<?php
// +----------------------------------------------------------------------
// | ThinkPHP [ WE CAN DO IT JUST THINK ]
// +----------------------------------------------------------------------
// | Copyright (c) 2006~2019 http://thinkphp.cn All rights reserved.
// +----------------------------------------------------------------------
// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
// +----------------------------------------------------------------------
// | Author: liu21st <liu21st@gmail.com>
// +----------------------------------------------------------------------

namespace think\model\relation;

use Closure;
use think\db\BaseQuery as Query;
use think\db\exception\DbException as Exception;
use think\Model;
use think\model\Relation;

/**
 * 多态一对一关联类
 */
class MorphOne extends Relation
{
    /**
     * 多态关联外键
     * @var string
     */
    protected $morphKey;

    /**
     * 多态字段
     * @var string
     */
    protected $morphType;

    /**
     * 多态类型
     * @var string
     */
    protected $type;

    /**
     * 绑定的关联属性
     * @var array
     */
    protected $bindAttr = [];

    /**
     * 构造函数
     * @access public
     * @param  Model  $parent    上级模型对象
     * @param  string $model     模型名
     * @param  string $morphKey  关联外键
     * @param  string $morphType 多态字段名
     * @param  string $type      多态类型
     */
    public function __construct(Model $parent, string $model, string $morphKey, string $morphType, string $type)
    {
        $this->parent    = $parent;
        $this->model     = $model;
        $this->type      = $type;
        $this->morphKey  = $morphKey;
        $this->morphType = $morphType;
        $this->query     = (new $model)->db();
    }

    /**
     * 延迟获取关联数据
     * @access public
     * @param  array   $subRelation 子关联名
     * @param  Closure $closure     闭包查询条件
     * @return Model
     */
    public function getRelation(array $subRelation = [], Closure $closure = null)
    {
        if ($closure) {
            $closure($this->getClosureType($closure));
        }

        $this->baseQuery();

        $relationModel = $this->query->relation($subRelation)->find();

        if ($relationModel) {
            if (!empty($this->bindAttr)) {
                // 绑定关联属性
                $this->bindAttr($this->parent, $relationModel);
            }

            $relationModel->setParent(clone $this->parent);
        } else {
            $relationModel = $this->getDefaultModel();
        }

        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
     * @param  string  $joinType JOIN类型
     * @param  Query   $query    Query对象
     * @return Query
     */
    public function has(string $operator = '>=', int $count = 1, string $id = '*', string $joinType = '', Query $query = null)
    {
        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
     * @param  string $joinType JOIN类型
     * @param  Query  $query    Query对象
     * @return Query
     */
    public function hasWhere($where = [], $fields = null, string $joinType = '', Query $query = null)
    {
        throw new Exception('relation not support: hasWhere');
    }

    /**
     * 预载入关联查询
     * @access public
     * @param  array   $resultSet   数据集
     * @param  string  $relation    当前关联名
     * @param  array   $subRelation 子关联名
     * @param  Closure $closure     闭包
     * @param  array   $cache       关联缓存
     * @return void
     */
    public function eagerlyResultSet(array &$resultSet, string $relation, array $subRelation, Closure $closure = null, array $cache = []): void
    {
        $morphType = $this->morphType;
        $morphKey  = $this->morphKey;
        $type      = $this->type;
        $range     = [];

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

        if (!empty($range)) {
            $data = $this->eagerlyMorphToOne([
                [$morphKey, 'in', $range],
                [$morphType, '=', $type],
            ], $subRelation, $closure, $cache);

            // 关联数据封装
            foreach ($resultSet as $result) {
                if (!isset($data[$result->$pk])) {
                    $relationModel = $this->getDefaultModel();
                } else {
                    $relationModel = $data[$result->$pk];
                    $relationModel->setParent(clone $result);
                    $relationModel->exists(true);
                }

