<?php

namespace Ulmus\Common;

abstract class Sql {

    public static function function($name, ...$arguments)
    {
        return new class($name, ...$arguments) {

            protected string $as = "";

            protected string $name;

            protected array $arguments;

            public function __construct( $name, ...$arguments) {
                $this->name = $name;
                $this->arguments = $arguments;
                $this->parseArguments();
            }

            public function __toString() {
                return implode(' ', array_filter([
                    "{$this->name}(" . implode(", ", $this->arguments) . ")",
                    $this->as ? "AS {$this->as}" : false,
                ]));
            }

            public function as($fieldName) {
                $this->as = $fieldName;
                return $this;
            }

            protected function parseArguments() {
                foreach($this->arguments as &$item) {
                    $item = Sql::escape($item);
                }
            }
        };
    }
    
    public static function identifier(string $identifier) : object
    {
        return new class($identifier) {
            
            protected string $identifier;
            
            public function __construct(string $identifier) {
                $this->identifier = $identifier;
            }
            
            public function __toString() {
                return $this->identifier;
            } 
        };
    }

    public static function escape($value)
    {
        switch(true) {
            case is_object($value):
                return (string) $value;

            case is_string($value):
                return "'$value'";

            case is_null($value):
                return "NULL";
        }

        return $value;
    }

    public static function parameter($value) : string
    {
        
    }
}