<?php

namespace FluentCart\Framework\Database\Orm\Relations;

use FluentCart\Framework\Support\Helper;
use FluentCart\Framework\Database\Orm\Model;
use FluentCart\Framework\Database\Orm\Builder;
use FluentCart\Framework\Database\Orm\Collection;
use FluentCart\Framework\Database\UniqueConstraintViolationException;
use FluentCart\Framework\Database\Orm\Relations\Concerns\InteractsWithDictionary;
use FluentCart\Framework\Database\Orm\Relations\Concerns\SupportsInverseRelations;

/**
 * @template TRelatedModel of Model
 */
abstract class HasOneOrMany extends Relation
{
    use InteractsWithDictionary, SupportsInverseRelations;

    /**
     * The foreign key of the parent model.
     *
     * @var string
     */
    protected $foreignKey;

    /**
     * The local key of the parent model.
     *
     * @var string
     */
    protected $localKey;

    /**
     * Create a new has one or many relationship instance.
     *
     * @param  \FluentCart\Framework\Database\Orm\Builder  $query
     * @param  \FluentCart\Framework\Database\Orm\Model  $parent
     * @param  string  $foreignKey
     * @param  string  $localKey
     * @return void
     */
    public function __construct(Builder $query, Model $parent, $foreignKey, $localKey)
    {
        $this->localKey = $localKey;
        $this->foreignKey = $foreignKey;

        parent::__construct($query, $parent);
    }

    /**
     * Create and return an un-saved instance of the related model.
     *
     * @param  array  $attributes
     * @return \FluentCart\Framework\Database\Orm\Model
     */
    public function make(array $attributes = [])
    {
        return Helper::tap(
            $this->related->newInstance($attributes),
            function ($instance) {
                $this->setForeignAttributesForCreate($instance);
            }
        );
    }

    /**
     * Create and return an un-saved instance of the related models.
     *
     * @param  iterable  $records
     * @return \FluentCart\Framework\Database\Orm\Collection
     */
    public function makeMany($records)
    {
        $instances = $this->related->newCollection();

        foreach ($records as $record) {
            $instances->push($this->make($record));
        }

        return $instances;
    }

    /**
     * Set the base constraints on the relation query.
     *
     * @return void
     */
    public function addConstraints()
    {
        if (static::$constraints) {
            $query = $this->getRelationQuery();

            $query->where($this->foreignKey, '=', $this->getParentKey());

            $query->whereNotNull($this->foreignKey);
        }
    }

    /**
     * Set the constraints for an eager load of the relation.
     *
     * @param  array  $models
     * @return void
     */
    public function addEagerConstraints(array $models)
    {
        $whereIn = $this->whereInMethod($this->parent, $this->localKey);

        $this->whereInEager(
            $whereIn,
            $this->foreignKey,
            $this->getKeys($models, $this->localKey),
            $this->getRelationQuery()
        );
    }

    /**
     * Match the eagerly loaded results to their single parents.
     *
     * @param  array  $models
     * @param  \FluentCart\Framework\Database\Orm\Collection  $results
     * @param  string  $relation
     * @return array
     */
    public function matchOne(array $models, Collection $results, $relation)
    {
        return $this->matchOneOrMany($models, $results, $relation, 'one');
    }

    /**
     * Match the eagerly loaded results to their many parents.
     *
     * @param  array  $models
     * @param  \FluentCart\Framework\Database\Orm\Collection  $results
     * @param  string  $relation
     * @return array
     */
    public function matchMany(array $models, Collection $results, $relation)
    {
        return $this->matchOneOrMany($models, $results, $relation, 'many');
    }

    /**
     * Match the eagerly loaded results to their many parents.
     *
     * @param  array  $models
     * @param  \FluentCart\Framework\Database\Orm\Collection  $results
     * @param  string  $relation
     * @param  string  $type
     * @return array
     */
    protected function matchOneOrMany(
        array $models,
        Collection $results,
        $relation,
        $type
    ) {
        $dictionary = $this->buildDictionary($results);

        // Once we have the dictionary we can simply spin through the parent models to
        // link them up with their children using the keyed dictionary to make the
        // matching very convenient and easy work. Then we'll just return them.
        foreach ($models as $model) {
            if (isset($dictionary[$key = $this->getDictionaryKey($model->getAttribute($this->localKey))])) {
                $model->setRelation(
                    $relation, $this->getRelationValue($dictionary, $key, $type)
                );
            }
        }

        return $models;
    }

    /**
     * Get the value of a relationship by one or many type.
     *
     * @param  array  $dictionary
     * @param  string  $key
     * @param  string  $type
     * @return mixed
     */
    protected function getRelationValue(array $dictionary, $key, $type)
    {
        $value = $dictionary[$key];

        return $type === 'one' ? reset($value) : $this->related->newCollection($value);
    }

