<?php

namespace App\Controllers;

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

class TeacherController
{
    /**
     * Check if Teacher Profile is complete or requires onboarding
     * GET /api/teacher/profile/status
     */
    public function profileStatus(Request $request, Response $response): void
    {
        $userId = $request->user_id;

        $user = Database::selectOne("SELECT id, uuid, full_name, role, status FROM users WHERE id = ? LIMIT 1", [$userId]);
        if (!$user) {
            $response->status(404)->json(['status' => 'error', 'message' => 'المعلم غير موجود']);
            return;
        }

        $profile = Database::selectOne("SELECT * FROM teacher_profiles WHERE user_id = ? LIMIT 1", [$userId]);

        $rawName = (string)($user['full_name'] ?? '');
        $decryptedName = Security::decrypt($rawName) ?: $rawName;
        if (empty($decryptedName)) {
            $decryptedName = 'معلم جديد';
        }
        
        $isComplete = !empty($profile) && !empty($profile['specialization']);

        $response->json([
            'status'        => 'success',
            'is_completed'  => $isComplete,
            'user' => [
                'uuid'      => $user['uuid'],
                'full_name' => $decryptedName,
                'role'      => $user['role'],
                'status'    => $user['status'],
            ],
            'profile'       => $profile ?: null
        ]);
    }

    /**
     * Complete or Update Teacher Onboarding Profile (Password, Name, Bio, Grades, Subjects)
     * POST /api/teacher/profile/setup
     */
    public function setupProfile(Request $request, Response $response): void
    {
        $userId = $request->user_id;
        $body = $request->getBody();

        $validator = new Validator();
        $isValid = $validator->validate($body, [
            'full_name'      => 'required',
            'specialization' => 'required',
            'password'       => 'required|min:8',
        ]);

        if (!$isValid) {
            $response->status(400)->json([
                'status'  => 'error',
                'message' => 'بيانات الملف الشخصي غير مكتملة أو كلمة المرور قصيرة (أقل من 8 خانات)',
                'errors'  => $validator->getErrors()
            ]);
            return;
        }

        $fullName       = trim((string)$body['full_name']);
        $specialization = trim((string)$body['specialization']);
        $bio            = trim((string)($body['bio'] ?? ''));
        $gradeLevels    = is_array($body['grade_levels'] ?? null) ? implode(',', $body['grade_levels']) : (string)($body['grade_levels'] ?? 'tawjihi_2008');
        $passwordHash   = Security::hashPassword((string)$body['password']);

        // 1. Update User table
        $encryptedName = Security::encrypt($fullName);
        Database::query(
            "UPDATE users SET full_name = ?, password_hash = ?, grade_level = ?, status = 'active' WHERE id = ?",
            [$encryptedName, $passwordHash, $gradeLevels, $userId]
        );

        // 2. Upsert Teacher Profile
        $existingProfile = Database::selectOne("SELECT id FROM teacher_profiles WHERE user_id = ? LIMIT 1", [$userId]);
        if ($existingProfile) {
            Database::query(
                "UPDATE teacher_profiles SET bio = ?, specialization = ? WHERE user_id = ?",
                [$bio, $specialization, $userId]
            );
        } else {
            Database::insert(
                "INSERT INTO teacher_profiles (user_id, bio, specialization, revenue_share_pct, contract_type) VALUES (?, ?, ?, 50.00, 'exclusive')",
                [$userId, $bio, $specialization]
            );
        }

        $response->json([
            'status'  => 'success',
            'message' => 'تم توثيق بيانات المعلم وإعداد كلمة المرور بنجاح!',
            'data'    => [
                'full_name'      => $fullName,
                'specialization' => $specialization,
                'grade_levels'   => $gradeLevels
            ]
        ]);
    }

    /**
     * Teacher Dashboard Statistics
     * GET /api/teacher/dashboard
     */
    public function getDashboard(Request $request, Response $response): void
    {
        $userId = $request->user_id;

        // Total Courses
        $coursesCount = (int)Database::selectOne("SELECT COUNT(*) as total FROM courses WHERE teacher_id = ?", [$userId])['total'];

        // Total Lessons
        $lessonsCount = (int)Database::selectOne(
            "SELECT COUNT(l.id) as total FROM lessons l JOIN courses c ON l.course_id = c.id WHERE c.teacher_id = ?",
            [$userId]
        )['total'];

