<?php

namespace App\Controllers;

use App\Core\Request;
use App\Core\Response;
use App\Core\Database;

class GuardianController
{
    public function requestChildLink(Request $request, Response $response): void
    {
        $body = $request->getBody();
        $nationalId = trim((string)($body['national_id'] ?? ''));
        $relationship = (string)($body['relationship_type'] ?? 'guardian');
        if (!preg_match('/^[0-9]{10}$/', $nationalId)) {
            $response->status(422)->json(['status' => 'error', 'message' => 'الرقم الوطني يجب أن يتكون من 10 أرقام']);
            return;
        }
        if (!in_array($relationship, ['father', 'mother', 'brother', 'guardian'], true)) {
            $relationship = 'guardian';
        }
        $student = Database::selectOne("SELECT id FROM students WHERE national_id_hash = ? LIMIT 1", [\App\Core\Security::blindIndex($nationalId)]);
        if (!$student) {
            // Do not reveal whether a national identity exists.
            $response->status(202)->json(['status' => 'pending', 'message' => 'تم استلام طلب الربط للمراجعة']);
            return;
        }
        $existing = Database::selectOne("SELECT id FROM guardian_students WHERE guardian_id = ? AND student_id = ? LIMIT 1", [$request->user_id, $student['id']]);
        if ($existing) {
            $response->json(['status' => 'success', 'message' => 'الطالب مرتبط بهذا الحساب مسبقاً']);
            return;
        }
        $uuid = $this->uuid();
        Database::query(
            "INSERT INTO guardian_link_requests (uuid, guardian_id, student_id, relationship_type, status)
             VALUES (?, ?, ?, ?, 'pending') ON DUPLICATE KEY UPDATE relationship_type = VALUES(relationship_type)",
            [$uuid, $request->user_id, $student['id'], $relationship]
        );
        $response->status(202)->json(['status' => 'pending', 'message' => 'أُرسل طلب الربط إلى الطالب للموافقة']);
    }

    public function pendingLinkRequests(Request $request, Response $response): void
    {
        $requests = Database::select(
            "SELECT glr.uuid, glr.relationship_type, glr.created_at, g.full_name AS guardian_name
             FROM guardian_link_requests glr JOIN guardians g ON g.id = glr.guardian_id
             WHERE glr.student_id = ? AND glr.status = 'pending' ORDER BY glr.created_at DESC",
            [$request->user_id]
        );
        $response->json(['status' => 'success', 'data' => $requests]);
    }

    public function reviewLinkRequest(Request $request, Response $response): void
    {
        $uuid = trim((string)($request->getBody()['request_uuid'] ?? ''));
        $decision = (string)($request->getBody()['decision'] ?? '');
        if (!in_array($decision, ['approved', 'rejected'], true)) {
            $response->status(422)->json(['status' => 'error', 'message' => 'قرار الربط غير صالح']);
            return;
        }
        $link = Database::selectOne(
            "SELECT * FROM guardian_link_requests WHERE uuid = ? AND student_id = ? AND status = 'pending' LIMIT 1",
            [$uuid, $request->user_id]
        );
        if (!$link) {
            $response->status(404)->json(['status' => 'error', 'message' => 'طلب الربط غير موجود']);
            return;
        }
        Database::query("UPDATE guardian_link_requests SET status = ?, reviewed_at = NOW() WHERE id = ?", [$decision, $link['id']]);
        if ($decision === 'approved') {
            Database::query(
                "INSERT INTO guardian_students (guardian_id, student_id, relationship_type) VALUES (?, ?, ?)
                 ON DUPLICATE KEY UPDATE relationship_type = VALUES(relationship_type), can_view_analytics = 1",
                [$link['guardian_id'], $request->user_id, $link['relationship_type']]
            );
        }
        $response->json(['status' => 'success', 'message' => $decision === 'approved' ? 'تم اعتماد ربط ولي الأمر' : 'تم رفض طلب الربط']);
    }

    /**
     * Get Dashboard Data for Guardian
     * GET /api/guardian/dashboard
     */
    public function getDashboard(Request $request, Response $response): void
    {
        $guardianId = $request->user_id;

        // Fetch children linked to this guardian
        $children = Database::select(
            "SELECT s.id, s.uuid, s.full_name, s.national_id, s.grade_level, s.stream
             FROM students s
             JOIN guardian_students gs ON gs.student_id = s.id
             WHERE gs.guardian_id = ?",
            [$guardianId]
        );

        $dashboardData = [];

        foreach ($children as $child) {
            $studentId = $child['id'];

            // 1. Mastery Analytics (Readiness)
            $mastery = Database::selectOne(
                "SELECT tawjihi_readiness_score, exams_passed_count, exams_total_count 
                 FROM student_mastery_analytics 
                 WHERE student_id = ? 
                 ORDER BY updated_at DESC LIMIT 1",
                [$studentId]
            );

            // 2. Socratic checkpoints count (in_video_checkpoint passed)
            $checkpointsCount = Database::selectOne(
                "SELECT COUNT(*) as cnt 
                 FROM exam_attempts ea 
                 JOIN exams e ON e.id = ea.exam_id 
                 WHERE ea.student_id = ? AND e.scope = 'in_video_checkpoint' AND ea.status = 'passed'",
                [$studentId]
            )['cnt'] ?? 0;

            // 3. Remediation count (weaknesses fixed)
            $remediationCount = Database::selectOne(
                "SELECT COUNT(DISTINCT ea.exam_id) as cnt 
                 FROM exam_attempts ea
                 WHERE ea.student_id = ? AND ea.status = 'needs_remediation'",
                [$studentId]
            )['cnt'] ?? 0;

