<?php

namespace App\Http\Controllers\Admin;

use App\Configuration;
use App\ExternalService;
use App\Facade\Theme;
use App\Facade\UserConfig;
use App\Http\Controllers\Controller;
use App\Http\Requests\StoreServiceRequest;
use App\Services\DropboxService;
use App\Storage;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\App;
use Illuminate\Support\Facades\View;

class ServiceController extends Controller
{
    /**
     * List of fields that must be encrypted before being saved.
     *
     * @var string[]
     */
    private $fieldsToEncrypt;

    /**
     * List of fields that depend on the service_type being configured.
     *
     * @var string[]
     */
    private $serviceTypeDependentFields;

    public function __construct()
    {
        $this->middleware('auth');
        View::share('is_admin', true);

        $this->serviceTypeDependentFields = ['app_id', 'app_secret'];
        $this->fieldsToEncrypt = ['app_id', 'app_secret'];
    }

    public function authoriseDropbox(Request $request)
    {
        $this->authorizeAccessToAdminPanel('admin:manage-storage');

        if (!$request->has('state') && !$request->has('code'))
        {
            // TODO flash an error
            return redirect('storages.index');
        }

        try
        {
            $storageID = decrypt($request->get('state'));

            $storage = Storage::where('id', intval($storageID))->first();
            if (is_null($storage))
            {
                // TODO flash an error
                return redirect('storages.index');
            }

            if (is_null($storage->externalService))
            {
                // TODO flash an error
                return redirect('storages.index');
            }

            switch ($storage->externalService->service_type)
            {
                case ExternalService::DROPBOX:
                    $dropbox = new DropboxService();
                    $dropbox->handleAuthenticationResponse($request, $storage);
                    // TODO flash a success message
                    return redirect(route('storage.index'));

                default:
                    // TODO flash an error
                    return redirect('storages.index');
            }
        }
        catch (\Exception $ex)
        {
            // TODO flash an error
            return redirect('storages.index');
        }
    }

    /**
     * Show the form for creating a new resource.
     *
     * @return \Illuminate\Http\Response
     */
    public function create(Request $request)
    {
        $this->authorizeAccessToAdminPanel('admin:manage-services');

        $serviceTypes = $this->serviceTypeList();
        $selectedServiceType = old('service_type', $request->get('service_type'));

        if (!array_key_exists($selectedServiceType, $serviceTypes))
        {
            $selectedServiceType = '';
        }

        $returnTo = old('return_to', $request->get('return_to'));
        if (!array_key_exists($returnTo, $this->validReturnLocations()))
        {
            $returnTo = '';
        }

        return Theme::render('admin.create_service', [
            'callbackUrls' => $this->callbackList(),
            'returnTo' => $returnTo,
            'selectedServiceType' => $selectedServiceType,
            'service' => new ExternalService(),
            'serviceTypes' => $serviceTypes
        ]);
    }

    public function delete(Request $request, $id)
    {
        $this->authorizeAccessToAdminPanel('admin:manage-users');

        $service = ExternalService::where('id', intval($id))->first();
        if (is_null($service))
        {
            App::abort(404);
        }

        if ($this->isServiceInUse($service))
        {
            $request->session()->flash('warning', trans('admin.cannot_delete_service_in_use'));
            return redirect(route('services.index'));
        }

        return Theme::render('admin.delete_service', ['service' => $service]);
    }

    /**
     * Remove the specified resource from storage.
     *
     * @param  int  $id
     * @return \Illuminate\Http\Response
     */
    public function destroy(Request $request, $id)
    {
        $this->authorizeAccessToAdminPanel('admin:manage-services');

        $service = ExternalService::where('id', intval($id))->first();
        if (is_null($service))
        {
            App::abort(404);
        }

        if ($this->isServiceInUse($service))
        {
            $request->session()->flash('warning', trans('admin.cannot_delete_service_in_use'));
            return redirect(route('services.index'));
        }

        try
        {
            $service->delete();
            $request->session()->flash('success', trans('admin.service_deletion_successful', [
                'name' => $service->name
            ]));
        }
        catch (\Exception $ex)
        {
            $request->session()->flash('error', trans('admin.service_deletion_failed', [
                'error_message' => $ex->getMessage(),
                'name' => $service->name
            ]));
        }

        return redirect(route('services.index'));
    }

    /**
     * Show the form for editing the specified resource.
     *
     * @param  int  $id
     * @return \Illuminate\Http\Response
     */
    public function edit(Request $request, $id)
    {
        $this->authorizeAccessToAdminPanel('admin:manage-services');

