<?php

namespace App\Http\Controllers;

use App\Exports\InvoicesExport;
use Carbon\Carbon;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Auth;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Log;
use Illuminate\Support\Facades\Storage;
use Illuminate\Support\Facades\Validator;
use Maatwebsite\Excel\Facades\Excel;
use PhpOffice\PhpSpreadsheet\Shared\Date as ExcelDate;

/**
 * Monsoon Yatra Activity List — MySQL-backed import + filtered report.
 *
 * Quick Action (Rapport admin, titans or team2 partition):
 *   Type: external_with_token
 *   URL:  https://<laravel-domain>/monsoonyatraactivitylist/report?token=TOKEN
 */
class MonsoonyatraactivitylistController extends Controller
{
    private const ALLOWED_DOMAINS = ['titans', 'team2'];

    private const ACTIVITIES_TABLE = 'team3_monsoon_yatra_activities';

    private const IMPORTS_TABLE = 'team3_monsoon_yatra_imports';

    private const SESSION_TOKEN_KEY = 'monsoon_yatra_report_token';

    private ?string $accessToken = null;

    private ?object $reportUser = null;

    public function __construct()
    {
        $this->_viewname = 'monsoonyatraactivitylist';
        $this->_title = 'Monsoon Yatra Activity List';
        $this->_base_url = '/monsoonyatraactivitylist';

        $this->middleware(function ($request, $next) {
            $action = $request->route('action');
            if (in_array($action, ['report', 'export'], true)) {
                return $next($request);
            }
            if ($action === null && $request->route()->getName() === 'monsoonyatraactivitylist-list' && $request->filled('token')) {
                return $next($request);
            }
            if (!Auth::check()) {
                return redirect('/login');
            }
            $this->assertAllowedWebAccess();

            return $next($request);
        });
    }

    public function list(Request $request)
    {
        $this->bootstrapTokenSession($request);
        if ($request->hasSession()) {
            $request->session()->save();
        }

        if ($request->filled('token')) {
            return redirect($this->buildUrl('/report', $request));
        }

        return redirect($this->_base_url . '/report');
    }

    public function report(Request $request)
    {
        $this->bootstrapTokenSession($request);
        if ($request->hasSession()) {
            $request->session()->save();
        }

        $token = $this->assertReportAccess($request);
        $filters = $this->resolveFilters($request);
        $query = $this->buildFilteredQuery($filters);
        $perPage = $this->resolvePerPage($request);
        $paginationAppends = $filters;
        if ($token !== '') {
            $paginationAppends['token'] = $token;
        }
        $rows = (clone $query)
            ->orderBy('zone')
            ->orderBy('state')
            ->orderBy('activity_date')
            ->orderBy('educator_name')
            ->orderBy('doctor_name')
            ->paginate($perPage)
            ->appends($paginationAppends);

        return $this->view('report')->with([
            'title' => $this->_title,
            'base_url' => $this->_base_url,
            'token' => $token,
            'rows' => $rows,
            'filters' => $filters,
            'filterOptions' => $this->filterOptions(),
            'canImport' => $this->userCanImport(),
            'buttons' => $this->getReportButtons(),
        ]);
    }

    public function export(Request $request)
    {
        $this->bootstrapTokenSession($request);
        $this->assertReportAccess($request);
        $filters = $this->resolveFilters($request);
        $rows = $this->buildFilteredQuery($filters)
            ->orderBy('zone')
            ->orderBy('state')
            ->orderBy('activity_date')
            ->orderBy('educator_name')
            ->orderBy('doctor_name')
            ->get();

        $header = [
            'Date', 'State', 'Zone', 'Educator HQ', 'Educator Name', 'Educator Manager',
            'Camp Area', 'Time', 'MSL Code', 'Doctor Name', 'Doctor Speciality', 'Chemist Name',
        ];

        $excelData = [$header];
        foreach ($rows as $row) {
            $excelData[] = [
                $this->formatDisplayDate($row->activity_date),
                $row->state,
                $row->zone,
                $row->educator_hq,
                $row->educator_name,
                $row->educator_manager,
                $row->camp_area,
                $row->activity_time,
                $row->msl_code,
                $row->doctor_name,
                $row->doctor_speciality,
                $row->chemist_name,
            ];
        }

        return Excel::download(new InvoicesExport($excelData), 'monsoon-yatra-activity-list.xlsx');
    }

    public function import(Request $request)
    {
        $this->assertAllowedAdmin();

