<?php

namespace App\Http\Controllers;

use App\Exports\InvoicesExport;
use App\Http\Requests\LambdaRequest;
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\Validator;
use Maatwebsite\Excel\Facades\Excel;

/**
 * Titans HCP Gathering Report — MySQL-backed import + token report.
 *
 * Quick Action (Rapport admin, titans partition):
 *   Type: external_with_token
 *   URL:  https://<laravel-domain>/titanshcpgatheringreport/report?token=TOKEN
 */
class TitanshcpgatheringreportController extends Controller
{
    private const DOMAIN = 'titans';

    private const SESSION_TOKEN_KEY = 'titans_hcp_gathering_report_token';

    private ?string $accessToken = null;

    private ?object $reportUser = null;

    public function __construct()
    {
        $this->_viewname = 'titanshcpgatheringreport';
        $this->_title = 'Titans HCP Gathering Report';
        $this->_base_url = '/titanshcpgatheringreport';

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

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

        $this->assertTitansAdmin();

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

        return $this->view('list')->with([
            'title' => $this->_title,
            'base_url' => $this->_base_url,
            'imports' => $imports,
            'buttons' => $this->getListButtons(),
        ]);
    }

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

        return $this->view('import')->with([
            'title' => 'Import Titans HCP Data',
            'base_url' => $this->_base_url,
        ]);
    }

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

        try {
            $validator = Validator::make($request->all(), [
                'report_month' => 'required|date_format:Y-m',
                'import_file' => 'required|file|max:10240',
            ], [
                'report_month.required' => 'Please select a report month.',
                'report_month.date_format' => 'Report month must be in YYYY-MM format.',
                '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.');
            }

            $reportMonth = $request->input('report_month');
            $importId = DB::table('titans_hcp_gathering_imports')->insertGetId([
                'file_name' => $file->getClientOriginalName(),
                'report_month' => $reportMonth,
                '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($columnIndex['pcode']) || !isset($columnIndex['legacy_code'])) {
                throw new \RuntimeException('Required columns PCODE and LEGACY_CODE were 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['pcode']) || empty($record['legacy_code'])) {
                        $skipped++;
                        continue;
                    }

                    $existing = DB::table('titans_hcp_gathering')
                        ->where('pcode', $record['pcode'])
                        ->where('legacy_code', $record['legacy_code'])
                        ->where('report_month', $reportMonth)
                        ->first();

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

                    if ($existing) {
                        DB::table('titans_hcp_gathering')->where('id', $existing->id)->update($payload);
                        $replaced++;
                    } else {
                        DB::table('titans_hcp_gathering')->insert(array_merge($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).';
            }
            if ($inserted === 0 && $replaced === 0) {
                $message .= ' No rows were imported. Check that PCODE and LEGACY_CODE columns are present and populated.';
            }

            return redirect('/titanshcpgatheringreports')->with('message', $message);
        } catch (\Throwable $e) {
            Log::error('Titans HCP gathering 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.');
        }
    }

    public function report(Request $request)
    {
        $token = $this->assertTitansAccess($request);
        $month = $this->resolveReportMonth($request);
        $months = $this->availableMonths();
        $rows = $this->fetchReportRows($month);
        $tmVisitLabel = $this->tmVisitColumnLabel($month);

        return $this->view('report')->with([
            'title' => $this->_title,
            'base_url' => $this->_base_url,
            'token' => $token,
            'month' => $month,
            'months' => $months,
            'rows' => $rows,
            'tm_visit_label' => $tmVisitLabel,
        ]);
    }

    public function export(Request $request)
    {
        $this->assertTitansAccess($request);
        $month = $this->resolveReportMonth($request);
        $rows = $this->fetchReportRows($month);
        $tmVisitLabel = $this->tmVisitColumnLabel($month);

        $header = [
            'ZBM', 'RBM', 'AREA', 'HQ', 'TM Name', 'HCP NAME',
            'LEGACY_CODE', 'PCODE', 'AgreementNo', 'Status', 'EAS ID',
            'Activity Report Status', 'Payment Status', 'Closure Done', 'Closure Approved',
            $tmVisitLabel,
        ];

        $excelData = [$header];
        foreach ($rows as $row) {
            $excelData[] = [
                $row->zbm,
                $row->rbm,
                $row->area,
                $row->hq,
                $row->tm_name,
                $row->hcp_name,
                $row->legacy_code,
                $row->pcode,
                $row->agreement_no,
                $row->status,
                $row->eas_id,
                $row->activity_report_status,
                $row->payment_status,
                $row->closure_done,
                $row->closure_approved,
                $row->tm_visit,
            ];
        }

