<?php

namespace App\Http\Controllers;

use App\Models\Interview;
use App\Models\InterviewWarning;
use App\Models\User;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Auth;
use Illuminate\Support\Facades\Http;
use Illuminate\Support\Facades\Storage;
use Illuminate\Support\Str;

class InterviewController extends Controller
{
    /**
     * Display the HR & Interviewer Live Assessment Portal.
     */
    public function index()
    {
        $user = Auth::user();

        // Check if user is Admin, HR, or has active assigned interview zone timeline
        if (!$user->isAdmin() && strtolower($user->role) !== 'hr' && !$user->hasActiveInterviewZone()) {
            return redirect()->route('dashboard')->with('error', 'Interview Zone is available only during active interview timelines assigned by HR or Admin.');
        }

        $interviews = $user->getAccessibleInterviews();
        $interviewers = User::orderBy('name', 'asc')->get();

        return view('interview.index', compact('interviews', 'interviewers'));
    }

    /**
     * Store a new Candidate Interview session created by HR.
     */
    public function store(Request $request)
    {
        $request->validate([
            'candidate_name' => 'required|string|max:255',
            'candidate_email' => 'required|email|max:255',
            'candidate_phone' => 'required|string|max:50',
            'scheduled_at' => 'nullable|date',
            'valid_hours' => 'required|integer|min:1|max:72',
            'language' => 'required|string',
            'assigned_interviewers' => 'nullable|array',
        ]);

        $tempPassword = 'Pass-' . rand(100000, 999999);
        $cleanPhone = preg_replace('/[^0-9]/', '', $request->candidate_phone);
        $cleanName = Str::slug($request->candidate_name);
        $submissionUniqueId = $cleanName . '_' . $cleanPhone . '_' . time();

        $scheduledAt = $request->scheduled_at ? \Carbon\Carbon::parse($request->scheduled_at) : now();
        $expiresAt = $scheduledAt->copy()->addHours((int)$request->valid_hours);

        $interview = Interview::create([
            'candidate_name' => $request->candidate_name,
            'candidate_email' => strtolower(trim($request->candidate_email)),
            'candidate_phone' => $request->candidate_phone,
            'temp_password' => $tempPassword,
            'scheduled_at' => $scheduledAt,
            'expires_at' => $expiresAt,
            'language' => $request->language,
            'status' => 'scheduled',
            'assigned_interviewers' => $request->assigned_interviewers ?? [],
            'proctor_logs' => [],
            'submission_unique_id' => $submissionUniqueId,
            'created_by' => Auth::id(),
        ]);

        return redirect()->route('interview.index')->with('success', 'Interview session created for ' . $request->candidate_name . '. Temporary login credentials generated!');
    }

    /**
     * Show Candidate Login Screen.
     */
    public function showCandidateLogin()
    {
        return view('interview.candidate_login');
    }

    /**
     * Handle Candidate Temporary Credentials Authentication.
     */
    public function loginCandidate(Request $request)
    {
        $request->validate([
            'identifier' => 'required|string', // Email or Phone
            'temp_password' => 'required|string',
        ]);

        $identifier = trim($request->identifier);

        $interview = Interview::where(function ($q) use ($identifier) {
            $q->where('candidate_email', strtolower($identifier))
              ->orWhere('candidate_phone', $identifier)
              ->orWhere('submission_unique_id', $identifier);
        })->where('temp_password', $request->temp_password)->first();

        if (!$interview) {
            return back()->with('error', 'Invalid candidate credentials or temporary password.');
        }

        if ($interview->status === 'blocked' || $interview->blocked_ip === $request->ip()) {
            return back()->with('error', 'Access Denied: Candidate email and IP address have been blocked by HR/Interviewer.');
        }

        if ($interview->isExpired()) {
            $interview->update(['status' => 'expired']);
            return back()->with('error', 'This candidate interview access window has expired. Please contact HR.');
        }

        // Set candidate session
        session(['candidate_interview_id' => $interview->id]);

        if ($interview->status === 'scheduled') {
            $interview->update(['status' => 'in_progress']);
        }

        return redirect()->route('interview.room', $interview->submission_unique_id);
    }

    /**
     * Show Candidate Live IDE Proctored Room.
     */
    public function showCandidateRoom($uniqueId)
    {
        $interview = Interview::where('submission_unique_id', $uniqueId)->firstOrFail();

        if ($interview->status === 'blocked') {
            return response()->view('interview.expired', compact('interview'), 403);
        }

        if ($interview->isExpired()) {
            $interview->update(['status' => 'expired']);
            return response()->view('interview.expired', compact('interview'), 403);
        }

        return view('interview.candidate_room', compact('interview'));
    }

    /**
     * Proxy Live Code Execution to Piston Multi-Language API.
     */
    public function executeCode(Request $request)
    {
        $request->validate([
            'language' => 'required|string',
            'code' => 'required|string',
            'interview_id' => 'nullable|string',
        ]);

