<?php

namespace Illuminate\Database\Eloquent;

use Closure;
use Illuminate\Support\Arr;
use Illuminate\Support\Str;
use Illuminate\Pagination\Paginator;
use Illuminate\Database\Query\Expression;
use Illuminate\Pagination\LengthAwarePaginator;
use Illuminate\Database\Eloquent\Relations\Relation;
use Illuminate\Database\Query\Builder as QueryBuilder;

class Builder
{
    /**
     * The base query builder instance.
     *
     * @var \Illuminate\Database\Query\Builder
     */
    protected $query;

    /**
     * The model being queried.
     *
     * @var \Illuminate\Database\Eloquent\Model
     */
    protected $model;

    /**
     * The relationships that should be eager loaded.
     *
     * @var array
     */
    protected $eagerLoad = [];

    /**
     * All of the registered builder macros.
     *
     * @var array
     */
    protected $macros = [];

    /**
     * A replacement for the typical delete function.
     *
     * @var \Closure
     */
    protected $onDelete;

    /**
     * The methods that should be returned from query builder.
     *
     * @var array
     */
    protected $passthru = [
        'insert', 'insertGetId', 'getBindings', 'toSql',
        'exists', 'count', 'min', 'max', 'avg', 'sum', 'getConnection',
    ];

    /**
     * Applied global scopes.
     *
     * @var array
     */
    protected $scopes = [];

    /**
     * Removed global scopes.
     *
     * @var array
     */
    protected $removedScopes = [];

    /**
     * Create a new Eloquent query builder instance.
     *
     * @param  \Illuminate\Database\Query\Builder  $query
     * @return void
     */
    public function __construct(QueryBuilder $query)
    {
        $this->query = $query;
    }

    /**
     * Register a new global scope.
     *
     * @param  string  $identifier
     * @param  \Illuminate\Database\Eloquent\Scope|\Closure  $scope
     * @return $this
     */
    public function withGlobalScope($identifier, $scope)
    {
        $this->scopes[$identifier] = $scope;

        if (method_exists($scope, 'extend')) {
            $scope->extend($this);
        }

        return $this;
    }

    /**
     * Remove a registered global scope.
     *
     * @param  \Illuminate\Database\Eloquent\Scope|string  $scope
     * @return $this
     */
    public function withoutGlobalScope($scope)
    {
        if (! is_string($scope)) {
            $scope = get_class($scope);
        }

        unset($this->scopes[$scope]);

        $this->removedScopes[] = $scope;

        return $this;
    }

    /**
     * Remove all or passed registered global scopes.
     *
     * @param  array|null  $scopes
     * @return $this
     */
    public function withoutGlobalScopes(array $scopes = null)
    {
        if (is_array($scopes)) {
            foreach ($scopes as $scope) {
                $this->withoutGlobalScope($scope);
            }
        } else {
            $this->scopes = [];
        }

        return $this;
    }

    /**
     * Get an array of global scopes that were removed from the query.
     *
     * @return array
     */
    public function removedScopes()
    {
        return $this->removedScopes;
    }

    /**
     * Find a model by its primary key.
     *
     * @param  mixed  $id
     * @param  array  $columns
     * @return \Illuminate\Database\Eloquent\Model|\Illuminate\Database\Eloquent\Collection|static[]|static|null
     */
    public function find($id, $columns = ['*'])
    {
        if (is_array($id)) {
            return $this->findMany($id, $columns);
        }

        $this->query->where($this->model->getQualifiedKeyName(), '=', $id);

        return $this->first($columns);
    }

    /**
     * Find multiple models by their primary keys.
     *
     * @param  array  $ids
     * @param  array  $columns
     * @return \Illuminate\Database\Eloquent\Collection
     */
    public function findMany($ids, $columns = ['*'])
    {
        if (empty($ids)) {
            return $this->model->newCollection();
        }

