<?php

namespace App\Http\Controllers\Api;

use App\Models\Configuration;
use App\Models\Project;
use App\Models\Student;
use App\Models\StudentClass;
use App\Models\TeacherClass;
use App\Services\SemesterScoreService;
use RuntimeException;
use Symfony\Component\HttpFoundation\Response;

class ProjectController extends BaseApiController
{
    protected Project $project;
    protected Configuration $config;
    protected Student $student;
    protected StudentClass $studentClass;
    protected TeacherClass $teacherClass;
    protected SemesterScoreService $semesterScoreService;
    protected string $schoolYear;
    protected string $semester;

    public function __construct()
    {
        parent::__construct();
        $this->project = model(Project::class);
        $this->config = model(Configuration::class);
        $this->student = model(Student::class);
        $this->studentClass = model(StudentClass::class);
        $this->teacherClass = model(TeacherClass::class);
        $this->semesterScoreService = app(SemesterScoreService::class);

        $this->schoolYear = (string) ($this->config->getConfig('school_year') ?? '');
        $this->semester = (string) ($this->config->getConfig('semester') ?? '');
    }

    /**
     * GET /api/v1/projects
     * List projects with optional filters
     */
    public function index()
    {
        $page = max(1, (int) ($this->request->getGet('page') ?? 1));
        $perPage = min(100, max(1, (int) ($this->request->getGet('per_page') ?? 20)));
        $studentId = $this->request->getGet('student_id');
        $classSectionId = $this->request->getGet('class_section_id');

        $query = $this->project->newQuery()
            ->where('school_year', $this->schoolYear)
            ->where('semester', $this->semester);

        if ($studentId) {
            $query->where('student_id', $studentId);
        }

        if ($classSectionId) {
            $query->where('class_section_id', $classSectionId);
        }

        $result = $this->paginate($query, $page, $perPage);

        return $this->success($result, 'Projects retrieved successfully');
    }

    /**
     * GET /api/v1/projects/{id}
     * Get a single project
     */
    public function show($id = null)
    {
        $project = $this->project->find($id);
        if (!$project) {
            return $this->error('Project not found', Response::HTTP_NOT_FOUND);
        }

        return $this->success($project, 'Project retrieved successfully');
    }

    /**
     * GET /api/v1/projects/student/{id}
     * Get projects for a specific student
     */
    public function getByStudent($id = null)
    {
        $projects = $this->project->newQuery()
            ->where('student_id', $id)
            ->where('school_year', $this->schoolYear)
            ->where('semester', $this->semester)
            ->orderBy('project_index', 'ASC')
            ->get()
            ->toArray();

        return $this->success($projects, 'Projects retrieved successfully');
    }

    /**
     * POST /api/v1/projects
     * Create a new project entry
     */
    public function store()
    {
        $user = $this->getCurrentUser();
        if (!$user) {
            return $this->respondError('Authentication required', Response::HTTP_UNAUTHORIZED);
        }

        $data = $this->payloadData();
        if (empty($data)) {
            return $this->error('Invalid request data', Response::HTTP_BAD_REQUEST);
        }

        $rules = [
            'student_id' => 'required|integer',
            'class_section_id' => 'required|integer',
            'project_index' => 'required|integer',
        ];

        $errors = $this->validateRequest($data, $rules);
        if (!empty($errors)) {
            return $this->respondValidationError($errors);
        }

        $projectData = [
            'student_id' => $data['student_id'],
            'class_section_id' => $data['class_section_id'],
            'project_index' => $data['project_index'],
            'score' => $data['score'] ?? null,
            'comment' => $data['comment'] ?? null,
            'school_year' => $this->schoolYear,
            'semester' => $this->semester,
            'updated_by' => $user->id,
        ];

        try {
            $project = $this->project->create($projectData);
            return $this->success($project->toArray(), 'Project created successfully', Response::HTTP_CREATED);
        } catch (\Throwable $e) {
            log_message('error', 'Project creation error: ' . $e->getMessage());
            return $this->respondError('Failed to create project', Response::HTTP_INTERNAL_SERVER_ERROR);
        }
    }

