<?php

namespace App\Http\Controllers\Bo;

use App\Enums\CustomerExportType;
use App\Http\Controllers\Controller;
use App\Http\Requests\Bo\CustomerExport;
use App\Models\Answer;
use App\Models\Brand;
use App\Models\Customer;
use App\Models\CustomerInfo;
use App\Models\CustomerLogin;
use App\Models\Question;
use App\Models\SingleOptin;
use App\Models\BrandContactList;
use Illuminate\Database\Eloquent\Builder;
use Illuminate\Database\Query\JoinClause;
use Illuminate\Http\Request;
use Illuminate\Support\Carbon;
use Illuminate\Support\Collection;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Schema;
use Illuminate\Support\Facades\Session;
use Illuminate\Support\Str;
use League\Csv\Writer;
use Symfony\Component\HttpFoundation\StreamedResponse;
use App\Lib\Helpers\MailjetHelper;

class CustomerController extends Controller
{
    /**
     * Create the controller instance.
     */
    public function __construct()
    {
        $this->authorizeResource(Customer::class);
    }

    /**
     * View all customers.
     *
     * @param \Illuminate\Http\Request $request
     * @return \Illuminate\Contracts\View\View
     */
    public function index(Request $request): \Illuminate\Contracts\View\View
    {
        $modelClass     = Customer::class;
        $modelTable     = (new Customer())->getTable();
        $questionModels = null;
        $answerModels   = null;
        $searchFields   = trans('Email, Prénom, Nom');

        // Reset session sorts.
        if ($request->rstSrts) {
            $this->resetSessionSorts($modelTable);
        }
        // Reset session filters.
        if ($request->rstFltrs) {
            $this->resetSessionFilters($modelTable);
        }

        if ($request->filled('search') || Session::get("crud.$modelTable.search")) {
            $columns = ['customer_infos.lastname', 'customer_infos.firstname'];
            $query   = $this->buildCustomerQuery();

            // Apply filters.
            $this->applyBrandFilter($request, $query, $modelTable, $questionModels, $answerModels);
            $this->applySearchFilter($request, $query, $modelTable, $columns);
            $this->applySort($request, $query, $modelTable);

            $customerModels = $query->with(['customer', 'brand'])->simplePaginate($this->getPagination());
        } //end if

        return view('bo.pages.customers.index', [
            'modelClass'     => $modelClass,
            'modelTable'     => $modelTable,
            'customerModels' => $customerModels ?? collect(),
            'searchFields'   => $searchFields,
            'questionModels' => $questionModels,
            'answerModels'   => $answerModels,
        ]);
    }

    /**
     * Show a specific custmer.
     *
     * @param \App\Models\Customer $customer
     * @param \App\Models\Brand    $brand
     * @return \Illuminate\Contracts\View\View
     */
    public function show(Customer $customer, Brand $brand): \Illuminate\Contracts\View\View
    {
        $customerInfos = CustomerInfo::query()->where('customer_id', $customer->id)
            ->where('brand_id', $brand->id)->firstOrFail();
        $customerLogin = CustomerLogin::query()->where('customer_id', $customer->id)
            ->where('brand_id', $brand->id)->first();

        return view('bo.pages.customers.show', compact(
            'customerInfos',
            'customerLogin'
        ));
    }

    /**
     * Delete a specific customer info.
     *
     * @param \App\Models\Customer $customer
     * @param \App\Models\Brand    $brand
     * @return \Illuminate\Http\RedirectResponse
     */
    public function delete(Customer $customer, Brand $brand): \Illuminate\Http\RedirectResponse
    {
        try {
            /** @var \App\Models\CustomerInfo */
            $customerInfo = $customer->info($brand, Customer::FIRST_OR_FAIL);
            /** @var \App\Models\CustomerLogin */
            $customerLogin = $customer->login($brand, Customer::FIRST_OR_FAIL);

