<?php

namespace Ulmus\Common;

use Ulmus\Annotation\Annotation,
    Ulmus\Annotation\Classes\Table,
    Ulmus\Annotation\Property\Field,
    Ulmus\Annotation\Property\Relation;

class EntityResolver {

    const KEY_ENTITY_NAME = 01;
    
    const KEY_COLUMN_NAME = 02;

    public string $entityClass;

    public array $uses;

    public array $class;

    public array $properties;

    public array $methods;
    
    protected array $fieldList = [];

    public function __construct(string $entityClass)
    {
        $this->entityClass = $entityClass;

        list($this->uses, $this->class, $this->methods, $this->properties) = array_values(
            ObjectReflection::fromClass($entityClass)->read()
        );
        
        $this->resolveAnnotations();
    }

    public function field($name, $fieldKey = self::KEY_ENTITY_NAME, $throwException = true) : ? array
    {
        try{
            return $this->fieldList($fieldKey)[$name];
        }
        catch(\Throwable $e) {
            if ( $throwException) {
                throw new \InvalidArgumentException("Can't find entity field's column named `$name` from entity {$this->entityClass}");   
            }
        }
        
        return null;
    }

    public function fieldList($fieldKey = self::KEY_ENTITY_NAME) : array
    {
        $fieldList = [];
        
        foreach($this->properties as $item) {
            foreach($item['tags'] ?? [] as $tag) {
                if ( $tag['object'] instanceof Field ) {
                    switch($fieldKey) {
                        case static::KEY_ENTITY_NAME:
                            $key = $item['name'];
                        break;

                        case static::KEY_COLUMN_NAME:
                            $key = strtolower($tag['object']->name ?? $item['name']);
                        break;

                        default:
                            throw new \InvalidArgumentException("Given `fieldKey` is unknown to the EntityResolver");
                    }

                    $fieldList[$key] = $item;
                    
                    break;
                }
            }
        }
        
        return $fieldList;
    }

    public function relation(string $name) : ? array
    {
        try{
            if ( null !== ( $this->properties[$name] ?? null ) ) {
                foreach($this->properties[$name]['tags'] ?? [] as $tag) {
                    if ( $tag['object'] instanceof Relation ) {
                        return $this->properties[$name];
                    }
                }
            }
            
            return [];
        }
        catch(\Throwable $e) {
            if ( $throwException) {
                throw new \InvalidArgumentException("Can't find entity relation's column named `$name` from entity {$this->entityClass}");   
            }
        }
        
        return null;
    }
    
    public function searchFieldAnnotation(string $field, Annotation $annotationType) : ? Annotation 
    {
        $found = $this->searchFieldAnnotationList($field, $annotationType);
        return $found ? $found[0] : null;
    }
    
    public function searchFieldAnnotationList(string $field, Annotation $annotationType) : array 
    {
        $list = [];
        
        if ( null !== ( $this->properties[$field] ?? null ) ) {
            foreach($this->properties[$field]['tags'] ?? [] as $tag) {
                if ( $tag['object'] instanceof $annotationType ) {
                    $list[] = $tag['object'];
                }
            }
        }
        
        return $list;
    }
    
    public function tableName() : string
    {
        if ( null === $table = $this->getAnnotationFromClassname( Table::class ) ) {
            throw new \LogicException("Your entity {$this->entityClass} seems to be missing a @Table() annotation");
        }

        if ( $table->name === "" ) {
            throw new \ArgumentCountError("Your entity {$this->entityClass} seems to be missing a `name` argument for your @Table() annotation");
        }

        return $table->name;
    }

    public function databaseAdapter() : ? \Ulmus\ConnectionAdapter
    {
        if ( null !== $table = $this->getAnnotationFromClassname( Table::class ) ) {
            if ( $table->adapter ?? null ) {
                if ( null === ( $adapter = \Ulmus\Ulmus::$registeredAdapters[$table->adapter] ?? null ) ) {
                    throw new \Exception("Requested database adapter ( {$table->adapter} ) is not registered.");
                }
                else {
                    return $adapter;
                }
            }
        }
        
        return null;
    }

    
    public function schemaName() : ? string
    {
        if ( null === $table = $this->getAnnotationFromClassname( Table::class ) ) {
            throw new \LogicException("Your entity {$this->entityClass} seems to be missing a @Table() annotation");
        }

        if ( $table->name === "" ) {
            throw new \ArgumentCountError("Your entity {$this->entityClass} seems to be missing a `schema` argument for your @Table() annotation");
        }

        return $table->schema ?? null;
    }

    public function getPrimaryKeyField() : ? array
    {
        foreach($this->fieldList() as $key => $value) {
            if ( null !== ( $field = $this->searchFieldAnnotation($key, new Field() ) ) ) {
                if ( false !== ( $field->attributes['primary_key'] ?? false ) ) {
                    return [ $key => $field ];
                }
            }
        }
        
        return null;
    }
    
    public function getCompoundKeyFields() : ? array
    {
        return null;
    }
    
    public function getUniqueFields() : ? array
    {
        return null;
    }

    /**
     * Transform an annotation into it's object's counterpart
     */
    public function getAnnotationFromClassname(string $className) : ? object
    {
        if ( $name = $this->uses[$className] ?? false ) {

            foreach(array_reverse($this->class['tags']) as $item) {
                if ( $item['tag'] === $name ) {
                    return $this->instanciateAnnotationObject($item);
                }

                foreach($this->properties as $item) {
                    foreach(array_reverse($item['tags']) as $item) {
                        if ( $item['tag'] === $name ) {
                            return $this->instanciateAnnotationObject($item);
                        }
                    }
                }

                foreach($this->methods as $item) {
                    foreach(array_reverse($item['tags']) as $item) {
                        if ( $item['tag'] === $name ) {
                            return $this->instanciateAnnotationObject($item);
                        }
                    }
                }
            }

            throw new \TypeError("Annotation `$className` could not be found within your object `{$this->entityClass}`");
        }
        else {
            throw new \InvalidArgumentException("Class `$className` was not found within {$this->entityClass} uses statement (or it's children / traits)");
        }

        return null;
    }

    public function instanciateAnnotationObject(array $tagDefinition) : Annotation
    {
        $arguments = $this->extractArguments($tagDefinition['arguments']);

        if ( false === $class = array_search($tagDefinition['tag'], $this->uses) ) {
            throw new \InvalidArgumentException("Annotation class `{$tagDefinition['tag']}` was not found within {$this->entityClass} uses statement (or it's children / traits)");
        }

        $obj = new $class(... $arguments['constructor']);

        foreach($arguments['setter'] as $key => $value) {
            $obj->$key = $value;
        }

        return $obj;
    }

    /**
     * Extracts arguments from an Annotation definition, easing object's declaration.
     */
    protected function extractArguments(array $arguments) : array
    {
        $list = [
            'setter' => [],
            'constructor' => [],
        ];

        ksort($arguments);

        foreach($arguments as $key => $value) {
            $list[ is_int($key) ? 'constructor' : 'setter' ][$key] = $value;
        }

        return $list;
    }

    protected function resolveAnnotations()
    {
        foreach($this->class['tags'] as &$tag) {
            $tag['object'] = $this->instanciateAnnotationObject($tag);
        }

        foreach($this->properties as &$property) {
            foreach($property['tags'] as &$tag){
                $tag['object'] = $this->instanciateAnnotationObject($tag);
            }
        }

        foreach($this->methods as &$method) {
            foreach($method['tags'] as &$tag){
                $tag['object'] = $this->instanciateAnnotationObject($tag);
            }
        }
    }
}