        $filename = 'titans-hcp-gathering-' . $month . '.xlsx';
        return Excel::download(new InvoicesExport($excelData), $filename);
    }

    protected function getListButtons(): array
    {
        return [
            ['title' => 'Import', 'link' => $this->_base_url . '/import'],
        ];
    }

    protected function assertTitansAdmin(): void
    {
        $user = Auth::user();
        $permissions = json_decode($user->permissions ?? '[]');
        if (!is_array($permissions)) {
            $permissions = [];
        }
        if (($user->domain ?? '') !== self::DOMAIN) {
            abort(403);
        }
        if (!in_array('all_data_access', $permissions, true) && !in_array('formexports_get_all', $permissions, true)) {
            abort(403);
        }
    }

    protected function assertTitansAccess(Request $request): string
    {
        $token = $this->resolveAccessToken($request);
        if (!$token) {
            abort(401, 'Access token is required');
        }

        $user = $this->getUserFromToken($token);
        if (!$user || !$this->isTitansUser($user)) {
            abort(403, 'Invalid access token or user is not in the Titans domain.');
        }

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

    protected function resolveAccessToken(Request $request): ?string
    {
        $fromRequest = $this->extractRequestToken($request);
        if ($fromRequest !== '') {
            $user = $this->getUserFromToken($fromRequest);
            if ($user && $this->isTitansUser($user)) {
                $this->persistAccessToken($request, $fromRequest);

                return $fromRequest;
            }
        }

        $storedToken = $this->loadPersistedToken($request);
        if ($storedToken !== '') {
            $user = $this->getUserFromToken($storedToken);
            if ($user && $this->isTitansUser($user)) {
                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);
    }

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

        return $this->normalizeRawToken((string) $request->session()->get(self::SESSION_TOKEN_KEY));
    }

    protected function forgetPersistedToken(Request $request): void
    {
        $request->session()->forget(self::SESSION_TOKEN_KEY);
    }

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

        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 isTitansUser(object $user): bool
    {
        $domain = strtolower((string) ($user->domain ?? ''));
        if ($domain === self::DOMAIN) {
            return true;
        }

        $partition = strtolower((string) ($user->partition ?? ''));
        return $partition === 'rapport-' . self::DOMAIN;
    }

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

    protected function resolveReportMonth(Request $request): string
    {
        $month = $request->input('month');
        if ($month && preg_match('/^\d{4}-\d{2}$/', $month)) {
            return $month;
        }
        $latest = DB::table('titans_hcp_gathering')->max('report_month');
        return $latest ?: Carbon::now()->format('Y-m');
    }

    protected function availableMonths(): array
    {
        $query = DB::table('titans_hcp_gathering')
            ->select('report_month')
            ->distinct();
        $query = $this->applyReportUserScope($query, $this->reportUser);

        return $query
            ->orderByDesc('report_month')
            ->pluck('report_month')
            ->all();
    }

    protected function fetchReportRows(string $month)
    {
        $query = DB::table('titans_hcp_gathering')
            ->where('report_month', $month);
        $query = $this->applyReportUserScope($query, $this->reportUser);

        return $query
            ->orderBy('hcp_name')
            ->orderBy('pcode')
            ->get();
    }

    protected function userHasAllDataAccess(?object $user): bool
    {
        if (!$user) {
            return false;
        }

        if (!empty($user->all_data_access)) {
            return true;
        }

        $permissions = $user->permissions ?? '[]';
        if (is_string($permissions)) {
            $permissions = json_decode($permissions, true);
        }
        if (!is_array($permissions)) {
            $permissions = [];
        }

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

    protected function resolveScopedHierarchyIds(?object $user): array
    {
        if (!$user || empty($user->id)) {
            return [];
        }

        $partition = 'rapport-' . ($user->domain ?? self::DOMAIN);
        $hierarchyIds = [];

        if (!empty($user->hierarchy)) {
            $hierarchyIds[] = $user->hierarchy;
        }

        try {
            $response = LambdaRequest::getrequest('ums', 'hierarchy/hierarchy_below_me', [
                'partition' => $partition,
                'user_id' => $user->id,
            ]);
            if (isset($response->data->hierarchies) && is_array($response->data->hierarchies)) {
                foreach ($response->data->hierarchies as $hierarchy) {
                    if (!empty($hierarchy->id)) {
                        $hierarchyIds[] = $hierarchy->id;
                    }
                }
            }
        } catch (\Throwable $e) {
            Log::warning('Titans HCP report hierarchy scope failed', [
                'user_id' => $user->id ?? null,
                'error' => $e->getMessage(),
            ]);
        }

        return array_values(array_unique(array_filter($hierarchyIds)));
    }

    protected function applyReportUserScope($query, ?object $user)
    {
        if (!$user || $this->userHasAllDataAccess($user)) {
            return $query;
        }

