<?php

namespace App\Services;

use App\Models\User;
use App\Models\Course\Course;
use App\Models\Course\CourseAssignment;
use App\Models\Course\CourseCart;
use App\Models\Course\CourseEnrollment;
use App\Models\Course\CourseLiveClass;
use App\Models\Course\CourseSection;
use App\Models\Course\SectionQuiz;
use App\Services\MediaService;
use App\Services\Course\CourseEnrollmentService;
use App\Services\Course\CoursePlayerService;
use App\Services\Course\CourseWishlistService;
use Illuminate\Support\Facades\Auth;
use Modules\Certificate\Models\CertificateTemplate;
use Modules\Certificate\Models\MarksheetTemplate;
use Modules\Exam\Services\ExamEnrollmentService;
use Modules\Exam\Services\ExamWishlistService;
use Modules\Exam\Services\ExamAttemptService;
use Modules\Exam\Models\Exam;
use Modules\Exam\Models\ExamEnrollment;
use Modules\Exam\Models\ExamAttempt;
use Modules\Exam\Services\ExamResourceService;
use Modules\Certificate\Services\CertificateService;

class StudentService extends MediaService
{
   public function __construct(
      private InstructorService $instructor,
      private CourseEnrollmentService $courseEnrollment,
      private CoursePlayerService $coursePlayer,
      private CourseWishlistService $courseWishlist,
      private ExamWishlistService $examWishlist,
      private ExamResourceService $examResource,
      private ExamEnrollmentService $examEnrollment,
      private ExamAttemptService $examAttempt,
      private CertificateService $certificate,
   ) {}

   function getCartCount(): int
   {
      $user = Auth::user();
      return CourseCart::where('user_id', $user->id)->count();
   }

   function getStudentData(?string $tab = 'courses'): array
   {
      $props = [];
      $user = Auth::user();
      $instructor = $this->instructor->getInstructorByUserId($user->id);
      $props['instructor'] = $instructor;

      switch ($tab) {
         case 'courses':
            $enrollments = $this->courseEnrollment->getEnrollments(['user_id' => $user->id]);

            foreach ($enrollments as $enrollment) {
               $watch_history = $this->coursePlayer->getWatchHistory($enrollment->course_id, $user->id);
               $completion = $this->coursePlayer->calculateCompletion($enrollment->course, $watch_history);
               $enrollment->watch_history = $watch_history;
               $enrollment->completion = $completion;
            }

            $props['courseEnrollments'] = $enrollments;
            break;

         case 'exams':
            $enrollments = $this->examEnrollment->getEnrollments(['user_id' => $user->id]);
            $props['examEnrollments'] = $enrollments;
            break;

         case 'wishlist':
            $courseWishlists = $this->courseWishlist->getWishlists(['user_id' => $user->id]);
            $examWishlists = $this->examWishlist->getWishlists(['user_id' => $user->id]);
            $props['courseWishlists'] = $courseWishlists;
            $props['examWishlists'] = $examWishlists;
            break;

         default:
            break;
      }

      return $props;
   }

   function updateProfile(array $data, string $id): User
   {
      $user = User::find($id);

      if (array_key_exists('photo', $data) && $data['photo']) {
         $data['photo'] = $this->addNewDeletePrev($user, $data['photo'], "profile");
      }

      $filteredData = array_filter($data, function ($value) {
         return $value !== null;
      });

      $user->update($filteredData);

      return $user;
   }

   public function getEnrolledCourse(string $id, User $user): Course
   {
      $enrollment = CourseEnrollment::where('user_id', $user->id)
         ->where('course_id', $id)
         ->first();

      if (!$enrollment) {
         abort(403, 'You are not enrolled in this course');
      }

      return Course::with(['instructor:id,user_id', 'instructor.user:id,name,photo'])->find($id);
   }

   public function getCourseModules(string $course_id)
   {
      return CourseSection::where('course_id', $course_id)
         ->with([
            'section_lessons',
            'section_quizzes'
         ])->get();
   }

   public function getCourseLiveClasses(string $course_id)
   {
      return CourseLiveClass::where('course_id', $course_id)->get();
   }

   public function getCourseAssignments(string $course_id, User $user)
   {
      return CourseAssignment::with([
         'submissions' => function ($query) use ($user) {
            $query->where('user_id', $user->id);
         }
      ])
         ->where('course_id', $course_id)
         ->get();
   }

   public function getCourseSectionQuizzes(string $course_id, User $user)
   {
      return CourseSection::where('course_id', $course_id)
         ->with([
            'section_quizzes' => function ($quiz) use ($user) {
               $quiz->with([
                  'quiz_submissions' => function ($query) use ($user) {
                     $query->where('user_id', $user->id);
                  },
                  'quiz_questions' => function ($question) use ($user) {
                     $question->with(['answers' => function ($answer) use ($user) {
                        $answer->where('user_id', $user->id);
                     }]);
                  }
               ]);
            }
         ])
         ->whereHas('section_quizzes')
         ->get();
   }