    /**
     * Build model dictionary keyed by the relation's foreign key.
     *
     * @param  \FluentCart\Framework\Database\Orm\Collection  $results
     * @return array
     */
    protected function buildDictionary(Collection $results)
    {
        $foreign = $this->getForeignKeyName();

        return $results->mapToDictionary(function ($result) use ($foreign) {
            return [$this->getDictionaryKey($result->{$foreign}) => $result];
        })->all();
    }

    /**
     * Find a model by its primary key or return a new instance of the related model.
     *
     * @param  mixed  $id
     * @param  array  $columns
     * @return \FluentCart\Framework\Support\Collection|\FluentCart\Framework\Database\Orm\Model
     */
    public function findOrNew($id, $columns = ['*'])
    {
        if (is_null($instance = $this->find($id, $columns))) {
            $instance = $this->related->newInstance();

            $this->setForeignAttributesForCreate($instance);
        }

        return $instance;
    }

    /**
     * Get the first related model record matching the attributes or instantiate it.
     *
     * @param  array  $attributes
     * @param  array  $values
     * @return \FluentCart\Framework\Database\Orm\Model
     */
    public function firstOrNew(array $attributes = [], array $values = [])
    {
        if (is_null($instance = $this->where($attributes)->first())) {
            $instance = $this->related->newInstance(array_merge($attributes, $values));

            $this->setForeignAttributesForCreate($instance);
        }

        return $instance;
    }

    /**
     * Get the first related record matching the attributes or create it.
     *
     * @param  array  $attributes
     * @param  array  $values
     * @return \FluentCart\Framework\Database\Orm\Model
     */
    public function firstOrCreate(array $attributes = [], array $values = [])
    {
        if (is_null($instance = (clone $this)->where($attributes)->first())) {
            $instance = $this->createOrFirst($attributes, $values);
        }

        return $instance;
    }

    /**
     * Attempt to create the record. If a unique constraint
     * violation occurs, attempt to find the matching record.
     *
     * @param  array  $attributes
     * @param  array  $values
     * @return TRelatedModel
     */
    public function createOrFirst(array $attributes = [], array $values = [])
    {
        try {
            return $this->getQuery()->withSavepointIfNeeded(fn () => $this->create(array_merge($attributes, $values)));
        } catch (UniqueConstraintViolationException $e) {
            if ($instance = $this->useWritePdo()->where($attributes)->first()) {
                return $instance;
            } throw $e;
        }
    }

    /**
     * Create or update a related record matching the attributes, and fill it with values.
     *
     * @param  array  $attributes
     * @param  array  $values
     * @return \FluentCart\Framework\Database\Orm\Model
     */
    public function updateOrCreate(array $attributes, array $values = [])
    {
        return Helper::tap(
            $this->firstOrCreate($attributes, $values),
            function ($instance) use ($values) {
                if (! $instance->wasRecentlyCreated) {
                    $instance->fill($values)->save();
                }
            }
        );
    }

    /**
     * Insert new records or update the existing ones.
     *
     * @param  array  $values
     * @param  array|string  $uniqueBy
     * @param  array|null  $update
     * @return int
     */
    public function upsert(array $values, $uniqueBy, $update = null)
    {
        if (! empty($values) && ! is_array(reset($values))) {
            $values = [$values];
        }

        foreach ($values as $key => $value) {
            $values[$key][$this->getForeignKeyName()] = $this->getParentKey();
        }

        return $this->getQuery()->upsert($values, $uniqueBy, $update);
    }

    /**
     * Attach a model instance to the parent model.
     *
     * @param  \FluentCart\Framework\Database\Orm\Model  $model
     * @return \FluentCart\Framework\Database\Orm\Model|false
     */
    public function save(Model $model)
    {
        $this->setForeignAttributesForCreate($model);

        return $model->save() ? $model : false;
    }

    /**
     * Attach a model instance without raising any events to the parent model.
     *
     * @param  TRelatedModel  $model
     * @return TRelatedModel|false
     */
    public function saveQuietly(Model $model)
    {
        return Model::withoutEvents(function () use ($model) {
            return $this->save($model);
        });
    }

    /**
     * Attach a collection of models to the parent instance.
     *
     * @param  iterable  $models
     * @return iterable
     */
    public function saveMany($models)
    {
        foreach ($models as $model) {
            $this->save($model);
        }

        return $models;
    }

    /**
     * Attach a collection of models to the parent instance
     * without raising any events to the parent model.
     *
     * @param  iterable<TRelatedModel>  $models
     * @return iterable<TRelatedModel>
     */
    public function saveManyQuietly($models)
    {
        return Model::withoutEvents(function () use ($models) {
            return $this->saveMany($models);
        });
    }

    /**
     * Create a new instance of the related model.
     *
     * @param  array  $attributes
     * @return \FluentCart\Framework\Database\Orm\Model
     */
    public function create(array $attributes = [])
    {
        return Helper::tap(
            $this->related->newInstance($attributes),
            function ($instance) {
                $this->setForeignAttributesForCreate($instance);
                $instance->save();
            }
        );
    }