        $imports = DB::table(self::IMPORTS_TABLE)
            ->orderByDesc('created_at')
            ->limit(100)
            ->get();

        return $this->view('import')->with([
            'title' => 'Import Monsoon Yatra Activity Data',
            'base_url' => $this->_base_url,
            'imports' => $imports,
        ]);
    }

    public function postimport(Request $request)
    {
        $this->assertAllowedAdmin();

        try {
            $validator = Validator::make($request->all(), [
                'import_file' => 'required|file|max:10240',
            ], [
                'import_file.required' => 'Please choose a file to upload.',
                'import_file.file' => 'The upload did not contain a valid file.',
                'import_file.max' => 'The file may not be larger than 10MB.',
            ]);

            if ($validator->fails()) {
                return redirect()->back()
                    ->withErrors($validator)
                    ->withInput()
                    ->with('error', $validator->errors()->first());
            }

            $file = $request->file('import_file');
            $extension = strtolower((string) $file->getClientOriginalExtension());
            if (!in_array($extension, ['xlsx', 'xls', 'csv'], true)) {
                return redirect()->back()
                    ->withInput()
                    ->with('error', 'Only .xlsx, .xls, and .csv files are supported.');
            }

            $importId = DB::table(self::IMPORTS_TABLE)->insertGetId([
                'file_name' => $file->getClientOriginalName(),
                'status' => 'processing',
                'uploaded_by' => (string) Auth::id(),
                'created_at' => now(),
                'updated_at' => now(),
            ]);

            $inserted = 0;
            $replaced = 0;
            $skipped = 0;
            $errors = [];

            $rows = $this->parseImportFile($file);
            if (empty($rows['headers']) || empty($rows['data'])) {
                throw new \RuntimeException('The file is empty or has no data rows.');
            }

            $columnIndex = $this->mapHeaderIndexes($rows['headers']);
            if (!isset($columnIndex['activity_date'])) {
                throw new \RuntimeException('Required column Date was not found in the file header row.');
            }

            foreach ($rows['data'] as $rowIndex => $row) {
                $lineNo = $rowIndex + 2;
                try {
                    $record = $this->mapRowToRecord($row, $columnIndex);
                    if (empty($record['activity_date'])) {
                        $skipped++;
                        continue;
                    }
                    if (empty($record['msl_code']) && empty($record['doctor_name'])) {
                        $skipped++;
                        continue;
                    }

                    $existing = DB::table(self::ACTIVITIES_TABLE)
                        ->where('activity_date', $record['activity_date'])
                        ->where('msl_code', $record['msl_code'] ?? '')
                        ->where('educator_name', $record['educator_name'] ?? '')
                        ->where('activity_time', $record['activity_time'] ?? '')
                        ->first();

                    $payload = array_merge($record, [
                        'import_id' => $importId,
                        'updated_at' => now(),
                    ]);

                    if ($existing) {
                        DB::table(self::ACTIVITIES_TABLE)->where('id', $existing->id)->update($payload);
                        $replaced++;
                    } else {
                        DB::table(self::ACTIVITIES_TABLE)->insert(array_merge($payload, [
                            'created_at' => now(),
                        ]));
                        $inserted++;
                    }
                } catch (\Throwable $e) {
                    $errors[] = $this->formatRowError($lineNo, $e);
                }
            }

            $status = empty($errors) ? 'completed' : 'completed_with_errors';
            $this->updateImportLog($importId, [
                'status' => $status,
                'total_rows' => count($rows['data']),
                'inserted_count' => $inserted,
                'replaced_count' => $replaced,
                'skipped_count' => $skipped,
                'error_count' => count($errors),
                'error_log' => empty($errors) ? null : implode("\n", array_slice($errors, 0, 50)),
                'processed_at' => now(),
                'updated_at' => now(),
            ]);