        $this->query->whereIn($this->model->getQualifiedKeyName(), $ids);

        return $this->get($columns);
    }

    /**
     * Find a model by its primary key or throw an exception.
     *
     * @param  mixed  $id
     * @param  array  $columns
     * @return \Illuminate\Database\Eloquent\Model|\Illuminate\Database\Eloquent\Collection
     *
     * @throws \Illuminate\Database\Eloquent\ModelNotFoundException
     */
    public function findOrFail($id, $columns = ['*'])
    {
        $result = $this->find($id, $columns);

        if (is_array($id)) {
            if (count($result) == count(array_unique($id))) {
                return $result;
            }
        } elseif (! is_null($result)) {
            return $result;
        }

        throw (new ModelNotFoundException)->setModel(get_class($this->model));
    }

    /**
     * Find a model by its primary key or return fresh model instance.
     *
     * @param  mixed  $id
     * @param  array  $columns
     * @return \Illuminate\Database\Eloquent\Model
     */
    public function findOrNew($id, $columns = ['*'])
    {
        if (! is_null($model = $this->find($id, $columns))) {
            return $model;
        }

        return $this->model->newInstance();
    }

    /**
     * Get the first record matching the attributes or instantiate it.
     *
     * @param  array  $attributes
     * @return \Illuminate\Database\Eloquent\Model
     */
    public function firstOrNew(array $attributes)
    {
        if (! is_null($instance = $this->where($attributes)->first())) {
            return $instance;
        }

        return $this->model->newInstance($attributes);
    }

    /**
     * Get the first record matching the attributes or create it.
     *
     * @param  array  $attributes
     * @return \Illuminate\Database\Eloquent\Model
     */
    public function firstOrCreate(array $attributes)
    {
        if (! is_null($instance = $this->where($attributes)->first())) {
            return $instance;
        }

        $instance = $this->model->newInstance($attributes);

        $instance->save();

        return $instance;
    }

    /**
     * Create or update a record matching the attributes, and fill it with values.
     *
     * @param  array  $attributes
     * @param  array  $values
     * @return \Illuminate\Database\Eloquent\Model
     */
    public function updateOrCreate(array $attributes, array $values = [])
    {
        $instance = $this->firstOrNew($attributes);

        $instance->fill($values)->save();

        return $instance;
    }

    /**
     * Execute the query and get the first result.
     *
     * @param  array  $columns
     * @return \Illuminate\Database\Eloquent\Model|static|null
     */
    public function first($columns = ['*'])
    {
        return $this->take(1)->get($columns)->first();
    }

    /**
     * Execute the query and get the first result or throw an exception.
     *
     * @param  array  $columns
     * @return \Illuminate\Database\Eloquent\Model|static
     *
     * @throws \Illuminate\Database\Eloquent\ModelNotFoundException
     */
    public function firstOrFail($columns = ['*'])
    {
        if (! is_null($model = $this->first($columns))) {
            return $model;
        }

        throw (new ModelNotFoundException)->setModel(get_class($this->model));
    }

    /**
     * Execute the query as a "select" statement.
     *
     * @param  array  $columns
     * @return \Illuminate\Database\Eloquent\Collection|static[]
     */
    public function get($columns = ['*'])
    {
        $builder = $this->applyScopes();

        $models = $builder->getModels($columns);

        // If we actually found models we will also eager load any relationships that
        // have been specified as needing to be eager loaded, which will solve the
        // n+1 query issue for the developers to avoid running a lot of queries.
        if (count($models) > 0) {
            $models = $builder->eagerLoadRelations($models);
        }

        return $builder->getModel()->newCollection($models);
    }

    /**
     * Get a single column's value from the first result of a query.
     *
     * @param  string  $column
     * @return mixed
     */
    public function value($column)
    {
        $result = $this->first([$column]);

        if ($result) {
            return $result->{$column};
        }
    }

    /**
     * Chunk the results of the query.
     *
     * @param  int  $count
     * @param  callable  $callback
     * @return bool
     */
    public function chunk($count, callable $callback)
    {
        $results = $this->forPage($page = 1, $count)->get();

        while (count($results) > 0) {
            // On each chunk result set, we will pass them to the callback and then let the
            // developer take care of everything within the callback, which allows us to
            // keep the memory low for spinning through large result sets for working.
            if (call_user_func($callback, $results) === false) {
                return false;
            }

            $page++;

            $results = $this->forPage($page, $count)->get();
        }

        return true;
    }

    /**
     * Chunk the results of a query by comparing numeric IDs.
     *
     * @param  int  $count
     * @param  callable  $callback
     * @param  string  $column
     * @return bool
     */
    public function chunkById($count, callable $callback, $column = 'id')
    {
        $lastId = null;

        $results = $this->forPageAfterId($count, 0, $column)->get();

        while (! $results->isEmpty()) {
            if (call_user_func($callback, $results) === false) {
                return false;
            }

            $lastId = $results->last()->{$column};

