<?php

namespace App\Http\Controllers\Api;

use App\Models\Configuration;
use App\Models\Staff;
use App\Models\TeacherClass;
use App\Models\User;
use Illuminate\Support\Facades\DB;
use Symfony\Component\HttpFoundation\Response;

class StaffController extends BaseApiController
{
    protected Staff $staff;
    protected User $user;
    protected TeacherClass $teacherClass;
    protected Configuration $config;
    protected string $schoolYear;
    protected string $semester;

    public function __construct()
    {
        parent::__construct();
        $this->staff        = model(Staff::class);
        $this->user         = model(User::class);
        $this->teacherClass = model(TeacherClass::class);
        $this->config       = model(Configuration::class);
        $this->schoolYear        = (string) ($this->config->getConfig('school_year') ?? '');
        $this->semester          = (string) ($this->config->getConfig('semester') ?? '');
    }

    public function index()
    {
        $page    = max(1, (int) ($this->request->getGet('page') ?? 1));
        $perPage = min(100, max(1, (int) ($this->request->getGet('per_page') ?? 20)));
        $role    = $this->request->getGet('role');

        // Roles we never show
        $excludedRoles = ['student', 'parent', 'guest', 'inactive'];
        $normalizedExcluded = array_map('strtolower', $excludedRoles);

        $placeholders = implode(',', array_fill(0, count($normalizedExcluded), '?'));

        $query = $this->staff->newQuery()
            ->whereRaw('LOWER(active_role) NOT IN (' . $placeholders . ')', $normalizedExcluded);

        if (!empty($role)) {
            $query->whereRaw('LOWER(active_role) = ?', [strtolower((string) $role)]);
        }

        $query->orderByDesc('created_at');

        // Preload assignments for the selected school year (across all semesters)
        $assignRows = DB::table('teacher_class as tc')
            ->select('tc.teacher_id', 'tc.position', 'cs.class_section_name')
            ->leftJoin('classSection as cs', 'cs.class_section_id', '=', 'tc.class_section_id')
            ->where('tc.school_year', (string) $this->schoolYear)
            ->get()
            ->toArray();

        $assignByTeacher = [];
        foreach ($assignRows as $row) {
            $teacherId = (int) ($row->teacher_id ?? 0);
            if ($teacherId <= 0) {
                continue;
            }
            $section = trim((string) ($row->class_section_name ?? ''));
            if ($section === '') {
                continue;
            }
            $position = strtolower((string) ($row->position ?? ''));
            if (!in_array($position, ['main', 'ta'], true)) {
                continue;
            }
            $assignByTeacher[$teacherId][] = $section . ' (' . $position . ')';
        }

        // Get all staff (not paginated) for issues count calculation
        $allStaff = $query->get()->toArray();
        $issuesCount = 0;

        foreach ($allStaff as $staff) {
            $roleName = strtolower((string) ($staff['active_role'] ?? ''));
            if (in_array($roleName, ['teacher', 'teacher_assistant'], true)) {
                $userId = (int) ($staff['user_id'] ?? 0);
                $labels = $assignByTeacher[$userId] ?? [];
                if (empty($labels)) {
                    $issuesCount++;
                }
            }
        }

        // Paginate the results
        $result = $this->paginate($query, $page, $perPage);

        // Apply transformations to paginated data
        foreach ($result['data'] as &$staff) {
            $userId = (int) ($staff['user_id'] ?? 0);
            $staff['school_id'] = $userId > 0 ? $this->user->getSchoolIdByUserId($userId) : null;

            $roleName = strtolower((string) ($staff['active_role'] ?? ''));
            if (in_array($roleName, ['teacher', 'teacher_assistant'], true)) {
                $labels = $assignByTeacher[$userId] ?? [];
                if (!empty($labels)) {
                    $staff['class_section'] = implode(', ', array_unique($labels));
                    $staff['verification_issue'] = false;
                } else {
                    $staff['class_section'] = 'No class assigned';
                    $staff['verification_issue'] = true;
                }
            } else {
                $staff['class_section'] = '—';
                $staff['verification_issue'] = false;
            }
        }

        return $this->success([
            'data' => $result['data'],
            'pagination' => $result['pagination'],
            'issues_count' => $issuesCount,
            'semester' => $this->semester,
            'school_year' => $this->schoolYear,
        ], 'Staff members retrieved successfully');
    }

    public function show($id = null)
    {
        $staff = $this->staff->find($id);
        if (!$staff) {
            return $this->respondError('Staff member not found', Response::HTTP_NOT_FOUND);
        }

