<?php

namespace Ulmus\Common;

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

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 = $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 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 primaryKeys() : array
    {

    }

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

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

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

                foreach($this->methods as $item) {
                    foreach($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);
            }
        }
    }
}