            $results = $this->forPageAfterId($count, $lastId, $column)->get();
        }

        return true;
    }

    /**
     * Execute a callback over each item while chunking.
     *
     * @param  callable  $callback
     * @param  int  $count
     * @return bool
     */
    public function each(callable $callback, $count = 1000)
    {
        if (is_null($this->query->orders) && is_null($this->query->unionOrders)) {
            $this->orderBy($this->model->getQualifiedKeyName(), 'asc');
        }

        return $this->chunk($count, function ($results) use ($callback) {
            foreach ($results as $key => $value) {
                if ($callback($value, $key) === false) {
                    return false;
                }
            }
        });
    }

    /**
     * Get an array with the values of a given column.
     *
     * @param  string  $column
     * @param  string|null  $key
     * @return \Illuminate\Support\Collection
     */
    public function pluck($column, $key = null)
    {
        $results = $this->toBase()->pluck($column, $key);

        // If the model has a mutator for the requested column, we will spin through
        // the results and mutate the values so that the mutated version of these
        // columns are returned as you would expect from these Eloquent models.
        if ($this->model->hasGetMutator($column)) {
            foreach ($results as $key => &$value) {
                $fill = [$column => $value];

                $value = $this->model->newFromBuilder($fill)->$column;
            }
        }

        return collect($results);
    }

    /**
     * Alias for the "pluck" method.
     *
     * @param  string  $column
     * @param  string  $key
     * @return \Illuminate\Support\Collection
     *
     * @deprecated since version 5.2. Use the "pluck" method directly.
     */
    public function lists($column, $key = null)
    {
        return $this->pluck($column, $key);
    }

    /**
     * Paginate the given query.
     *
     * @param  int  $perPage
     * @param  array  $columns
     * @param  string  $pageName
     * @param  int|null  $page
     * @return \Illuminate\Contracts\Pagination\LengthAwarePaginator
     *
     * @throws \InvalidArgumentException
     */
    public function paginate($perPage = null, $columns = ['*'], $pageName = 'page', $page = null)
    {
        $query = $this->toBase();

        $total = $query->getCountForPagination();

        $this->forPage(
            $page = $page ?: Paginator::resolveCurrentPage($pageName),
            $perPage = $perPage ?: $this->model->getPerPage()
        );

        return new LengthAwarePaginator($this->get($columns), $total, $perPage, $page, [
            'path' => Paginator::resolveCurrentPath(),
            'pageName' => $pageName,
        ]);
    }

    /**
     * Paginate the given query into a simple paginator.
     *
     * @param  int  $perPage
     * @param  array  $columns
     * @param  string  $pageName
     * @param  int|null  $page
     * @return \Illuminate\Contracts\Pagination\Paginator
     */
    public function simplePaginate($perPage = null, $columns = ['*'], $pageName = 'page', $page = null)
    {
        $page = $page ?: Paginator::resolveCurrentPage($pageName);

        $perPage = $perPage ?: $this->model->getPerPage();

        $this->skip(($page - 1) * $perPage)->take($perPage + 1);

        return new Paginator($this->get($columns), $perPage, $page, [
            'path' => Paginator::resolveCurrentPath(),
            'pageName' => $pageName,
        ]);
    }

    /**
     * Update a record in the database.
     *
     * @param  array  $values
     * @return int
     */
    public function update(array $values)
    {
        return $this->toBase()->update($this->addUpdatedAtColumn($values));
    }

    /**
     * Increment a column's value by a given amount.
     *
     * @param  string  $column
     * @param  int  $amount
     * @param  array  $extra
     * @return int
     */
    public function increment($column, $amount = 1, array $extra = [])
    {
        $extra = $this->addUpdatedAtColumn($extra);

        return $this->toBase()->increment($column, $amount, $extra);
    }

    /**
     * Decrement a column's value by a given amount.
     *
     * @param  string  $column
     * @param  int  $amount
     * @param  array  $extra
     * @return int
     */
    public function decrement($column, $amount = 1, array $extra = [])
    {
        $extra = $this->addUpdatedAtColumn($extra);

        return $this->toBase()->decrement($column, $amount, $extra);
    }

    /**
     * Add the "updated at" column to an array of values.
     *
     * @param  array  $values
     * @return array
     */
    protected function addUpdatedAtColumn(array $values)
    {
        if (! $this->model->usesTimestamps()) {
            return $values;
        }

