<?php

namespace App\Controllers;

use App\Models\UserModel;
use App\Models\DoctorModel;
use App\Models\DoctorSpecializationModel;
use App\Models\PatientModel;
use App\Models\AppointmentModel;
use App\Models\SpecializationModel;

class Admin extends BaseController
{
    private function formatFullName(?string $firstName, ?string $lastName, string $fallback = ''): string
    {
        $fullName = trim(trim((string) $firstName) . ' ' . trim((string) $lastName));

        return $fullName !== '' ? $fullName : $fallback;
    }

    private function generateAccountPassword(int $length = 12): string
    {
        $alphabet = 'ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz23456789!@#$%';
        $maxIndex = strlen($alphabet) - 1;
        $password = '';

        for ($i = 0; $i < $length; $i++) {
            $password .= $alphabet[random_int(0, $maxIndex)];
        }

        return $password;
    }

    private function parseSpecializations($specializationInput): array
    {
        $specializations = [];

        if (is_array($specializationInput)) {
            foreach ($specializationInput as $item) {
                $item = trim((string) $item);
                if ($item !== '' && ! in_array($item, $specializations, true)) {
                    $specializations[] = $item;
                }
            }
        } else {
            $single = trim((string) $specializationInput);
            if ($single !== '') {
                $specializations[] = $single;
            }
        }

        return $specializations;
    }

    private function buildExperienceString(?int $years, ?int $months): ?string
    {
        $experienceParts = [];

        if ($years !== null && $years > 0) {
            $experienceParts[] = $years . ' year' . ($years === 1 ? '' : 's');
        }

        if ($months !== null && $months > 0) {
            $experienceParts[] = $months . ' month' . ($months === 1 ? '' : 's');
        }

        return $experienceParts !== [] ? implode(' ', $experienceParts) : null;
    }

    private function parseExperienceString(?string $experience): array
    {
        $experience = trim((string) $experience);
        $years      = 0;
        $months     = 0;

        if ($experience !== '' && preg_match('/(\d+)\s+year/i', $experience, $yearMatch)) {
            $years = (int) $yearMatch[1];
        }

        if ($experience !== '' && preg_match('/(\d+)\s+month/i', $experience, $monthMatch)) {
            $months = (int) $monthMatch[1];
        }

        return [
            'experience_years'  => $years,
            'experience_months' => $months,
        ];
    }

    private function getPatientFormData(int $userId): ?array
    {
        $userModel    = new UserModel();
        $patientModel = new PatientModel();

        $user    = $userModel->find($userId);
        $patient = $patientModel->findByUserId($userId);

        if (! $user || ! $patient) {
            return null;
        }

        return [
            'patient'     => $patient,
            'user'        => $user,
            'first_name'  => $user['first_name'] ?? '',
            'last_name'   => $user['last_name'] ?? '',
        ];
    }

    private function getDoctorFormData(int $userId): ?array
    {
        $userModel                 = new UserModel();
        $doctorModel               = new DoctorModel();
        $specializationModel       = new SpecializationModel();
        $doctorSpecializationModel = new DoctorSpecializationModel();

        $user   = $userModel->find($userId);
        $doctor = $doctorModel->findByUserId($userId);

        if (! $user || ! $doctor) {
            return null;
        }

        $selectedSpecializations = $doctorSpecializationModel->getNamesForDoctor((int) $doctor['id']);

        if ($selectedSpecializations === []) {
            $selectedSpecializations = $this->parseSpecializations($doctor['specialization'] ?? []);
        }

        return array_merge($this->parseExperienceString($doctor['experience'] ?? null), [
            'doctor'                  => $doctor,
            'user'                    => $user,
            'first_name'              => $user['first_name'] ?? '',
            'last_name'               => $user['last_name'] ?? '',
            'specializationOptions'   => $specializationModel->getOptionNames(),
            'selectedSpecializations' => $selectedSpecializations,
        ]);
    }

    public function dashboard()
    {
        if ($r = $this->requireRole('admin')) {
            return $r;
        }

        $doctorModel      = new DoctorModel();
        $patientModel     = new PatientModel();
        $appointmentModel = new AppointmentModel();
        $userModel        = new UserModel();
        $adminId          = (int) session()->get('id');
        $adminUser        = $userModel->find($adminId);