        $hierarchyIds = $this->resolveScopedHierarchyIds($user);
        $userId = (string) ($user->id ?? '');

        return $query->where(function ($scopedQuery) use ($hierarchyIds, $userId) {
            if (empty($hierarchyIds) && $userId === '') {
                $scopedQuery->whereRaw('1 = 0');
                return;
            }

            if (!empty($hierarchyIds)) {
                $scopedQuery->whereIn('hierarchy_id', $hierarchyIds);
            }
            if ($userId !== '') {
                $scopedQuery->orWhere('user_id', $userId);
            }
        });
    }

    protected function tmVisitColumnLabel(string $month): string
    {
        try {
            return Carbon::createFromFormat('Y-m', $month)->format('F') . ' TM Visit';
        } catch (\Throwable $e) {
            return 'TM Visit';
        }
    }

    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 = [];
        $tmVisitIndex = null;
        foreach ($headers as $index => $header) {
            $normalized = $this->normalizeHeader((string) $header);
            if (str_contains($normalized, 'tm visit')) {
                $tmVisitIndex = $index;
                continue;
            }
            $field = $this->headerToField($normalized);
            if ($field) {
                $map[$field] = $index;
            }
        }
        if ($tmVisitIndex !== null) {
            $map['tm_visit'] = $tmVisitIndex;
        }
        return $map;
    }

    protected function headerToField(string $normalized): ?string
    {
        $aliases = [
            's.no' => 'sno',
            'sno' => 'sno',
            's no' => 'sno',
            'zbm' => 'zbm',
            'rbm' => 'rbm',
            'area' => 'area',
            'hq' => 'hq',
            'tm name' => 'tm_name',
            'hcp name' => 'hcp_name',
            'doctor_id' => 'doctor_id',
            'doctor id' => 'doctor_id',
            'hierarchy_id' => 'hierarchy_id',
            'hierarchy id' => 'hierarchy_id',
            'user_id' => 'user_id',
            'user id' => 'user_id',
            'legacy_code' => 'legacy_code',
            'legacy code' => 'legacy_code',
            'pcode' => 'pcode',
            'agreementno' => 'agreement_no',
            'agreement no' => 'agreement_no',
            'status' => 'status',
            'eas id' => 'eas_id',
            'activity report status' => 'activity_report_status',
            'payment status' => 'payment_status',
            'closure done' => 'closure_done',
            'closure approved' => 'closure_approved',
        ];
        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);
        };

        $sno = $get('sno');
        return [
            'sno' => is_numeric($sno) ? (int) $sno : null,
            'zbm' => $get('zbm'),
            'rbm' => $get('rbm'),
            'area' => $get('area'),
            'hq' => $get('hq'),
            'tm_name' => $get('tm_name'),
            'hcp_name' => $get('hcp_name'),
            'doctor_id' => $get('doctor_id'),
            'hierarchy_id' => $get('hierarchy_id'),
            'user_id' => $get('user_id'),
            'legacy_code' => $get('legacy_code'),
            'pcode' => $get('pcode'),
            'agreement_no' => $get('agreement_no'),
            'status' => $get('status'),
            'eas_id' => $get('eas_id'),
            'activity_report_status' => $get('activity_report_status'),
            'payment_status' => $get('payment_status'),
            'closure_done' => $get('closure_done'),
            'closure_approved' => $get('closure_approved'),
            'tm_visit' => $get('tm_visit'),
        ];
    }

    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;
            }
        }

        if (function_exists('iconv')) {
            $converted = @iconv('UTF-8', 'UTF-8//IGNORE', $value);
            if ($converted !== false) {
                $value = $converted;
            }
        } elseif (function_exists('mb_convert_encoding')) {
            $value = mb_convert_encoding($value, 'UTF-8', 'UTF-8');
        }

        $value = preg_replace('/[\x00-\x08\x0B\x0C\x0E-\x1F]/', '', $value) ?? '';
        $value = trim($value);

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

    protected function formatRowError(int $lineNo, \Throwable $e): string
    {
        $message = $e->getMessage();
        if (str_contains($message, 'Incorrect string value')) {
            return "Row {$lineNo}: Invalid characters in row data.";
        }

        $message = $this->sanitizeDbString($message) ?: '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('titans_hcp_gathering_imports')->where('id', $importId)->update($payload);
    }
}