        $column = $this->model->getUpdatedAtColumn();

        return Arr::add($values, $column, $this->model->freshTimestampString());
    }

    /**
     * Delete a record from the database.
     *
     * @return mixed
     */
    public function delete()
    {
        if (isset($this->onDelete)) {
            return call_user_func($this->onDelete, $this);
        }

        return $this->toBase()->delete();
    }

    /**
     * Run the default delete function on the builder.
     *
     * @return mixed
     */
    public function forceDelete()
    {
        return $this->query->delete();
    }

    /**
     * Register a replacement for the default delete function.
     *
     * @param  \Closure  $callback
     * @return void
     */
    public function onDelete(Closure $callback)
    {
        $this->onDelete = $callback;
    }

    /**
     * Get the hydrated models without eager loading.
     *
     * @param  array  $columns
     * @return \Illuminate\Database\Eloquent\Model[]
     */
    public function getModels($columns = ['*'])
    {
        $results = $this->query->get($columns);

        $connection = $this->model->getConnectionName();

        return $this->model->hydrate($results, $connection)->all();
    }

    /**
     * Eager load the relationships for the models.
     *
     * @param  array  $models
     * @return array
     */
    public function eagerLoadRelations(array $models)
    {
        foreach ($this->eagerLoad as $name => $constraints) {
            // For nested eager loads we'll skip loading them here and they will be set as an
            // eager load on the query to retrieve the relation so that they will be eager
            // loaded on that query, because that is where they get hydrated as models.
            if (strpos($name, '.') === false) {
                $models = $this->loadRelation($models, $name, $constraints);
            }
        }

        return $models;
    }

    /**
     * Eagerly load the relationship on a set of models.
     *
     * @param  array  $models
     * @param  string  $name
     * @param  \Closure  $constraints
     * @return array
     */
    protected function loadRelation(array $models, $name, Closure $constraints)
    {
        // First we will "back up" the existing where conditions on the query so we can
        // add our eager constraints. Then we will merge the wheres that were on the
        // query back to it in order that any where conditions might be specified.
        $relation = $this->getRelation($name);

        $relation->addEagerConstraints($models);

        call_user_func($constraints, $relation);

        $models = $relation->initRelation($models, $name);

        // Once we have the results, we just match those back up to their parent models
        // using the relationship instance. Then we just return the finished arrays
        // of models which have been eagerly hydrated and are readied for return.
        $results = $relation->getEager();

        return $relation->match($models, $results, $name);
    }

    /**
     * Get the relation instance for the given relation name.
     *
     * @param  string  $name
     * @return \Illuminate\Database\Eloquent\Relations\Relation
     */
    public function getRelation($name)
    {
        // We want to run a relationship query without any constrains so that we will
        // not have to remove these where clauses manually which gets really hacky
        // and is error prone while we remove the developer's own where clauses.
        $relation = Relation::noConstraints(function () use ($name) {
            return $this->getModel()->$name();
        });

        $nested = $this->nestedRelations($name);

        // If there are nested relationships set on the query, we will put those onto
        // the query instances so that they can be handled after this relationship
        // is loaded. In this way they will all trickle down as they are loaded.
        if (count($nested) > 0) {
            $relation->getQuery()->with($nested);
        }

        return $relation;
    }

    /**
     * Get the deeply nested relations for a given top-level relation.
     *
     * @param  string  $relation
     * @return array
     */
    protected function nestedRelations($relation)
    {
        $nested = [];

        // We are basically looking for any relationships that are nested deeper than
        // the given top-level relationship. We will just check for any relations
        // that start with the given top relations and adds them to our arrays.
        foreach ($this->eagerLoad as $name => $constraints) {
            if ($this->isNested($name, $relation)) {
                $nested[substr($name, strlen($relation.'.'))] = $constraints;
            }
        }

        return $nested;
    }

    /**
     * Determine if the relationship is nested.
     *
     * @param  string  $name
     * @param  string  $relation
     * @return bool
     */
    protected function isNested($name, $relation)
    {
        $dots = Str::contains($name, '.');

        return $dots && Str::startsWith($name, $relation.'.');
    }

    /**
     * Add a basic where clause to the query.
     *
     * @param  string  $column
     * @param  string  $operator
     * @param  mixed   $value
     * @param  string  $boolean
     * @return $this
     */
    public function where($column, $operator = null, $value = null, $boolean = 'and')
    {
        if ($column instanceof Closure) {
            $query = $this->model->newQueryWithoutScopes();

            call_user_func($column, $query);

