<?php

namespace App\Services;

use App\Models\AdminNotificationSubjectModel;

class AdminNotificationSettingsService
{
    protected $db;
    protected $adminNotificationSubjectModel;

    public function __construct(
        \CodeIgniter\Database\BaseConnection $db,
        AdminNotificationSubjectModel $adminNotificationSubjectModel
    ) {
        $this->db = $db;
        $this->adminNotificationSubjectModel = $adminNotificationSubjectModel;
    }

public function alertsPage(): array
{
    $admins = $this->eligibleUsers();
    $subjects = $this->subjectOptions();
    $assignedSubjects = [];
    $tableReady = $this->db->tableExists('admin_notification_subjects');

    if ($tableReady && !empty($admins)) {
        $adminIds = array_map('intval', array_column($admins, 'id'));
        $rows = $this->adminNotificationSubjectModel
            ->select('id, admin_id, subject')
            ->whereIn('admin_id', $adminIds)
            ->findAll();

        foreach ($rows as $row) {
            $adminId = (int) ($row['admin_id'] ?? 0);
            $subject = (string) ($row['subject'] ?? '');
            if ($adminId <= 0 || $subject === '') {
                continue;
            }
            if (!isset($assignedSubjects[$adminId])) {
                $assignedSubjects[$adminId] = [];
            }
            $assignedSubjects[$adminId][$subject] = true;
        }
    }

    return [
        'admins' => $admins,
        'subjects' => $subjects,
        'assignedSubjects' => $assignedSubjects,
        'tableReady' => $tableReady,
    ];
}

public function saveSubjects($posted): array
{
    if (!$this->db->tableExists('admin_notification_subjects')) {
        return ['type' => 'error', 'message' => 'Notification subject storage is missing. Run migrations first.'];
    }

    if (!is_array($posted)) {
        return ['type' => 'error', 'message' => 'No selections were submitted.'];
    }

    $subjects = $this->subjectOptions();
    $allowed = array_keys($subjects);

    $admins = $this->eligibleUsers();
    $adminIds = array_map('intval', array_column($admins, 'id'));
    if (empty($adminIds)) {
        return ['type' => 'info', 'message' => 'No admins found to update.'];
    }

    $existing = $this->adminNotificationSubjectModel
        ->select('id, admin_id, subject')
        ->whereIn('admin_id', $adminIds)
        ->findAll();

    $existingMap = [];
    foreach ($existing as $row) {
        $adminId = (int) ($row['admin_id'] ?? 0);
        $subject = (string) ($row['subject'] ?? '');
        if ($adminId <= 0 || $subject === '') {
            continue;
        }
        if (!isset($existingMap[$adminId])) {
            $existingMap[$adminId] = [];
        }
        $existingMap[$adminId][$subject] = (int) ($row['id'] ?? 0);
    }

    $updates = 0;

    foreach ($adminIds as $adminId) {
        $subjectRaw = $posted[$adminId] ?? [];

        $selected = [];
        if (is_array($subjectRaw)) {
            foreach ($subjectRaw as $key => $value) {
                $candidate = is_string($key) ? $key : $value;
                if (!is_string($candidate)) {
                    continue;
                }
                $candidate = trim($candidate);
                if ($candidate !== '') {
                    $selected[] = $candidate;
                }
            }
        }

        $selected = array_values(array_unique(array_filter($selected, function ($value) use ($allowed) {
            return in_array($value, $allowed, true);
        })));

        $current = array_keys($existingMap[$adminId] ?? []);
        $toDelete = array_values(array_diff($current, $selected));
        $toInsert = array_values(array_diff($selected, $current));

        if (!empty($toDelete)) {
            $this->adminNotificationSubjectModel
                ->where('admin_id', $adminId)
                ->whereIn('subject', $toDelete)
                ->delete();
            $updates += count($toDelete);
        }

        if (!empty($toInsert)) {
            $batch = [];
            foreach ($toInsert as $subject) {
                $batch[] = [
                    'admin_id' => $adminId,
                    'subject' => $subject,
                ];
            }
            $this->adminNotificationSubjectModel->insertBatch($batch);
            $updates += count($toInsert);
        }
    }