            DB::transaction(function () use (
                $brand,
                $customer,
                $customerLogin,
                $customerInfo
            ) {
                if (
                    $customerInfo->delete() === false ||
                    $customerLogin->delete() === false
                ) {
                    throw new \ErrorException('Api failed to delete customer.');
                };

                $customer->optInHistory()->whereHas('brand', function ($q) use ($brand) {
                    $q->where('id', $brand->id);
                })->delete();

                $logins  = $customer->logins()->count();
                $infos   = $customer->infos()->count();
                $history = $customer->optInHistory()->count();

                // If customer is not associated with any brand then delete.
                if (!$logins and !$infos and !$history) {
                    if ($customer->delete() === false) {
                        throw new \ErrorException('Api failed to update customer.');
                    }
                }
            });
        } catch (\ErrorException $e) {
            return redirect()->route('bo.customers.index')
                ->with('error', trans('Le compte n\'a pas pu être supprimé.'));
        } //end try

        return redirect()->route('bo.customers.index')->with('warning', trans('Compte supprimé.'));
    }

    /**
     * Show export the customers form.
     *
     * @return \Illuminate\Contracts\View\View
     */
    public function export(): \Illuminate\Contracts\View\View
    {
        $this->authorize('export', Customer::class);
        $brands = Brand::all();
        return view('bo.pages.customers.export', compact(
            'brands'
        ));
    }

    /**
     * Exports customers following the requested export type.
     *
     * @param \App\Http\Requests\Bo\CustomerExport $request
     * @return \Symfony\Component\HttpFoundation\StreamedResponse|\Illuminate\Http\RedirectResponse
     * @throws \Exception If the request export type in not handled.
     */
    public function exportSubmit(
        CustomerExport $request
    ): \Symfony\Component\HttpFoundation\StreamedResponse|\Illuminate\Http\RedirectResponse {
        $pagination = 2000;

        $w = $this->buildCsvWriter($request->action);

        $exportType = CustomerExportType::make(\intval($request->export_type));

        $response = $this->buildStreamedResponse($exportType);

        switch ($exportType) {
            case CustomerExportType::both:
                $continue = true;
                // ! Continue
            case CustomerExportType::customer:
                $page = 1;
                /** @var \Illuminate\Database\Eloquent\Builder $req */
                $req   = CustomerInfo::query()->where('brand_id', $request->brand)
                    ->where('opt_in', true);
                $total = $req->count();
                $pages = \ceil($total / $pagination);
                do {
                    /** @var \Illuminate\Pagination\LengthAwarePaginator $items */
                    $items = $req->with('customer', function ($q) {
                        $q->select(['id', 'email']);
                    })->paginate(
                        $pagination,
                        ['lastname', 'firstname', 'hashcode', 'customer_id'],
                        'page',
                        $page
                    );
                    $items->map(function (CustomerInfo $customerInfo) use ($w) {
                        $w->insertOne([
                            'lastname' => $customerInfo->lastname,
                            'firstname' => $customerInfo->firstname,
                            'email' => $customerInfo->customer->email,
                            'hashcode' => $customerInfo->hashcode
                        ]);
                    });
                } while ($page++ <= $pages);
                if (!isset($continue)) {
                    break;
                }
                // ! Continue
            case CustomerExportType::singleOptin:
                SingleOptin::query()->whereHas('brand', function (Builder $q) use ($request) {
                    $q->where('id', $request->brand);
                })->get()->map(function (SingleOptin $singleOptin) use ($w) {
                    $w->insertOne([
                        'lastname' => '',
                        'firstname' => '',
                        'email' => $singleOptin->email,
                        'hashcode' => $singleOptin->hashcode
                    ]);
                });
                break;
            default:
                throw new \Exception(sprintf('Unhandled CustomerExportType %s', $exportType->label()));
        } //end switch

        if ($request->action === "export") {
            return $this->buildCsvDownloadResponse($response, $w);
        }

        return $this->importToMailjet($request, $w)
    }

    /**
     * Reset all session sorts.
     *
     * @param string $table
     * @return void
     */
    private function resetSessionSorts(string $table): void
    {
        Session::forget([
            "crud.$table.sort_col",
            "crud.$table.sort_way",
        ]);
    }