        $staff['school_id'] = $this->user->getSchoolIdByUserId((int) ($staff['user_id'] ?? 0));

        return $this->success($staff, 'Staff member retrieved successfully');
    }

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

        $now = utc_now();
        $payload = [
            'firstname'   => trim((string) ($data['firstname'] ?? '')),
            'lastname'    => trim((string) ($data['lastname'] ?? '')),
            'email'       => trim((string) ($data['email'] ?? '')),
            'phone'       => trim((string) ($data['phone'] ?? '')),
            'role_name'   => trim((string) ($data['role_name'] ?? '')),
            'school_year' => trim((string) ($data['school_year'] ?? $this->schoolYear)),
            'status'      => trim((string) ($data['status'] ?? 'Active')),
            'created_at'  => $now,
            'updated_at'  => $now,
        ];

        // Set active_role from role_name if provided
        if (!empty($payload['role_name'])) {
            $payload['active_role'] = strtolower($payload['role_name']);
        }

        try {
            $inserted = $this->staff->insert($payload);
            if (!$inserted) {
                return $this->respondError('Failed to create staff member', Response::HTTP_INTERNAL_SERVER_ERROR);
            }

            // Fetch the created record
            $staff = $this->staff->where('created_at', $now)->orderBy('id', 'DESC')->first();
            return $this->success($staff, 'Staff member added successfully', Response::HTTP_CREATED);
        } catch (\Throwable $e) {
            \Illuminate\Support\Facades\Log::error('Staff creation error: ' . $e->getMessage());
            return $this->respondError('Failed to create staff member', Response::HTTP_INTERNAL_SERVER_ERROR);
        }
    }

    public function update($id = null)
    {
        $staff = $this->staff->find($id);
        if (!$staff) {
            return $this->respondError('Staff member not found', Response::HTTP_NOT_FOUND);
        }

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

        // Only update fields provided by the request to avoid wiping data
        $updateData = [];
        $allowedFields = ['firstname', 'lastname', 'email', 'phone', 'role_name', 'school_year', 'status'];

        foreach ($allowedFields as $field) {
            if (array_key_exists($field, $data)) {
                $value = $data[$field];
                if ($value !== null && $value !== '') {
                    $updateData[$field] = trim((string) $value);
                }
            }
        }

        // Set active_role from role_name if role_name is being updated
        if (isset($updateData['role_name']) && !empty($updateData['role_name'])) {
            $updateData['active_role'] = strtolower($updateData['role_name']);
        }

        // Always bump updated_at
        $updateData['updated_at'] = utc_now();

        if (empty($updateData)) {
            return $this->respondError('No changes detected', Response::HTTP_BAD_REQUEST);
        }

        try {
            $updated = $this->staff->update($id, $updateData);
            if (!$updated) {
                return $this->respondError('Failed to update staff member', Response::HTTP_INTERNAL_SERVER_ERROR);
            }

            $updatedStaff = $this->staff->find($id);
            return $this->success($updatedStaff, 'Staff member updated successfully');
        } catch (\Throwable $e) {
            \Illuminate\Support\Facades\Log::error('Staff update error: ' . $e->getMessage());
            return $this->respondError('Failed to update staff member', Response::HTTP_INTERNAL_SERVER_ERROR);
        }
    }

    public function destroy($id = null)
    {
        $staff = $this->staff->find($id);
        if (!$staff) {
            return $this->respondError('Staff member not found', Response::HTTP_NOT_FOUND);
        }

        try {
            $this->staff->delete($id);
            return $this->respondDeleted(null, 'Staff member deleted successfully');
        } catch (\Throwable $e) {
            \Illuminate\Support\Facades\Log::error('Staff deletion error: ' . $e->getMessage());
            return $this->respondError('Failed to delete staff member', Response::HTTP_INTERNAL_SERVER_ERROR);
        }
    }
}