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

    /**
     * 预载入关联查询
     * @access public
     * @param  Model   $result      数据对象
     * @param  string  $relation    当前关联名
     * @param  array   $subRelation 子关联名
     * @param  Closure $closure     闭包
     * @param  array   $cache       关联缓存
     * @return void
     */
    public function eagerlyResult(Model $result, string $relation, array $subRelation = [], Closure $closure = null, array $cache = []): void
    {
        $pk = $result->getPk();

        if (isset($result->$pk)) {
            $pk   = $result->$pk;
            $data = $this->eagerlyMorphToOne([
                [$this->morphKey, '=', $pk],
                [$this->morphType, '=', $this->type],
            ], $subRelation, $closure, $cache);

            if (isset($data[$pk])) {
                $relationModel = $data[$pk];
                $relationModel->setParent(clone $result);
                $relationModel->exists(true);
            } else {
                $relationModel = $this->getDefaultModel();
            }

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

    /**
     * 多态一对一 关联模型预查询
     * @access protected
     * @param  array   $where       关联预查询条件
     * @param  array   $subRelation 子关联
     * @param  Closure $closure     闭包
     * @param  array   $cache       关联缓存
     * @return array
     */
    protected function eagerlyMorphToOne(array $where, array $subRelation = [], $closure = null, array $cache = []): array
    {
        // 预载入关联查询 支持嵌套预载入
        if ($closure) {
            $this->baseQuery = true;
            $closure($this->getClosureType($closure));
        }

        $list = $this->query
            ->where($where)
            ->with($subRelation)
            ->cache($cache[0] ?? false, $cache[1] ?? null, $cache[2] ?? null)
            ->select();
        $morphKey = $this->morphKey;

        // 组装模型数据
        $data = [];

        foreach ($list as $set) {
            $data[$set->$morphKey] = $set;
        }

        return $data;
    }

    /**
     * 保存（新增）当前关联数据对象
     * @access public
     * @param  mixed   $data 数据 可以使用数组 关联模型对象
     * @param  boolean $replace 是否自动识别更新和写入
     * @return Model|false
     */
    public function save($data, bool $replace = true)
    {
        if ($data instanceof Model) {
            $data = $data->getData();
        }

        $model = $this->make();
        return $model->replace($replace)->save($data) ? $model : false;
    }

    /**
     * 创建关联对象实例
     * @param array|Model $data
     * @return Model
     */
    public function make($data = []): Model
    {
        if ($data instanceof Model) {
            $data = $data->getData();
        }

        // 保存关联表数据
        $pk = $this->parent->getPk();

        $data[$this->morphKey]  = $this->parent->$pk;
        $data[$this->morphType] = $this->type;

        return new $this->model($data);
    }

    /**
     * 执行基础查询（进执行一次）
     * @access protected
     * @return void
     */
    protected function baseQuery(): void
    {
        if (empty($this->baseQuery) && $this->parent->getData()) {
            $pk = $this->parent->getPk();

            $this->query->where([
                [$this->morphKey, '=', $this->parent->$pk],
                [$this->morphType, '=', $this->type],
            ]);
            $this->baseQuery = true;
        }
    }

    /**
     * 绑定关联表的属性到父模型属性
     * @access public
     * @param  array $attr 要绑定的属性列表
     * @return $this
     */
    public function bind(array $attr)
    {
        $this->bindAttr = $attr;

        return $this;
    }

    /**
     * 获取绑定属性
     * @access public
     * @return array
     */
    public function getBindAttr(): array
    {
        return $this->bindAttr;
    }

    /**
     * 绑定关联属性到父模型
     * @access protected
     * @param  Model $result 父模型对象
     * @param  Model $model  关联模型对象
     * @return void
     * @throws Exception
     */
    protected function bindAttr(Model $result, Model $model = null): void
    {
        foreach ($this->bindAttr as $key => $attr) {
            $key   = is_numeric($key) ? $attr : $key;
            $value = $result->getOrigin($key);

            if (!is_null($value)) {
                throw new Exception('bind attr has exists:' . $key);
            }

            $result->setAttr($key, $model ? $model->$attr : null);
        }
    }
}