        $langKey = strtolower(trim($request->language));
        $code = $request->code;
        $output = '';

        // 1. Ultra-Fast Piston Code Execution API (sub-second for C, C++, Java, JS, Python, PHP, Go, Rust)
        $pistonLangMap = [
            'python' => 'python',
            'py' => 'python',
            'javascript' => 'javascript',
            'js' => 'javascript',
            'c' => 'c',
            'cpp' => 'c++',
            'c++' => 'c++',
            'java' => 'java',
            'php' => 'php',
            'laravel' => 'php',
            'go' => 'go',
            'rust' => 'rust',
        ];

        if (isset($pistonLangMap[$langKey])) {
            try {
                $pistonLang = $pistonLangMap[$langKey];
                $response = Http::timeout(4)->post('https://emkc.org/api/v2/piston/execute', [
                    'language' => $pistonLang,
                    'version' => '*',
                    'files' => [
                        ['content' => $code]
                    ]
                ]);

                if ($response->successful()) {
                    $resData = $response->json();
                    $output = $resData['run']['output'] ?? ($resData['run']['stdout'] ?? '');
                    if (empty($output) && !empty($resData['run']['stderr'])) {
                        $output = $resData['run']['stderr'];
                    }
                }
            } catch (\Exception $e) {}
        }

        // 2. Instant Local Process Runner Fallback
        if (empty($output)) {
            try {
                if (in_array($langKey, ['javascript', 'js'])) {
                    $process = new \Symfony\Component\Process\Process(['node', '-e', $code]);
                    $process->setTimeout(3);
                    $process->run();
                    $out = $process->getOutput() ?: $process->getErrorOutput();
                    $output = trim($out) ?: 'JavaScript executed successfully (no stdout).';
                } elseif ($langKey === 'python') {
                    $process = new \Symfony\Component\Process\Process(['python', '-c', $code]);
                    $process->setTimeout(3);
                    $process->run();
                    $out = $process->getOutput() ?: $process->getErrorOutput();
                    $output = trim($out) ?: 'Python executed successfully (no stdout).';
                } elseif (in_array($langKey, ['php', 'laravel'])) {
                    ob_start();
                    try {
                        $cleanCode = preg_replace('/^\s*<\?php\s*/i', '', $code);
                        eval($cleanCode);
                        $out = ob_get_clean();
                        $output = trim($out) ?: 'PHP code executed successfully.';
                    } catch (\Throwable $e) {
                        ob_end_clean();
                        $output = 'PHP Evaluation Error: ' . $e->getMessage();
                    }
                }
            } catch (\Exception $e) {}
        }

        if (empty($output)) {
            $output = "=== Code Execution Status ===\nSolution executed.\nLanguage: " . strtoupper($langKey);
        }

        // Auto-persist candidate code + execution output directly to interview model
        $interviewId = $request->input('interview_id');
        if ($interviewId) {
            $interview = Interview::where('id', $interviewId)->orWhere('submission_unique_id', $interviewId)->first();
            if ($interview) {
                $interview->update([
                    'submitted_code' => $code,
                    'submitted_language' => $langKey,
                    'code_output' => $output,
                ]);
            }
        }

        return response()->json(['success' => true, 'output' => $output]);
    }

    /**
     * Save Candidate Submitted Code & Execution Results.
     */
    public function submitCode(Request $request, $id)
    {
        $interview = Interview::findOrFail($id);

        $request->validate([
            'code' => 'required|string',
            'language' => 'required|string',
            'output' => 'nullable|string',
        ]);

        $interview->update([
            'submitted_code' => $request->code,
            'submitted_language' => $request->language,
            'code_output' => $request->output,
            'status' => 'completed',
        ]);

        return response()->json([
            'success' => true,
            'message' => 'Code submitted successfully under unique ID: ' . $interview->submission_unique_id,
            'unique_id' => $interview->submission_unique_id
        ]);
    }

    /**
     * Log Anti-Cheat Proctoring Violations (Tab Switch, Focus Loss, Gaze Anomaly).
     */
    public function logViolation(Request $request, $id)
    {
        $interview = Interview::findOrFail($id);

        $type = $request->input('type'); // tab_switch, focus_lost, paste_event, gaze_anomaly, question_repetition, external_ai_detected
        $details = $request->input('details', '');

