<?php

namespace App\Services;

use CodeIgniter\Database\BaseConnection;

/**
 * @deprecated Use EnrollmentRegistrationEmailService instead. This legacy sender is retained for reference only.
 */
class RegistrationOpeningEmailService
{
    public const TEMPLATE_KEY = 'registration_opening';

    private BaseConnection $db;
    private EmailService $emailService;

    public function __construct(?BaseConnection $db = null, ?EmailService $emailService = null)
    {
        $this->db = $db ?? \Config\Database::connect();
        $this->emailService = $emailService ?? new EmailService();
    }

    public function sendForDate(\DateTimeInterface $date, bool $force = false, ?string $testEmail = null, bool $dryRun = false): array
    {
        $summary = [
            'school_years' => 0,
            'recipients' => 0,
            'sent' => 0,
            'failed' => 0,
            'skipped' => 0,
            'dry_run' => $dryRun,
            'messages' => [],
        ];

        foreach ($this->registrationYearsForDate($date, $force) as $schoolYear) {
            $summary['school_years']++;

            $recipients = $testEmail !== null
                ? [[
                    'user_id' => null,
                    'family_id' => null,
                    'email' => $testEmail,
                    'name' => 'Parent',
                ]]
                : $this->parentEmailRecipients();

            if ($recipients === []) {
                $summary['messages'][] = sprintf('No parent emails found for %s.', $schoolYear['name']);
                continue;
            }

            [$subject, $body] = $this->composeEmail($schoolYear);
            if ($testEmail !== null) {
                $subject = '[TEST] ' . $subject;
            }

            foreach ($recipients as $recipient) {
                if ($testEmail === null && ! $dryRun && $this->alreadySentForRecipient($schoolYear, $recipient['email'])) {
                    $summary['skipped']++;
                    continue;
                }

                $summary['recipients']++;
                $personalizedBody = $this->replaceTokens($body, $schoolYear, $recipient);
                $personalizedSubject = $this->replaceTokens($subject, $schoolYear, $recipient);

                $sent = $dryRun || $this->emailService->send($recipient['email'], $personalizedSubject, $personalizedBody, 'general');
                $sent ? $summary['sent']++ : $summary['failed']++;

                if (! $dryRun) {
                    $this->logAttempt($schoolYear, $recipient, $personalizedSubject, $personalizedBody, $sent);
                }
            }
        }

        return $summary;
    }

    public function registrationYearsForDate(\DateTimeInterface $date, bool $force = false): array
    {
        $builder = $this->db->table('school_years')
            ->where('registration_starts_on IS NOT NULL');

        if (! $force) {
            $builder->where('registration_starts_on', $date->format('Y-m-d'));
        }

        return $builder->orderBy('registration_starts_on', 'ASC')
            ->get()
            ->getResultArray();
    }

    public function parentEmailRecipients(): array
    {
        $recipients = [];

        $hasFamilyGuardians = $this->db->tableExists('family_guardians');

        if ($this->db->tableExists('roles') && $this->db->tableExists('user_roles')) {
            $builder = $this->db->table('users u')
                ->select($hasFamilyGuardians ? 'u.id AS user_id, fg.family_id, u.firstname, u.lastname, u.email' : 'u.id AS user_id, NULL AS family_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('LOWER(r.name)', 'parent')
                ->where('u.email IS NOT NULL')
                ->where('u.email !=', '');

            if ($hasFamilyGuardians) {
                $builder->join('family_guardians fg', 'fg.user_id = u.id', 'left')
                    ->groupStart()
                        ->where('fg.id IS NULL')
                        ->orWhere('fg.receive_emails', 1)
                    ->groupEnd();
            }

            if ($this->hasField('user_roles', 'deleted_at')) {
                $builder->where('ur.deleted_at', null);
            }

            foreach ($builder->get()->getResultArray() as $row) {
                $this->addRecipient($recipients, $row);
            }
        }

        if ($hasFamilyGuardians) {
            $guardianBuilder = $this->db->table('family_guardians fg')
                ->select('u.id AS user_id, fg.family_id, u.firstname, u.lastname, u.email')
                ->join('users u', 'u.id = fg.user_id', 'inner')
                ->where('fg.receive_emails', 1)
                ->where('u.email IS NOT NULL')
                ->where('u.email !=', '');

            foreach ($guardianBuilder->get()->getResultArray() as $row) {
                $this->addRecipient($recipients, $row);
            }
        }

        uasort($recipients, static fn(array $a, array $b): int => strcasecmp($a['email'], $b['email']));

        return array_values($recipients);
    }

    public function alreadySentForSchoolYear(array $schoolYear): bool
    {
        $schoolYearId = (int) ($schoolYear['id'] ?? 0);
        $schoolYearName = (string) ($schoolYear['name'] ?? '');

        $builder = $this->db->table('communication_logs')
            ->where('template_key', self::TEMPLATE_KEY)
            ->where('status', 'sent')
            ->groupStart();

        if ($schoolYearId > 0) {
            $builder->like('metadata', '"school_year_id":' . $schoolYearId);
        }

        if ($schoolYearName !== '') {
            if ($schoolYearId > 0) {
                $builder->orLike('metadata', '"school_year":"' . $this->escapeJsonLikeValue($schoolYearName) . '"');
            } else {
                $builder->like('metadata', '"school_year":"' . $this->escapeJsonLikeValue($schoolYearName) . '"');
            }
        }

        $builder->groupEnd();

        return $builder->countAllResults() > 0;
    }

    public function alreadySentForRecipient(array $schoolYear, string $email): bool
    {
        $schoolYearId = (int) ($schoolYear['id'] ?? 0);
        $schoolYearName = (string) ($schoolYear['name'] ?? '');

