scaffold/src/Database/Model.php

<?php

	namespace vlw\Scaffold\Database;

	use vlw\Scaffold\Database\Database;

	require_once "Database.php";

	/**
	 * Abstract reading, creating, and updating of database entities.
	 */
	abstract class Model {
		public const DATE_FORMAT     = Database::DATE_FORMAT;
		public const DATETIME_FORMAT = Database::DATETIME_FORMAT;

		abstract public string $id { get; }

		protected readonly Database $db;
		private bool $_resolved = false;
		private bool $_isset;
		private ?array $_row;

		/**
		 * Insert values into a database table
		 *
		 * @param string $table The target database table
		 */
		protected static function create(string $table, array $values): bool {
			return new Database()->from($table)->insert($values);
		}

		/**
		 * Create a new Model to retrieve a specific entity
		 *
		 * @param string $table Target table where the entity is stored
		 * @param array<string> $columns An array of strings for each target database column
		 * @param array<array> $where vlw/MySQL->where() to locate the target entity
		 */
		public function __construct(
			public readonly string $table,
			public readonly array $columns,
			public readonly array $where
		) {
			$this->db = new Database();
		}

		/**
		 * Fetch and store column values for instanced row
		 *
		 * @return ?array<array> The column and value of each target database column
		 */
		private ?array $row {
			get {
				// Return existing row data
				if ($this->_resolved) { return $this->_row; }

				$this->_resolved = true;
				$this->_row = $this->db
					->from($this->table)
					->where($this->where)
					->limit(1)
					->select($this->columns)
					->fetch_assoc() ?? null;

				// Set isset property if property null
				$this->_isset ??= $this->_row !== null;
				return $this->_row;
			}
		}

		/**
		 * Returns true if instanced target ebity exists
		 *
		 * @return bool Entity exists
		 */
		public function isset(): bool {
			return $this->_isset ??= new Database()
				->from($this->table)
				->where($this->where)
				->limit(1)
				->select()
				->num_rows === 1;
		}

		/**
		 * Get current row column value
		 *
		 * @param string $key Target column
		 * @return mixed Value of target column
		 */
		public function get(string $key): mixed {
			return $this->row[$key] ?? null;
		}

		/**
		 * Update current row column with value
		 *
		 * @param string $key Target column to update
		 * @param mixed $value New value of target column
		 * @return bool Update was successful
		 */
		public function set(string $key, mixed $value): bool {
			$this->_row[$key] = $value;

			return $this->db
				->from($this->table)
				->where($this->where)
				->update([$key => $value]);
		}
	}