   public function getCourseLessonResources(string $course_id)
   {
      return CourseSection::where('course_id', $course_id)
         ->whereHas('section_lessons', function ($query) {
            $query->whereHas('resources');
         })
         ->with([
            'section_lessons' => function ($lesson) {
               $lesson->whereHas('resources')
                  ->select([
                     'id',
                     'title',
                     'course_id',
                     'course_section_id'
                  ])
                  ->with(['resources']);
            }
         ])
         ->get();
   }

   function getEnrolledCourseOverview(string $course_id, string $tab, User $user): array
   {
      $system = app('system_settings');
      $fields = $system?->fields ?? [];
      $showCourseCertificate = $fields['show_course_certificate'] ?? true;
      $showCourseMarksheet = $fields['show_course_marksheet'] ?? true;

      return [
         'modules' => $tab === 'modules' ? $this->getCourseModules($course_id) : null,
         'live_classes' => $tab === 'live_classes' ? $this->getCourseLiveClasses($course_id) : null,
         'assignments' => $tab === 'assignments' ? $this->getCourseAssignments($course_id, $user) : null,
         'quizzes' => $tab === 'quizzes' ? $this->getCourseSectionQuizzes($course_id, $user) : null,
         'resources' => $tab === 'resources' ? $this->getCourseLessonResources($course_id) : null,
         'certificateTemplate' => $tab === 'certificate' && $showCourseCertificate ? $this->certificate->getActiveCertificateTemplate('course') : null,
         'marksheetTemplate' => $tab === 'certificate' && $showCourseMarksheet ? $this->certificate->getActiveMarksheetTemplate('course') : null,
         'studentMarks' => $tab === 'certificate' && $showCourseMarksheet ? $this->calculateStudentMarks($course_id, $user->id) : null,
      ];
   }

   function calculateStudentMarks(string $course_id, string $user_id): array
   {
      // Calculate Assignment Marks
      $assignments = CourseAssignment::where('course_id', $course_id)
         ->with(['submissions' => function ($query) use ($user_id) {
            $query->where('user_id', $user_id)
               ->where('status', 'graded'); // Only count graded submissions
         }])
         ->get();

      $totalAssignmentMarks = 0;
      $obtainedAssignmentMarks = 0;

      foreach ($assignments as $assignment) {
         $totalAssignmentMarks += $assignment->total_mark;

         // Get the best submission (highest marks)
         $bestSubmission = $assignment->submissions->sortByDesc('marks_obtained')->first();
         if ($bestSubmission) {
            $obtainedAssignmentMarks += $bestSubmission->marks_obtained;
         }
      }

      $assignmentPercentage = $totalAssignmentMarks > 0
         ? round(($obtainedAssignmentMarks / $totalAssignmentMarks) * 100, 2)
         : 0;

      // Calculate Quiz Marks
      $quizzes = SectionQuiz::where('course_id', $course_id)
         ->with(['quiz_submissions' => function ($query) use ($user_id) {
            $query->where('user_id', $user_id);
         }])
         ->get();

      $totalQuizMarks = 0;
      $obtainedQuizMarks = 0;

      foreach ($quizzes as $quiz) {
         $totalQuizMarks += $quiz->total_mark;

         // Get the best submission (highest total_marks)
         $bestSubmission = $quiz->quiz_submissions->sortByDesc('total_marks')->first();
         if ($bestSubmission) {
            $obtainedQuizMarks += $bestSubmission->total_marks;
         }
      }

      $quizPercentage = $totalQuizMarks > 0
         ? round(($obtainedQuizMarks / $totalQuizMarks) * 100, 2)
         : 0;

      // Calculate Overall Percentage
      $overallPercentage = 0;
      $hasAssignments = $totalAssignmentMarks > 0;
      $hasQuizzes = $totalQuizMarks > 0;

      if ($hasAssignments && $hasQuizzes) {
         // If both exist, average them
         $overallPercentage = round(($assignmentPercentage + $quizPercentage) / 2, 2);
      } elseif ($hasAssignments) {
         $overallPercentage = $assignmentPercentage;
      } elseif ($hasQuizzes) {
         $overallPercentage = $quizPercentage;
      }

      // Determine Grade
      $grade = calculateGrade($overallPercentage);

      return [
         'assignment' => [
            'total' => $totalAssignmentMarks,
            'obtained' => $obtainedAssignmentMarks,
            'percentage' => $assignmentPercentage,
         ],
         'quiz' => [
            'total' => $totalQuizMarks,
            'obtained' => $obtainedQuizMarks,
            'percentage' => $quizPercentage,
         ],
         'overall' => [
            'percentage' => $overallPercentage,
            'grade' => $grade,
         ],
      ];
   }

   function getEnrolledExamTabProps(string $exam_id, string $tab, User $user): array
   {
      $data = [
         'result' => null,
         'resources' => null,
         'certificateTemplate' => null,
         'marksheetTemplate' => null,
         'studentMarks' => null,
      ];

      if ($tab === 'certificate') {
         $data['certificateTemplate'] = $this->certificate->getActiveCertificateTemplate('exam');
         $data['marksheetTemplate'] = $this->certificate->getActiveMarksheetTemplate('exam');
         $data['studentMarks'] = $this->examEnrollment->calculateStudentExamMarks($exam_id, $user->id);
      }

      // if ($tab === 'resources') {
      //    $data['resources'] = $this->examResource->getExamResources($exam_id);
      // }

      return $data;
   }
}