<?php

namespace Bluesquare\Connect;

use Bluesquare\Connect\Traits\HasConnectSync;
use GuzzleHttp\Client;
use Illuminate\Http\Request;
use Illuminate\Support\Str;
use Psr\Http\Message\StreamInterface;

class Connect
{
    protected $app;
    protected $synchronized = [];

    public function __construct(array $app)
    {
        $this->app = $app;
    }

    // User config

    public function setSynchronized($models)
    {
        $this->synchronized = [];

        foreach ($models as $model)
        {
            if (!in_array(HasConnectSync::class, class_uses($model)))
                throw new ConnectException("$model does not implement HasConnectSync trait.");

            $class = explode('\\', $model);
            $resource = $model::$connectResource ?? end($class);

            $this->synchronized[$resource] = $model;
        }
    }

    // API

    /**
     * @param $method
     * @param $uri
     * @param null $data
     * @return \Psr\Http\Message\StreamInterface
     * @throws ConnectException
     */
    public function request($method, $uri, $data = null, $auth = true): StreamInterface
    {
        $url = config('bconnect.url') ?? 'https://connect.bluesquare.io';
        $url = $url . '/' . trim($uri, '/');

        $client = new Client();

        $config = [
            'headers' => [
                'Accept' => 'application/json'
            ]
        ];

        if ($auth === true) {
            $config['Authorization'] = 'Bearer ' . $this->getAccessToken();
        }
        elseif ($auth !== false) {
            $config['Authorization'] = 'Bearer ' . $auth;
        }

        if (!is_null($data)) {
            $config['form_params'] = $data;
        }

        try {
             return json_decode(
                 $client->request($method, $url, $config)->getBody(),
                 true
             );

        } catch(\Exception $e) {
            $this->deleteAccessToken();
            throw new ConnectException($e->getMessage());
        }
    }

    // OAuth (user)

    public function redirect($state = null)
    {
        if (is_null($state))
            $state = Str::random();

        $states = session()->get('connect_states');
        if (!is_array($states))
            $states = [];
        $states[] = $state;
        session()->put('connect_states', $states);

        $query = http_build_query([
            'client_id' => config('bconnect.client_id'),
            'scope' => config('bconnect.scopes'),
            'redirect_uri' => config('bconnect.redirect'),
            'response_type' => 'code',
            'state' => $state
        ]);

        $url = config('bconnect.url') . '/oauth/authorize?' . $query;
        return redirect()->to($url);
    }

    public function loginFromCallback(Request $request)
    {
        // State check

        if (!session()->has('connect_states'))
            abort(403, "Session expired");

        $states = session()->get('connect_states');

        if (!is_array($states))
            abort(403, "Session expired");

        if (!$request->has('state') || !in_array($request->state, $states))
            abort(403, "Invalid state");

        unset($states[array_search($request->state, $states)]);

        session()->put('connect_states', $states);

        // Code check

        if (!$request->has('code'))
            abort(403, "Missing authorization code");

        $code = $request->code;

        // Access token

        $data = $this->request('post', 'oauth/token', [
            'grant_type' => 'authorization_code',
            'client_id' => config('bconnect.client_id'),
            'client_secret' => config('bconnect.client_secret'),
            'scope' => config('bconnect.user_scopes'),
            'authorization_code' => $code
        ], false);

        return $data;
    }

    // OAuth (client)

    public function getAccessToken()
    {
        $access_token = cache()->get('bconnect.access_token');
        $access_token_expiration = cache()->get('bconnect.access_token_expiration');

        if ($access_token && $access_token_expiration > time() + 60) {
            return $access_token;
        }

        $data = $this->request('post', '/oauth/token', [
            'grant_type' => 'client_credentials',
            'client_id' => config('bconnect.client_id'),
            'client_secret' => config('bconnect.client_secret'),
            'scope' => config('bconnect.client_scopes')
        ], false);

        cache()->set('bconnect.access_token', $data['access_token']);
        cache()->set('bconnect.access_token_expiration', time() + $data['expires_in']);

        return $data['access_token'];
    }

    public function deleteAccessToken()
    {
        cache()->delete('bconnect.access_token');
        cache()->delete('bconnect.access_token_expiration');
    }

    // Webhooks handler

    /**
     * @param Request $request
     * @return bool
     */
    public function handleWebhook(Request $request)
    {
        $data = $request->validate([
            'connectEventType' => 'required|in:created,updated,deleted',
            'connectResourceType' => 'required',
            'connectResourceTable' => 'required',
            'connectResourceData' => 'required|array',
            'connectResourceData.id' => 'required'
        ]);

        if (!array_key_exists($data['connectResourceType'], $this->synchronized))
            return false;

        $model = $this->synchronized[$data['connectResourceType']];
        $method = $this->getEventMethod($data['connectEventType']);
        $data = $data['connectResourceData'];
        $model::$method($data['id'], $data);

        return true;
    }

    // Resources endpoints

    public function getAll($resourceType)
    {
        return $this->request('get', "api/resources/$resourceType");
    }

    public function get($resourceType, $resourceId)
    {
        return $this->request('get', "api/resources/$resourceType/$resourceId");
    }

    // Resources sync

    public function syncAll($resourceTypes = null)
    {
        $resourceTypes = $resourceTypes ?? $this->synchronized;

        foreach ($resourceTypes as $resourceType)
        {
            if (!array_key_exists($resourceType, $this->synchronized))
                throw new ConnectException("Resource $resourceType not declared as synchronized.");

            $resources = $this->getAll($resourceType);
            $model = $this->synchronized[$resourceType];
            $identifiers = [];

            foreach ($resources as $data)
            {
                $identifiers[] = intval($data['id']);
                $this->sync($resourceType, $data['id'], $data);
            }

            foreach ($model::all() as $item)
            {
                if (!in_array(intval($item->id), $identifiers))
                    $item->delete();
            }
        }
    }

    public function sync($resourceType, $resourceId, $resourceData = null)
    {
        if (is_null($resourceData)) {
            $resourceData = $this->get($resourceType, $resourceId);
        }

        $model = $this->synchronized[$resourceType];
        $item = $model::find($resourceId);
        $method = $this->getEventMethod($item ? 'updated' : 'created');
        $model::$method($resourceId, $resourceData);
    }

    //

    protected function getEventMethod($event)
    {
        return 'onConnectResource' . ucfirst($event);
    }
}