<?php
if ( ! defined( 'ABSPATH' ) ) exit;

/**
 * ACQUIS_Mailchimp
 *
 * Subscribes leads to a Mailchimp audience via the Mailchimp Marketing API v3.
 * Supports tags, merge fields, and double opt-in.
 */
class ACQUIS_Mailchimp {

    const API_BASE = 'https://<dc>.api.mailchimp.com/3.0';

    /**
     * Subscribe a lead to the configured Mailchimp audience.
     *
     * @param  int    $lead_id
     * @param  string $email
     * @param  string $full_name
     * @return array  ['success' => bool, 'message' => string]
     */
    public static function subscribe( $lead_id, $email, $full_name ) {
        if ( ! self::is_enabled() ) {
            return array( 'success' => false, 'message' => 'Mailchimp integration disabled.' );
        }
        // Adding an address to a mailing list is marketing: an unsubscribed address is never re-added.
        if ( ! apply_filters( 'acquis_marketing_allowed', true, $email ) ) {
            return array( 'success' => false, 'message' => 'Skipped: this address unsubscribed from marketing.' );
        }

        $api_key  =get_option( 'acquis_mailchimp_api_key', '' );
        $list_id  = get_option( 'acquis_mailchimp_list_id', '' );
        $tags_raw = get_option( 'acquis_mailchimp_tags', '' );
        $dbl_optin = (bool) get_option( 'acquis_mailchimp_double_optin', false );

        if ( empty( $api_key ) || empty( $list_id ) ) {
            return array( 'success' => false, 'message' => 'Mailchimp API key or List ID not configured.' );
        }

        // Parse data center from API key  (e.g. us21 from xxxx-us21)
        $parts = explode( '-', $api_key );
        $dc    = count( $parts ) === 2 ? trim( $parts[1] ) : 'us1';

        $base_url  = str_replace( '<dc>', $dc, self::API_BASE );
        $endpoint  = "{$base_url}/lists/{$list_id}/members";

        // Split name into first / last
        $name_parts = explode( ' ', trim( $full_name ), 2 );
        $fname      = $name_parts[0];
        $lname      = isset( $name_parts[1] ) ? $name_parts[1] : '';

        $payload = array(
            'email_address' => $email,
            'status'        => $dbl_optin ? 'pending' : 'subscribed',
            'merge_fields'  => array(
                'FNAME' => $fname,
                'LNAME' => $lname,
            ),
        );

        // Tags
        $tags = array_filter( array_map( 'trim', explode( ',', $tags_raw ) ) );
        if ( ! empty( $tags ) ) {
            $payload['tags'] = array_values( $tags );
        }

        // If subscriber already exists, PATCH instead of POST (avoids error 400)
        $subscriber_hash = md5( strtolower( $email ) );
        $check_url       = "{$base_url}/lists/{$list_id}/members/{$subscriber_hash}";

        $check_response = self::api_request( 'GET', $check_url, array(), $api_key );
        $method         = ( isset( $check_response['http_code'] ) && $check_response['http_code'] === 200 ) ? 'PUT' : 'POST';
        $url            = ( 'PUT' === $method ) ? $check_url : $endpoint;

        $response = self::api_request( $method, $url, $payload, $api_key );

        $success = in_array( $response['http_code'] ?? 0, array( 200, 201 ), true );
        $message = $success
            ? "Subscribed to Mailchimp list {$list_id}."
            : ( $response['body']['detail'] ?? 'Unknown Mailchimp API error.' );

        ACQUIS_Database::log_integration(
            $lead_id, 'mailchimp',
            $success ? 'success' : 'failed',
            wp_json_encode( $response['body'] ?? array() )
        );

        // Apply tags separately (Mailchimp tags endpoint)
        if ( $success && ! empty( $tags ) ) {
            self::apply_tags( $base_url, $list_id, $subscriber_hash, $api_key, $tags );
        }

        return array( 'success' => $success, 'message' => $message );
    }

    /**
     * Apply tags via the member tags endpoint (POST).
     */
    private static function apply_tags( $base_url, $list_id, $subscriber_hash, $api_key, $tags ) {
        $tags_payload = array(
            'tags' => array_map( function( $t ) { return array( 'name' => $t, 'status' => 'active' ); }, $tags ),
        );
        self::api_request(
            'POST',
            "{$base_url}/lists/{$list_id}/members/{$subscriber_hash}/tags",
            $tags_payload,
            $api_key
        );
    }

    /**
     * Fetch all available lists for the settings dropdown.
     *
     * @param  string $api_key
     * @return array  Array of ['id' => ..., 'name' => ...]
     */
    public static function get_lists( $api_key ) {
        if ( empty( $api_key ) ) return array();
        $parts    = explode( '-', $api_key );
        $dc       = count( $parts ) === 2 ? trim( $parts[1] ) : 'us1';
        $base_url = str_replace( '<dc>', $dc, self::API_BASE );
        $response = self::api_request( 'GET', "{$base_url}/lists?count=100", array(), $api_key );

        if ( empty( $response['body']['lists'] ) ) return array();

        return array_map( function( $list ) {
            return array( 'id' => $list['id'], 'name' => $list['name'] );
        }, $response['body']['lists'] );
    }

    public static function is_enabled() {
        return (bool) get_option( 'acquis_mailchimp_enabled', false );
    }

    /**
     * Shared HTTP helper using wp_remote_request.
     */
    private static function api_request( $method, $url, $body, $api_key ) {
        $args = array(
            'method'  => strtoupper( $method ),
            'headers' => array(
                'Authorization' => 'Basic ' . base64_encode( 'anystring:' . $api_key ),
                'Content-Type'  => 'application/json',
            ),
            'timeout' => 15,
        );
        if ( ! empty( $body ) ) {
            $args['body'] = wp_json_encode( $body );
        }
        $response  = wp_remote_request( $url, $args );
        $http_code = wp_remote_retrieve_response_code( $response );
        $raw_body  = wp_remote_retrieve_body( $response );
        $decoded   = json_decode( $raw_body, true );

        return array( 'http_code' => $http_code, 'body' => $decoded, 'raw' => $raw_body );
    }
}