<?php

namespace App\Services;

use App\Contracts\ImportExport;
use App\Contracts\Service;
use App\Models\Airport;
use App\Models\Expense;
use App\Repositories\FlightRepository;
use App\Services\ImportExport\AircraftImporter;
use App\Services\ImportExport\AirportImporter;
use App\Services\ImportExport\ExpenseImporter;
use App\Services\ImportExport\FareImporter;
use App\Services\ImportExport\FlightImporter;
use App\Services\ImportExport\SubfleetImporter;
use Illuminate\Support\Facades\Log;
use Illuminate\Support\Facades\Validator;
use Illuminate\Validation\ValidationException;
use League\Csv\Exception;
use League\Csv\Reader;

class ImportService extends Service
{
    protected $flightRepo;

    /**
     * ImporterService constructor.
     *
     * @param FlightRepository $flightRepo
     */
    public function __construct(FlightRepository $flightRepo)
    {
        $this->flightRepo = $flightRepo;
    }

    /**
     * Throw a validation error back up because it will automatically show
     * itself under the CSV file upload, and nothing special needs to be done
     *
     * @param $error
     * @param $e
     *
     * @throws ValidationException
     */
    protected function throwError($error, \Exception $e = null): void
    {
        Log::error($error);
        if ($e) {
            Log::error($e->getMessage());
        }

        $validator = Validator::make([], []);
        $validator->errors()->add('csv_file', $error);

        throw new ValidationException($validator);
    }

    /**
     * @param $csv_file
     *
     * @throws ValidationException
     *
     * @return Reader
     */
    public function openCsv($csv_file)
    {
        try {
            $reader = Reader::createFromPath($csv_file);
            $reader->setDelimiter(',');
            $reader->setEnclosure('"');
            return $reader;
        } catch (Exception $e) {
            $this->throwError('Error opening CSV: '.$e->getMessage(), $e);
        }
    }

    /**
     * Run the actual importer, pass in one of the Import classes which implements
     * the ImportExport interface
     *
     * @param              $file_path
     * @param ImportExport $importer
     *
     * @throws ValidationException
     *
     * @return array
     */
    protected function runImport($file_path, ImportExport $importer): array
    {
        $reader = $this->openCsv($file_path);

        $cols = array_keys($importer->getColumns());
        $first_header = $cols[0];

        $first = true;
        $records = $reader->getRecords($cols);
        foreach ($records as $offset => $row) {
            // check if the first row being read is the header
            if ($first) {
                $first = false;

                if ($row[$first_header] !== $first_header) {
                    $this->throwError('CSV file doesn\'t seem to match import type');
                }

                continue;
            }

            // Do a sanity check on the number of columns first
            if (!$importer->checkColumns($row)) {
                $importer->errorLog('Number of columns in row doesn\'t match');
                continue;
            }

            // turn it into a collection and run some filtering
            $row = collect($row)->map(function ($val, $index) {
                $val = trim($val);
                if ($val === '') {
                    return;
                }

                return $val;
            })->toArray();

            // Try to validate
            $validator = Validator::make($row, $importer->getColumns());
            if ($validator->fails()) {
                $errors = 'Error in row '.$offset.','.implode(';', $validator->errors()->all());
                $importer->errorLog($errors);
                continue;
            }

            $importer->import($row, $offset);
        }

        return $importer->status;
    }

    /**
     * Import aircraft
     *
     * @param string $csv_file
     * @param bool   $delete_previous
     *
     * @throws ValidationException
     *
     * @return mixed
     */
    public function importAircraft($csv_file, bool $delete_previous = true)
    {
        if ($delete_previous) {
            // TODO: delete airports
        }

        $importer = new AircraftImporter();
        return $this->runImport($csv_file, $importer);
    }

    /**
     * Import airports
     *
     * @param string $csv_file
     * @param bool   $delete_previous
     *
     * @throws ValidationException
     *
     * @return mixed
     */
    public function importAirports($csv_file, bool $delete_previous = true)
    {
        if ($delete_previous) {
            Airport::truncate();
        }

        $importer = new AirportImporter();
        return $this->runImport($csv_file, $importer);
    }

    /**
     * Import expenses
     *
     * @param string $csv_file
     * @param bool   $delete_previous
     *
     * @throws ValidationException
     *
     * @return mixed
     */
    public function importExpenses($csv_file, bool $delete_previous = true)
    {
        if ($delete_previous) {
            Expense::truncate();
        }

        $importer = new ExpenseImporter();
        return $this->runImport($csv_file, $importer);
    }

    /**
     * Import fares
     *
     * @param string $csv_file
     * @param bool   $delete_previous
     *
     * @throws ValidationException
     *
     * @return mixed
     */
    public function importFares($csv_file, bool $delete_previous = true)
    {
        if ($delete_previous) {
            // TODO: Delete all from: fares
        }

        $importer = new FareImporter();
        return $this->runImport($csv_file, $importer);
    }

    /**
     * Import flights
     *
     * @param string $csv_file
     * @param bool   $delete_previous
     *
     * @throws ValidationException
     *
     * @return mixed
     */
    public function importFlights($csv_file, bool $delete_previous = true)
    {
        if ($delete_previous) {
            // TODO: Delete all from: flights, flight_field_values
        }

        $importer = new FlightImporter();
        return $this->runImport($csv_file, $importer);
    }

    /**
     * Import subfleets
     *
     * @param string $csv_file
     * @param bool   $delete_previous
     *
     * @throws ValidationException
     *
     * @return mixed
     */
    public function importSubfleets($csv_file, bool $delete_previous = true)
    {
        if ($delete_previous) {
            // TODO: Cleanup subfleet data
        }

        $importer = new SubfleetImporter();
        return $this->runImport($csv_file, $importer);
    }
}