    /**
     * PATCH /api/v1/projects/{id}
     * Update a project entry
     */
    public function update($id = null)
    {
        $project = $this->project->find($id);
        if (!$project) {
            return $this->error('Project not found', Response::HTTP_NOT_FOUND);
        }

        $user = $this->getCurrentUser();
        if (!$user) {
            return $this->respondError('Authentication required', Response::HTTP_UNAUTHORIZED);
        }

        $data = $this->payloadData();
        if (empty($data)) {
            return $this->error('Invalid request data', Response::HTTP_BAD_REQUEST);
        }

        $allowedFields = ['score', 'comment', 'project_index'];
        $updateData = [];
        foreach ($allowedFields as $field) {
            if (array_key_exists($field, $data)) {
                $updateData[$field] = $data[$field];
            }
        }

        if (empty($updateData)) {
            return $this->error('No valid fields to update', Response::HTTP_BAD_REQUEST);
        }

        $updateData['updated_by'] = $user->id;
        $updateData['updated_at'] = utc_now();

        try {
            $this->project->update($id, $updateData);
            $updatedProject = $this->project->find($id);
            return $this->success($updatedProject, 'Project updated successfully');
        } catch (\Throwable $e) {
            log_message('error', 'Project update error: ' . $e->getMessage());
            return $this->respondError('Failed to update project', Response::HTTP_INTERNAL_SERVER_ERROR);
        }
    }

    /**
     * GET /api/v1/projects/add-project
     * Get project data for teacher's class section (equivalent to addProject view)
     */
    public function addProject()
    {
        $updatedBy = $this->getCurrentUserId();
        if (!$updatedBy) {
            return $this->respondError('Authentication required', Response::HTTP_UNAUTHORIZED);
        }

        $teacherClass = $this->teacherClass->where('teacher_id', $updatedBy)->first();
        if (!$teacherClass) {
            return $this->respondError('No class section found for the current teacher.', Response::HTTP_NOT_FOUND);
        }

        $classSectionId = $teacherClass['class_section_id'];
        session()->put('class_section_id', $classSectionId);

        $projectRows = $this->project
            ->select('id, project_index')
            ->where('class_section_id', $classSectionId)
            ->where('updated_by', $updatedBy)
            ->where('semester', $this->semester)
            ->where('school_year', $this->schoolYear)
            ->orderBy('project_index', 'ASC')
            ->findAll();

        $projectHeaders = [];
        foreach ($projectRows as $row) {
            $projectHeaders[$row['project_index']][] = $row['id'];
        }

        $headerLabels = array_keys($projectHeaders);

        $studentsClasses = $this->studentClass->where('class_section_id', $classSectionId)->findAll();
        $students = [];

        foreach ($studentsClasses as $studentClass) {
            $studentId = $studentClass['student_id'];
            $student = $this->student->find($studentId);
            if ($student) {
                $scores = [];
                foreach ($projectHeaders as $index => $ids) {
                    $entry = $this->project
                        ->where('student_id', $studentId)
                        ->where('project_index', $index)
                        ->where('class_section_id', $classSectionId)
                        ->where('semester', $this->semester)
                        ->first();

                    $scores[$index] = $entry['score'] ?? '';
                }

                $students[] = [
                    'student_id' => $studentId,
                    'firstname' => $student['firstname'],
                    'lastname' => $student['lastname'],
                    'scores' => $scores
                ];
            }
        }

        usort($students, fn($a, $b) => strcmp($a['lastname'], $b['lastname']) ?: strcmp($a['firstname'], $b['firstname']));

        return $this->success([
            'students' => $students,
            'project_headers' => $headerLabels,
            'semester' => $this->semester,
            'school_year' => $this->schoolYear,
            'class_section_id' => $classSectionId
        ], 'Project data retrieved successfully');
    }