        $data['totalDoctors']      = $doctorModel->countAll();
        $data['totalPatients']     = $patientModel->countAll();
        $data['totalAppointments'] = $appointmentModel->countAll();
        $data['activeToday']       = $appointmentModel->countForDate(date('Y-m-d'));
        $data['recentActivity']    = $appointmentModel->getRecentActivity(6);
        $data['latestDoctors']     = $doctorModel->getLatestDoctors(5);
        $data['latestPatients']    = $patientModel->getLatestPatients(5);
        $data['adminName']  = $this->formatFullName($adminUser['first_name'] ?? '', $adminUser['last_name'] ?? '', 'Administrator');
        $data['adminEmail'] = $adminUser['email'] ?? '';

        return view('admin/dashboard', $data);
    }

    public function doctors()
    {
        if ($r = $this->requireRole('admin')) {
            return $r;
        }

        return view('admin/doctors');
    }

    public function deleteDoctor($id)
    {
        if ($r = $this->requireRole('admin')) {
            return $r;
        }

        $id = (int) $id;
        if ($id < 1) {
            return redirect()->to(site_url('admin/doctors'));
        }

        $userModel                 = new UserModel();
        $doctorModel               = new DoctorModel();
        $appointmentModel          = new AppointmentModel();
        $doctorSpecializationModel = new DoctorSpecializationModel();

        $doctor = $doctorModel->findByUserId($id);
        if ($doctor) {
            $appointmentModel->deleteByDoctorId((int) $doctor['id']);
            $doctorSpecializationModel->deleteByDoctorId((int) $doctor['id']);
            $doctorModel->delete($doctor['id']);
        }

        $userModel->delete($id);

        return redirect()->to(site_url('admin/doctors'));
    }

    public function patients()
    {
        if ($r = $this->requireRole('admin')) {
            return $r;
        }

        return view('admin/patients');
    }

    public function deletePatient($id)
    {
        if ($r = $this->requireRole('admin')) {
            return $r;
        }

        $id = (int) $id;
        if ($id < 1) {
            return redirect()->to(site_url('admin/patients'));
        }

        $userModel        = new UserModel();
        $patientModel     = new PatientModel();
        $appointmentModel = new AppointmentModel();

        $patient = $patientModel->findByUserId($id);
        if ($patient) {
            $appointmentModel->deleteByPatientId((int) $patient['id']);
            $patientModel->delete($patient['id']);
        }

        $userModel->delete($id);

        return redirect()->to(site_url('admin/patients'));
    }

    public function appointments()
    {
        if ($r = $this->requireRole('admin')) {
            return $r;
        }

        $appointmentModel       = new AppointmentModel();
        $data['appointments']   = $appointmentModel->getAdminAppointments();

        return view('admin/appointments', $data);
    }

    public function addDoctor()
    {
        if ($r = $this->requireRole('admin')) {
            return $r;
        }

        $specializationModel = new SpecializationModel();

        return view('admin/add_doctor', [
            'specializationOptions' => $specializationModel->getOptionNames(),
            'isEdit'                => false,
        ]);
    }

    public function addPatient()
    {
        if ($r = $this->requireRole('admin')) {
            return $r;
        }

        return view('admin/add_patient', [
            'isEdit' => false,
        ]);
    }

    public function editDoctor($encryptedId)
    {
        if ($r = $this->requireRole('admin')) {
            return $r;
        }
        $id = decrypt_id($encryptedId);
        if (! ctype_digit((string) $id)) {
            return redirect()->to(site_url('admin/doctors'))->with('error', 'Invalid doctor link.');
        }
        $doctorData = $this->getDoctorFormData((int) $id);
        if (! $doctorData) {
            return redirect()->to(site_url('admin/doctors'))->with('error', 'Doctor not found.');
        }

        return view('admin/add_doctor', array_merge($doctorData, [
            'isEdit' => true,
        ]));
    }

    public function editPatient($encryptedId)
    {
        if ($r = $this->requireRole('admin')) {
            return $r;
        }

        $id = decrypt_id($encryptedId);
        if (! ctype_digit((string) $id)) {
            return redirect()->to(site_url('admin/patients'))->with('error', 'Invalid patient link.');
        }

        $patientData = $this->getPatientFormData((int) $id);
        if (! $patientData) {
            return redirect()->to(site_url('admin/patients'))->with('error', 'Patient not found.');
        }

        return view('admin/add_patient', array_merge($patientData, [
            'isEdit' => true,
        ]));
    }

    public function storeDoctor()
    {
        if ($r = $this->requireRole('admin')) {
            return $r;
        }