            $message = "Import complete. Inserted: {$inserted}, Replaced: {$replaced}, Skipped: {$skipped}.";
            if (!empty($errors)) {
                $message .= ' Errors: ' . count($errors) . ' (see import log).';
            }

            return redirect($this->_base_url . '/import')->with('message', $message);
        } catch (\Throwable $e) {
            Log::error('Monsoon Yatra activity import failed', [
                'error' => $e->getMessage(),
                'user_id' => Auth::id(),
            ]);

            if (isset($importId)) {
                $this->updateImportLog($importId, [
                    'status' => 'failed',
                    'error_log' => $e->getMessage(),
                    'processed_at' => now(),
                    'updated_at' => now(),
                ]);
            }

            return redirect()->back()
                ->withInput()
                ->with('error', $this->sanitizeDbString($e->getMessage()) ?: 'Import failed.');
        }
    }

    protected function getReportButtons(): array
    {
        $buttons = [];
        if (Auth::check() && $this->userCanImport()) {
            $buttons[] = ['title' => 'Import', 'link' => $this->_base_url . '/import'];
        }

        return $buttons;
    }

    protected function userCanImport(): bool
    {
        $permissions = $this->resolveUserPermissions();

        return in_array('all_data_access', $permissions, true)
            || in_array('formexports_get_all', $permissions, true);
    }

    protected function resolveUserPermissions(): array
    {
        if ($this->reportUser !== null) {
            $permissions = $this->reportUser->permissions ?? [];
            if (is_array($permissions)) {
                return $permissions;
            }
            if (($this->reportUser->all_data_access ?? false) === true) {
                return ['all_data_access'];
            }

            return [];
        }

        $user = Auth::user();
        if ($user === null) {
            return [];
        }

        $permissions = json_decode($user->permissions ?? '[]', true);

        return is_array($permissions) ? $permissions : [];
    }

    protected function assertAllowedWebAccess(): void
    {
        $user = Auth::user();
        if (!$this->userDomainIsAllowed((string) ($user->domain ?? ''))) {
            abort(403);
        }
    }

    protected function assertAllowedAdmin(): void
    {
        $this->assertAllowedWebAccess();
        if (!$this->userCanImport()) {
            abort(403);
        }
    }

    protected function assertReportAccess(Request $request): string
    {
        $token = $this->resolveAccessToken($request);
        if ($token) {
            $payload = $this->decodeTokenPayload($token);
            $user = $this->getUserFromToken($token);
            if (!$user || !$this->isAllowedDomainUser($user)) {
                abort(403, 'Access denied. A valid titans or team2 token is required.');
            }
            if ($this->isTokenPayloadExpired($payload)) {
                $this->forgetPersistedToken($request);
                abort(401, 'Your access token has expired. Please open a fresh link from the app.');
            }

            $this->accessToken = $token;
            $this->reportUser = $user;

            return $token;
        }

        if (Auth::check() && $this->userDomainIsAllowed((string) (Auth::user()->domain ?? ''))) {
            return '';
        }

        if ($request->filled('token')) {
            abort(403, 'Invalid or truncated access token. Please open the full link from the app.');
        }

        abort(401, 'Access token is required. Open this report with ?token=... from the app.');
    }

    protected function bootstrapTokenSession(Request $request): void
    {
        $token = $this->extractRequestToken($request);
        if ($token === '') {
            return;
        }

        $payload = $this->decodeTokenPayload($token);
        $user = is_object($payload) ? ($payload->user ?? null) : null;
        if ($user && $this->isAllowedDomainUser($user) && !$this->isTokenPayloadExpired($payload)) {
            $this->persistAccessToken($request, $token);
        }
    }

    protected function resolveAccessToken(Request $request): ?string
    {
        $fromRequest = $this->extractRequestToken($request);
        if ($fromRequest !== '') {
            $payload = $this->decodeTokenPayload($fromRequest);
            $user = is_object($payload) ? ($payload->user ?? null) : null;
            if ($user && $this->isAllowedDomainUser($user) && !$this->isTokenPayloadExpired($payload)) {
                $this->persistAccessToken($request, $fromRequest);

                return $fromRequest;
            }
        }

        $storedToken = $this->loadPersistedToken($request);
        if ($storedToken !== '') {
            $payload = $this->decodeTokenPayload($storedToken);
            $user = is_object($payload) ? ($payload->user ?? null) : null;
            if ($user && $this->isAllowedDomainUser($user) && !$this->isTokenPayloadExpired($payload)) {
                return $storedToken;
            }

            $this->forgetPersistedToken($request);
        }

        return null;
    }

    protected function extractRequestToken(Request $request): string
    {
        $raw = $request->query('token', $request->input('token'));
        if ($raw === null || $raw === '') {
            $raw = $request->header('Authorization') ?? '';
        }

        return $this->normalizeRawToken((string) $raw);
    }

    protected function persistAccessToken(Request $request, string $token): void
    {
        $request->session()->put(self::SESSION_TOKEN_KEY, $token);
        $this->tokenStorage()->put($this->tokenStoragePath($request), $token);
    }

    protected function loadPersistedToken(Request $request): string
    {
        if ($request->session()->has(self::SESSION_TOKEN_KEY)) {
            $sessionToken = $this->normalizeRawToken((string) $request->session()->get(self::SESSION_TOKEN_KEY));
            if ($sessionToken !== '') {
                return $sessionToken;
            }
        }

