<?php
 
namespace App\Models;
 
use \App\Entity\Group;
 
class Groups {
	public function total_group_by_user(int $user_id) :int {
		$tablename = Group::get_tablename();
		$sql = "SELECT COUNT(*) FROM `{$tablename}` WHERE `user_id`='{$user_id}'";
 
		$result = app() -> db() -> query($sql);
		if(!$result) {
			return throw new \Exception("Error of db query");
		}
 
		$d = $result -> fetch_assoc();
		return $d["COUNT(*)"];
	}
 
	public function create_group(int $user_id, String $title, String $type) :Group {
		$group = new Group();
		
		$group -> user_id = $user_id;
		$group -> title = $title;
		$group -> type = $type;
		$group -> position = $this -> total_group_by_user($user_id) + 1;
		$group -> update_at = get_formatted_timestamp();
		$group -> create_at = get_formatted_timestamp();
 
		$group -> create_new();
 
		return $group;
	}
 
	public function get_groups_by_user_id(int $user_id) :Array {
		$tablename = Group::get_tablename();
		$sql = "SELECT * FROM `{$tablename}` WHERE `user_id`='{$user_id}' ORDER BY `position` ASC";
		$results = app() -> db() -> query($sql);
 
		if(!$results) {
			return throw new \Exception("Error of query to database");
		}	
 
		$groups = [];
 
		while($row = $results -> fetch_assoc()) {
			$groups[] = Group::instance_from_data($row);
		}
 
		return $groups;
	}
 
	public function change_group_position(int $group_id, int $new_position) :bool {
		$tablename = Group::get_tablename();
		$session = get_current_session();
		$groups = $session -> user() -> get_groups();
 
		list($selected_group) = array_values(array_filter($groups, function($group) use($group_id) {
			return $group -> get_id() == $group_id;
		}));
 
		$pos_min = min($selected_group -> position, $new_position);
		$pos_max = max($selected_group -> position, $new_position);
		$current_position = $selected_group->position;
 
		foreach($groups as $i => $group) {
			if($group -> position < $pos_min or $group -> position > $pos_max) {
				continue;
			}
 
			if($group -> get_id() == $group_id) {
				$group -> position = $new_position;
				continue;
			}
 
			if ($new_position > $current_position) {
				if ($group->position > $current_position && $group->position <= $new_position) {
					$group->position--;
				}
			} else {
				if ($group->position < $current_position && $group->position >= $new_position) {
					$group->position++;
				}
			}
		}
 
		array_map(function($group){
			$group -> update();
		}, $groups);
 
		return true;
	}
}