            $this->query->addNestedWhereQuery($query->getQuery(), $boolean);
        } else {
            call_user_func_array([$this->query, 'where'], func_get_args());
        }

        return $this;
    }

    /**
     * Add an "or where" clause to the query.
     *
     * @param  string  $column
     * @param  string  $operator
     * @param  mixed   $value
     * @return \Illuminate\Database\Eloquent\Builder|static
     */
    public function orWhere($column, $operator = null, $value = null)
    {
        return $this->where($column, $operator, $value, 'or');
    }

    /**
     * Add a relationship count / exists condition to the query.
     *
     * @param  string  $relation
     * @param  string  $operator
     * @param  int     $count
     * @param  string  $boolean
     * @param  \Closure|null  $callback
     * @return \Illuminate\Database\Eloquent\Builder|static
     */
    public function has($relation, $operator = '>=', $count = 1, $boolean = 'and', Closure $callback = null)
    {
        if (strpos($relation, '.') !== false) {
            return $this->hasNested($relation, $operator, $count, $boolean, $callback);
        }

        $relation = $this->getHasRelationQuery($relation);

        // If we only need to check for the existence of the relation, then we can
        // optimize the subquery to only run a "where exists" clause instead of
        // the full "count" clause. This will make the query run much faster.
        $queryType = $this->shouldRunExistsQuery($operator, $count)
                ? 'getRelationQuery' : 'getRelationCountQuery';

        $query = $relation->{$queryType}($relation->getRelated()->newQuery(), $this);

        if ($callback) {
            call_user_func($callback, $query);
        }

        return $this->addHasWhere(
            $query, $relation, $operator, $count, $boolean
        );
    }

    /**
     * Add nested relationship count / exists conditions to the query.
     *
     * @param  string  $relations
     * @param  string  $operator
     * @param  int     $count
     * @param  string  $boolean
     * @param  \Closure|null  $callback
     * @return \Illuminate\Database\Eloquent\Builder|static
     */
    protected function hasNested($relations, $operator = '>=', $count = 1, $boolean = 'and', $callback = null)
    {
        $relations = explode('.', $relations);

        // In order to nest "has", we need to add count relation constraints on the
        // callback Closure. We'll do this by simply passing the Closure its own
        // reference to itself so it calls itself recursively on each segment.
        $closure = function ($q) use (&$closure, &$relations, $operator, $count, $boolean, $callback) {
            if (count($relations) > 1) {
                $q->whereHas(array_shift($relations), $closure);
            } else {
                $q->has(array_shift($relations), $operator, $count, 'and', $callback);
            }
        };

        return $this->has(array_shift($relations), '>=', 1, $boolean, $closure);
    }

    /**
     * Add a relationship count / exists condition to the query.
     *
     * @param  string  $relation
     * @param  string  $boolean
     * @param  \Closure|null  $callback
     * @return \Illuminate\Database\Eloquent\Builder|static
     */
    public function doesntHave($relation, $boolean = 'and', Closure $callback = null)
    {
        return $this->has($relation, '<', 1, $boolean, $callback);
    }

    /**
     * Add a relationship count / exists condition to the query with where clauses.
     *
     * @param  string    $relation
     * @param  \Closure  $callback
     * @param  string    $operator
     * @param  int       $count
     * @return \Illuminate\Database\Eloquent\Builder|static
     */
    public function whereHas($relation, Closure $callback, $operator = '>=', $count = 1)
    {
        return $this->has($relation, $operator, $count, 'and', $callback);
    }

    /**
     * Add a relationship count / exists condition to the query with where clauses.
     *
     * @param  string  $relation
     * @param  \Closure|null  $callback
     * @return \Illuminate\Database\Eloquent\Builder|static
     */
    public function whereDoesntHave($relation, Closure $callback = null)
    {
        return $this->doesntHave($relation, 'and', $callback);
    }

    /**
     * Add a relationship count / exists condition to the query with an "or".
     *
     * @param  string  $relation
     * @param  string  $operator
     * @param  int     $count
     * @return \Illuminate\Database\Eloquent\Builder|static
     */
    public function orHas($relation, $operator = '>=', $count = 1)
    {
        return $this->has($relation, $operator, $count, 'or');
    }

    /**
     * Add a relationship count / exists condition to the query with where clauses and an "or".
     *
     * @param  string    $relation
     * @param  \Closure  $callback
     * @param  string    $operator
     * @param  int       $count
     * @return \Illuminate\Database\Eloquent\Builder|static
     */
    public function orWhereHas($relation, Closure $callback, $operator = '>=', $count = 1)
    {
        return $this->has($relation, $operator, $count, 'or', $callback);
    }

