<?php
namespace Zadex\Forms\Integrations;

defined('ABSPATH') || exit;

use WP_Error;

/**
 * ConvertKit (Kit) API v3 (`https://api.convertkit.com/v3`, `api_key` parameter).
 *
 *  - with a form: POST /forms/{form}/subscribe {api_key, email, first_name, fields, tags: [tag ids]}
 *  - without a form but with tags: POST /tags/{first tag}/subscribe (same body, the other tags in `tags`)
 *  - lists (forms): GET /forms?api_key=
 * `convertkit_tags` holds numeric tag ids (names are ignored: the v3 subscribe call only takes ids).
 */
final class ConvertKit extends EmailProvider
{
    public const BASE = 'https://api.convertkit.com/v3';

    public function id(): string
    {
        return 'convertkit';
    }

    public function label(): string
    {
        return 'ConvertKit';
    }

    public function configured(): bool
    {
        return Credentials::has('convertkit_api_key');
    }

    public function needs_list(): bool
    {
        return false; // a form OR a tag is enough (checked in subscribe()).
    }

    public function lists()
    {
        if (!$this->configured()) {
            return new WP_Error('zadex_integration_not_configured', 'ConvertKit API key missing.');
        }
        $r = Http::request('GET', self::BASE . '/forms?api_key=' . rawurlencode(Credentials::get('convertkit_api_key')));
        return $r instanceof WP_Error ? $r : self::options($r['json']['forms'] ?? [], 'id', 'name');
    }

    public function subscribe(array $contact)
    {
        $tags = array_values(array_map('intval', array_filter($contact['tags'], 'ctype_digit')));
        $form = preg_replace('/\D/', '', $contact['list']) ?? '';
        if ($form === '' && !$tags) {
            return new WP_Error('zadex_integration_no_list', 'ConvertKit: choose a form or enter a tag id.');
        }
        $body = ['api_key' => Credentials::get('convertkit_api_key'), 'email' => $contact['email']];
        if ($contact['first_name'] !== '') {
            $body['first_name'] = $contact['first_name'];
        }
        $fields = $contact['fields'];
        if ($contact['last_name'] !== '' && !isset($fields['last_name'])) {
            $fields['last_name'] = $contact['last_name'];
        }
        if ($fields) {
            $body['fields'] = $fields;
        }
        if ($form !== '') {
            $url = self::BASE . '/forms/' . $form . '/subscribe';
        } else {
            $url = self::BASE . '/tags/' . array_shift($tags) . '/subscribe';
        }
        if ($tags) {
            $body['tags'] = $tags;
        }
        $r = Http::json('POST', $url, $body);
        return $r instanceof WP_Error ? $r : true;
    }
}