<?php

declare(strict_types=1);

namespace ywxapp\middleware;

use Closure;
use think\App;
use think\exception\HttpException;
use think\Request;
use think\Response;

/**
 * 多根目录多应用中间件
 *
 * 核心语义：
 * - "blog"        → 按 roots顺序查找，找到第一个匹配即用
 * - "app2:blog"   → 强制在 /app2/blog找，找不到直接 404
 * - 都不支持"先查 app找不到再降级到 app2"再降级这种串行写法
 *   （显式前缀必须严格匹配，避免行为不可预测）
 */
class MultiApp
{
    protected App $app;

    /** @var array<string,string> 根目录标识 => 绝对路径 */
    protected array $roots = [];

    /** @var array<string,string> 根目录标识 => 命名空间前缀 */
    protected array $namespaces = [];

    public function __construct(App $app)
    {
        $this->app        = $app;
        $this->roots      = $app->config->get('app.app_roots', [
            'app' => $app->getBasePath(),
            'addon' => $app->getRootPath() . 'addon' . DIRECTORY_SEPARATOR,
        ]);
        // $this->namespaces = $app->config->get('app.app_namespaces', [
        //     'app' => 'app',
        //     'addon' => 'addon',
        // ]);
        $this->namespaces =  [
            'app' => 'app',
            'addon' => 'addon',
        ];
    }

    public function handle($request, Closure $next)
    {
        if (!$this->parseMultiApp()) {
            return $next($request);
        }
        return $this->app->middleware
            ->pipeline('app')
            ->send($request)
            ->then(function ($request) use ($next) {
                return $next($request);
            });
    }

    protected function getRoutePath(): string
    {
        return $this->app->getAppPath() . 'route' . DIRECTORY_SEPARATOR;
    }

    /**
     * 核心解析
     */
    protected function parseMultiApp(): bool
    {
        $scriptName = $this->getScriptName();
        $defaultApp = $this->app->config->get('app.default_app') ?: 'index';
        $appName    = $this->app->http->getName();

        // ==================== 阶段 1:独立入口 / 显式绑定 ====================
        if ($appName || ($scriptName && !in_array($scriptName, ['index', 'router', 'think']))) {
            $appName = $appName ?: $scriptName;
            $this->app->http->setBind();

            // 独立入口可不走 domain_bind,直接解析
            $resolved = $this->resolve($appName);
            if (!$resolved) {
                throw new HttpException(404, 'app not exists:' . $appName);
            }
            return $this->applyResolved($resolved, $appName);
        }

        // ==================== 阶段 2: 自动识别 ====================
        $this->app->http->setBind(false);
        $appName = null;

        // -------- 2.1 域名绑定 --------
        $bind = $this->app->config->get('app.domain_bind', []);
        if (!empty($bind)) {
            $subDomain = $this->app->request->subDomain();
            $domain    = $this->app->request->host(true);
            if (isset($bind[$domain])) {
                $appName = $bind[$domain];
                $this->app->http->setBind();
            } elseif (isset($bind[$subDomain])) {
                $appName = $bind[$subDomain];
                $this->app->http->setBind();
            } elseif (isset($bind['*'])) {
                $appName = $bind['*'];
                $this->app->http->setBind();
            }
        }

        if ($this->app->http->isBind()) {
            $resolved = $this->resolve($appName);
            if (!$resolved) {
                throw new HttpException(404, 'app not exists:' . $appName);
            }
            return $this->applyResolved($resolved, $appName);
        }

        // -------- 2.2 URL 路径识别 --------
        $path = $this->app->request->pathinfo();
        $map  = $this->app->config->get('app.app_map', []);
        $deny = $this->app->config->get('app.deny_app_list', []);

        $fullName = current(explode('/', $path));
        if (strpos($fullName, '.')) {
            $fullName = strstr($fullName, '.', true);
        }

        // 分支1: 命中 app_map
        if (isset($map[$fullName])) {
            if ($map[$fullName] instanceof Closure) {
                $mapped = call_user_func_array($map[$fullName], [$this->app]) ?: $fullName;
            } else {
                $mapped = $map[$fullName];
            }
            $resolved = $this->resolve($mapped);
        }
        // 分支 2: 黑名单 / map 显式禁用
        elseif ($fullName !== '' && (false !== array_search($fullName, $map) || in_array($fullName, $deny))) {
            throw new HttpException(404, 'app not exists:' . $fullName);
        }
        // 分支 3: map 通配 *
        elseif ($fullName !== '' && isset($map['*'])) {
            $resolved = $this->resolve($map['*']);
        }
        // 分支 4: URL 段本身带前缀(强制指定根)
        elseif (str_contains($fullName, ':')) {
            $resolved = $this->resolve($fullName);
        }
        // 分支 5: 默认行为 —— 多根顺序查找
        else {
            $name = $fullName !== '' ? $fullName : null;
            // URL 没给应用名 → 用 default_app
            $name ??= $defaultApp;
            $resolved = $this->resolve($name); // ← prefix='',走多根查找
        }

