<?php

namespace Illuminate\Broadcasting\Broadcasters;

use Exception;
use ReflectionClass;
use ReflectionFunction;
use Illuminate\Support\Str;
use Illuminate\Container\Container;
use Illuminate\Contracts\Routing\UrlRoutable;
use Illuminate\Contracts\Routing\BindingRegistrar;
use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
use Illuminate\Contracts\Broadcasting\Broadcaster as BroadcasterContract;

abstract class Broadcaster implements BroadcasterContract
{
    /**
     * The registered channel authenticators.
     *
     * @var array
     */
    protected $channels = [];

    /**
     * The binding registrar instance.
     *
     * @var BindingRegistrar
     */
    protected $bindingRegistrar;

    /**
     * Register a channel authenticator.
     *
     * @param  string  $channel
     * @param  callable|string  $callback
     * @return $this
     */
    public function channel($channel, $callback)
    {
        $this->channels[$channel] = $callback;

        return $this;
    }

    /**
     * Authenticate the incoming request for a given channel.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  string  $channel
     * @return mixed
     * @throws \Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException
     */
    protected function verifyUserCanAccessChannel($request, $channel)
    {
        foreach ($this->channels as $pattern => $callback) {
            if (! Str::is(preg_replace('/\{(.*?)\}/', '*', $pattern), $channel)) {
                continue;
            }

            $parameters = $this->extractAuthParameters($pattern, $channel, $callback);

            $handler = $this->normalizeChannelHandlerToCallable($callback);

            if ($result = $handler($request->user(), ...$parameters)) {
                return $this->validAuthenticationResponse($request, $result);
            }
        }

        throw new AccessDeniedHttpException;
    }

    /**
     * Extract the parameters from the given pattern and channel.
     *
     * @param  string  $pattern
     * @param  string  $channel
     * @param  callable|string  $callback
     * @return array
     */
    protected function extractAuthParameters($pattern, $channel, $callback)
    {
        $callbackParameters = $this->extractParameters($callback);

        return collect($this->extractChannelKeys($pattern, $channel))->reject(function ($value, $key) {
            return is_numeric($key);
        })->map(function ($value, $key) use ($callbackParameters) {
            return $this->resolveBinding($key, $value, $callbackParameters);
        })->values()->all();
    }

    /**
     * Extracts the parameters out of what the user passed to handle the channel authentication.
     *
     * @param  callable|string  $callback
     * @return \ReflectionParameter[]
     * @throws \Exception
     */
    protected function extractParameters($callback)
    {
        if (is_callable($callback)) {
            return (new ReflectionFunction($callback))->getParameters();
        } elseif (is_string($callback)) {
            return $this->extractParametersFromClass($callback);
        }

        throw new Exception('Given channel handler is an unknown type.');
    }

    /**
     * Extracts the parameters out of a class channel's "join" method.
     *
     * @param  string  $callback
     * @return \ReflectionParameter[]
     * @throws \Exception
     */
    protected function extractParametersFromClass($callback)
    {
        $reflection = new ReflectionClass($callback);

        if (! $reflection->hasMethod('join')) {
            throw new Exception('Class based channel must define a "join" method.');
        }

        return $reflection->getMethod('join')->getParameters();
    }

    /**
     * Extract the channel keys from the incoming channel name.
     *
     * @param  string  $pattern
     * @param  string  $channel
     * @return array
     */
    protected function extractChannelKeys($pattern, $channel)
    {
        preg_match('/^'.preg_replace('/\{(.*?)\}/', '(?<$1>[^\.]+)', $pattern).'/', $channel, $keys);

        return $keys;
    }

    /**
     * Resolve the given parameter binding.
     *
     * @param  string  $key
     * @param  string  $value
     * @param  array  $callbackParameters
     * @return mixed
     */
    protected function resolveBinding($key, $value, $callbackParameters)
    {
        $newValue = $this->resolveExplicitBindingIfPossible($key, $value);

        return $newValue === $value ? $this->resolveImplicitBindingIfPossible(
            $key, $value, $callbackParameters
        ) : $newValue;
    }

    /**
     * Resolve an explicit parameter binding if applicable.
     *
     * @param  string  $key
     * @param  mixed  $value
     * @return mixed
     */
    protected function resolveExplicitBindingIfPossible($key, $value)
    {
        $binder = $this->binder();

        if ($binder && $binder->getBindingCallback($key)) {
            return call_user_func($binder->getBindingCallback($key), $value);
        }

        return $value;
    }

    /**
     * Resolve an implicit parameter binding if applicable.
     *
     * @param  string  $key
     * @param  mixed  $value
     * @param  array  $callbackParameters
     * @return mixed
     * @throws \Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException
     */
    protected function resolveImplicitBindingIfPossible($key, $value, $callbackParameters)
    {
        foreach ($callbackParameters as $parameter) {
            if (! $this->isImplicitlyBindable($key, $parameter)) {
                continue;
            }

            $instance = $parameter->getClass()->newInstance();

            if (! $model = $instance->resolveRouteBinding($value)) {
                throw new AccessDeniedHttpException;
            }

            return $model;
        }

        return $value;
    }

    /**
     * Determine if a given key and parameter is implicitly bindable.
     *
     * @param  string  $key
     * @param  \ReflectionParameter  $parameter
     * @return bool
     */
    protected function isImplicitlyBindable($key, $parameter)
    {
        return $parameter->name === $key && $parameter->getClass() &&
                        $parameter->getClass()->isSubclassOf(UrlRoutable::class);
    }

    /**
     * Format the channel array into an array of strings.
     *
     * @param  array  $channels
     * @return array
     */
    protected function formatChannels(array $channels)
    {
        return array_map(function ($channel) {
            return (string) $channel;
        }, $channels);
    }

    /**
     * Get the model binding registrar instance.
     *
     * @return \Illuminate\Contracts\Routing\BindingRegistrar
     */
    protected function binder()
    {
        if (! $this->bindingRegistrar) {
            $this->bindingRegistrar = Container::getInstance()->bound(BindingRegistrar::class)
                        ? Container::getInstance()->make(BindingRegistrar::class) : null;
        }

        return $this->bindingRegistrar;
    }

    /**
     * Normalize the given callback into a callable.
     *
     * @param  mixed  $callback
     * @return callable|\Closure
     */
    protected function normalizeChannelHandlerToCallable($callback)
    {
        return is_callable($callback) ? $callback : function (...$args) use ($callback) {
            return Container::getInstance()
                ->make($callback)
                ->join(...$args);
        };
    }
}