        // Automatically run AI Speech/Transcript Inspection if violation is speech/question repetition/phone call
        $aiVerdict = null;
        if (in_array($type, ['question_repetition', 'question_repeat_lower', 'talking_secondary_person', 'talking_on_phone', 'reading_external_device'])) {
            $aiDetector = new \App\Services\AiCheatingDetectorService();
            $aiVerdict = $aiDetector->analyzeSpeechTranscript($details, $interview->candidate_notes ?? '');
        }

        $logs = $interview->proctor_logs ?? [];
        $logs[] = [
            'type' => $type,
            'details' => $details,
            'ai_verdict' => $aiVerdict,
            'timestamp' => now()->toIso8601String(),
        ];

        $interview->update(['proctor_logs' => $logs]);

        return response()->json(['success' => true, 'total_violations' => count($logs), 'ai_verdict' => $aiVerdict]);
    }

    /**
     * Interviewer / HR sends a Silent Warning to Candidate.
     */
    public function sendWarning(Request $request, $id)
    {
        $interview = Interview::findOrFail($id);

        $request->validate([
            'message' => 'required|string|max:500',
        ]);

        $warning = InterviewWarning::create([
            'interview_id' => $interview->id,
            'message' => $request->message,
            'sent_by' => Auth::id(),
        ]);

        return response()->json(['success' => true, 'warning' => $warning]);
    }

    /**
     * Send Real-Time Chat Message from Candidate to Interviewer/HR.
     */
    public function candidateSendMessage(Request $request, $id)
    {
        $interview = Interview::findOrFail($id);
        $request->validate(['message' => 'required|string|max:500']);

        $warning = InterviewWarning::create([
            'interview_id' => $interview->id,
            'message' => $request->message,
            'sent_by' => null, // null sent_by indicates candidate sender
        ]);

        return response()->json(['success' => true, 'warning' => $warning]);
    }

    /**
     * Live Sync Candidate Code (before submission).
     */
    public function syncCandidateCode(Request $request, $id)
    {
        $interview = Interview::findOrFail($id);
        $updateData = [
            'submitted_code' => $request->input('code'),
            'submitted_language' => $request->input('language', $interview->language),
        ];
        if ($request->has('output')) {
            $updateData['code_output'] = $request->input('output');
        }
        $interview->update($updateData);
        return response()->json(['success' => true]);
    }

    /**
     * Save Candidate Live Notepad Content.
     */
    public function saveCandidateNotes(Request $request, $id)
    {
        $interview = Interview::findOrFail($id);
        $interview->update(['candidate_notes' => $request->input('notes')]);
        return response()->json(['success' => true]);
    }

    /**
     * Save Candidate Live Canvas Drawing Data URL.
     */
    public function saveCandidateDrawing(Request $request, $id)
    {
        $interview = Interview::findOrFail($id);
        $interview->update(['candidate_drawing' => $request->input('drawing')]);
        return response()->json(['success' => true]);
    }

    /**
     * Regenerate Temporary Candidate Password (by Interviewer/HR).
     */
    public function regeneratePassword($id)
    {
        $interview = Interview::findOrFail($id);
        $newPass = 'Pass-' . rand(100000, 999999);
        $interview->update(['temp_password' => $newPass]);
        return response()->json(['success' => true, 'new_password' => $newPass]);
    }

    /**
     * Block Candidate Session, Email & Client IP (by Interviewer/HR).
     */
    public function blockCandidate(Request $request, $id)
    {
        $interview = Interview::findOrFail($id);
        $clientIp = $request->ip();

        $interview->update([
            'status' => 'blocked',
            'blocked_ip' => $clientIp,
        ]);

        // Also block user record if exists
        User::where('email', strtolower($interview->candidate_email))
            ->update(['is_blocked' => true]);

        return response()->json([
            'success' => true,
            'message' => 'Candidate ' . $interview->candidate_name . ' (' . $interview->candidate_email . ') and IP ' . $clientIp . ' have been blocked successfully.'
        ]);
    }

    /**
     * Serve Storage File (Recordings & Public Assets) directly with Range Support for Video Streaming.
     */
    public function serveStorageFile($path)
    {
        $sanitizedPath = ltrim(str_replace('..', '', $path), '/');

        $candidatePaths = [
            storage_path('app/public/' . $sanitizedPath),
            storage_path('app/private/public/' . $sanitizedPath),
            storage_path('app/private/' . $sanitizedPath),
            storage_path('app/' . $sanitizedPath),
            public_path('storage/' . $sanitizedPath),
            public_path($sanitizedPath),
        ];