        $path = $this->tokenStoragePath($request);
        if ($this->tokenStorage()->exists($path)) {
            return $this->normalizeRawToken((string) $this->tokenStorage()->get($path));
        }

        return '';
    }

    protected function forgetPersistedToken(Request $request): void
    {
        $request->session()->forget(self::SESSION_TOKEN_KEY);
        $path = $this->tokenStoragePath($request);
        if ($this->tokenStorage()->exists($path)) {
            $this->tokenStorage()->delete($path);
        }
    }

    protected function tokenStoragePath(Request $request): string
    {
        return 'monsoon_yatra_report_tokens/' . hash('sha256', $request->session()->getId());
    }

    protected function tokenStorage()
    {
        return Storage::disk('local');
    }

    protected function isTokenPayloadExpired(?object $payload): bool
    {
        if (!is_object($payload) || !isset($payload->exp)) {
            return false;
        }

        return (int) $payload->exp < time();
    }

    protected function normalizeRawToken(string $token): string
    {
        $token = trim($token);
        if (stripos($token, 'Bearer ') === 0) {
            $token = trim(substr($token, 7));
        }

        if (substr_count($token, '.') === 2) {
            $parts = explode('.', $token);
            $parts[1] = str_replace(' ', '+', $parts[1]);
            if (isset($parts[2])) {
                $parts[2] = str_replace(' ', '+', $parts[2]);
            }
            $token = implode('.', $parts);
        }

        return $token;
    }

    protected function getUserFromToken(string $token): ?object
    {
        $payload = $this->decodeTokenPayload($token);
        if (!is_object($payload)) {
            return null;
        }

        $user = $payload->user ?? null;
        if (!is_object($user)) {
            return null;
        }

        if (!isset($user->permissions) && isset($payload->permissions)) {
            $user->permissions = $payload->permissions;
        }
        if (!isset($user->all_data_access) && isset($payload->all_data_access)) {
            $user->all_data_access = $payload->all_data_access;
        }

        return $user;
    }

    protected function decodeTokenPayload(string $token): ?object
    {
        $token = $this->normalizeRawToken($token);
        $parts = explode('.', $token);
        if (count($parts) < 2 || $parts[1] === '') {
            return null;
        }

        $payloadSegment = strtr($parts[1], '-_', '+/');
        $padding = strlen($payloadSegment) % 4;
        if ($padding > 0) {
            $payloadSegment .= str_repeat('=', 4 - $padding);
        }

        $payload = json_decode(base64_decode($payloadSegment));

        return is_object($payload) ? $payload : null;
    }

    protected function userDomainIsAllowed(string $domain): bool
    {
        return in_array(strtolower($domain), self::ALLOWED_DOMAINS, true);
    }

    protected function isAllowedDomainUser(object $user): bool
    {
        $domain = strtolower((string) ($user->domain ?? ''));
        if ($this->userDomainIsAllowed($domain)) {
            return true;
        }

        $partition = strtolower((string) ($user->partition ?? ''));
        foreach (self::ALLOWED_DOMAINS as $allowedDomain) {
            if ($partition === 'rapport-' . $allowedDomain) {
                return true;
            }
        }

        return false;
    }

    protected function buildUrl(string $path, Request $request): string
    {
        $query = array_filter([
            'token' => $request->input('token') ?: $request->session()->get(self::SESSION_TOKEN_KEY),
        ]);
        $url = $this->_base_url . $path;
        if (!empty($query)) {
            $url .= '?' . http_build_query($query);
        }

        return $url;
    }

    protected function resolvePerPage(Request $request): int
    {
        $allowed = [25, 50, 100, 200];
        $perPage = (int) $request->input('per_page', 50);

        return in_array($perPage, $allowed, true) ? $perPage : 50;
    }

    protected function resolveFilters(Request $request): array
    {
        $dateMode = $request->input('date_mode', 'single');
        if (!in_array($dateMode, ['single', 'range'], true)) {
            $dateMode = 'single';
        }