    /**
     * Reset all session filters.
     *
     * @param string $table
     * @return void
     */
    private function resetSessionFilters(string $table): void
    {
        Session::forget([
            "crud.$table.brand",
            "crud.$table.question",
            "crud.$table.answer",
            "crud.$table.search",
        ]);
    }

    /**
     * Build the customer query.
     *
     * @return Builder
     */
    private function buildCustomerQuery(): Builder
    {
        return CustomerInfo::query()
            ->join('customer_logins', function (JoinClause $join) {
                $join->on('customer_logins.brand_id', '=', 'customer_infos.brand_id')
                    ->on('customer_logins.customer_id', '=', 'customer_infos.customer_id');
            })
            ->join('customers', fn($join) => $join->on('customers.id', '=', 'customer_infos.customer_id'))
            ->join('brands', fn($join) => $join->on('brands.id', '=', 'customer_infos.brand_id'));
    }

    /**
     * Build the streamed HTTP response.
     *
     * @param CustomerExportType $exportType
     * @return StreamedResponse
     */
    private function buildStreamedResponse(CustomerExportType $exportType): StreamedResponse
    {
        // * We send the CSV using Symfony StreamedResponse.
        $response = new StreamedResponse();
        $response->headers->set('Content-Encoding', 'none');
        $response->headers->set('Content-Type', 'text/csv; charset=UTF-8');
        $response->headers->set('Description', 'File Transfer');
        $response->headers->set(
            'Content-Disposition',
            sprintf(
                'attachment; filename="Export pour newsletter %s %s.csv"',
                Carbon::now()->isoFormat('DD-MM-YYYY_HH-mm'),
                Str::slug($exportType->label())
            )
        );

        return $response;
    }

    /**
     * Build the CSV writer.
     *
     * @param string $action
     * @return Writer
     */
    private function buildCsvWriter(string $action): Writer
    {
        if ($action === 'export') {
            $header = '"lastname";"firstname";"email";"hashcode"';

            $w = Writer::createFromString($header . PHP_EOL);
            $w->setDelimiter(';');
        } else {
            $header = 'lastname,firstname,email,hashcode';

            $w = Writer::createFromString($header . PHP_EOL);
            $w->setDelimiter(',');
        }

        $w->setEnclosure('"');
        $w->setOutputBOM(Writer::BOM_UTF8);

        return $w;
    }

    /**
     * Attach a download callback to the response.
     *
     * @param StreamedResponse $response
     * @param Writer           $writer
     * @return StreamedResponse
     */
    private function buildCsvDownloadResponse(StreamedResponse $response, Writer $writer): StreamedResponse
    {
        /*
            We create a callable to output the CSV in chunk
            with Symfony StreamResponse you can flush the body content if necessary
            see Symfony documentation for more information
        */

        // * The flush value should depend on your CSV size.
        $flush_threshold = 1000;

        $response->setCallback(function () use ($writer, $flush_threshold) {
            foreach ($writer->chunk(1024) as $offset => $chunk) {
                echo $chunk;
                if ($offset % $flush_threshold === 0) {
                    flush();
                }
            }
        });

        return $response;
    }

    /**
     * Import contacts to Mailjet
     *
     * @param CustomerExport $request
     * @param Writer         $writer
     * @return \Illuminate\Http\RedirectResponse
     */
    private function importToMailjet(CustomerExport $request, Writer $writer): \Illuminate\Http\RedirectResponse
    {
        $brandModel  = Brand::find($request->brand);
        $contactList = MailjetHelper::createContactList(
            sprintf("%s - %s", now()->format('d/m/Y'), $brandModel->name)
        );

        if (empty($contactList)) {
            return back()->withErrors('Impossible de créer la liste de contacts Mailjet.');
        }

        $mailjetListId = $contactList[0]['ID'];