        // Also check with alternate extensions (.webm / .mp4) if requested file extension differs
        $baseNoExt = preg_replace('/\.(mp4|webm|m4v|mov)$/i', '', $sanitizedPath);
        if ($baseNoExt !== $sanitizedPath) {
            $candidatePaths[] = storage_path('app/public/' . $baseNoExt . '.webm');
            $candidatePaths[] = storage_path('app/public/' . $baseNoExt . '.mp4');
            $candidatePaths[] = storage_path('app/private/public/' . $baseNoExt . '.webm');
            $candidatePaths[] = storage_path('app/private/public/' . $baseNoExt . '.mp4');
            $candidatePaths[] = public_path($baseNoExt . '.webm');
            $candidatePaths[] = public_path($baseNoExt . '.mp4');
        }

        $filePath = null;
        foreach ($candidatePaths as $cp) {
            if (file_exists($cp) && is_file($cp)) {
                $filePath = $cp;
                break;
            }
        }

        if (!$filePath) {
            abort(404, 'Storage file not found.');
        }

        // Read first 12 bytes to accurately detect container format (WebM vs MP4 vs Image)
        $handle = @fopen($filePath, 'rb');
        $header = $handle ? fread($handle, 12) : '';
        if ($handle) fclose($handle);

        $extension = strtolower(pathinfo($filePath, PATHINFO_EXTENSION));
        $isWebmHeader = str_starts_with($header, "\x1A\x45\xDF\xA3");

        if ($isWebmHeader || $extension === 'webm') {
            $mimeType = 'video/webm';
        } elseif (str_contains($header, 'ftyp') || in_array($extension, ['mp4', 'm4v'])) {
            $mimeType = 'video/mp4';
        } elseif ($extension === 'png') {
            $mimeType = 'image/png';
        } elseif (in_array($extension, ['jpg', 'jpeg'])) {
            $mimeType = 'image/jpeg';
        } else {
            $mimeType = @mime_content_type($filePath) ?: 'application/octet-stream';
        }

        $fileSize = filesize($filePath);
        $headers = [
            'Content-Type' => $mimeType,
            'Accept-Ranges' => 'bytes',
            'Cache-Control' => 'public, max-age=86400',
        ];

        // Enable HTTP 206 Partial Content Range support required for HTML5 video playback/seeking
        $range = request()->header('Range');
        if ($range && preg_match('/bytes=(\d+)-(\d+)?/', $range, $matches)) {
            $start = (int) $matches[1];
            $end = isset($matches[2]) && $matches[2] !== '' ? (int) $matches[2] : ($fileSize - 1);

            if ($start > $end || $start >= $fileSize) {
                return response('', 416, ['Content-Range' => "bytes */{$fileSize}"]);
            }

            $end = min($end, $fileSize - 1);
            $length = $end - $start + 1;

            $headers['Content-Range'] = "bytes {$start}-{$end}/{$fileSize}";
            $headers['Content-Length'] = (string) $length;

            return response()->stream(function () use ($filePath, $start, $length) {
                $file = fopen($filePath, 'rb');
                if ($file) {
                    fseek($file, $start);
                    $bufferSize = 1024 * 64;
                    $bytesLeft = $length;
                    while ($bytesLeft > 0 && !feof($file)) {
                        $readSize = min($bufferSize, $bytesLeft);
                        $data = fread($file, $readSize);
                        if ($data === false) break;
                        echo $data;
                        flush();
                        $bytesLeft -= strlen($data);
                    }
                    fclose($file);
                }
            }, 206, $headers);
        }

        $headers['Content-Length'] = (string) $fileSize;
        return response()->file($filePath, $headers);
    }

    /**
     * Get normalized recordings list sorted in descending order of creation timestamp (newest first).
     */
    private function getFormattedRecordings($interview)
    {
        $rawRecordings = $interview->recordings ?? [];
        if (!is_array($rawRecordings) || empty($rawRecordings)) {
            if (!empty($interview->recording_path)) {
                $rawRecordings = [[
                    'url' => $interview->recording_path,
                    'filename' => basename($interview->recording_path),
                    'created_at' => $interview->updated_at ? $interview->updated_at->toIso8601String() : now()->toIso8601String(),
                ]];
            } else {
                $rawRecordings = [];
            }
        }

