<?php

namespace App\Http\Requests;

use App\Services\MenuService;
use Illuminate\Foundation\Http\FormRequest;

class GateRequest extends FormRequest
{
    /**
     * @var string
     */
    protected $currentRoute;

    /**
     * @var array
     */
    protected $tracks;

    /**
     * 通用鉴权
     *
     * @return bool
     */
    public function authorize():bool
    {
        if (!$this->ajax() && !$this->authorizeGate())$this->sameOriginMatching();
        return true;
    }

    public function rules():array
    {
        return [];
    }

    /**
     * 授权门鉴定
     *
     * @return bool
     */
    public function authorizeGate():bool
    {
        $this->currentRoute = ltrim($this->getPathInfo(),"/");
        /** @var MenuService $service */
        $service = app("MenuService");
        if (!$this->matchingRoute($service->getVisibleMenuListAll()))return false;//全量匹配失败直接授权失败 此时正确做法应该是404
        $correctStack = $this->tracks; //全量匹配下的 正确栈节点
        $this->tracks = [];//栈节点制空 存储目标节点
        if (!$this->matchingRoute($service->getVisibleFunctionList()))return false;//部分匹配下的授权失败
        return count($correctStack)==count($this->tracks); //正确栈与目标栈 对比
    }

    /**
     * 递归匹配路由
     *
     * 每次递归 各自记录自己的栈路径
     * 每次匹配成功都将当前栈路径替换全局栈路径
     * 替换后如果存在节点继续匹配 直至节点为空得出最终的栈终点
     */
    private function matchingRoute(array $routes,array $tagStack = [],bool $successMark = false):bool
    {
        foreach ($routes as $route){
            $currentStack = $tagStack;$currentStack[] = $route["name"];
            $match = $this->matching($route["route"] ?? "");
            if ($match){$this->tracks = $currentStack;$successMark = true;}
            if ($route["child"] ?? false){
                if ($this->matchingRoute($route["child"],$currentStack,$successMark))return true;
            }
        }
        return $successMark;
    }

    private function matching($tag):bool
    {
        if (!$tag)return false;
        $tag = explode("?",$tag)[0];//去除参数
        if ($this->currentRoute == $tag)return true; //相等
        if (strpos($tag,"*")===false)return false;//无泛匹配符
        $cr = explode("/",$this->currentRoute);
        $tr = explode("/",$tag);
        $crLen = count($cr);
        $trLen = count($tr);
        if ($crLen<$trLen)return false;
        if ($crLen>$trLen && $tr[$trLen-1]=='*'){
            $cr = array_slice($cr,0,$trLen);
            $crLen = $trLen;
        }
        if ($crLen!=$trLen)return false;
        foreach ($tr as $index=>$item){
            if ($item=='*')$tr[$index] = $cr[$index];
        }
        return implode("/",$cr) == implode("/",$tr);
    }

    /**
     * 递归一个同源节点 返回可用URL 深度取决于$this->tracks的长度
     *
     * @param array $routes
     * @param int $depth
     *
     * @return string|null
     */
    private function searchOrigin(array $routes,int $depth = 0):?string
    {
        $url = null;//预设返回URL
        foreach ($routes as $route){
            //如果目标栈长度大于当前深度 且 当前节点与目标节点name相同 且 当前节点有子节点存在，递归进入子节点，深度加1
            if (count($this->tracks)>$depth &&
                $this->tracks[$depth]==$route["name"] &&
                ($route["child"] ?? false))
            {
                $currentChildUrl = $this->searchOrigin($route["child"],$depth+1);
                if ($currentChildUrl)return $currentChildUrl;
            }
            if (!$url && ($route["route"] ?? ""))$url = $route["route"]; //取最近的同源的URL
        }
        return $url;
    }

    /**
     * 同源匹配 此时已经拿到同源节点 $this->tracks 需要在此节点上寻找一个允许的权限
     */
    public function sameOriginMatching()
    {
        $url = null;
        //目标节点存在
        if ($this->tracks)$url = $this->searchOrigin(app("MenuService")->getVisibleFunctionList());
        if (!$url)$url = 'denied';
        header('Location: /'.$url,true,301);
        die();
        //目标节点为空的话说明一级节点都无权访问
        // 此时返回一级同源节点就无意义 会产生误导性，所以前往无权页面
        //正常情况下这个预设不会被正常用户触发
    }
}