<?php

namespace ChargeForms\Includes\Integrations;

use ChargeForms\Includes\Settings;
use ChargeForms\Includes\Api_Log;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Built-in CRM/SaaS integration: subscribes a submitter to a Mailchimp
 * audience on every submission. The API key is a single site-wide
 * credential (Settings::get('mailchimp_api_key') — Mailchimp's own account
 * model is one key per account, same reasoning Stripe/PayPal keys already
 * use); which audience a given form subscribes to, its tags, and whether
 * new subscribers land as pending (double opt-in) or subscribed are all
 * per-form (Form::settings.integrations.mailchimp).
 *
 * Field mapping is intentionally minimal rather than a full drag-to-map UI:
 * the form's first Email-type field supplies the subscriber's address (no
 * value, no-op — see process()), and its first Name-type field, if any, is
 * split on the first space into FNAME/LNAME merge fields. ChargeForms has no
 * dedicated first-name/last-name field type today (see fields/builtins.js —
 * "Name" is a single text-like field), so this is the same practical
 * heuristic most lightweight form-plugin Mailchimp integrations ship with
 * for a first version, not a placeholder.
 */
class Mailchimp_Integration extends Abstract_Integration {

	private static $pending_form_id = null;
	private static $pending_context = null;

	const RETRY_HOOK          = 'chargeforms_retry_mailchimp';
	const MAX_ATTEMPTS        = 3;
	const RETRY_DELAY_SECONDS = 300;

	public static function boot() {
		add_action( self::RETRY_HOOK, [ __CLASS__, 'handle_retry' ], 10, 5 );
	}

	public function key(): string {
		return 'mailchimp';
	}

	public function label(): string {
		return __( 'Mailchimp', 'chargeforms' );
	}

	public function is_configured( array $settings ): bool {
		return ! empty( $settings['enabled'] ) && ! empty( $settings['list_id'] ) && '' !== Settings::get( 'mailchimp_api_key', '' );
	}

	public function process( array $values, array $form, int $entry_id, array $settings, $attempt = 1 ) {
		$api_key = Settings::get( 'mailchimp_api_key', '' );
		$list_id = $settings['list_id'];

		$email = Contact_Field_Mapper::find_email( $form, $values );
		if ( '' === $email ) {
			// Not every submission of a form with Mailchimp enabled will
			// necessarily have filled in an Email field left optional — this
			// is an expected no-op, not a failure worth logging as an error.
			Api_Log::log( 'mailchimp', $form['id'], '', null, __( 'Skipped — no valid email value in this submission.', 'chargeforms' ) );
			return;
		}

		$merge_fields = $this->build_merge_fields( $form, $values );
		$status       = ! empty( $settings['double_optin'] ) ? 'pending' : 'subscribed';

		self::$pending_form_id = $form['id'];
		self::$pending_context = [
			'values' => $values, 'form' => $form, 'entry_id' => $entry_id, 'settings' => $settings, 'attempt' => $attempt,
		];

		$result = Mailchimp_Client::upsert_member( $api_key, $list_id, $email, $merge_fields, $status );

		if ( is_wp_error( $result ) ) {
			$data = $result->get_error_data();
			Api_Log::log( 'mailchimp', $form['id'], "/lists/{$list_id}/members", $data['status'] ?? null, $result->get_error_message() );
			$this->maybe_retry( $attempt );
			self::$pending_form_id = null;
			self::$pending_context = null;
			return;
		}

		Api_Log::log( 'mailchimp', $form['id'], "/lists/{$list_id}/members", 200, sprintf( /* translators: %s: subscriber status */ __( 'Subscribed (%s).', 'chargeforms' ), $status ) );

		$tags = $this->parse_tags( $settings['tags'] ?? '' );
		if ( ! empty( $tags ) ) {
			$tag_result = Mailchimp_Client::set_tags( $api_key, $list_id, $email, $tags );
			if ( is_wp_error( $tag_result ) ) {
				Api_Log::log( 'mailchimp', $form['id'], "/lists/{$list_id}/members/tags", null, $tag_result->get_error_message() );
			}
		}

		self::$pending_form_id = null;
		self::$pending_context = null;
	}

	/** WP-Cron callback — re-attempts a delivery that previously failed, same shape as Webhook_Integration::handle_retry(). */
	public static function handle_retry( $values, $form, $entry_id, $settings, $attempt ) {
		( new self() )->process( $values, $form, $entry_id, $settings, $attempt );
	}

	private function maybe_retry( $attempt ) {
		if ( ! self::$pending_context || $attempt >= self::MAX_ATTEMPTS ) {
			return;
		}
		$ctx = self::$pending_context;
		wp_schedule_single_event(
			time() + self::RETRY_DELAY_SECONDS,
			self::RETRY_HOOK,
			[ $ctx['values'], $ctx['form'], $ctx['entry_id'], $ctx['settings'], $ctx['attempt'] + 1 ]
		);
	}

	private function build_merge_fields( array $form, array $values ) {
		$name = Contact_Field_Mapper::split_name( $form, $values );
		if ( empty( $name ) ) {
			return [];
		}
		$merge = [ 'FNAME' => $name['first'] ];
		if ( ! empty( $name['last'] ) ) {
			$merge['LNAME'] = $name['last'];
		}
		return $merge;
	}

	/** Comma-separated tag list → trimmed, non-empty tag names. */
	private function parse_tags( $raw ) {
		return array_values( array_filter( array_map( 'trim', explode( ',', (string) $raw ) ) ) );
	}
}