<?php namespace Illuminate\Database\Eloquent;

class SoftDeletingScope implements ScopeInterface {

	/**
	 * All of the extensions to be added to the builder.
	 *
	 * @var array
	 */
	protected $extensions = ['ForceDelete', 'Restore', 'WithTrashed', 'OnlyTrashed'];

	/**
	 * Apply the scope to a given Eloquent query builder.
	 *
	 * @param  \Illuminate\Database\Eloquent\Builder  $builder
	 * @return void
	 */
	public function apply(Builder $builder)
	{
		$model = $builder->getModel();

		$builder->whereNull($model->getQualifiedDeletedAtColumn());

		$this->extend($builder);
	}

	/**
	 * Remove the scope from the given Eloquent query builder.
	 *
	 * @param  \Illuminate\Database\Eloquent\Builder  $builder
	 * @return void
	 */
	public function remove(Builder $builder)
	{
		$column = $builder->getModel()->getQualifiedDeletedAtColumn();

		$query = $builder->getQuery();

		foreach ((array) $query->wheres as $key => $where)
		{
			// If the where clause is a soft delete date constraint, we will remove it from
			// the query and reset the keys on the wheres. This allows this developer to
			// include deleted model in a relationship result set that is lazy loaded.
			if ($this->isSoftDeleteConstraint($where, $column))
			{
				unset($query->wheres[$key]);

				$query->wheres = array_values($query->wheres);
			}
		}
	}

	/**
	 * Extend the query builder with the needed functions.
	 *
	 * @param  \Illuminate\Database\Eloquent\Builder  $builder
	 * @return void
	 */
	public function extend(Builder $builder)
	{
		foreach ($this->extensions as $extension)
		{
			$this->{"add{$extension}"}($builder);
		}

		$builder->onDelete(function(Builder $builder)
		{
			$column = $this->getDeletedAtColumn($builder);

			return $builder->update(array(
				$column => $builder->getModel()->freshTimestampString()
			));
		});
	}

	/**
	 * Get the "deleted at" column for the builder.
	 *
	 * @param  \Illuminate\Database\Eloquent\Builder  $builder
	 * @return string
	 */
	protected function getDeletedAtColumn(Builder $builder)
	{
		if (count($builder->getQuery()->joins) > 0)
		{
			return $builder->getModel()->getQualifiedDeletedAtColumn();
		}
		else
		{
			return $builder->getModel()->getDeletedAtColumn();
		}
	}

	/**
	 * Add the force delete extension to the builder.
	 *
	 * @param  \Illuminate\Database\Eloquent\Builder  $builder
	 * @return void
	 */
	protected function addForceDelete(Builder $builder)
	{
		$builder->macro('forceDelete', function(Builder $builder)
		{
			return $builder->getQuery()->delete();
		});
	}

	/**
	 * Add the restore extension to the builder.
	 *
	 * @param  \Illuminate\Database\Eloquent\Builder  $builder
	 * @return void
	 */
	protected function addRestore(Builder $builder)
	{
		$builder->macro('restore', function(Builder $builder)
		{
			$builder->withTrashed();

			return $builder->update(array($builder->getModel()->getDeletedAtColumn() => null));
		});
	}

	/**
	 * Add the with-trashed extension to the builder.
	 *
	 * @param  \Illuminate\Database\Eloquent\Builder  $builder
	 * @return void
	 */
	protected function addWithTrashed(Builder $builder)
	{
		$builder->macro('withTrashed', function(Builder $builder)
		{
			$this->remove($builder);

			return $builder;
		});
	}

	/**
	 * Add the only-trashed extension to the builder.
	 *
	 * @param  \Illuminate\Database\Eloquent\Builder  $builder
	 * @return void
	 */
	protected function addOnlyTrashed(Builder $builder)
	{
		$builder->macro('onlyTrashed', function(Builder $builder)
		{
			$this->remove($builder);

			$builder->getQuery()->whereNotNull($builder->getModel()->getQualifiedDeletedAtColumn());

			return $builder;
		});
	}

	/**
	 * Determine if the given where clause is a soft delete constraint.
	 *
	 * @param  array   $where
	 * @param  string  $column
	 * @return bool
	 */
	protected function isSoftDeleteConstraint(array $where, $column)
	{
		return $where['type'] == 'Null' && $where['column'] == $column;
	}

}