool $entityStrictFieldsDeclaration = false;
    
    /**
     * @Ignore
     */
    protected array $entityDatasetUnmatchedFields = [];
    
    /**
     * @Ignore
     */
    public array $entityLoadedDataset = [];
    
    /**
     * @Ignore
     */
    public function __get(string $name)
    {
        $entityResolver =  $this->resolveEntity();

        # Resolve relations here if one is called

        # @TODO REFACTOR THIS CODE ASAP !
        if ( $this->isLoaded() ) {
            if ( null !== ( $join= $entityResolver->searchFieldAnnotation($name, new Join() ) ) ) {
                $vars = [];

                $entity = $join->entity ?? $entityResolver->properties[$name]['type'];

                foreach($this->entityDatasetUnmatchedFields as $key => $value) {
                    $len = strlen( $name ) + 1;

                    if ( substr($key, 0, $len ) === "{$name}$" ) {
                        $vars[substr($key, $len)] = $value;
                    }
                }

                if ( [] !== $data = (array_values(array_unique($vars)) !== [ null ] ? $vars : []) ) { 
                    return ( new $entity() )->fromArray($data);    
                }
            }
            
            if ( null !== ( $relation = $entityResolver->searchFieldAnnotation($name, new Relation() ) ) ) {
                $relationType = strtolower(str_replace(['-', '_', ' '], '', $relation->type));

                $order = $entityResolver->searchFieldAnnotationList($name, new OrderBy() );
                $where = $entityResolver->searchFieldAnnotationList($name, new Where() );

                if ( $relation->entity ?? false ) {
                    $baseEntity = $relation->entity();

                    $repository = $baseEntity->repository();

                    foreach($where as $condition) {
                        $repository->where($condition->field, is_callable($condition->value) ? $f = call_user_func_array($condition->value, [ $this ]) : $condition->value, $condition->operator);
                    }

                    foreach($order as $item) {
                        $repository->orderBy($item->field, $item->order);
                    }

                    $field = $relation->key;
                }

                switch( $relationType ) {
                    case 'onetoone':       
                        if ($relation->foreignKey) {             
                            $repository->where( is_object($relation->foreignKey) ? $relation->foreignKey : $baseEntity->field($relation->foreignKey), is_callable($field) ? $field($this) : $this->$field );
                        }
                        
                        $this->eventExecute(Event\EntityRelationLoadInterface::class, $name, $repository);
                        
                        $result = call_user_func([$repository, $relation->function]);

                        if ( count($result) === 0 ) {
                            return $baseEntity;
                        }

                        return $this->$name = $result[0];

                    case 'onetomany':
                        if ($relation->foreignKey) {
                            $repository->where( is_object($relation->foreignKey) ? $relation->foreignKey : $baseEntity->field($relation->foreignKey), is_callable($field) ? $field($this) : $this->$field );
                        }
                        $this->eventExecute(Event\EntityRelationLoadInterface::class, $name, $repository);

                        return $this->$name = call_user_func([$repository, $relation->function]);

                    case 'manytomany':
                        if ( false === $relation->bridge ?? false ) {
                            throw new \Exception("Your many-to-many @Relation() from variable `$name` is missing a 'bridge' value.");
                        }

                        $bridgeEntity = Ulmus::resolveEntity($relation->bridge);
                        $bridgeRelation = $bridgeEntity->searchFieldAnnotation($relation->field, new Relation() );
                        $relationRelation = $bridgeEntity->searchFieldAnnotation($relation->foreignField, new Relation() );

                        if ($relationRelation === null) {
                            throw new \Exception("@Relation annotation not found for field `{$relation->foreignField}` in entity {$relation->bridge}");
                        }

                        $repository = $relationRelation->entity()->repository();

                        $bridgeAlias = uniqid("bridge_");
                        $relationAlias = uniqid("relation_");

                        # @TODO Rewrite to be done here, this code must move somewhere else...
                        $repository->select("{$repository->alias}.*")
                            ->join(Query\Join::TYPE_INNER, $bridgeEntity->tableName(), $relation->bridge::field($relationRelation->key, $bridgeAlias), $relationRelation->entity::field($relationRelation->foreignKey), $bridgeAlias)
                            ->join(Query\Join::TYPE_INNER, $this->resolveEntity()->tableName(), $relation->bridge::field($bridgeRelation->key, $bridgeAlias), static::field($bridgeRelation->foreignKey, $relationAlias), $relationAlias)
                            ->where( static::field($bridgeRelation->foreignKey, $relationAlias), $this->{$bridgeRelation->foreignKey} );