    /**
     * Add the "has" condition where clause to the query.
     *
     * @param  \Illuminate\Database\Eloquent\Builder  $hasQuery
     * @param  \Illuminate\Database\Eloquent\Relations\Relation  $relation
     * @param  string  $operator
     * @param  int  $count
     * @param  string  $boolean
     * @return \Illuminate\Database\Eloquent\Builder
     */
    protected function addHasWhere(Builder $hasQuery, Relation $relation, $operator, $count, $boolean)
    {
        $this->mergeModelDefinedRelationWheresToHasQuery($hasQuery, $relation);

        if ($this->shouldRunExistsQuery($operator, $count)) {
            $not = ($operator === '<' && $count === 1);

            return $this->addWhereExistsQuery($hasQuery->toBase(), $boolean, $not);
        }

        return $this->whereCountQuery($hasQuery->toBase(), $operator, $count, $boolean);
    }

    /**
     * Check if we can run an "exists" query to optimize performance.
     *
     * @param  string  $operator
     * @param  int  $count
     * @return bool
     */
    protected function shouldRunExistsQuery($operator, $count)
    {
        return ($operator === '>=' || $operator === '<') && $count === 1;
    }

    /**
     * Add a sub query count clause to the query.
     *
     * @param  \Illuminate\Database\Query\Builder $query
     * @param  string  $operator
     * @param  int  $count
     * @param  string  $boolean
     * @return $this
     */
    protected function whereCountQuery(QueryBuilder $query, $operator = '>=', $count = 1, $boolean = 'and')
    {
        if (is_numeric($count)) {
            $count = new Expression($count);
        }

        $this->query->addBinding($query->getBindings(), 'where');

        return $this->where(new Expression('('.$query->toSql().')'), $operator, $count, $boolean);
    }

    /**
     * Merge the "wheres" from a relation query to a has query.
     *
     * @param  \Illuminate\Database\Eloquent\Builder  $hasQuery
     * @param  \Illuminate\Database\Eloquent\Relations\Relation  $relation
     * @return void
     */
    protected function mergeModelDefinedRelationWheresToHasQuery(Builder $hasQuery, Relation $relation)
    {
        $removedScopes = $hasQuery->removedScopes();

        $relationQuery = $relation->withoutGlobalScopes($removedScopes)->toBase();

        // Here we have the "has" query and the original relation. We need to copy over any
        // where clauses the developer may have put in the relationship function over to
        // the has query, and then copy the bindings from the "has" query to the main.
        $hasQuery->withoutGlobalScopes()->mergeWheres(
            $relationQuery->wheres, $relationQuery->getBindings()
        );
    }

    /**
     * Get the "has relation" base query instance.
     *
     * @param  string  $relation
     * @return \Illuminate\Database\Eloquent\Relations\Relation
     */
    protected function getHasRelationQuery($relation)
    {
        return Relation::noConstraints(function () use ($relation) {
            return $this->getModel()->$relation();
        });
    }

    /**
     * Set the relationships that should be eager loaded.
     *
     * @param  mixed  $relations
     * @return $this
     */
    public function with($relations)
    {
        if (is_string($relations)) {
            $relations = func_get_args();
        }

        $eagers = $this->parseWithRelations($relations);

        $this->eagerLoad = array_merge($this->eagerLoad, $eagers);

        return $this;
    }

    /**
     * Add subselect queries to count the relations.
     *
     * @param  mixed  $relations
     * @return $this
     */
    public function withCount($relations)
    {
        if (is_null($this->query->columns)) {
            $this->query->select(['*']);
        }

        $relations = is_array($relations) ? $relations : func_get_args();

        foreach ($this->parseWithRelations($relations) as $name => $constraints) {
            // Here we will get the relationship count query and prepare to add it to the main query
            // as a sub-select. First, we'll get the "has" query and use that to get the relation
            // count query. We will normalize the relation name then append _count as the name.
            $relation = $this->getHasRelationQuery($name);

            $query = $relation->getRelationCountQuery(
                $relation->getRelated()->newQuery(), $this
            );

            call_user_func($constraints, $query);