    /**
     * Create a new instance of the related model
     * without raising any events to the parent model.
     *
     * @param  array  $attributes
     * @return TRelatedModel
     */
    public function createQuietly(array $attributes = [])
    {
        return Model::withoutEvents(fn () => $this->create($attributes));
    }

    /**
     * Create a new instance of the related model. Allow mass-assignment.
     *
     * @param  array  $attributes
     * @return \FluentCart\Framework\Database\Orm\Model
     */
    public function forceCreate(array $attributes = [])
    {
        $attributes[$this->getForeignKeyName()] = $this->getParentKey();

        return $this->related->forceCreate($attributes);
    }

    /**
     * Create a new instance of the related model with
     * mass assignment without raising model events.
     *
     * @param  array  $attributes
     * @return TRelatedModel
     */
    public function forceCreateQuietly(array $attributes = [])
    {
        return Model::withoutEvents(fn () => $this->forceCreate($attributes));
    }

    /**
     * Create a Collection of new instances of the related model.
     *
     * @param  iterable  $records
     * @return \FluentCart\Framework\Database\Orm\Collection
     */
    public function createMany(iterable $records)
    {
        $instances = $this->related->newCollection();

        foreach ($records as $record) {
            $instances->push($this->create($record));
        }

        return $instances;
    }

    /**
     * Create a Collection of new instances of the related
     * model without raising any events to the parent model.
     *
     * @param  iterable  $records
     * @return \FluentCart\Framework\Database\Orm\Collection<int, TRelatedModel>
     */
    public function createManyQuietly(iterable $records)
    {
        return Model::withoutEvents(fn () => $this->createMany($records));
    }

    /**
     * Set the foreign ID for creating a related model.
     *
     * @param  \FluentCart\Framework\Database\Orm\Model  $model
     * @return void
     */
    protected function setForeignAttributesForCreate(Model $model)
    {
        $model->setAttribute($this->getForeignKeyName(), $this->getParentKey());
    }

    /**
     * Add the constraints for a relationship query.
     *
     * @param  \FluentCart\Framework\Database\Orm\Builder  $query
     * @param  \FluentCart\Framework\Database\Orm\Builder  $parentQuery
     * @param  array|mixed  $columns
     * @return \FluentCart\Framework\Database\Orm\Builder
     */
    public function getRelationExistenceQuery(
        Builder $query,
        Builder $parentQuery,
        $columns = ['*']
    ) {
        if ($query->getQuery()->from == $parentQuery->getQuery()->from) {
            return $this->getRelationExistenceQueryForSelfRelation(
                $query, $parentQuery, $columns
            );
        }

        return parent::getRelationExistenceQuery($query, $parentQuery, $columns);
    }

    /**
     * Add the constraints for a relationship query on the same table.
     *
     * @param  \FluentCart\Framework\Database\Orm\Builder  $query
     * @param  \FluentCart\Framework\Database\Orm\Builder  $parentQuery
     * @param  array|mixed  $columns
     * @return \FluentCart\Framework\Database\Orm\Builder
     */
    public function getRelationExistenceQueryForSelfRelation(
        Builder $query,
        Builder $parentQuery,
        $columns = ['*']
    ) {
        $query->from(
            $query->getModel()->getTable().' as '.$hash = $this->getRelationCountHash()
        );

        $query->getModel()->setTable($hash);

        return $query->select($columns)->whereColumn(
            $this->getQualifiedParentKeyName(),
            '=',
            $hash.'.'.$this->getForeignKeyName()
        );
    }

    /**
     * Alias to set the "limit" value of the query.
     *
     * @param  int  $value
     * @return $this
     */
    public function take($value)
    {
        return $this->limit($value);
    }

    /**
     * Set the "limit" value of the query.
     *
     * @param  int  $value
     * @return $this
     */
    public function limit($value)
    {
        if ($this->parent->exists) {
            $this->query->limit($value);
        } else {
            $this->query->groupLimit($value, $this->getExistenceCompareKey());
        }

        return $this;
    }

    /**
     * Get the key for comparing against the parent key in "has" query.
     *
     * @return string
     */
    public function getExistenceCompareKey()
    {
        return $this->getQualifiedForeignKeyName();
    }

    /**
     * Get the key value of the parent's local key.
     *
     * @return mixed
     */
    public function getParentKey()
    {
        return $this->parent->getAttribute($this->localKey);
    }

    /**
     * Get the fully qualified parent key name.
     *
     * @return string
     */
    public function getQualifiedParentKeyName()
    {
        return $this->parent->qualifyColumn($this->localKey);
    }

    /**
     * Get the plain foreign key.
     *
     * @return string
     */
    public function getForeignKeyName()
    {
        $segments = explode('.', $this->getQualifiedForeignKeyName());

        return end($segments);
    }

    /**
     * Get the foreign key for the relationship.
     *
     * @return string
     */
    public function getQualifiedForeignKeyName()
    {
        return $this->foreignKey;
    }

    /**
     * Get the local key for the relationship.
     *
     * @return string
     */
    public function getLocalKeyName()
    {
        return $this->localKey;
    }
}