                        foreach($where as $condition) {
                            $repository->where($condition->field, $condition->value, $condition->operator);
                        }

                        foreach($order as $item) {
                            $repository->orderBy($item->field, $item->order);
                        }

                        $this->eventExecute(Event\EntityRelationLoadInterface::class, $name, $repository);
                        
                        $this->$name = call_user_func([ $repository, $relationRelation->function ]);

                        if ($relation->bridgeField ?? false) {
                            $repository = $relationRelation->entity::repository();

                            $repository->select("$bridgeAlias.*")
                                ->join(Query\Join::TYPE_INNER, $bridgeEntity->tableName(), $relation->bridge::field($relationRelation->key, $bridgeAlias), $relationRelation->entity::field($relationRelation->foreignKey), $bridgeAlias)
                                ->join(Query\Join::TYPE_INNER, $this->resolveEntity()->tableName(), $relation->bridge::field($bridgeRelation->key, $bridgeAlias), static::field($bridgeRelation->foreignKey, $relationAlias), $relationAlias)
                                ->where( static::field($bridgeRelation->foreignKey, $relationAlias), $this->{$bridgeRelation->foreignKey} );

                            foreach($where as $condition) {
                                $repository->where($condition->field, $condition->value, $condition->operator);
                            }

                            foreach($order as $item) {
                                $repository->orderBy($item->field, $item->order);
                            }

                            $bridgeName = $relation->bridgeField;

                            $this->$bridgeName = $repository->collectionFromQuery($relation->bridge);
                        }

                        return $this->$name;
                }
            
                return;
            }
        }

        throw new \Exception(sprintf("[%s] - Undefined variable: %s", static::class, $name));
    }
    
    /**
     * @Ignore
     */
    public function __isset(string $name) : bool
    {
        if ( $this->isLoaded() && static::resolveEntity()->searchFieldAnnotation($name, new Relation() ) ) {
            return true;
        }

        return isset($this->$name);
    }
    
    /**
     * @Ignore
     */
    public function entityFillFromDataset(iterable $dataset, bool $isLoadedDataset = false) : self
    {
        $loaded = $this->isLoaded();
        
        $entityResolver = $this->resolveEntity();

        foreach($dataset as $key => $value) {
            $field = $entityResolver->field(strtolower($key), EntityResolver::KEY_COLUMN_NAME, false) ?? null;
            
            if ( $field === null ) {
                $field = $entityResolver->field($key, EntityResolver::KEY_ENTITY_NAME, false);
            } 
            
            if ( $field === null ) {
                if ($this->entityStrictFieldsDeclaration ) {
                    throw new \Exception("Field `$key` can not be found within your entity ".static::class);
                }
                else {
                    $this->entityDatasetUnmatchedFields[$key] = $value;
                }
            }
            elseif ( is_null($value) ) {
                $this->{$field['name']} = null;
            }
            elseif ( $field['type'] === 'array' ) {
                if ( is_string($value)) {
                    $this->{$field['name']} = substr($value, 0, 1) === "a" ? unserialize($value) : json_decode($value, true);
                }
                elseif ( is_array($value) ) {
                    $this->{$field['name']} = $value;
                }
            }
            elseif ( EntityField::isScalarType($field['type']) ) {

                if ( $field['type'] === 'string' ) {
                    $annotation = $entityResolver->searchFieldAnnotation($field['name'], new Field() );
                
                    if ( $annotation->length ?? null ) {
                        $value = substr($value, 0, $annotation->length);
                    }
                }
        
                $this->{$field['name']} = $value;
            }
            elseif ( ! $field['builtin'] ) {
                $this->{$field['name']} = Ulmus::instanciateObject($field['type'], [ $value ]);
            }
            
            # Keeping original data to diff on UPDATE query
            if ( ! $loaded || $isLoadedDataset ) {
                #if ( $field !== null ) {
                #    $annotation = $entityResolver->searchFieldAnnotation($field['name'], new Field() );
                #    $this->entityLoadedDataset[$annotation ? $annotation->name : $field['name']] = $dataset;       # <--------- THIS TO FIX !!!!!!
                #}
                $this->entityLoadedDataset = array_change_key_case($dataset, \CASE_LOWER);
            }
        }
        
        return $this;
    }

    public function resetVirtualProperties() : self
    {
        foreach($this->resolveEntity()->properties as $prop => $property) {
            if ( ! $property['builtin'] ) {
                foreach($property['tags'] as $tag) {
                    if ( in_array(strtolower($tag['tag']), [ 'relation', 'join' ] ) ) {
                        unset($this->$prop);
                    }
                }
            }
        }

        return $this;
    }
    
    /**
     * @Ignore
     */
    public function fromArray(iterable $dataset) : self
    {
        return $this->entityFillFromDataset($dataset);
    }
    