        // ===== 查找失败处理 =====
        if (!$resolved) {
            // app_express=true 且不是显式前缀时 → 兜底 default_app
            $express = $this->app->config->get('app.app_express', false);
            if ($express && !str_contains($fullName, ':')) {
                $resolved = $this->resolve($defaultApp);
            }
            if (!$resolved) {
                throw new HttpException(404, 'app not exists:' . ($fullName ?: $defaultApp));
            }
        }

        // 重写 pathinfo: 把 URL 第一段剥掉
        if ($fullName) {
            $this->app->request->setRoot('/' . $fullName);
            $this->app->request->setPathinfo(
                strpos($path, '/') ? ltrim(strstr($path, '/'), '/') : ''
            );
        }

        return $this->applyResolved($resolved, $fullName);
    }

    /**
     * 解析应用名为最终 [prefix, name, appPath]
     * 支持：
     *   "app2:blog" → ['app2', 'blog', '/www/app2/blog/']
     *   "blog"      → ['',     'blog', null]  ← 调用方拿到 null 时按 roots 顺序兜底
     */
    protected function resolve(string $appName): ?array
    {
        [$prefix, $name] = $this->splitAppName($appName);

        if ($prefix !== '') {
            // 显式前缀: 必须严格匹配,失败立即返回 null(不再降级)
            if (!isset($this->roots[$prefix])) {
                return null;
            }
            $path = $this->roots[$prefix] . $name . DIRECTORY_SEPARATOR;
            return is_dir($path) ? [$prefix, $name, $path] : null;
        }

        // 多根顺序查找
        foreach ($this->roots as $key => $root) {
            $path = $root . $name . DIRECTORY_SEPARATOR;
            if (is_dir($path)) {
                return [$key, $name, $path];
            }
        }
        return null;
    }

    /**
     * 拆分应用名
     *   "app2:blog" → ["app2", "blog"]
     *   "blog"      → ["",     "blog"]
     */
    protected function splitAppName(string $fullName): array
    {
        if ($fullName !== '' && str_contains($fullName, ':')) {
            [$prefix, $name] = explode(':', $fullName, 2);
            return [$prefix ?: '', $name];
        }
        return ['', $fullName];
    }

    protected function getScriptName(): string
    {
        if (isset($_SERVER['SCRIPT_FILENAME'])) {
            $file = $_SERVER['SCRIPT_FILENAME'];
        } elseif (isset($_SERVER['argv'][0])) {
            $file = realpath($_SERVER['argv'][0]);
        }
        return isset($file) ? pathinfo($file, PATHINFO_FILENAME) : '';
    }

    /**
     * 把 resolve() 结果落地到 App上下文
     */
    protected function applyResolved(array $resolved, string $urlName): bool
    {
        [$prefix, $name, $appPath] = $resolved;

        $this->app->http->name($name);

        // 应用目录
        $this->app->setAppPath($appPath);

        // 命名空间
        $nsPrefix = $this->namespaces[$prefix] ?? $prefix;
        $this->app->setNamespace($nsPrefix . '\\' . $name);

        // 运行时: 按根 + 应用双层隔离
        $this->app->setRuntimePath(
            $this->app->getRuntimePath() . $prefix . DIRECTORY_SEPARATOR . $name . DIRECTORY_SEPARATOR
        );

        // 路由目录
        $this->app->http->setRoutePath($this->getRoutePath());

        // 应用专属配置/中间件/provider/语言包
        $this->loadApp($name, $appPath);

        return true;
    }

    protected function loadApp(string $appName, string $appPath): void
    {
        if (is_file($appPath . 'common.php')) {
            include_once $appPath . 'common.php';
        }

        $files = glob($appPath . 'config' . DIRECTORY_SEPARATOR . '*' . $this->app->getConfigExt());
        foreach ($files as $file) {
            $this->app->config->load($file, pathinfo($file, PATHINFO_FILENAME));
        }

        if (is_file($appPath . 'event.php')) {
            $this->app->loadEvent(include $appPath . 'event.php');
        }
        if (is_file($appPath . 'middleware.php')) {
            $this->app->middleware->import(include $appPath . 'middleware.php', 'app');
        }
        if (is_file($appPath . 'provider.php')) {
            $this->app->bind(include $appPath . 'provider.php');
        }

        $this->app->loadLangPack($this->app->lang->defaultLangSet());
    }
}