<?php

namespace cx_newsletter;

abstract class database_converter
implements database_converter_interface {
    public function __construct() {
        $this->target = null;
    }

    protected function check_target() : void {
        if ($this->target === null) {
            throw $this->not_loaded_exception();
        }

        if (!$this->target->is_complete()) {
            throw $this->not_complete_exception();
        }
    }

    protected function not_complete_exception() : \exception {
        $exception = "\n\n";
        $exception .= 'Item in the builder is not complete.';    
        $exception .= "\n\n";

        return new \exception($exception);      
    }

    protected function check_all_exists(array $target, array $list) : void {
        foreach ($list as $name) {
            if (!array_key_exists($name, $target)) {
                throw $this->not_found_exception($name);
            }
        }
    }

    protected function id_or_null(array $target, string $name = 'id') : ?int {
        if (array_key_exists($name, $target)) {
            return intval($target[$name]);
        }

        return null;
    }

    protected function not_loaded_exception() : \exception {
        $exception = "\n\n";
        $exception .= 'Any content had not being loaded to this converter.';
        $exception .= "\n\n";

        return new \exception($exception); 
    }

    protected function not_found_exception(string $name) : \exception {
        $exception = "\n\n";
        $exception .= 'Item with name "'.$name.'" not found.';
        $exception .= "\n\n";

        return new \exception($exception); 
    }

    public function load_object(object $target) : self {
        $this->target = $target;

        return $this;
    }

    public function get_object() : object {
        return $this->target;
    }

    protected function is_loaded() : bool {
        return $this->target !== null;
    }

    protected function string_from_date(?\datetime $what) : ?string {
        if ($what === null) {
            return null;
        }

        return $what->format(\datetimeinterface::RFC3339);
    }

    protected function date_or_null(?string $what) : ?\datetime {
        if ($what === null or strtoupper($what) === 'NULL') {
            return null;
        }
        
        $time = \datetime::createfromformat(
            'Y-m-d H:i:s',
            $what
        );
        
        if ($time === false) {
            return null;
        }
        
        return $time;
    }

    protected \exception $not_loaded_exception;
    protected ?object $target;
}