    /**
     * @Ignore
     */
    public function entityGetDataset(bool $includeRelations = false, bool $returnSource = false) : array
    {
        if ( $returnSource ) {
            return $this->entityLoadedDataset;
        }
        
        $dataset = [];
        
        $entityResolver = $this->resolveEntity();
        
        foreach($entityResolver->fieldList(Common\EntityResolver::KEY_ENTITY_NAME, true) as $key => $field) {
            $annotation = $entityResolver->searchFieldAnnotation($key, new Field() );

            if ( isset($this->$key) ) { 
                $realKey = $annotation->name ?? $key;
                
                switch (true) {
                    case is_object($this->$key):
                        $dataset[$realKey] = Ulmus::convertObject($this->$key);
                    break;
                        
                    case is_array($this->$key):    
                        $dataset[$realKey] = Ulmus::encodeArray($this->$key);
                    break;
                    
                    default:
                       $dataset[$realKey] = $this->$key;
                }
            }
            elseif ( $field['nullable'] ) {
                $dataset[ $annotation->name ?? $key ] = null;
            }
        }
        
        if ($includeRelations) {
            foreach($entityResolver->properties as $name => $field){
                $relation = $entityResolver->searchFieldAnnotation($name, new Relation() );
                
                if ( $relation && isset($this->$name) && ($relation->entity ?? $relation->bridge) !== static::class ) {
                    if ( null !== $value = $this->$name ?? null ) {
                        if ( is_iterable($value) ) {
                            $list = [];
                            
                            foreach($value as $entity) {
                                $list[] = $entity->entityGetDataset(false);
                            }
                            
                            $dataset[$name] = $list;
                        }
                        elseif ( is_object($value) ) {
                            $dataset[$name] = $value->entityGetDataset(false);
                        }
                    }
                }
            }
        }  
        
        return $dataset;
    }
    
    /**
     * @Ignore
     */
    public function toArray($includeRelations = false) : array
    {
        return $this->entityGetDataset($includeRelations);
    }
    
    /**
     * @Ignore
     */
    public function toCollection() : EntityCollection
    {
        return static::entityCollection([ $this->toArray() ]);
    }
    
    /**
     * @Ignore
     */
    public function isLoaded() : bool
    {
        if ( null === $pkField = $this->resolveEntity()->getPrimaryKeyField($this) ) {
            throw new Exception\EntityPrimaryKeyUnknown(sprintf("Entity %s has no field containing attributes 'primary_key'", static::class));
        }
        
        $key = key($pkField);
        
        return isset($this->$key);
    }

    /**
     * @Ignore
     */
    public function __sleep() 
    {
        return array_keys($this->resolveEntity()->fieldList());
    }
    
    /**
     * @Ignore
     */
    public function jsonSerialize()
    {
        return $this->entityGetDataset(); 
    }
    
    /**
     * @Ignore
     */
    public static function resolveEntity() : EntityResolver
    {
        return Ulmus::resolveEntity(static::class);
    }

    /**
     * @Ignore
     */
    public static function repository(string $alias = Repository::DEFAULT_ALIAS) : Repository
    {
        return Ulmus::repository(static::class, $alias);
    }

    /**
     * @Ignore
     */
    public static function entityCollection(...$arguments) : EntityCollection
    {
        $collection = new EntityCollection(...$arguments);
        $collection->entityClass = static::class;

        return $collection;
    }

    /**
     * @Ignore
     */
    public static function queryBuilder() : QueryBuilder
    {
        return Ulmus::queryBuilder(static::class);
    }

    /**
     * @Ignore
     */
    public static function field($name, ? string $alias = null) : EntityField
    {
        return new EntityField(static::class, $name, $alias ?: Repository::DEFAULT_ALIAS, Ulmus::resolveEntity(static::class));
    }

    /**
     * @Ignore
     */
    public static function fields(array $fields, ? string $alias = null) : string
    {
        return implode(', ', array_map(function($item) use ($alias){
            return static::field($item, $alias);
        }, $fields));
    }
}