<?php
declare(strict_types=1);

namespace Cf7stg;

final class CF7Source implements Interface_Spam_Source
{
    public function register(): void
    {
        add_filter('wpcf7_spam', [$this, 'on_spam'], 9999, 2);
        add_action('wpcf7_submission', [$this, 'on_submission'], 20, 1);
    }

    public function on_spam($spam, $submission): bool
    {
        if ($spam === true && is_object($submission)) {
            $this->enqueue_from_submission($submission, 'Honeypot or filter');
        }
        return (bool)$spam;
    }

    public function on_submission($submission): void
    {
        if (!is_object($submission) || !method_exists($submission, 'get_status')) return;
        if ($submission->get_status() !== 'spam') return;
        $this->enqueue_from_submission($submission, 'Статус spam');
    }

    private function enqueue_from_submission($submission, string $fallback_reason): void
    {
        $fields = method_exists($submission, 'get_posted_data') ? (array)$submission->get_posted_data() : [];
        $form = method_exists($submission, 'get_contact_form') ? $submission->get_contact_form() : null;
        $form_title = $form && method_exists($form, 'title') ? $form->title() : '';
        $form_id = $form && method_exists($form, 'id') ? (int)$form->id() : null;

        $reason = $this->detect_reason($submission, $fallback_reason);
        $classification = Classifier::classify($fields, ['reason' => $reason]);
        $label = $classification['label'];
        $decision = self::decide_drop_action($label);

        if ($decision['action'] === 'skip') {
            Settings::increment_drop_counter($decision['counter_mode']);
            return;
        }

        if (!self::should_enqueue($label, $fields, $submission)) {
            return;
        }

        $post_id = FlamingoHelper::find_post_id_for_submission($submission);
        if ($post_id !== null && Queue::exists_for_flamingo($post_id, false)) {
            return;
        }

        $ip = $this->remote_addr();
        $ua = isset($_SERVER['HTTP_USER_AGENT']) ? (string)$_SERVER['HTTP_USER_AGENT'] : '';

        $payload = MessageFormatter::build([
            'fields'         => $fields,
            'classification' => $classification,
            'site_title'     => Settings::get_site_title(),
            'form_title'     => $form_title,
            'submitted_at'   => wp_date('d.m.Y H:i'),
            'reason'         => $reason,
            'ip'             => $ip,
            'user_agent'     => $ua,
            'is_retro'       => false,
            'dry_run_drop'   => $decision['action'] === 'enqueue_marked',
        ]);

        if ($decision['action'] === 'enqueue_marked') {
            Settings::increment_drop_counter($decision['counter_mode']);
        }

        Queue::enqueue([
            'flamingo_post_id' => $post_id,
            'form_id'          => $form_id,
            'source_key'       => 'cf7',
            'payload_json'     => wp_json_encode($payload),
            'label'            => $label,
            'is_retro'         => 0,
        ]);
    }

    private function detect_reason($submission, string $fallback): string
    {
        $data = method_exists($submission, 'get_posted_data') ? (array)$submission->get_posted_data() : [];
        // Honeypot plugin by Nocean adds a non-empty field usually prefixed by 'wpcf7_hp' or a custom name.
        foreach ($data as $k => $v) {
            if (is_string($k) && (stripos($k, 'honeypot') !== false || stripos($k, 'wpcf7_hp') !== false) && !empty($v)) {
                return 'Honeypot';
            }
        }
        if (method_exists($submission, 'get_spam_log') && $submission->get_spam_log()) {
            return 'Akismet';
        }
        return $fallback;
    }

    private function remote_addr(): string
    {
        foreach (['HTTP_X_FORWARDED_FOR', 'REMOTE_ADDR'] as $key) {
            if (!empty($_SERVER[$key])) {
                $first = explode(',', (string)$_SERVER[$key])[0];
                return trim($first);
            }
        }
        return '';
    }

    /**
     * Decides what to do with a classified submission based on its label and the
     * dry-run setting. Pure function — no side effects.
     *
     * @return array{action:'enqueue'|'enqueue_marked'|'skip',counter_mode:?string}
     */
    public static function decide_drop_action(string $label): array
    {
        if ($label !== 'drop') {
            return ['action' => 'enqueue', 'counter_mode' => null];
        }
        if (Settings::is_dry_run_drop()) {
            return ['action' => 'enqueue_marked', 'counter_mode' => 'dry_run'];
        }
        return ['action' => 'skip', 'counter_mode' => 'real'];
    }

    /**
     * Filterable gate — allows external code to block non-drop submissions
     * via filter `cf7stg_should_enqueue`.
     */
    public static function should_enqueue(string $label, array $fields, $submission): bool
    {
        return (bool)apply_filters('cf7stg_should_enqueue', true, $label, $fields, $submission);
    }
}