        $formatted = [];
        foreach ($rawRecordings as $idx => $rec) {
            if (is_string($rec)) {
                $rec = [
                    'url' => $rec,
                    'filename' => basename($rec),
                    'created_at' => $interview->updated_at ? $interview->updated_at->toIso8601String() : now()->toIso8601String(),
                ];
            }
            $url = $rec['url'] ?? '';
            $urlPath = parse_url($url, PHP_URL_PATH) ?? $url;
            $cleanPath = ltrim(str_replace(['/storage/', 'storage/'], '', $urlPath), '/');
            $streamUrl = url('/media-stream/' . $cleanPath);

            $ext = strtolower(pathinfo($cleanPath, PATHINFO_EXTENSION));
            $mimeType = in_array($ext, ['mp4', 'm4v']) ? 'video/mp4' : 'video/webm';

            $rec['original_index'] = $idx;
            $rec['stream_url'] = $streamUrl;
            $rec['download_url'] = route('interview.download-recording', $interview->id) . '?index=' . $idx;
            $rec['mime_type'] = $mimeType;
            $formatted[] = $rec;
        }

        // Sort descending by created_at timestamp (newest first)
        usort($formatted, function ($a, $b) {
            $timeA = isset($a['created_at']) ? strtotime($a['created_at']) : 0;
            $timeB = isset($b['created_at']) ? strtotime($b['created_at']) : 0;
            return $timeB <=> $timeA;
        });

        return $formatted;
    }

    /**
     * Live Polling Endpoint for Candidate Warnings & HR Monitoring.
    /**
     * Get all currently active interview calls accessible to the logged-in user.
     */
    public function getActiveCalls(Request $request)
    {
        $user = Auth::user();
        if (!$user) {
            return response()->json(['active_calls' => [], 'current_user_id' => null]);
        }

        $accessible = $user->getAccessibleInterviews();
        $activeCalls = [];

        foreach ($accessible as $interview) {
            // Auto-terminate call session if interview timeline has expired
            if ($interview->isExpired()) {
                if ($interview->call_status === 'active') {
                    $interview->update(['call_status' => 'ended']);
                }
                continue;
            }

            if ($interview->call_status === 'active') {
                $starterName = 'Panelist';
                if ($interview->call_started_by) {
                    $starter = User::find($interview->call_started_by);
                    if ($starter) {
                        $starterName = $starter->name;
                    }
                }

                $activeCalls[] = [
                    'id' => $interview->id,
                    'candidate_name' => $interview->candidate_name,
                    'candidate_email' => $interview->candidate_email,
                    'submission_unique_id' => $interview->submission_unique_id,
                    'call_status' => $interview->call_status,
                    'call_started_by' => $interview->call_started_by,
                    'starter_name' => $starterName,
                    'call_started_at' => $interview->call_started_at ? $interview->call_started_at->toIso8601String() : null,
                ];
            }
        }

        return response()->json([
            'active_calls' => $activeCalls,
            'current_user_id' => $user->id,
        ]);
    }

    /**
     * Live Polling Endpoint for Candidate Warnings & HR Monitoring.
     */
    public function getPollData($id)
    {
        $interview = Interview::with(['warnings.sender', 'callStarter'])
            ->where('id', $id)
            ->orWhere('submission_unique_id', $id)
            ->firstOrFail();

        // Enforce expiration: ended call status if timeline is expired
        if ($interview->isExpired()) {
            if ($interview->call_status === 'active') {
                $interview->update(['call_status' => 'ended']);
            }
        }

        $formattedRecordings = $this->getFormattedRecordings($interview);

        $starterName = $interview->callStarter ? $interview->callStarter->name : null;

        $globalScreenshotsEnabled = \App\Models\Setting::get('enable_candidate_screenshots', '1') === '1';
        $interviewScreenshotsEnabled = (bool) ($interview->enable_tab_switch_screenshot ?? true);
        $effectiveScreenshotEnabled = $globalScreenshotsEnabled && $interviewScreenshotsEnabled;

        return response()->json([
            'status' => $interview->status,
            'call_status' => $interview->isExpired() ? 'ended' : ($interview->call_status ?? 'idle'),
            'call_started_by' => $interview->call_started_by,
            'starter_name' => $starterName,
            'call_started_at' => $interview->call_started_at ? $interview->call_started_at->toIso8601String() : null,
            'enable_tab_switch_screenshot' => $effectiveScreenshotEnabled,
            'global_screenshot_enabled' => $globalScreenshotsEnabled,
            'tab_switch_screenshots' => $interview->tab_switch_screenshots ?? [],
            'submitted_code' => $interview->submitted_code,
            'submitted_language' => $interview->submitted_language,
            'code_output' => $interview->code_output,
            'candidate_notes' => $interview->candidate_notes,
            'candidate_drawing' => $interview->candidate_drawing,
            'temp_password' => $interview->temp_password,
            'blocked_ip' => $interview->blocked_ip,
            'proctor_logs' => $interview->proctor_logs ?? [],
            'recording_path' => $interview->recording_path,
            'recordings' => $formattedRecordings,
            'warnings' => $interview->warnings,
            'is_expired' => $interview->isExpired(),
        ]);
    }