        $rules = [
            'first_name'        => 'required|min_length[2]|max_length[50]|alpha_space',
            'last_name'         => 'required|min_length[2]|max_length[50]|alpha_space',
            'email'             => 'required|valid_email|is_unique[users.email]',
            'experience_years'  => 'required|integer|greater_than_equal_to[0]|less_than_equal_to[60]',
            'experience_months' => 'required|integer|greater_than_equal_to[0]|less_than_equal_to[11]',
            'fees'              => 'permit_empty|decimal',
        ];
        
        if (! $this->validate($rules)) {
            return redirect()->back()->withInput();
        }

        $userModel   = new UserModel();
        $doctorModel = new DoctorModel();
        $specializationModel = new SpecializationModel();
        $doctorSpecializationModel = new DoctorSpecializationModel();
        $db          = \Config\Database::connect();

        $firstName = trim((string) $this->request->getPost('first_name'));
        $lastName  = trim((string) $this->request->getPost('last_name'));
        $specializationInput = $this->request->getPost('specialization');

        $specializations = $this->parseSpecializations($specializationInput);

        if ($specializations === []) {
            return redirect()->back()->withInput()->with('error', 'Please select at least one specialization.');
        }

        $specializationValue = implode(', ', $specializations);
        if (strlen($specializationValue) > 191) {
            return redirect()->back()->withInput()->with('error', 'Selected specializations are too long. Please reduce them.');
        }

        $yearsRaw  = (string) $this->request->getPost('experience_years');
        $monthsRaw = (string) $this->request->getPost('experience_months');
        $years     = $yearsRaw === '' ? null : (int) $yearsRaw;
        $months    = $monthsRaw === '' ? null : (int) $monthsRaw;

        $experience = $this->buildExperienceString($years, $months);
        $generatedPassword = $this->generateAccountPassword();

        $db->transStart();

        $userData = [
            'first_name' => $firstName,
            'last_name'  => $lastName,
            'email'      => trim((string) $this->request->getPost('email')),
            'password'   => password_hash($generatedPassword, PASSWORD_DEFAULT),
            'role'       => 'doctor',
            'status'     => 'active',
        ];

        if (! $userModel->skipValidation(true)->insert($userData)) {
            $db->transRollback();

            return redirect()->back()->withInput()->with('error', 'Could not create doctor login account.');
        }

        $userId = (int) $userModel->getInsertID();

        $doctorRow = [
            'user_id'        => $userId,
            'specialization' => $specializationValue,
            'experience'     => $experience,
            'fees'           => $this->request->getPost('fees') !== '' && $this->request->getPost('fees') !== null
                ? $this->request->getPost('fees')
                : null,
        ];

        if (! $doctorModel->skipValidation(true)->insert($doctorRow)) {
            $db->transRollback();

            return redirect()->back()->withInput()->with('error', 'Could not create doctor profile.');
        }

        $doctorId           = (int) $doctorModel->getInsertID();
        $specializationMap  = $specializationModel->ensureNamesExist($specializations);
        $specializationIds  = array_values($specializationMap);
        $doctorSpecializationModel->syncDoctorSpecializations($doctorId, $specializationIds, (int) session()->get('id'));

        $db->transComplete();

        if (! $db->transStatus()) {
            return redirect()->back()->withInput()->with('error', 'Transaction failed.');
        }

        return redirect()->to(site_url('admin/doctors'))->with('success', 'Doctor account created. Generated password: ' . $generatedPassword);
    }

    public function storePatient()
    {
        if ($r = $this->requireRole('admin')) {
            return $r;
        }

        $rules = [
            'first_name' => 'required|min_length[2]|max_length[50]|alpha_space',
            'last_name'  => 'required|min_length[2]|max_length[50]|alpha_space',
            'email'      => 'required|valid_email|is_unique[users.email]',
            'phone'      => 'required|min_length[10]|max_length[15]',
            'age'        => 'permit_empty|integer|greater_than_equal_to[0]|less_than_equal_to[120]',
            'gender'     => 'permit_empty|in_list[male,female,other]',
        ];

        if (! $this->validate($rules)) {
            return redirect()->back()->withInput();
        }

        $userModel    = new UserModel();
        $patientModel = new PatientModel();
        $db           = \Config\Database::connect();

        $firstName         = trim((string) $this->request->getPost('first_name'));
        $lastName          = trim((string) $this->request->getPost('last_name'));
        $generatedPassword = $this->generateAccountPassword();
        $ageRaw            = (string) $this->request->getPost('age');

        $db->transStart();