        return [
            'date_mode' => $dateMode,
            'activity_date' => trim((string) $request->input('activity_date', '')),
            'date_from' => trim((string) $request->input('date_from', '')),
            'date_to' => trim((string) $request->input('date_to', '')),
            'zone' => trim((string) $request->input('zone', '')),
            'state' => trim((string) $request->input('state', '')),
            'educator_hq' => trim((string) $request->input('educator_hq', '')),
            'educator_name' => trim((string) $request->input('educator_name', '')),
            'per_page' => (string) $this->resolvePerPage($request),
        ];
    }

    protected function buildFilteredQuery(array $filters)
    {
        $query = DB::table(self::ACTIVITIES_TABLE);

        if ($filters['date_mode'] === 'range') {
            $from = $this->normalizeFilterDate($filters['date_from']);
            $to = $this->normalizeFilterDate($filters['date_to']);
            if ($from) {
                $query->where('activity_date', '>=', $from);
            }
            if ($to) {
                $query->where('activity_date', '<=', $to);
            }
        } else {
            $date = $this->normalizeFilterDate($filters['activity_date']);
            if ($date) {
                $query->where('activity_date', $date);
            }
        }

        foreach (['zone', 'state', 'educator_hq', 'educator_name'] as $field) {
            if ($filters[$field] !== '') {
                $query->where($field, $filters[$field]);
            }
        }

        return $query;
    }

    protected function filterOptions(): array
    {
        $zones = DB::table(self::ACTIVITIES_TABLE)->whereNotNull('zone')->where('zone', '!=', '')->distinct()->orderBy('zone')->pluck('zone');
        $states = DB::table(self::ACTIVITIES_TABLE)->whereNotNull('state')->where('state', '!=', '')->distinct()->orderBy('state')->pluck('state');
        $hqs = DB::table(self::ACTIVITIES_TABLE)->whereNotNull('educator_hq')->where('educator_hq', '!=', '')->distinct()->orderBy('educator_hq')->pluck('educator_hq');
        $educators = DB::table(self::ACTIVITIES_TABLE)->whereNotNull('educator_name')->where('educator_name', '!=', '')->distinct()->orderBy('educator_name')->pluck('educator_name');

        return [
            'zones' => $zones,
            'states' => $states,
            'educator_hqs' => $hqs,
            'educator_names' => $educators,
        ];
    }

    protected function normalizeFilterDate(string $value): ?string
    {
        if ($value === '') {
            return null;
        }
        if (preg_match('/^\d{4}-\d{2}-\d{2}$/', $value)) {
            return $value;
        }

        return $this->parseActivityDate($value);
    }

    protected function parseActivityDate(?string $value): ?string
    {
        if ($value === null || trim($value) === '') {
            return null;
        }

        $value = trim($value);
        if (preg_match('/^\d{4}-\d{2}-\d{2}$/', $value)) {
            return $value;
        }

        // Two-digit year formats must be tried before d/m/Y — otherwise "01/07/26" becomes year 0026.
        foreach (['d/m/y', 'j/n/y', 'd-m-y', 'd/m/Y', 'j/n/Y', 'd-m-Y'] as $format) {
            try {
                $parsed = Carbon::createFromFormat('!' . $format, $value);
                $year = (int) $parsed->format('Y');
                if ($year >= 1970 && $year <= 2100) {
                    return $parsed->format('Y-m-d');
                }
            } catch (\Throwable $e) {
                continue;
            }
        }

        if (is_numeric($value)) {
            $numeric = (float) $value;
            if ($numeric > 30000 && $numeric < 60000) {
                try {
                    return ExcelDate::excelToDateTimeObject($numeric)->format('Y-m-d');
                } catch (\Throwable $e) {
                    // fall through
                }
            }
        }

        if (preg_match('/^\d{4}-\d{2}-\d{2}/', $value)) {
            try {
                $parsed = Carbon::parse($value);
                $year = (int) $parsed->format('Y');
                if ($year >= 1970 && $year <= 2100) {
                    return $parsed->format('Y-m-d');
                }
            } catch (\Throwable $e) {
                return null;
            }
        }

        return null;
    }

    protected function formatDisplayDate(?string $value): string
    {
        if ($value === null || $value === '') {
            return '';
        }
        try {
            return Carbon::parse($value)->format('d/m/Y');
        } catch (\Throwable $e) {
            return $value;
        }
    }

    protected function parseImportFile($file): array
    {
        $extension = strtolower($file->getClientOriginalExtension());
        if (in_array($extension, ['xlsx', 'xls'], true)) {
            $data = Excel::toArray([], $file);
            if (empty($data[0])) {
                return ['headers' => [], 'data' => []];
            }
            $sheet = $data[0];
            $headers = array_shift($sheet);

