<?php

namespace App\Http\Controllers;

use App\Exports\AdherencePobDriveExport;
use App\Http\Requests\LambdaRequest;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Auth;

class AdherencepobdrivereportController extends Controller
{
    private const REPORT_START = '2026-04-01';

    public function __construct()
    {
        $this->_service = 'reports';
        $this->_module = 'team2_reports';
        $this->_viewname = 'adherencepobdrivereport';
        $this->_title = 'Adherence Pack POB Drive';
        $this->_base_url = '/adherencepobdrivereport';
    }

    public static function canDownload($user): bool
    {
        if (!$user || ($user->domain ?? '') !== 'team2') {
            return false;
        }

        $permissions = json_decode($user->permissions ?? '[]');
        if (is_array($permissions) && in_array('all_data_access', $permissions, true)) {
            return true;
        }

        $designation = strtoupper(trim(self::tokenDesignation($user->access_token ?? '')));

        return $designation === 'HO' || $designation === 'ADMIN';
    }

    public function list(Request $request)
    {
        return redirect($this->_base_url . '/report');
    }

    public function report(Request $request)
    {
        $this->assertCanDownload();
        $months = $this->monthChoices();
        $selected = trim((string) $request->query('month', ''));
        if (!in_array($selected, $months, true)) {
            $selected = $this->currentMonth();
        }

        $reportError = session('reportError');
        $sections = [];
        try {
            $data = $this->fetchReport($selected);
            $export = new AdherencePobDriveExport($data, $selected);
            if (!method_exists($export, 'sections')) {
                throw new \RuntimeException('The report view is out of date. Deploy app/Exports/AdherencePobDriveExport.php and reload PHP.');
            }
            $sections = $export->sections();
        } catch (\Throwable $e) {
            $reportError = $e->getMessage();
        }

        return $this->view('report')->with([
            'title' => $this->_title,
            'base_url' => $this->_base_url,
            'months' => $months,
            'selectedMonth' => $selected,
            'reportError' => $reportError,
            'sections' => $sections,
        ]);
    }

    public function export(Request $request)
    {
        $this->assertCanDownload();
        $months = $this->monthChoices();
        $month = trim((string) $request->query('month', ''));
        if (!in_array($month, $months, true)) {
            $month = $this->currentMonth();
        }

        try {
            $data = $this->fetchReport($month);
        } catch (\RuntimeException $e) {
            return $this->backToReport($month, $e->getMessage());
        }

        return (new AdherencePobDriveExport($data, $month))->download();
    }

    /**
     * @return object
     */
    private function fetchReport(string $month)
    {
        $token = Auth::user()->access_token ?? '';
        try {
            $response = LambdaRequest::getrequest(
                $this->_service,
                $this->_module . '/adherence_report',
                ['month' => $month],
                $token,
                120
            );
        } catch (\Throwable $e) {
            throw new \RuntimeException('Failed to load the adherence report.');
        }

        if (!is_object($response) || strtolower((string) ($response->status ?? '')) !== 'success' || !is_object($response->data ?? null)) {
            $message = is_object($response) ? trim((string) ($response->message ?? '')) : '';
            throw new \RuntimeException($message !== '' ? $message : 'Failed to load the adherence report.');
        }

        return $response->data;
    }

    /**
     * @return array<int, string>
     */
    private function monthChoices(): array
    {
        $cursor = new \DateTimeImmutable(self::REPORT_START);
        $end = new \DateTimeImmutable('first day of this month');
        $months = [];
        while ($cursor <= $end) {
            $months[] = $cursor->format('F Y');
            $cursor = $cursor->modify('+1 month');
        }
        if ($months === []) {
            $months[] = $this->currentMonth();
        }

        return $months;
    }

    private function currentMonth(): string
    {
        return date('F Y');
    }

    private function assertCanDownload(): void
    {
        if (!self::canDownload(Auth::user())) {
            abort(403, 'You do not have access to this report.');
        }
    }

    private function backToReport(string $month, string $message)
    {
        return redirect($this->_base_url . '/report?month=' . urlencode($month))->with('reportError', $message);
    }

    private static function tokenDesignation(string $token): string
    {
        $token = trim($token);
        if (stripos($token, 'Bearer ') === 0) {
            $token = trim(substr($token, 7));
        }
        $parts = explode('.', $token);
        if (count($parts) < 2) {
            return '';
        }
        $segment = strtr($parts[1], '-_', '+/');
        $pad = strlen($segment) % 4;
        if ($pad > 0) {
            $segment .= str_repeat('=', 4 - $pad);
        }
        $payload = json_decode(base64_decode($segment));
        $user = is_object($payload) ? ($payload->user ?? null) : null;
        if (!is_object($user)) {
            return '';
        }

        return (string) ($user->designation ?? '');
    }
}