<?php

namespace libs;

trait DataStorage {
	protected $changed_fields = [];
	protected int $id;

	public function get_id() :int {
		return $this -> id;
	}

	public static function get_tablename() :String {
		return self::$tablename;
	}

	public function get_chanched_fields() :Array {
		return $this -> changed_fields;
	}

	public function create_new() :int {
		if(count($this -> data_fields) != count($this -> data)) {
			return 0;
		}

		$fields = "`" . implode("`,`", array_keys($this -> data)) . "`";
		$values = "'" . implode("','", array_values($this -> data)) . "'";
		
		$tablename = self::get_tablename();
		$sql = "INSERT INTO `{$tablename}`({$fields}) VALUES ({$values})";
		$result = app() -> db() -> query($sql);

		$this -> id = app() -> db() -> last_insert_id();
		return $result;
	}

	public function init_by_field(String $field, $val) :bool {
		$tablename = self::get_tablename();
		$sql = "SELECT * FROM `{$tablename}` WHERE `{$field}`='{$val}'";
		$result = app() -> db() -> query($sql);

		if(!$result or !$result -> num_rows) {
			return false;
		}

    $this -> data = $result -> fetch_assoc();
    $this -> id = $this -> data["id"];

		return true;
	}

	public function update() :bool {
		!$this -> id and throw new \Exception("Tried updating of uninizialized object");

		if(!count($this -> changed_fields)) {
			return true;
		}

		$fields = [];
		
		foreach($this -> changed_fields as $field_name) {
			$fields[] = "`{$field_name}`='{$this -> data[$field_name]}'";
		}
		
		$fields = implode(",", $fields);

		$tablename = self::get_tablename();
		$sql = "UPDATE `{$tablename}` SET {$fields} WHERE `id`='{$this -> id}' LIMIT 1";
		return app() -> db() -> query($sql);
	}

	public function init_by_id(int $id) :bool {
		return $this -> init_by_field("id", $id);
	}

	public function remove() :bool {
		!$this -> id and throw new \Exception("Tried removing of uninizialized object");

		$tablename = self::get_tablename();
		$sql = "DELETE FROM `{$tablename}` WHERE `id`='{$this -> id}'";
		return app() -> db() -> query($sql);
	}
}