    /**
     * Update Interview Call Session Status (active, idle, ended).
     */
    public function updateCallStatus(Request $request, $id)
    {
        $interview = Interview::where('id', $id)
            ->orWhere('submission_unique_id', $id)
            ->firstOrFail();
        $status = $request->input('call_status', 'idle');
        $isRejoin = $request->boolean('is_rejoin', false);

        $updateData = ['call_status' => $status];
        $isNewCall = false;

        if ($status === 'active') {
            if (!$isRejoin && ($interview->call_status !== 'active' || !$interview->call_started_at)) {
                $updateData['call_started_by'] = Auth::id();
                $updateData['call_started_at'] = now();
                $isNewCall = true;
            }
        } elseif (in_array($status, ['ended', 'idle'])) {
            $updateData['call_started_by'] = null;
            $updateData['call_started_at'] = null;
        }

        $interview->update($updateData);

        $starterName = Auth::user() ? Auth::user()->name : 'Panelist';

        return response()->json([
            'success' => true,
            'call_status' => $status,
            'is_new_call' => $isNewCall,
            'call_started_by' => $interview->call_started_by,
            'starter_name' => $starterName,
            'call_started_at' => $interview->call_started_at ? $interview->call_started_at->toIso8601String() : null,
        ]);
    }

    /**
     * Upload & Save Candidate System Screen Screenshot under public/uploads/candidate_screenshots/{unique_id}/.
     */
    public function uploadTabScreenshot(Request $request, $id)
    {
        $interview = Interview::where('id', $id)
            ->orWhere('submission_unique_id', $id)
            ->firstOrFail();

        $globalEnabled = \App\Models\Setting::get('enable_candidate_screenshots', '1') === '1';
        $interviewEnabled = !isset($interview->enable_tab_switch_screenshot) || $interview->enable_tab_switch_screenshot;

        if (!$globalEnabled || !$interviewEnabled) {
            return response()->json([
                'success' => false,
                'message' => 'Candidate system screenshot capture is disabled by admin setting.'
            ]);
        }

        $reason = $request->input('reason', 'tab_switch'); // 'call_start' or 'tab_switch'
        $filename = 'screenshot_' . $reason . '_' . time() . '_' . rand(100, 999) . '.jpg';
        $uniqueFolder = $interview->submission_unique_id ?: $interview->id;
        $subDir = 'uploads/candidate_screenshots/' . $uniqueFolder;
        $destinationPath = public_path($subDir);

        if (!file_exists($destinationPath)) {
            mkdir($destinationPath, 0777, true);
        }

        $url = null;
        if ($request->hasFile('screenshot')) {
            $file = $request->file('screenshot');
            $file->move($destinationPath, $filename);
            $url = asset($subDir . '/' . $filename);
        } elseif ($request->input('image')) {
            $base64Image = $request->input('image');
            if (str_contains($base64Image, ',')) {
                $base64Image = explode(',', $base64Image)[1];
            }
            $base64Image = str_replace(' ', '+', $base64Image);
            $imageData = base64_decode($base64Image);
            if ($imageData !== false && strlen($imageData) > 0) {
                file_put_contents($destinationPath . '/' . $filename, $imageData);
                $url = asset($subDir . '/' . $filename);
            }
        }

        if ($url) {
            $relativePath = '/' . $subDir . '/' . $filename;
            $fullFilePath = $destinationPath . '/' . $filename;

            // Automatically analyze candidate system screen capture using AI Vision Engine
            $aiDetector = new \App\Services\AiCheatingDetectorService();
            $aiVerdict = $aiDetector->analyzeScreenshot($fullFilePath);

            $screenshotEntry = [
                'url' => $relativePath,
                'full_url' => $url,
                'filename' => $filename,
                'ai_verdict' => $aiVerdict,
                'timestamp' => now()->toIso8601String(),
                'reason' => $reason,
            ];

            $screenshots = $interview->tab_switch_screenshots ?? [];
            $screenshots[] = $screenshotEntry;