            $this->selectSub($query->getQuery(), snake_case($name).'_count');
        }

        return $this;
    }

    /**
     * Parse a list of relations into individuals.
     *
     * @param  array  $relations
     * @return array
     */
    protected function parseWithRelations(array $relations)
    {
        $results = [];

        foreach ($relations as $name => $constraints) {
            // If the "relation" value is actually a numeric key, we can assume that no
            // constraints have been specified for the eager load and we'll just put
            // an empty Closure with the loader so that we can treat all the same.
            if (is_numeric($name)) {
                $f = function () {
                    //
                };

                list($name, $constraints) = [$constraints, $f];
            }

            // We need to separate out any nested includes. Which allows the developers
            // to load deep relationships using "dots" without stating each level of
            // the relationship with its own key in the array of eager load names.
            $results = $this->parseNestedWith($name, $results);

            $results[$name] = $constraints;
        }

        return $results;
    }

    /**
     * Parse the nested relationships in a relation.
     *
     * @param  string  $name
     * @param  array   $results
     * @return array
     */
    protected function parseNestedWith($name, $results)
    {
        $progress = [];

        // If the relation has already been set on the result array, we will not set it
        // again, since that would override any constraints that were already placed
        // on the relationships. We will only set the ones that are not specified.
        foreach (explode('.', $name) as $segment) {
            $progress[] = $segment;

            if (! isset($results[$last = implode('.', $progress)])) {
                $results[$last] = function () {
                    //
                };
            }
        }

        return $results;
    }

    /**
     * Call the given model scope on the underlying model.
     *
     * @param  string  $scope
     * @param  array   $parameters
     * @return \Illuminate\Database\Query\Builder
     */
    protected function callScope($scope, $parameters)
    {
        array_unshift($parameters, $this);

        $query = $this->getQuery();

        // We will keep track of how many wheres are on the query before running the
        // scope so that we can properly group the added scope constraints in the
        // query as their own isolated nested where statement and avoid issues.
        $originalWhereCount = count($query->wheres);

        $result = call_user_func_array([$this->model, $scope], $parameters) ?: $this;

        if ($this->shouldNestWheresForScope($query, $originalWhereCount)) {
            $this->nestWheresForScope($query, $originalWhereCount);
        }

        return $result;
    }

    /**
     * Apply the scopes to the Eloquent builder instance and return it.
     *
     * @return \Illuminate\Database\Eloquent\Builder|static
     */
    public function applyScopes()
    {
        if (! $this->scopes) {
            return $this;
        }

        $builder = clone $this;

        $query = $builder->getQuery();

        // We will keep track of how many wheres are on the query before running the
        // scope so that we can properly group the added scope constraints in the
        // query as their own isolated nested where statement and avoid issues.
        $originalWhereCount = count($query->wheres);

        $whereCounts = [$originalWhereCount];

        foreach ($this->scopes as $scope) {
            $this->applyScope($scope, $builder);

            // Again, we will keep track of the count each time we add where clauses so that
            // we will properly isolate each set of scope constraints inside of their own
            // nested where clause to avoid any conflicts or issues with logical order.
            $whereCounts[] = count($query->wheres);
        }

        if ($this->shouldNestWheresForScope($query, $originalWhereCount)) {
            $this->nestWheresForScope($query, $whereCounts);
        }

        return $builder;
    }

    /**
     * Apply a single scope on the given builder instance.
     *
     * @param  \Illuminate\Database\Eloquent\Scope|\Closure  $scope
     * @param  \Illuminate\Database\Eloquent\Builder  $builder
     * @return void
     */
    protected function applyScope($scope, $builder)
    {
        if ($scope instanceof Closure) {
            $scope($builder);
        } elseif ($scope instanceof Scope) {
            $scope->apply($builder, $this->getModel());
        }
    }

    /**
     * Determine if the scope added after the given offset should be nested.
     *
     * @param  \Illuminate\Database\Query\Builder  $query
     * @param  int  $originalWhereCount
     * @return bool
     */
    protected function shouldNestWheresForScope(QueryBuilder $query, $originalWhereCount)
    {
        return count($query->wheres) > $originalWhereCount;
    }

    /**
     * Nest where conditions by slicing them at the given where count.
     *
     * @param  \Illuminate\Database\Query\Builder  $query
     * @param  int|array  $whereCounts
     * @return void
     */
    protected function nestWheresForScope(QueryBuilder $query, $whereCounts)
    {
        // Here, we totally remove all of the where clauses since we are going to
        // rebuild them as nested queries by slicing the groups of wheres into
        // their own sections. This is to prevent any confusing logic order.
        $allWheres = $query->wheres;

        $query->wheres = [];

        // We will construct where offsets by adding the outer most offsets to the
        // collection (0 and total where count) while also flattening the array
        // and extracting unique values, ensuring that all wheres are sliced.
        $whereOffsets = collect([0, $whereCounts, count($allWheres)])
                    ->flatten()->unique();