        $service = ExternalService::where('id', intval($id))->first();
        if (is_null($service))
        {
            App::abort(404);
        }

        // Decrypt the fields that are stored as encrypted in the DB
        foreach ($this->fieldsToEncrypt as $field)
        {
            if (!empty($service->$field))
            {
                $service->$field = decrypt($service->$field);
            }
        }

        return Theme::render('admin.edit_service', [
            'callbackUrls' => $this->callbackList(),
            'service' => $service,
            'serviceTypes' => $this->serviceTypeList()
        ]);
    }

    /**
     * Display a listing of the resource.
     *
     * @return \Illuminate\Http\Response
     */
    public function index(Request $request)
    {
        $this->authorizeAccessToAdminPanel('admin:manage-services');

        $services = ExternalService::orderBy('name')
            ->paginate(UserConfig::get('items_per_page'));

        return Theme::render('admin.list_services', [
            'error' => $request->session()->get('error'),
            'services' => $services,
            'success' => $request->session()->get('success'),
            'warning' => $request->session()->get('warning')
        ]);
    }

    /**
     * Store a newly created resource in storage.
     *
     * @param  \Illuminate\Http\Request  $request
     * @return \Illuminate\Http\Response
     */
    public function store(StoreServiceRequest $request)
    {
        $this->authorizeAccessToAdminPanel('admin:manage-services');

        $service = new ExternalService($request->only(['name', 'service_type']));

        foreach ($this->serviceTypeDependentFields as $field)
        {
            if ($request->has($field))
            {
                $service->$field = in_array($field, $this->fieldsToEncrypt)
                    ? encrypt($request->get($field))
                    : $request->get($field);
            }
        }

        $service->save();

        $returnToLocations = $this->validReturnLocations();
        $returnTo = $request->get('return_to');

        if (array_key_exists($returnTo, $returnToLocations))
        {
            return redirect($returnToLocations[$returnTo]);
        }

        return redirect(route('services.index'));
    }

    /**
     * Update the specified resource in storage.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  int  $id
     * @return \Illuminate\Http\Response
     */
    public function update(StoreServiceRequest $request, $id)
    {
        $this->authorizeAccessToAdminPanel('admin:manage-services');

        $service = ExternalService::where('id', intval($id))->first();
        if (is_null($service))
        {
            App::abort(404);
        }

        $service->fill($request->only(['name', 'service_type']));

        foreach ($this->serviceTypeDependentFields as $field)
        {
            if ($request->has($field))
            {
                $service->$field = in_array($field, $this->fieldsToEncrypt)
                    ? encrypt($request->get($field))
                    : $request->get($field);
            }
        }

        $service->save();

        return redirect(route('services.index'));
    }

    private function callbackList()
    {
        $dropboxService = new DropboxService();

        return [
            ExternalService::DROPBOX => $dropboxService->callbackUrl(),
            ExternalService::FACEBOOK => route('login_callback.facebook'),
            ExternalService::GOOGLE => route('login_callback.google'),
            ExternalService::TWITTER => route('login_callback.twitter')
        ];
    }

    private function isServiceInUse(ExternalService $service)
    {
        switch ($service->service_type)
        {
            case ExternalService::FACEBOOK:
                // Cannot delete Facebook service if it's set as the login provider
                $facebookConfig = Configuration::where('key', 'facebook_external_service_id')->first();
                return !is_null($facebookConfig) && intval($facebookConfig->value) == $service->id;

            case ExternalService::GOOGLE:
                // Cannot delete Google service if it's set as the login provider
                $googleConfig = Configuration::where('key', 'google_external_service_id')->first();
                return !is_null($googleConfig) && intval($googleConfig->value) == $service->id;

            case ExternalService::DROPBOX:
                return Storage::where('external_service_id', $service->id)->count() > 0;

            case ExternalService::TWITTER:
                // Cannot delete Twitter service if it's set as the login provider
                $twitterConfig = Configuration::where('key', 'twitter_external_service_id')->first();
                return !is_null($twitterConfig) && intval($twitterConfig->value) == $service->id;
        }

        return true;
    }

    private function serviceTypeList()
    {
        return [
            ExternalService::DROPBOX => trans(sprintf('services.%s', ExternalService::DROPBOX)),
            ExternalService::FACEBOOK => trans(sprintf('services.%s', ExternalService::FACEBOOK)),
            ExternalService::GOOGLE => trans(sprintf('services.%s', ExternalService::GOOGLE)),
            ExternalService::TWITTER => trans(sprintf('services.%s', ExternalService::TWITTER))
        ];
    }

    private function validReturnLocations()
    {
        return [
            'settings' => route('admin.settings')
        ];
    }
}