<?php

namespace think\model\relation;

use think\db\Query;
use think\Loader;
use think\Model;

class BelongsTo extends OneToOne
{
    /**
     * 构造函数
     * @access public
     * @param Model  $parent 上级模型对象
     * @param string $model 模型名
     * @param string $foreignKey 关联外键
     * @param string $localKey 关联主键
     * @param string $joinType JOIN类型
     * @param string $relation  关联名
     */
    public function __construct(Model $parent, $model, $foreignKey, $localKey, $joinType = 'INNER', $relation = null)
    {
        $this->parent     = $parent;
        $this->model      = $model;
        $this->foreignKey = $foreignKey;
        $this->localKey   = $localKey;
        $this->joinType   = $joinType;
        $this->query      = (new $model)->db();
        $this->relation   = $relation;
    }

    /**
     * 延迟获取关联数据
     * @param string   $subRelation 子关联名
     * @param \Closure $closure     闭包查询条件
     * @access public
     * @return array|false|\PDOStatement|string|Model
     */
    public function getRelation($subRelation = '', $closure = null)
    {
        $foreignKey = $this->foreignKey;
        if ($closure) {
            call_user_func_array($closure, [ & $this->query]);
        }
        $relationModel = $this->query
            ->removeWhereField($this->localKey)
            ->where($this->localKey, $this->parent->$foreignKey)
            ->relation($subRelation)
            ->find();

        if ($relationModel) {
            $relationModel->setParent(clone $this->parent);
        }

        return $relationModel;
    }

    /**
     * 根据关联条件查询当前模型
     * @access public
     * @param string  $operator 比较操作符
     * @param integer $count    个数
     * @param string  $id       关联表的统计字段
     * @return Query
     */
    public function has($operator = '>=', $count = 1, $id = '*')
    {
        return $this->parent;
    }

    /**
     * 根据关联条件查询当前模型
     * @access public
     * @param  mixed  $where 查询条件（数组或者闭包）
     * @param  mixed  $fields   字段
     * @return Query
     */
    public function hasWhere($where = [], $fields = null)
    {
        $table    = $this->query->getTable();
        $model    = basename(str_replace('\\', '/', get_class($this->parent)));
        $relation = basename(str_replace('\\', '/', $this->model));

        if (is_array($where)) {
            foreach ($where as $key => $val) {
                if (false === strpos($key, '.')) {
                    $where[$relation . '.' . $key] = $val;
                    unset($where[$key]);
                }
            }
        }
        $fields = $this->getRelationQueryFields($fields, $model);

        return $this->parent->db()->alias($model)
            ->field($fields)
            ->join([$table => $relation], $model . '.' . $this->foreignKey . '=' . $relation . '.' . $this->localKey, $this->joinType)
            ->where($where);
    }

    /**
     * 预载入关联查询（数据集）
     * @access public
     * @param array     $resultSet 数据集
     * @param string    $relation 当前关联名
     * @param string    $subRelation 子关联名
     * @param \Closure  $closure 闭包
     * @return void
     */
    protected function eagerlySet(&$resultSet, $relation, $subRelation, $closure)
    {
        $localKey   = $this->localKey;
        $foreignKey = $this->foreignKey;

        $range = [];
        foreach ($resultSet as $result) {
            // 获取关联外键列表
            if (isset($result->$foreignKey)) {
                $range[] = $result->$foreignKey;
            }
        }

        if (!empty($range)) {
            $this->query->removeWhereField($localKey);
            $data = $this->eagerlyWhere($this->query, [
                $localKey => [
                    'in',
                    $range,
                ],
            ], $localKey, $relation, $subRelation, $closure);
            // 关联属性名
            $attr = Loader::parseName($relation);
            // 关联数据封装
            foreach ($resultSet as $result) {
                // 关联模型
                if (!isset($data[$result->$foreignKey])) {
                    $relationModel = null;
                } else {
                    $relationModel = $data[$result->$foreignKey];
                    $relationModel->setParent(clone $result);
                    $relationModel->isUpdate(true);
                }

                if (!empty($this->bindAttr)) {
                    // 绑定关联属性
                    $this->bindAttr($relationModel, $result, $this->bindAttr);
                } else {
                    // 设置关联属性
                    $result->setRelation($attr, $relationModel);
                }
            }
        }
    }

    /**
     * 预载入关联查询（数据）
     * @access public
     * @param Model     $result 数据对象
     * @param string    $relation 当前关联名
     * @param string    $subRelation 子关联名
     * @param \Closure  $closure 闭包
     * @return void
     */
    protected function eagerlyOne(&$result, $relation, $subRelation, $closure)
    {
        $localKey   = $this->localKey;
        $foreignKey = $this->foreignKey;
        $this->query->removeWhereField($localKey);
        $data = $this->eagerlyWhere($this->query, [$localKey => $result->$foreignKey], $localKey, $relation, $subRelation, $closure);
        // 关联模型
        if (!isset($data[$result->$foreignKey])) {
            $relationModel = null;
        } else {
            $relationModel = $data[$result->$foreignKey];
            $relationModel->setParent(clone $result);
            $relationModel->isUpdate(true);
        }
        if (!empty($this->bindAttr)) {
            // 绑定关联属性
            $this->bindAttr($relationModel, $result, $this->bindAttr);
        } else {
            // 设置关联属性
            $result->setRelation(Loader::parseName($relation), $relationModel);
        }
    }

    /**
     * 添加关联数据
     * @access public
     * @param Model $model       关联模型对象
     * @return Model
     */
    public function associate($model)
    {
        $foreignKey = $this->foreignKey;
        $pk         = $model->getPk();

        $this->parent->setAttr($foreignKey, $model->$pk);
        $this->parent->save();

        return $this->parent->setRelation($this->relation, $model);
    }

    /**
     * 注销关联数据
     * @access public
     * @return Model
     */
    public function dissociate()
    {
        $foreignKey = $this->foreignKey;

        $this->parent->setAttr($foreignKey, null);
        $this->parent->save();

        return $this->parent->setRelation($this->relation, null);
    }

    /**
     * 执行基础查询（仅执行一次）
     * @access protected
     * @return void
     */
    protected function baseQuery()
    {
        if (empty($this->baseQuery)) {
            if (isset($this->parent->{$this->foreignKey})) {
                // 关联查询带入关联条件
                $this->query->where($this->localKey, '=', $this->parent->{$this->foreignKey});
            }

            $this->baseQuery = true;
        }
    }
}