        $sliceFrom = $whereOffsets->shift();

        foreach ($whereOffsets as $sliceTo) {
            $this->sliceWhereConditions(
                $query, $allWheres, $sliceFrom, $sliceTo
            );

            $sliceFrom = $sliceTo;
        }
    }

    /**
     * Create a slice of where conditions at the given offsets and nest them if needed.
     *
     * @param  \Illuminate\Database\Query\Builder  $query
     * @param  array  $wheres
     * @param  int  $sliceFrom
     * @param  int  $sliceTo
     * @return void
     */
    protected function sliceWhereConditions(QueryBuilder $query, array $wheres, $sliceFrom, $sliceTo)
    {
        $whereSlice = array_slice($wheres, $sliceFrom, $sliceTo - $sliceFrom);

        $whereBooleans = collect($whereSlice)->pluck('boolean');

        // Here we'll check if the given subset of where clauses contains any "or"
        // booleans and in this case create a nested where expression. That way
        // we don't add any unnecessary nesting thus keeping the query clean.
        if ($whereBooleans->contains('or')) {
            $query->wheres[] = $this->nestWhereSlice($whereSlice);
        } else {
            $query->wheres = array_merge($query->wheres, $whereSlice);
        }
    }

    /**
     * Create a where array with nested where conditions.
     *
     * @param  array  $whereSlice
     * @return array
     */
    protected function nestWhereSlice($whereSlice)
    {
        $whereGroup = $this->getQuery()->forNestedWhere();

        $whereGroup->wheres = $whereSlice;

        return ['type' => 'Nested', 'query' => $whereGroup, 'boolean' => 'and'];
    }

    /**
     * Get the underlying query builder instance.
     *
     * @return \Illuminate\Database\Query\Builder|static
     */
    public function getQuery()
    {
        return $this->query;
    }

    /**
     * Get a base query builder instance.
     *
     * @return \Illuminate\Database\Query\Builder
     */
    public function toBase()
    {
        return $this->applyScopes()->getQuery();
    }

    /**
     * Set the underlying query builder instance.
     *
     * @param  \Illuminate\Database\Query\Builder  $query
     * @return $this
     */
    public function setQuery($query)
    {
        $this->query = $query;

        return $this;
    }

    /**
     * Get the relationships being eagerly loaded.
     *
     * @return array
     */
    public function getEagerLoads()
    {
        return $this->eagerLoad;
    }

    /**
     * Set the relationships being eagerly loaded.
     *
     * @param  array  $eagerLoad
     * @return $this
     */
    public function setEagerLoads(array $eagerLoad)
    {
        $this->eagerLoad = $eagerLoad;

        return $this;
    }

    /**
     * Get the model instance being queried.
     *
     * @return \Illuminate\Database\Eloquent\Model
     */
    public function getModel()
    {
        return $this->model;
    }

    /**
     * Set a model instance for the model being queried.
     *
     * @param  \Illuminate\Database\Eloquent\Model  $model
     * @return $this
     */
    public function setModel(Model $model)
    {
        $this->model = $model;

        $this->query->from($model->getTable());

        return $this;
    }

    /**
     * Extend the builder with a given callback.
     *
     * @param  string    $name
     * @param  \Closure  $callback
     * @return void
     */
    public function macro($name, Closure $callback)
    {
        $this->macros[$name] = $callback;
    }

    /**
     * Get the given macro by name.
     *
     * @param  string  $name
     * @return \Closure
     */
    public function getMacro($name)
    {
        return Arr::get($this->macros, $name);
    }

    /**
     * Dynamically handle calls into the query instance.
     *
     * @param  string  $method
     * @param  array   $parameters
     * @return mixed
     */
    public function __call($method, $parameters)
    {
        if (isset($this->macros[$method])) {
            array_unshift($parameters, $this);

            return call_user_func_array($this->macros[$method], $parameters);
        }

        if (method_exists($this->model, $scope = 'scope'.ucfirst($method))) {
            return $this->callScope($scope, $parameters);
        }

        if (in_array($method, $this->passthru)) {
            return call_user_func_array([$this->toBase(), $method], $parameters);
        }

        call_user_func_array([$this->query, $method], $parameters);

        return $this;
    }

    /**
     * Force a clone of the underlying query builder when cloning.
     *
     * @return void
     */
    public function __clone()
    {
        $this->query = clone $this->query;
    }
}
