<?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();

        // Must be Admin, HR, or assigned interviewer
        $interviews = Interview::with(['creator', 'warnings.sender'])
            ->orderBy('created_at', 'desc')
            ->get();

        $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',
            '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();

        $expiresAt = now()->addHours((int)$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,
            '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->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->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',
        ]);

        $langMap = [
            'python' => ['language' => 'python', 'version' => '3.10.0'],
            'c' => ['language' => 'c', 'version' => '10.2.0'],
            'cpp' => ['language' => 'c++', 'version' => '10.2.0'],
            'java' => ['language' => 'java', 'version' => '15.0.2'],
            'php' => ['language' => 'php', 'version' => '8.2.3'],
            'laravel' => ['language' => 'php', 'version' => '8.2.3'],
            'javascript' => ['language' => 'javascript', 'version' => '18.15.0'],
        ];

        $targetLang = $langMap[strtolower($request->language)] ?? ['language' => 'python', 'version' => '3.10.0'];

        try {
            $response = Http::post('https://emkc.org/api/v2/piston/execute', [
                'language' => $targetLang['language'],
                'version' => $targetLang['version'],
                'files' => [
                    [
                        'name' => 'solution',
                        'content' => $request->code,
                    ]
                ],
            ]);

            if ($response->successful()) {
                $data = $response->json();
                $output = $data['run']['output'] ?? 'No output generated.';
                return response()->json(['success' => true, 'output' => $output]);
            }

            return response()->json(['success' => false, 'output' => 'Execution engine error: ' . $response->status()]);
        } catch (\Exception $e) {
            return response()->json(['success' => false, 'output' => 'Code runner service error: ' . $e->getMessage()]);
        }
    }

    /**
     * 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
        $details = $request->input('details', '');

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

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

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

    /**
     * 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]);
    }

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

        return response()->json([
            'status' => $interview->status,
            'submitted_code' => $interview->submitted_code,
            'submitted_language' => $interview->submitted_language,
            'code_output' => $interview->code_output,
            'proctor_logs' => $interview->proctor_logs ?? [],
            'warnings' => $interview->warnings,
            'is_expired' => $interview->isExpired(),
        ]);
    }

    /**
     * Save Candidate Silent Video Recording Blob / Snapshot Stream.
     */
    public function uploadRecording(Request $request, $id)
    {
        $interview = Interview::findOrFail($id);

        if ($request->hasFile('video')) {
            $file = $request->file('video');
            $filename = 'interview_' . $interview->submission_unique_id . '_' . time() . '.webm';
            $path = $file->storeAs('public/recordings', $filename);

            $interview->update(['recording_path' => Storage::url($path)]);
            return response()->json(['success' => true, 'path' => Storage::url($path)]);
        }

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