            $hasAiTool = !empty($aiVerdict['is_cheating']) && !empty($aiVerdict['ai_tool_detected']);

            if ($reason === 'call_start') {
                $logType = 'call_start_screenshot';
                $logMsg = '📸 CALL STARTED SYSTEM SNAPSHOT: System screen snapshot captured automatically when call started.';
            } elseif ($hasAiTool) {
                $logType = 'external_ai_detected';
                $toolName = $aiVerdict['ai_tool_detected'];
                $logMsg = "🤖 candidate might use external ai ({$toolName}): " . $aiVerdict['summary'];
            } else {
                $logType = 'tab_switch';
                $logMsg = '📸 Candidate switched browser tab or window: System screen screenshot captured for interviewer & admin review.';
            }

            $logs = $interview->proctor_logs ?? [];
            $logs[] = [
                'type' => $logType,
                'details' => $logMsg,
                'ai_verdict' => $aiVerdict,
                'screenshot_url' => $relativePath,
                'timestamp' => now()->toIso8601String(),
            ];

            $interview->update([
                'tab_switch_screenshots' => $screenshots,
                'proctor_logs' => $logs,
            ]);

            return response()->json([
                'success' => true,
                'url' => $relativePath,
                'full_url' => $url,
                'ai_verdict' => $aiVerdict,
                'total_screenshots' => count($screenshots),
            ]);
        }

        return response()->json(['success' => false, 'message' => 'No image payload received']);
    }

    /**
     * Admin Toggle Enable/Disable Candidate Tab Switch Screenshot Capture.
     */
    public function toggleTabScreenshot(Request $request, $id)
    {
        $interview = Interview::where('id', $id)
            ->orWhere('submission_unique_id', $id)
            ->firstOrFail();

        $enable = $request->boolean('enable', true);
        $interview->update(['enable_tab_switch_screenshot' => $enable]);

        return response()->json([
            'success' => true,
            'enable_tab_switch_screenshot' => $enable,
            'message' => $enable ? 'Tab-switch screenshot capture ENABLED.' : 'Tab-switch screenshot capture DISABLED.'
        ]);
    }

    /**
     * Save Candidate Video Recording under public/uploads/candidate_recordings/{unique_id}/.
     */
    public function uploadRecording(Request $request, $id)
    {
        $interview = Interview::where('id', $id)
            ->orWhere('submission_unique_id', $id)
            ->firstOrFail();

        if ($request->hasFile('video')) {
            $file = $request->file('video');
            $ext = strtolower($file->getClientOriginalExtension() ?: 'webm');
            if (!in_array($ext, ['mp4', 'webm', 'm4v', 'mov'])) {
                $ext = 'webm';
            }

            $uniqueFolder = $interview->submission_unique_id ?: $interview->id;
            $subDir = 'uploads/candidate_recordings/' . $uniqueFolder;
            $destinationPath = public_path($subDir);
            if (!file_exists($destinationPath)) {
                mkdir($destinationPath, 0777, true);
            }

            $filename = 'recording_' . time() . '.' . $ext;
            $file->move($destinationPath, $filename);
            $url = asset($subDir . '/' . $filename);
            $relativePath = '/' . $subDir . '/' . $filename;

            $recordings = $interview->recordings ?? [];
            if (!is_array($recordings)) {
                $recordings = $interview->recording_path ? [$interview->recording_path] : [];
            }
            $recordings[] = [
                'url' => $relativePath,
                'full_url' => $url,
                'filename' => $filename,
                'created_at' => now()->toIso8601String(),
            ];

            $interview->update([
                'recording_path' => $relativePath,
                'recordings' => $recordings,
            ]);

            return response()->json(['success' => true, 'path' => $relativePath, 'url' => $url, 'recordings' => $recordings]);
        }

        return response()->json(['success' => false, 'message' => 'No video payload received']);
    }

    /**
     * Download Candidate Video Recording as File.
     */
    public function downloadRecording(Request $request, $id)
    {
        $interview = Interview::findOrFail($id);
        $index = (int) $request->input('index', 0);
        $recordings = $interview->recordings ?? [];

        $targetUrl = null;
        if (!empty($recordings) && isset($recordings[$index])) {
            $rec = $recordings[$index];
            $targetUrl = is_array($rec) ? ($rec['url'] ?? null) : $rec;
        }

        if (!$targetUrl) {
            $targetUrl = $interview->recording_path;
        }

        if (!$targetUrl) {
            return back()->with('error', 'No video recording found for this candidate profile.');
        }

        $urlPath = parse_url($targetUrl, PHP_URL_PATH) ?? $targetUrl;
        $sanitizedPath = ltrim(str_replace(['/storage/', 'storage/'], '', $urlPath), '/');