    /**
     * POST /api/v1/projects/update-scores
     * Update project scores for multiple students
     */
    public function updateProjectScores()
    {
        $updatedBy = $this->getCurrentUserId();
        if (!$updatedBy) {
            return $this->respondError('Authentication required', Response::HTTP_UNAUTHORIZED);
        }

        $payload = $this->payloadData();
        $scores = $payload['scores'] ?? null;
        $classSectionId = (int) ($payload['class_section_id'] ?? session()->get('class_section_id') ?? 0);

        if ($classSectionId <= 0) {
            return $this->respondError('Class section ID is required', Response::HTTP_BAD_REQUEST);
        }

        if (!is_array($scores)) {
            return $this->respondError('No project scores submitted.', Response::HTTP_BAD_REQUEST);
        }

        try {
            foreach ($scores as $studentId => $projects) {
                if (!is_numeric($studentId)) continue;

                $student = $this->student->find($studentId);
                if (!$student) continue;

                foreach ($projects as $index => $score) {
                    if (!is_numeric($score)) continue;

                    $existing = $this->project->where([
                        'student_id' => $studentId,
                        'project_index' => $index,
                        'class_section_id' => $classSectionId,
                        'semester' => $this->semester
                    ])->first();

                    $data = [
                        'student_id' => $studentId,
                        'school_id' => $student['school_id'] ?? '',
                        'class_section_id' => $classSectionId,
                        'updated_by' => $updatedBy,
                        'project_index' => $index,
                        'score' => is_numeric($score) ? (float)$score : null,
                        'semester' => $this->semester,
                        'school_year' => $this->schoolYear,
                        'updated_at' => utc_now(),
                    ];

                    if ($existing) {
                        $this->project->update($existing['id'], $data);
                    } else {
                        $data['created_at'] = utc_now();
                        $this->project->insert($data);
                    }
                }
            }

            $studentTeacherInfo = $this->student->getStudentInfoByClassSectionId($classSectionId);

            // Call the updateScoresForStudents method
            try {
                $this->semesterScoreService->updateScoresForStudents($studentTeacherInfo);
            } catch (RuntimeException $e) {
                log_message('error', 'Failed to update semester scores: ' . $e->getMessage());
            }

            return $this->success(null, 'Project scores updated successfully.');
        } catch (\Throwable $e) {
            log_message('error', 'Update project scores error: ' . $e->getMessage());
            return $this->respondError('Failed to update project scores: ' . $e->getMessage(), Response::HTTP_INTERNAL_SERVER_ERROR);
        }
    }

    /**
     * POST /api/v1/projects/add-column
     * Add a new project column for all students in a class section
     */
    public function addNextProjectColumn()
    {
        $updatedBy = $this->getCurrentUserId();
        if (!$updatedBy) {
            return $this->respondError('Authentication required', Response::HTTP_UNAUTHORIZED);
        }

        $payload = $this->payloadData();
        $classSectionId = (int) ($payload['class_section_id'] ?? session()->get('class_section_id') ?? 0);

        if ($classSectionId <= 0) {
            return $this->respondError('Class section ID is required', Response::HTTP_BAD_REQUEST);
        }

        try {
            $existingIndexes = $this->project
                ->select('project_index')
                ->where('class_section_id', $classSectionId)
                ->where('updated_by', $updatedBy)
                ->where('semester', $this->semester)
                ->where('school_year', $this->schoolYear)
                ->groupBy('project_index')
                ->orderBy('project_index', 'DESC')
                ->findAll();

            $maxIndex = 0;
            foreach ($existingIndexes as $row) {
                if (isset($row['project_index']) && is_numeric($row['project_index'])) {
                    $maxIndex = max($maxIndex, (int)$row['project_index']);
                }
            }

            $nextIndex = $maxIndex + 1;