        $userData = [
            'first_name' => $firstName,
            'last_name'  => $lastName,
            'email'      => trim((string) $this->request->getPost('email')),
            'password'   => password_hash($generatedPassword, PASSWORD_DEFAULT),
            'role'       => 'patient',
            'status'     => 'active',
        ];

        if (! $userModel->skipValidation(true)->insert($userData)) {
            $db->transRollback();

            return redirect()->back()->withInput()->with('error', 'Could not create patient login account.');
        }

        $userId = (int) $userModel->getInsertID();

        $patientRow = [
            'user_id' => $userId,
            'age'     => $ageRaw !== '' ? (int) $ageRaw : null,
            'gender'  => $this->request->getPost('gender') !== '' ? $this->request->getPost('gender') : null,
            'phone'   => trim((string) $this->request->getPost('phone')),
        ];

        if (! $patientModel->skipValidation(true)->insert($patientRow)) {
            $db->transRollback();

            return redirect()->back()->withInput()->with('error', 'Could not create patient profile.');
        }

        $db->transComplete();

        if (! $db->transStatus()) {
            return redirect()->back()->withInput()->with('error', 'Transaction failed.');
        }

        return redirect()->to(site_url('admin/patients'))->with('success', 'Patient account created. Generated password: ' . $generatedPassword);
    }

    public function updateDoctor($encryptedId)
    {
        if ($r = $this->requireRole('admin')) {
            return $r;
        }
        $id = decrypt_id($encryptedId);
        if (! ctype_digit((string) $id)) {
            return redirect()->to(site_url('admin/doctors'))->with('error', 'Invalid doctor link.');
        }
        $userId      = (int) $id;
        $doctorData  = $this->getDoctorFormData($userId);
        if (! $doctorData) {
            return redirect()->to(site_url('admin/doctors'))->with('error', 'Doctor not found.');
        }

        $rules = [
            'first_name'        => 'required|min_length[2]|max_length[50]|alpha_space',
            'last_name'         => 'required|min_length[2]|max_length[50]|alpha_space',
            'email'             => 'required|valid_email|is_unique[users.email,id,' . $userId . ']',
            'experience_months' => 'required|integer|greater_than_equal_to[0]|less_than_equal_to[11]',
            'experience_years'  => 'required|integer|greater_than_equal_to[0]|less_than_equal_to[60]',
            'fees'              => 'permit_empty|decimal',
        ];

        if (! $this->validate($rules)) {
            return redirect()->back()->withInput();
        }

        $userModel                 = new UserModel();
        $doctorModel               = new DoctorModel();
        $specializationModel       = new SpecializationModel();
        $doctorSpecializationModel = new DoctorSpecializationModel();
        $db                        = \Config\Database::connect();

        $firstName             = trim((string) $this->request->getPost('first_name'));
        $lastName              = trim((string) $this->request->getPost('last_name'));
        $specializationInput   = $this->request->getPost('specialization');
        $specializations       = $this->parseSpecializations($specializationInput);

        if ($specializations === []) {
            return redirect()->back()->withInput()->with('error', 'Please select at least one specialization.');
        }

        $specializationValue = implode(', ', $specializations);
        if (strlen($specializationValue) > 191) {
            return redirect()->back()->withInput()->with('error', 'Selected specializations are too long. Please reduce them.');
        }

        $yearsRaw   = (string) $this->request->getPost('experience_years');
        $monthsRaw  = (string) $this->request->getPost('experience_months');
        $years      = $yearsRaw === '' ? null : (int) $yearsRaw;
        $months     = $monthsRaw === '' ? null : (int) $monthsRaw;
        $experience = $this->buildExperienceString($years, $months);

        $db->transStart();

        $userModel->update($userId, [
            'first_name' => $firstName,
            'last_name'  => $lastName,
            'email'      => trim((string) $this->request->getPost('email')),
        ]);

        $doctorModel->update($doctorData['doctor']['id'], [
            'specialization' => $specializationValue,
            'experience'     => $experience,
            'fees'           => $this->request->getPost('fees') !== '' && $this->request->getPost('fees') !== null
                ? $this->request->getPost('fees')
                : null,
        ]);

        $specializationMap = $specializationModel->ensureNamesExist($specializations);
        $doctorSpecializationModel->syncDoctorSpecializations((int) $doctorData['doctor']['id'], array_values($specializationMap), (int) session()->get('id'));

