<?php

namespace Nest\Database\Query;

use Nest\Database\Database;
use Nest\Database\Query\Join\HasJoin;
use Nest\Database\Query\Where\HasWhere;
use Nest\Database\Exceptions\Query\MissingConditionValueException;

/**
 * Builder of a SELECT query.
 */
class SelectQuery
{
	use HasJoin;
	use HasWhere;

	/**
	 * Selected columns.
	 * @var (Raw|string)[]
	 */
	protected array $selected = [];

	/**
	 * Limit of results to get.
	 * NULL = no limit.
	 * @var int|null
	 */
	protected ?int $limit = null;

	/**
	 * Create a new SELECT query.
	 * @param Database $database The database on which to execute the query.
	 * @param string $table Base table of the SELECT query.
	 */
	public function __construct(protected Database $database, protected string $table)
	{}

	/**
	 * Get the database on which to execute the query.
	 * @return Database
	 */
	public function getDatabase(): Database
	{
		return $this->database;
	}

	/**
	 * Get retrieved table name.
	 * @return string Selected table name.
	 */
	public function getTableName(): string
	{
		return $this->table;
	}

	/**
	 * Reset selected columns.
	 * @return $this
	 */
	public function resetSelect(): static
	{
		$this->selected = [];
		return $this;
	}

	/**
	 * Add selected columns.
	 * @param string|Raw ...$selectedColumns Selected columns.
	 * @return $this
	 */
	public function select(string|Raw ...$selectedColumns): static
	{
		// Append SELECTed columns.
		array_push($this->selected, ...$selectedColumns);
		return $this;
	}

	/**
	 * Add raw selected SQL.
	 * @param string ...$rawSelect Raw selected SQL.
	 * @return $this
	 */
	public function selectRaw(string ...$rawSelect): static
	{
		// Append raw SQL SELECT.
		array_push($this->selected, ...array_map(fn (string $rawSql) => new Raw($rawSql), $rawSelect));
		return $this;
	}

	/**
	 * Set the new limit of results.
	 * @param int|null $limit Limit of retrieved results. NULL to remove the limit.
	 * @return $this
	 */
	public function limit(?int $limit): static
	{
		$this->limit = $limit;
		return $this;
	}

	/**
	 * Build SELECT query.
	 * @return Raw SQL and its bindings.
	 * @throws MissingConditionValueException
	 */
	public function build(): Raw
	{
		// Build SELECT query and return its result.
		return $this->database->getQueriesAdapter()->buildSelect($this->table,
			// Select all columns by default.
			empty($this->selected) ? [new Raw("*")] : $this->selected,
			$this->joins,
			$this->wheres,
			$this->limit,
		);
	}

	/**
	 * Execute SELECT query.
	 * @return object[] SELECT query result.
	 * @throws MissingConditionValueException
	 */
	public function execute(): array
	{
		// Execute built query and return result.
		return $this->database->getQueriesAdapter()->select($this->table,
			// Select all columns by default.
			empty($this->selected) ? [new Raw("*")] : $this->selected,
			$this->joins,
			$this->wheres,
			$this->limit,
		);
	}
}