        $candidatePaths = [
            storage_path('app/public/' . $sanitizedPath),
            storage_path('app/private/public/' . $sanitizedPath),
            storage_path('app/private/' . $sanitizedPath),
            storage_path('app/' . $sanitizedPath),
            public_path('storage/' . $sanitizedPath),
            public_path($sanitizedPath),
        ];

        $baseNoExt = preg_replace('/\.(mp4|webm|m4v|mov)$/i', '', $sanitizedPath);
        if ($baseNoExt !== $sanitizedPath) {
            $candidatePaths[] = storage_path('app/public/' . $baseNoExt . '.webm');
            $candidatePaths[] = storage_path('app/public/' . $baseNoExt . '.mp4');
            $candidatePaths[] = storage_path('app/private/public/' . $baseNoExt . '.webm');
            $candidatePaths[] = storage_path('app/private/public/' . $baseNoExt . '.mp4');
        }

        $filePath = null;
        foreach ($candidatePaths as $cp) {
            if (file_exists($cp) && is_file($cp)) {
                $filePath = $cp;
                break;
            }
        }

        if ($filePath && file_exists($filePath)) {
            $handle = @fopen($filePath, 'rb');
            $header = $handle ? fread($handle, 12) : '';
            if ($handle) fclose($handle);

            $isWebm = str_starts_with($header, "\x1A\x45\xDF\xA3") || str_ends_with($filePath, '.webm');
            $ext = $isWebm ? 'webm' : 'mp4';
            $mimeType = $isWebm ? 'video/webm' : 'video/mp4';

            $downloadFilename = 'candidate_' . Str::slug($interview->candidate_name) . '_recording_' . ($index + 1) . '.' . $ext;
            return response()->download($filePath, $downloadFilename, [
                'Content-Type' => $mimeType,
            ]);
        }

        return redirect($targetUrl);
    }

    /**
     * Generate Comprehensive Executive Candidate Evaluation & Behavioral Report (PDF View).
     */
    public function generateReport($id)
    {
        $interview = Interview::with(['warnings.sender'])->findOrFail($id);

        $logs = is_array($interview->proctor_logs) ? $interview->proctor_logs : [];
        $tabSwitches = 0;
        $focusLosses = 0;
        $gazeAnomalies = 0;
        $pasteEvents = 0;
        $lowerGazeViolations = 0;
        $questionRepeatViolations = 0;

        foreach ($logs as $l) {
            $type = $l['type'] ?? '';
            if ($type === 'tab_switch') $tabSwitches++;
            if ($type === 'focus_lost') $focusLosses++;
            if (in_array($type, ['gaze_anomaly', 'gaze_fixed_staring'])) $gazeAnomalies++;
            if ($type === 'paste_event') $pasteEvents++;
            if ($type === 'gaze_lower_device') $lowerGazeViolations++;
            if (in_array($type, ['question_repeat_lower', 'question_repetition'])) $questionRepeatViolations++;
        }

        $totalViolations = count($logs);

        // Calculate Integrity Score %
        if ($totalViolations === 0) {
            $integrityScore = 100;
            $integrityLabel = 'Exceptional Integrity';
            $integrityColor = '#10b981';
        } elseif ($totalViolations <= 2 && $lowerGazeViolations === 0 && $questionRepeatViolations === 0) {
            $integrityScore = 85;
            $integrityLabel = 'Low Behavioral Risk';
            $integrityColor = '#06b6d4';
        } elseif ($totalViolations <= 5) {
            $integrityScore = 60;
            $integrityLabel = 'Moderate Integrity Concern';
            $integrityColor = '#f59e0b';
        } else {
            $integrityScore = 25;
            $integrityLabel = 'High Malpractice Risk';
            $integrityColor = '#ef4444';
        }

        // Technical Code Score
        $codeScore = 0;
        if (!empty($interview->submitted_code)) {
            $codeScore += 50;
            if (!empty($interview->code_output) && !str_contains(strtolower($interview->code_output), 'error')) {
                $codeScore += 40;
            } else {
                $codeScore += 20;
            }
            if (!empty($interview->candidate_notes) || !empty($interview->candidate_drawing)) {
                $codeScore += 10;
            }
        }
        $interview->formatted_recordings = $this->getFormattedRecordings($interview);

        return view('interview.report', compact(
            'interview',
            'logs',
            'tabSwitches',
            'focusLosses',
            'gazeAnomalies',
            'pasteEvents',
            'lowerGazeViolations',
            'questionRepeatViolations',
            'integrityScore',
            'integrityLabel',
            'integrityColor',
            'codeScore'
        ));
    }
}