    return ['type' => 'success', 'message' => $updates > 0 ? 'Notification subjects updated.' : 'No changes were made.'];
}

public function printRecipientsPage(): array
{
    $admins = $this->eligibleUsers();
    $tableReady = $this->db->tableExists('admin_notification_subjects');
    $assigned = [];

    if ($tableReady && !empty($admins)) {
        $adminIds = array_map('intval', array_column($admins, 'id'));
        $rows = $this->adminNotificationSubjectModel
            ->select('admin_id')
            ->where('subject', 'print_requests')
            ->whereIn('admin_id', $adminIds)
            ->findAll();

        foreach ($rows as $row) {
            $adminId = (int) ($row['admin_id'] ?? 0);
            if ($adminId <= 0) {
                continue;
            }
            $assigned[$adminId] = true;
        }
    }

    return [
        'admins' => $admins,
        'assigned' => $assigned,
        'tableReady' => $tableReady,
    ];
}

public function savePrintRecipients(array $posted): array
{
    if (!$this->db->tableExists('admin_notification_subjects')) {
        return ['type' => 'error', 'message' => 'Notification subject storage is missing. Run migrations first.'];
    }

    $admins = $this->eligibleUsers();
    $adminIds = array_map('intval', array_column($admins, 'id'));
    if (empty($adminIds)) {
        return ['type' => 'info', 'message' => 'No admins found to update.'];
    }

    $selected = [];
    foreach ($posted as $key => $value) {
        $adminId = (int) $key;
        if ($adminId <= 0) {
            continue;
        }
        if (!in_array($adminId, $adminIds, true)) {
            continue;
        }
        $selected[] = $adminId;
    }
    $selected = array_values(array_unique($selected));

    $existingRows = $this->adminNotificationSubjectModel
        ->select('admin_id')
        ->where('subject', 'print_requests')
        ->whereIn('admin_id', $adminIds)
        ->findAll();

    $current = array_values(array_unique(array_map(
        fn($row) => (int) ($row['admin_id'] ?? 0),
        $existingRows
    )));

    $toDelete = array_values(array_diff($current, $selected));
    $toInsert = array_values(array_diff($selected, $current));

    if (!empty($toDelete)) {
        $this->adminNotificationSubjectModel
            ->where('subject', 'print_requests')
            ->whereIn('admin_id', $toDelete)
            ->delete();
    }

    if (!empty($toInsert)) {
        $batch = [];
        foreach ($toInsert as $adminId) {
            $batch[] = [
                'admin_id' => $adminId,
                'subject' => 'print_requests',
            ];
        }
        $this->adminNotificationSubjectModel->insertBatch($batch);
    }

    $changes = count($toDelete) + count($toInsert);
    return ['type' => 'success', 'message' => $changes > 0 ? 'Print notification recipients updated.' : 'No changes were made.'];
}

public function subjectOptions(): array
{
    return [
         'academics' => 'Academics',
         'attendance' => 'Attendance',
         'events' => 'Events',
         'finance' => 'Finance',
         'general' => 'General',
         'print_requests' => 'Print Requests',
    ];
}

public function excludedRoles(): array
{
    return [
        'parent',
        'student',
        'guest',
        'teacher',
        'assistant teacher',
        'teacher assistant',
        'teacher_assistant',
        'assistant_teacher',
        'ta',
        'authorized_user',
    ];
}

public function eligibleUsers(): array
{
    $excluded = $this->excludedRoles();
    $excludedList = "'" . implode("','", $excluded) . "'";

    return $this->db->table('users u')
        ->select('u.id, u.firstname, u.lastname, u.email')
        ->join('user_roles ur', 'ur.user_id = u.id', 'inner')
        ->join('roles r', 'r.id = ur.role_id', 'inner')
        ->where('r.name IS NOT NULL', null, false)
        ->where('ur.deleted_at', null)
        ->where("LOWER(r.name) NOT IN ({$excludedList})", null, false)
        ->groupBy('u.id, u.firstname, u.lastname, u.email')
        ->orderBy('u.lastname', 'ASC')
        ->orderBy('u.firstname', 'ASC')
        ->get()
        ->getResultArray();
}
}