        // Total Unique Active Students
        $studentsCount = (int)Database::selectOne(
            "SELECT COUNT(DISTINCT lp.user_id) as total FROM lesson_progress lp 
             JOIN lessons l ON lp.lesson_id = l.id 
             JOIN courses c ON l.course_id = c.id 
             WHERE c.teacher_id = ?",
            [$userId]
        )['total'];

        $response->json([
            'status' => 'success',
            'data'   => [
                'courses_count'  => $coursesCount,
                'lessons_count'  => $lessonsCount,
                'students_count' => $studentsCount,
                'rating'         => 4.9,
                'completion_avg' => 87.5
            ]
        ]);
    }

    /**
     * List Teacher's Courses
     * GET /api/teacher/courses
     */
    public function getCourses(Request $request, Response $response): void
    {
        $userId = $request->user_id;

        $courses = Database::select(
            "SELECT c.id, c.uuid, c.title, c.description, c.semester, c.price_jod, c.is_published, c.created_at,
                    COUNT(l.id) as lessons_total
             FROM courses c
             LEFT JOIN lessons l ON l.course_id = c.id
             WHERE c.teacher_id = ?
             GROUP BY c.id
             ORDER BY c.id DESC",
            [$userId]
        );

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

    /**
     * Add New Course
     * POST /api/teacher/courses
     */
    public function addCourse(Request $request, Response $response): void
    {
        $body = $request->getBody();
        $title       = trim((string)($body['title'] ?? ''));
        $description = trim((string)($body['description'] ?? ''));
        $subjectId   = (int)($body['subject_id'] ?? 1);
        $semester    = (string)($body['semester'] ?? 'first');
        $price       = (float)($body['price_jod'] ?? 35.00);

        if (empty($title)) {
            $response->status(400)->json([
                'status'  => 'error',
                'message' => 'عنوان الدورة مطلوب'
            ]);
            return;
        }

        $uuid = sprintf('%04x%04x-%04x-%04x-%04x-%04x%04x%04x',
            mt_rand(0, 0xffff), mt_rand(0, 0xffff),
            mt_rand(0, 0xffff),
            mt_rand(0, 0x0fff) | 0x4000,
            mt_rand(0, 0x3fff) | 0x8000,
            mt_rand(0, 0xffff), mt_rand(0, 0xffff), mt_rand(0, 0xffff)
        );

        $courseId = Database::insert(
            "INSERT INTO courses (uuid, subject_id, teacher_id, title, description, semester, price_jod, is_published) VALUES (?, ?, ?, ?, ?, ?, ?, 1)",
            [$uuid, $subjectId, $request->user_id, $title, $description, $semester, $price]
        );

        $response->status(201)->json([
            'status'  => 'success',
            'message' => 'تم إنشاء الدورة بنجاح',
            'data'    => [
                'course_id' => $courseId,
                'uuid'      => $uuid
            ]
        ]);
    }

    /**
     * Add New Lesson to Course
     * POST /api/teacher/lessons
     */
    public function addLesson(Request $request, Response $response): void
    {
        $body = $request->getBody();
        $courseId      = (int)($body['course_id'] ?? 0);
        $title         = trim((string)($body['title'] ?? ''));
        $bunnyVideoId  = trim((string)($body['bunny_video_id'] ?? ''));
        $duration      = (int)($body['duration_seconds'] ?? 0);
        $sequenceOrder = (int)($body['sequence_order'] ?? 1);

        if (!$courseId || empty($title) || empty($bunnyVideoId)) {
            $response->status(400)->json([
                'status'  => 'error',
                'message' => 'معرف الدورة، عنوان الدرس، ومعرف فيديو Bunny مطلوبين'
            ]);
            return;
        }

        // Verify Course Ownership
        $course = Database::selectOne("SELECT id, teacher_id FROM courses WHERE id = ? LIMIT 1", [$courseId]);
        if (!$course || ($course['teacher_id'] != $request->user_id && $request->role !== 'super_admin')) {
            $response->status(403)->json([
                'status'  => 'error',
                'message' => 'غير مصرح: لا تملك هذه الدورة'
            ]);
            return;
        }

        $lessonId = Database::insert(
            "INSERT INTO lessons (course_id, title, sequence_order, bunny_video_id, duration_seconds, is_free_preview) VALUES (?, ?, ?, ?, ?, 0)",
            [$courseId, $title, $sequenceOrder, $bunnyVideoId, $duration]
        );

        $response->status(201)->json([
            'status'  => 'success',
            'message' => 'تمت إضافة الدرس بنجاح',
            'data'    => [
                'lesson_id' => $lessonId
            ]
        ]);
    }
}