        BrandContactList::create([
            'brand_id'        => $brandModel->getKey(),
            'mailjet_list_id' => $mailjetListId,
        ]);

        $csvData   = MailjetHelper::uploadCsvFile($mailjetListId, $writer->toString());
        $importJob = MailjetHelper::importContacts($mailjetListId, $csvData['ID']);

        return back()->with('success', 'Liste créée et contacts importés avec succès.');
    }

    /**
     * Apply all filters (brand, question, answer).
     *
     * @param \Illuminate\Http\Request              $request
     * @param \Illuminate\Database\Eloquent\Builder $query
     * @param string                                $table
     * @param \Illuminate\Support\Collection|null   $questionModels
     * @param \Illuminate\Support\Collection|null   $answerModels
     * @return void
     */
    private function applyBrandFilter(
        Request $request,
        Builder &$query,
        string $table,
        ?Collection &$questionModels,
        ?Collection &$answerModels
    ): void {
        $brand = $request->brand ?? Session::get("crud.$table.brand");
        if (!(int) $brand) {
            return;
        }
        Session::put("crud.$table.brand", $brand);
        $query->where('customer_infos.brand_id', $brand);

        $questionModels = Question::getAllModelsFromBrand($brand);

        if (($request->filled('question') || Session::has("crud.$table.question")) && $questionModels->count()) {
            $question = $request->question ?? Session::get("crud.$table.question");
            Session::put("crud.$table.question", $question);

            $answerModels    = Answer::getAllAnswersFromQuestion($question);
            $questionAnswers = Question::find($question)?->answers->modelKeys() ?? [];

            $query->whereHas('customer.answers', fn($q) => $q->whereIn('answer_id', $questionAnswers));

            if (
                ($request->filled('answer') || Session::has("crud.$table.answer"))
                && $questionModels->count()
                && $answerModels->count()
            ) {
                $answer = $request->answer ?? Session::get("crud.$table.answer");
                Session::put("crud.$table.answer", $answer);

                $query->whereHas('customer.answers', fn($q) => $q->whereKey($answer));
            }
        }
    }

    /**
     * Apply the search filter.
     *
     * @param \Illuminate\Http\Request              $request
     * @param \Illuminate\Database\Eloquent\Builder $query
     * @param string                                $table
     * @param array                                 $columns
     * @return void
     */
    private function applySearchFilter(Request $request, Builder &$query, string $table, array $columns): void
    {
        $search = $request->search ?? Session::get("crud.$table.search");
        Session::put("crud.$table.search", $search);

        $query->where(function ($q) use ($columns, $search) {
            foreach ($columns as $column) {
                $q->orWhere($column, 'LIKE', "%$search%");
            }

            $q->orWhere('customers.email', 'LIKE', "%$search%")
                ->orWhere('customer_logins.last_connection', 'LIKE', "%$search%");
        });
    }

    /**
     * Apply sorts.
     *
     * @param \Illuminate\Http\Request              $request
     * @param \Illuminate\Database\Eloquent\Builder $query
     * @param string                                $table
     * @return void
     */
    private function applySort(Request $request, Builder &$query, string $table): void
    {
        $sortCol = $request->sort_col ?? Session::get("crud.$table.sort_col");
        $sortWay = $request->sort_way ?? Session::get("crud.$table.sort_way");

        if ($sortCol) {
            Session::put("crud.$table.sort_col", $sortCol);
        }
        if ($sortWay) {
            Session::put("crud.$table.sort_way", $sortWay);
        }

        $sortable = [
            'brands.name',
            'customers.email',
            'customer_infos.firstname',
            'customer_infos.lastname',
            'customer_infos.opt_in',
            'customer_logins.last_connection',
            'customer_logins.status',
        ];

        if ($sortCol && $sortWay && (Schema::hasColumn($table, $sortCol) || in_array($sortCol, $sortable))) {
            $query->orderBy($sortCol, $sortWay);
        }
    }
}