            // 4. Real Error Notebook metrics from student_error_notebook
            $errorStats = Database::selectOne(
                "SELECT 
                    COUNT(*) as total_errors,
                    COALESCE(SUM(CASE WHEN status = 'mastered' THEN 1 ELSE 0 END), 0) as mastered_count,
                    COALESCE(SUM(CASE WHEN status != 'mastered' THEN 1 ELSE 0 END), 0) as pending_count
                 FROM student_error_notebook
                 WHERE student_id = ?",
                [$studentId]
            );
            $totalErrors = (int)($errorStats['total_errors'] ?? 0);
            $masteredErrors = (int)($errorStats['mastered_count'] ?? 0);
            $pendingErrors = (int)($errorStats['pending_count'] ?? 0);
            $errorMasteryPercentage = $totalErrors > 0 ? round(($masteredErrors / $totalErrors) * 100, 1) : 100.0;

            // 5. Forensic Weakness Log (Recent exam attempts with AI diagnostic)
            $diagnosticLogs = Database::select(
                "SELECT ea.percentage, ea.status, ea.weak_topics_json, ea.ai_diagnostic_report, ea.completed_at, e.title as exam_title, e.scope
                 FROM exam_attempts ea
                 JOIN exams e ON e.id = ea.exam_id
                 WHERE ea.student_id = ?
                 ORDER BY ea.id DESC LIMIT 5",
                [$studentId]
            );

            // Process weak topics JSON
            foreach ($diagnosticLogs as &$log) {
                if (!empty($log['weak_topics_json'])) {
                    $log['weak_topics'] = json_decode($log['weak_topics_json'], true) ?: [];
                } else {
                    $log['weak_topics'] = [];
                }
                unset($log['weak_topics_json']);
            }

            $dashboardData[] = [
                'student' => [
                    'id' => $child['id'],
                    'uuid' => $child['uuid'],
                    'name' => $child['full_name'],
                    'national_id' => $this->maskNationalId((string)$child['national_id']),
                    'grade_stream' => ($child['grade_level'] ?? 'غير محدد') . ' (' . ($child['stream'] ?? 'عام') . ')'
                ],
                'metrics' => [
                    'readiness_score' => $mastery ? (float)$mastery['tawjihi_readiness_score'] : 0.0,
                    'checkpoints_passed' => (int)$checkpointsCount,
                    'remediations_flagged' => (int)$remediationCount,
                    'exams_passed_count' => $mastery ? (int)$mastery['exams_passed_count'] : 0,
                    'exams_total_count' => $mastery ? (int)$mastery['exams_total_count'] : 0,
                    'error_notebook' => [
                        'total_errors' => $totalErrors,
                        'mastered_count' => $masteredErrors,
                        'pending_count' => $pendingErrors,
                        'mastery_percentage' => $errorMasteryPercentage,
                    ],
                    'errors_total' => $totalErrors,
                    'errors_mastered' => $masteredErrors,
                    'errors_pending' => $pendingErrors,
                    'errors_mastery_rate' => $errorMasteryPercentage,
                ],
                'diagnostics' => $diagnosticLogs
            ];
        }

        $response->json([
            'status' => 'success',
            'data'   => [
                'children' => $dashboardData
            ]
        ]);
    }

    /**
     * Get Child's Error Notebook for Guardian inspection
     * GET /api/guardian/children/{id}/error-notebook
     */
    public function getChildErrorNotebook(Request $request, Response $response): void
    {
        $guardianId = (int)$request->user_id;
        $studentId = (int)$request->getParam('id');

        // Verify guardian link and analytical authorization
        $linked = Database::selectOne(
            "SELECT id FROM guardian_students WHERE guardian_id = ? AND student_id = ? AND can_view_analytics = 1 LIMIT 1",
            [$guardianId, $studentId]
        );
        if (!$linked) {
            $response->status(403)->json(['status' => 'error', 'message' => 'غير مصرح بالوصول إلى دفتر أخطاء هذا الطالب']);
            return;
        }

        $items = Database::select(
            "SELECT * FROM student_error_notebook WHERE student_id = ? ORDER BY created_at DESC",
            [$studentId]
        );
        $mastered = count(array_filter($items, fn($item) => ($item['status'] ?? '') === 'mastered'));
        $total = count($items);
        $bySubject = [];
        foreach ($items as $item) {
            $name = (string)($item['subject_name'] ?? '');
            if ($name !== '') $bySubject[$name] = ($bySubject[$name] ?? 0) + 1;
        }

        $response->json([
            'status' => 'success',
            'data' => [
                'summary' => [
                    'total_errors' => $total,
                    'mastered_count' => $mastered,
                    'pending_count' => $total - $mastered,
                    'mastery_percentage' => $total > 0 ? round(($mastered / $total) * 100, 1) : 100.0,
                    'by_subject' => $bySubject,
                ],
                'items' => $items,
            ],
        ]);
    }

    private function maskNationalId(string $storedValue): string
    {
        if ($storedValue === '') {
            return '';
        }

        try {
            $decrypted = \App\Core\Security::decrypt($storedValue);
            $nationalId = $decrypted !== '' ? $decrypted : $storedValue;
        } catch (\Throwable $e) {
            $nationalId = $storedValue;
        }

        return strlen($nationalId) >= 4
            ? str_repeat('*', max(0, strlen($nationalId) - 4)) . substr($nationalId, -4)
            : '****';
    }

    private function uuid(): string
    {
        $data = random_bytes(16);
        $data[6] = chr((ord($data[6]) & 0x0f) | 0x40);
        $data[8] = chr((ord($data[8]) & 0x3f) | 0x80);
        return vsprintf('%s%s-%s-%s-%s-%s%s%s', str_split(bin2hex($data), 4));
    }
}