        $builder = $this->db->table('communication_logs')
            ->where('template_key', self::TEMPLATE_KEY)
            ->where('status', 'sent')
            ->like('recipients', '"' . strtolower(trim($email)) . '"')
            ->groupStart();

        if ($schoolYearId > 0) {
            $builder->like('metadata', '"school_year_id":' . $schoolYearId);
        }

        if ($schoolYearName !== '') {
            if ($schoolYearId > 0) {
                $builder->orLike('metadata', '"school_year":"' . $this->escapeJsonLikeValue($schoolYearName) . '"');
            } else {
                $builder->like('metadata', '"school_year":"' . $this->escapeJsonLikeValue($schoolYearName) . '"');
            }
        }

        $builder->groupEnd();

        return $builder->countAllResults() > 0;
    }

    private function addRecipient(array &$recipients, array $row): void
    {
        $email = strtolower(trim((string) ($row['email'] ?? '')));
        if (! filter_var($email, FILTER_VALIDATE_EMAIL)) {
            return;
        }

        $name = trim((string) ($row['firstname'] ?? '') . ' ' . (string) ($row['lastname'] ?? ''));
        $recipients[$email] = [
            'user_id' => isset($row['user_id']) ? (int) $row['user_id'] : null,
            'family_id' => isset($row['family_id']) ? (int) $row['family_id'] : null,
            'email' => $email,
            'name' => $name !== '' ? $name : 'Parent',
        ];
    }

    private function composeEmail(array $schoolYear): array
    {
        $template = $this->loadTemplate();

        $subject = $template['subject'] ?? 'Registration is now open for {{school_year}}';
        $bodyHtml = $template['body'] ?? $this->defaultBody();
        $bodyHtml = $this->replaceTokens($bodyHtml, $schoolYear, ['name' => 'Parent', 'email' => '']);

        $body = view('emails/_wrap_layout', [
            'title' => $this->replaceTokens($subject, $schoolYear, ['name' => 'Parent', 'email' => '']),
            'body_html' => $bodyHtml,
        ], ['saveData' => true]);

        return [$subject, $body];
    }

    private function loadTemplate(): ?array
    {
        if (! $this->db->tableExists('email_templates')) {
            return null;
        }

        $fields = $this->db->getFieldNames('email_templates');
        $keyField = in_array('code', $fields, true) ? 'code' : 'template_key';
        $bodyField = in_array('body_html', $fields, true) ? 'body_html' : 'body';

        $row = $this->db->table('email_templates')
            ->select('subject, ' . $bodyField . ' AS body')
            ->where($keyField, self::TEMPLATE_KEY)
            ->where('is_active', 1)
            ->get()
            ->getRowArray();

        return $row ?: null;
    }

    private function replaceTokens(string $text, array $schoolYear, array $recipient): string
    {
        $registrationEnds = trim((string) ($schoolYear['registration_ends_on'] ?? ''));
        $deadline = $registrationEnds !== '' ? $registrationEnds : 'the posted deadline';

        return strtr($text, [
            '{{name}}' => (string) ($recipient['name'] ?? 'Parent'),
            '{{parent_name}}' => (string) ($recipient['name'] ?? 'Parent'),
            '{{school_year}}' => (string) ($schoolYear['name'] ?? ''),
            '{{registration_starts_on}}' => (string) ($schoolYear['registration_starts_on'] ?? ''),
            '{{registration_ends_on}}' => $registrationEnds,
            '{{registration_deadline}}' => $deadline,
            '{{registration_url}}' => site_url('user'),
            '{{login_url}}' => site_url('login'),
            '{{school_name}}' => 'Al Rahma Sunday School',
        ]);
    }

    private function defaultBody(): string
    {
        return <<<'HTML'
<p>Dear {{name}},</p>
<p>Registration is now open for the {{school_year}} school year.</p>
<p>Please complete your registration through the school portal. The registration deadline is {{registration_deadline}}.</p>
<p><a href="{{registration_url}}">Start registration</a></p>
<p>If you already have an account, you can also log in here: <a href="{{login_url}}">{{login_url}}</a></p>
<p>Regards,<br>{{school_name}}</p>
HTML;
    }

    private function logAttempt(array $schoolYear, array $recipient, string $subject, string $body, bool $sent): void
    {
        $this->db->table('communication_logs')->insert([
            'student_id' => 0,
            'family_id' => $recipient['family_id'] ?: null,
            'student_name' => 'All Families',
            'template_key' => self::TEMPLATE_KEY,
            'subject' => $subject,
            'body' => $body,
            'recipients' => json_encode([$recipient['email']]),
            'status' => $sent ? 'sent' : 'failed',
            'error_message' => $sent ? null : 'Email send failed',
            'sent_by' => null,
            'metadata' => json_encode([
                'campaign' => self::TEMPLATE_KEY,
                'school_year_id' => (int) ($schoolYear['id'] ?? 0),
                'school_year' => (string) ($schoolYear['name'] ?? ''),
                'registration_starts_on' => $schoolYear['registration_starts_on'] ?? null,
                'registration_ends_on' => $schoolYear['registration_ends_on'] ?? null,
                'recipient_user_id' => $recipient['user_id'],
            ]),
        ]);
    }

    private function hasField(string $table, string $field): bool
    {
        return in_array($field, $this->db->getFieldNames($table), true);
    }

    private function escapeJsonLikeValue(string $value): string
    {
        return trim(json_encode($value), '"');
    }
}