<?php

namespace Nest\Database\Query\Where;

use Nest\Database\Exceptions\Query\NoPrimaryFieldException;
use Nest\Model\Entities;
use Nest\Model\Entity;

/**
 * Add where capacity to a query builder.
 */
trait HasWhere
{
	/**
	 * Conditions in where clause.
	 * @var ConditionBuilder[]
	 */
	protected array $wheres = [];

	/**
	 * Reset WHERE conditions.
	 * @return $this
	 */
	public function resetWheres(): static
	{
		$this->wheres = [];
		return $this;
	}

	/**
	 * Add a where condition.
	 * @param string|callable $column The column of the condition, or a condition builder callable.
	 * @param mixed|null $operator The operator of the condition (or the value if no value is passed).
	 * @param mixed|null $value The value of the condition.
	 * @return $this
	 */
	public function where(string|callable $column, mixed $operator = null, mixed $value = null): static
	{
		if (is_callable($column))
		{ // Callable condition builder.
			$this->wheres[] = $column(new ConditionBuilder());
		}
		else
		{ // Simple condition, registering it.
			if (!empty($operator) && empty($value))
			{ // If there are 2 parameters, considering the second one as the value, with default operator.
				$value = $operator;
				$operator = null;
			}

			if (!empty($value))
			{ // A value is defined.
				// Default operator: "=".
				if (empty($operator)) $operator = "=";

				// Create the simple condition.
				$this->wheres[] = (new ConditionBuilder())->column($column)->operator($operator)->value($value);
			}
			else
			{ // No value is given, considering a simple existence check.
				$this->whereExists($column);
			}
		}

		return $this;
	}

	/**
	 * Add a where IN condition.
	 * @param string $column The column of the condition.
	 * @param array $values The values of the condition.
	 * @return $this
	 */
	public function whereIn(string $column, array $values): static
	{
		return $this->where($column, "IN", $values);
	}

	/**
	 * Add a where condition on a column as a value.
	 * @param string $column The column of the condition.
	 * @param string $operator The operator of the condition (or the value column if no value is passed).
	 * @param string|null $valueColumn The value column of the condition.
	 * @return $this
	 */
	public function whereColumn(string $column, string $operator, ?string $valueColumn = null): static
	{
		if (!empty($operator) && empty($valueColumn))
		{ // If there are 2 parameters, considering the second one as the value, with default operator.
			$valueColumn = $operator;
			$operator = "=";
		}

		// Create the simple condition.
		$this->wheres[] = (new ConditionBuilder())->column($column)->operator($operator)->column($valueColumn);

		return $this;
	}

	/**
	 * Add a where exists condition.
	 * @param string $column The column to check for existence.
	 * @return $this
	 */
	public function whereExists(string $column): static
	{
		// Create an existence check.
		$this->wheres[] = (new ConditionBuilder())->column($column)->exists();
		return $this;
	}

	/**
	 * Add condition to find given entities.
	 * @param Entity|Entities $entities Entity or entities to find.
	 * @return $this
	 * @throws NoPrimaryFieldException
	 */
	public function whereKeyOf(Entity|Entities $entities): static
	{
		// Normalize parameter to a simple entities array.
		if ($entities instanceof Entities)
			$entitiesArray = $entities->get();
		else
			$entitiesArray = [$entities];

		// Initialize entities conditions.
		$entitiesConditions = [];
		foreach ($entitiesArray as $entity)
		{ // Add condition for each entity to find.
			// Get current entity primary fields and normalize it to an array.
			$primaryFields = $entity->getPrimaryFields();
			if (!is_array($primaryFields)) $primaryFields = [$primaryFields];

			if (empty($primaryFields))
				// If there are no primary fields, thrown an exception to ensure not to do something on EVERY rows.
				throw new NoPrimaryFieldException($entity);

			// Create conditions for current entity.
			$entityConditions = [];
			foreach ($primaryFields as $primaryField)
				// Create a condition builder for each field.
				$entityConditions[] = fn (ConditionBuilder $condition) =>
					$condition->column($primaryField)->equals()->value($entity->$primaryField);

			// Add the full entity condition to the entities conditions array.
			$entitiesConditions[] = fn (ConditionBuilder $condition) => $condition->and(...$entityConditions);
		}

		// Add condition to match every entities.
		return $this->where(fn (ConditionBuilder $condition) => (
			$condition->or(...$entitiesConditions)
		));
	}
}