            return ['headers' => $headers, 'data' => $sheet];
        }

        $lines = array_map('str_getcsv', file($file->getRealPath()));
        $headers = array_shift($lines) ?: [];

        return ['headers' => $headers, 'data' => $lines];
    }

    protected function normalizeHeader(string $header): string
    {
        $header = preg_replace('/^\xEF\xBB\xBF/', '', $header);
        $header = strtolower(trim(preg_replace('/\s+/', ' ', $header)));

        return $header;
    }

    protected function mapHeaderIndexes(array $headers): array
    {
        $map = [];
        foreach ($headers as $index => $header) {
            $field = $this->headerToField($this->normalizeHeader((string) $header));
            if ($field) {
                $map[$field] = $index;
            }
        }

        return $map;
    }

    protected function headerToField(string $normalized): ?string
    {
        $aliases = [
            'date' => 'activity_date',
            'state' => 'state',
            'zone' => 'zone',
            'educator hq' => 'educator_hq',
            'educator name' => 'educator_name',
            'educator manager' => 'educator_manager',
            'camp area' => 'camp_area',
            'time' => 'activity_time',
            'msl code' => 'msl_code',
            'doctor name' => 'doctor_name',
            'doctor speciality' => 'doctor_speciality',
            'doctor specialty' => 'doctor_speciality',
            'chemist name' => 'chemist_name',
        ];

        return $aliases[$normalized] ?? null;
    }

    protected function mapRowToRecord(array $row, array $columnIndex): array
    {
        $get = function (string $field) use ($row, $columnIndex) {
            if (!isset($columnIndex[$field])) {
                return null;
            }
            $value = $row[$columnIndex[$field]] ?? null;
            if ($value === null || $value === '') {
                return null;
            }

            return $this->sanitizeDbString((string) $value);
        };

        $rawDate = isset($columnIndex['activity_date']) ? ($row[$columnIndex['activity_date']] ?? null) : null;
        $activityDate = $this->parseActivityDate($this->normalizeImportDateValue($rawDate));

        return [
            'activity_date' => $activityDate,
            'state' => $get('state'),
            'zone' => $get('zone'),
            'educator_hq' => $get('educator_hq'),
            'educator_name' => $get('educator_name'),
            'educator_manager' => $get('educator_manager'),
            'camp_area' => $get('camp_area'),
            'activity_time' => $get('activity_time'),
            'msl_code' => $get('msl_code'),
            'doctor_name' => $get('doctor_name'),
            'doctor_speciality' => $get('doctor_speciality'),
            'chemist_name' => $get('chemist_name'),
        ];
    }

    protected function normalizeImportDateValue($value): ?string
    {
        if ($value === null || $value === '') {
            return null;
        }

        if ($value instanceof \DateTimeInterface) {
            return $value->format('Y-m-d');
        }

        if (is_numeric($value)) {
            $numeric = (float) $value;
            if ($numeric > 30000 && $numeric < 60000) {
                try {
                    return ExcelDate::excelToDateTimeObject($numeric)->format('Y-m-d');
                } catch (\Throwable $e) {
                    // fall through to string parsing
                }
            }
        }

        return $this->sanitizeDbString((string) $value);
    }

    protected function sanitizeDbString(?string $value): ?string
    {
        if ($value === null) {
            return null;
        }

        $value = str_replace("\0", '', $value);
        if (!mb_check_encoding($value, 'UTF-8')) {
            $converted = @iconv('Windows-1252', 'UTF-8//IGNORE', $value);
            if ($converted !== false && $converted !== '') {
                $value = $converted;
            }
        }
        $value = trim($value);

        return $value === '' ? null : $value;
    }

    protected function formatRowError(int $lineNo, \Throwable $e): string
    {
        $message = $this->sanitizeDbString($e->getMessage()) ?: 'Unknown row error.';
        if (strlen($message) > 240) {
            $message = substr($message, 0, 240) . '...';
        }

        return "Row {$lineNo}: {$message}";
    }

    protected function updateImportLog(int $importId, array $payload): void
    {
        if (array_key_exists('error_log', $payload)) {
            $payload['error_log'] = $payload['error_log'] === null
                ? null
                : $this->sanitizeDbString((string) $payload['error_log']);
        }

        DB::table(self::IMPORTS_TABLE)->where('id', $importId)->update($payload);
    }
}