        $db->transComplete();

        if (! $db->transStatus()) {
            return redirect()->back()->withInput()->with('error', 'Could not update doctor.');
        }

        return redirect()->to(site_url('admin/doctors'))->with('success', 'Doctor updated successfully.');
    }

    public function updatePatient($encryptedId)
    {
        if ($r = $this->requireRole('admin')) {
            return $r;
        }

        $id = decrypt_id($encryptedId);
        if (! ctype_digit((string) $id)) {
            return redirect()->to(site_url('admin/patients'))->with('error', 'Invalid patient link.');
        }

        $userId      = (int) $id;
        $patientData = $this->getPatientFormData($userId);
        if (! $patientData) {
            return redirect()->to(site_url('admin/patients'))->with('error', 'Patient not found.');
        }

        $rules = [
            'first_name' => 'required|min_length[2]|max_length[50]|alpha_space',
            'last_name'  => 'required|min_length[2]|max_length[50]|alpha_space',
            'email'      => 'required|valid_email|is_unique[users.email,id,' . $userId . ']',
            'phone'      => 'required|min_length[10]|max_length[15]',
            'age'        => 'permit_empty|integer|greater_than_equal_to[0]|less_than_equal_to[120]',
            'gender'     => 'permit_empty|in_list[male,female,other]',
        ];

        if (! $this->validate($rules)) {
            return redirect()->back()->withInput();
        }

        $userModel    = new UserModel();
        $patientModel = new PatientModel();
        $db           = \Config\Database::connect();

        $firstName = trim((string) $this->request->getPost('first_name'));
        $lastName  = trim((string) $this->request->getPost('last_name'));
        $ageRaw    = (string) $this->request->getPost('age');

        $db->transStart();

        $userModel->update($userId, [
            'first_name' => $firstName,
            'last_name'  => $lastName,
            'email'      => trim((string) $this->request->getPost('email')),
        ]);

        $patientModel->update($patientData['patient']['id'], [
            'age'    => $ageRaw !== '' ? (int) $ageRaw : null,
            'gender' => $this->request->getPost('gender') !== '' ? $this->request->getPost('gender') : null,
            'phone'  => trim((string) $this->request->getPost('phone')),
        ]);

        $db->transComplete();

        if (! $db->transStatus()) {
            return redirect()->back()->withInput()->with('error', 'Could not update patient.');
        }

        return redirect()->to(site_url('admin/patients'))->with('success', 'Patient updated successfully.');
    }
    public function checkEmail()
    {
        $email      = (string) $this->request->getPost('email');
        $excludeId  = (int) $this->request->getPost('exclude_id');

        $userModel = new UserModel();

        return $this->response->setJSON([
            'exists' => $userModel->emailExistsExcept($email, $excludeId > 0 ? $excludeId : null)
        ]);
    }
    public function getDoctors()
    {
        if ($r = $this->requireRole('admin')) {
            return $r;
        }

        helper('encryption');

        $doctorModel = new DoctorModel();
        $doctors     = $doctorModel->getAdminDoctorList('doctor_id', 'asc');
        $payload     = [];

        foreach ($doctors as $doc) {
            $payload[] = [
                'user_id'           => (int) ($doc->user_id ?? 0),
                'formatted_user_id' => $doc->formatted_user_id ?? null,
                'name'              => $doc->name ?? null,
                'email'             => $doc->email ?? null,
                'specialization'    => $doc->specialization ?? null,
                'experience'        => $doc->experience ?? null,
                'fees'              => $doc->fees ?? null,
                'status'            => $doc->status ?? null,
                'edit_token'        => encrypt_id($doc->user_id ?? 0),
            ];
        }

        return $this->response->setJSON([
            'data' => $payload,
        ]);
    }

    public function getPatients()
    {
        if ($r = $this->requireRole('admin')) {
            return $r;
        }

        helper('encryption');

        $patientModel = new PatientModel();
        $patients     = $patientModel->getAdminPatientList('patient_id', 'asc');
        $payload      = [];

        foreach ($patients as $patient) {
            $payload[] = [
                'user_id'           => (int) ($patient->user_id ?? 0),
                'formatted_user_id' => $patient->formatted_user_id ?? null,
                'name'              => $patient->name ?? null,
                'email'             => $patient->email ?? null,
                'phone'             => $patient->phone ?? null,
                'status'            => $patient->status ?? null,
                'edit_token'        => encrypt_id($patient->user_id ?? 0),
            ];
        }

        return $this->response->setJSON([
            'data' => $payload,
        ]);
    }
}