            $students = $this->studentClass->where('class_section_id', $classSectionId)->findAll();

            $insertedCount = 0;
            foreach ($students as $student) {
                $exists = $this->project->where([
                    'student_id' => $student['student_id'],
                    'project_index' => $nextIndex,
                    'class_section_id' => $classSectionId,
                    'semester' => $this->semester,
                    'school_year' => $this->schoolYear,
                ])->first();

                if (!$exists) {
                    $studentRecord = $this->student->find($student['student_id']);
                    $this->project->insert([
                        'student_id' => $student['student_id'],
                        'school_id' => $studentRecord['school_id'] ?? '',
                        'class_section_id' => $classSectionId,
                        'updated_by' => $updatedBy,
                        'project_index' => $nextIndex,
                        'score' => null,
                        'semester' => $this->semester,
                        'school_year' => $this->schoolYear,
                        'created_at' => utc_now(),
                        'updated_at' => utc_now()
                    ]);
                    $insertedCount++;
                }
            }

            return $this->success([
                'status' => 'success',
                'project_index' => $nextIndex,
                'students_processed' => $insertedCount
            ], 'Project column added successfully');
        } catch (\Throwable $e) {
            log_message('error', 'Add project column error: ' . $e->getMessage());
            return $this->respondError('Failed to add project column: ' . $e->getMessage(), Response::HTTP_INTERNAL_SERVER_ERROR);
        }
    }

    /**
     * GET /api/v1/projects/management
     * Get project management data for a class section
     */
    public function showProjectMngt()
    {
        // Accept POST first, then GET (query string), then session fallback
        $incomingId = $this->request->getPost('class_section_id');
        if (!$incomingId) {
            $incomingId = $this->request->getGet('class_section_id');
        }

        $classSectionId = (int) ($incomingId ?: (session()->get('class_section_id') ?? 0));

        if ($classSectionId <= 0) {
            return $this->respondError('No class section found for the current teacher or selection.', Response::HTTP_BAD_REQUEST);
        }

        session()->put('class_section_id', $classSectionId);

        $projectScores = $this->getProjectScoresByStudent($classSectionId, $this->semester, $this->schoolYear);
        $students = $this->getStudentsByClassSectionAndYear($classSectionId, $this->schoolYear);
        $projectHeaders = $this->getProjectHeaders($classSectionId, $this->semester, $this->schoolYear);

        return $this->success([
            'project_scores' => $projectScores,
            'students' => $students,
            'semester' => $this->semester,
            'school_year' => $this->schoolYear,
            'project_headers' => $projectHeaders,
            'class_section_id' => $classSectionId,
        ], 'Project management data retrieved successfully');
    }

    /**
     * POST /api/v1/projects/update
     * Update project scores (management endpoint)
     */
    public function updateProject()
    {
        $payload = $this->payloadData();
        $scores = $payload['scores'] ?? null;
        $studentIds = $payload['student_ids'] ?? null;
        $semester = $payload['semester'] ?? $this->semester;
        $schoolYear = $payload['school_year'] ?? $this->schoolYear;
        $updatedBy = $payload['teacher_id'] ?? $this->getCurrentUserId();
        $classSectionId = (int) ($payload['class_section_id'] ?? session()->get('class_section_id') ?? 0);

        if (!$updatedBy) {
            return $this->respondError('Authentication required', Response::HTTP_UNAUTHORIZED);
        }

        if ($classSectionId <= 0) {
            return $this->respondError('Class section ID is required', Response::HTTP_BAD_REQUEST);
        }

        if ($scores && $studentIds && $semester && $schoolYear) {
            try {
                $this->saveProjectScores($scores, $studentIds, $semester, $schoolYear, $updatedBy, $classSectionId);

                $studentTeacherInfo = $this->student->getStudentInfoByClassSectionId($classSectionId);

                // Call the updateScoresForStudents method
                try {
                    $this->semesterScoreService->updateScoresForStudents($studentTeacherInfo);
                } catch (RuntimeException $e) {
                    log_message('error', 'Failed to update semester scores: ' . $e->getMessage());
                }

                return $this->success(null, 'Project scores updated successfully.');
            } catch (\Throwable $e) {
                log_message('error', 'Update project error: ' . $e->getMessage());
                return $this->respondError('Failed to update scores: ' . $e->getMessage(), Response::HTTP_INTERNAL_SERVER_ERROR);
            }
        }

        return $this->respondError('Failed to update scores. Missing required data.', Response::HTTP_BAD_REQUEST);
    }

    /**
     * Helper: Save project scores for multiple students
     */
    private function saveProjectScores(array $scores, array $studentIds, string $semester, string $schoolYear, int $updatedBy, int $classSectionId)
    {
        $now = utc_now();

        foreach ($studentIds as $studentId) {
            if (!isset($scores[$studentId])) {
                continue;
            }

            foreach ($scores[$studentId] as $index => $score) {
                // Check if the record exists
                $existing = $this->project
                    ->where('student_id', $studentId)
                    ->where('project_index', $index)
                    ->where('semester', $semester)
                    ->where('school_year', $schoolYear)
                    ->where('class_section_id', $classSectionId)
                    ->where('updated_by', $updatedBy)
                    ->first();

                $student = $this->student->find($studentId);
                $data = [
                    'student_id' => $studentId,
                    'class_section_id' => $classSectionId,
                    'updated_by' => $updatedBy,
                    'project_index' => $index,
                    'score' => is_numeric($score) ? floatval($score) : null,
                    'semester' => $semester,
                    'school_year' => $schoolYear,
                    'updated_at' => $now,
                ];

                if ($existing && isset($existing['id'])) {
                    $this->project->update($existing['id'], $data);
                } else {
                    $data['created_at'] = $now;
                    $data['school_id'] = $student['school_id'] ?? '';
                    $this->project->insert($data);
                }
            }
        }
    }

    /**
     * Helper: Get project headers for a class section
     */
    private function getProjectHeaders($classSectionId, $semester, $schoolYear)
    {
        $rows = $this->project
            ->select('project_index')
            ->where('class_section_id', $classSectionId)
            ->where('semester', $semester)
            ->where('school_year', $schoolYear)
            ->orderBy('project_index', 'ASC')
            ->findAll();

        $headers = [];
        foreach ($rows as $row) {
            $index = $row['project_index'];
            if (!is_array($index)) {
                $headers[$index] = true;
            }
        }

        ksort($headers);
        return array_keys($headers);
    }

    /**
     * Helper: Get students by class section and year
     */
    private function getStudentsByClassSectionAndYear($classSectionId, $schoolYear)
    {
        // Step 1: Get student IDs from student_class table
        $studentClassRows = $this->studentClass
            ->select('student_id')
            ->where('class_section_id', $classSectionId)
            ->where('school_year', $schoolYear)
            ->findAll();

        $studentIds = array_column($studentClassRows, 'student_id');

        if (empty($studentIds)) {
            return []; // No students found
        }

        // Step 2: Get student data from students table
        $students = $this->student
            ->whereIn('id', $studentIds)
            ->orderBy('lastname', 'ASC')
            ->findAll();

        return $students;
    }

    /**
     * Helper: Get project scores by student
     */
    private function getProjectScoresByStudent($classSectionId, $semester, $schoolYear)
    {
        $rows = $this->project
            ->select('student_id, project_index, score')
            ->where('class_section_id', $classSectionId)
            ->where('semester', $semester)
            ->where('school_year', $schoolYear)
            ->findAll();

        $studentScores = [];
        foreach ($rows as $row) {
            $studentId = $row['student_id'];
            $index = $row['project_index'];
            $score = $row['score'];

            $studentScores[$studentId]['scores'][$index] = $score;
        }

        return $studentScores;
    }
}