<?php
/**
 * ADSD RCC Mailer — wp_mail wrapper with:
 *  - Admin-configured From name + From email
 *  - Optional SMTP (phpmailer_init hook) — no extra library needed
 *  - Full send-error capture and DB logging
 *  - Test-email AJAX endpoint
 *
 * FREE sending works out of the box via WordPress wp_mail (your server sendmail).
 * If that fails, enable SMTP and use any free service:
 *   Gmail      smtp.gmail.com:587  (needs App Password)
 *   Brevo      smtp-relay.brevo.com:587  (free 300/day)
 *   Mailgun    smtp.mailgun.org:587
 *   SendGrid   smtp.sendgrid.net:587
 *   Outlook    smtp-mail.outlook.com:587
 *
 * @package AdsdReferralCouponcoreEcosystem
 */

defined( 'ABSPATH' ) || exit;

class ADSD_RCC_Mailer {

    private static ?ADSD_RCC_Mailer $instance = null;

    private string $last_error = '';

    public static function instance(): self {
        if ( null === self::$instance ) {
            self::$instance = new self();
        }
        return self::$instance;
    }

    private function __construct() {
        add_action( 'wp_ajax_adsd_rcc_send_test_email', [ $this, 'ajax_send_test_email' ] );
        add_action( 'phpmailer_init',              [ $this, 'configure_smtp' ] );
    }

    // ─── SMTP ─────────────────────────────────────────────────────────────────

    public function configure_smtp( $phpmailer ): void {
        $s = ADSD_RCC_Settings::instance();

        if ( ! $s->get_bool( 'smtp_enabled', false ) ) {
            return;
        }

        $host = trim( (string) $s->get( 'smtp_host', '' ) );
        $port = $s->get_int( 'smtp_port', 587 );
        $user = trim( (string) $s->get( 'smtp_user', '' ) );
        $pass = ADSD_RCC_Crypto::decrypt( (string) $s->get( 'smtp_pass', '' ) ); // decrypt stored password
        $enc  = $s->get( 'smtp_encryption', 'tls' );

        if ( ! $host || ! $user ) {
            return;
        }

        $phpmailer->isSMTP();
        $phpmailer->Host       = $host;
        $phpmailer->SMTPAuth   = true;
        $phpmailer->Port       = $port;
        $phpmailer->Username   = $user;
        $phpmailer->Password   = $pass;
        $phpmailer->SMTPSecure = ( $enc === 'ssl' )
            ? PHPMailer\PHPMailer\PHPMailer::ENCRYPTION_SMTPS
            : PHPMailer\PHPMailer\PHPMailer::ENCRYPTION_STARTTLS;

        $phpmailer->setFrom( $this->from_email(), $this->from_name() );
        $phpmailer->addReplyTo( $this->from_email(), $this->from_name() );
    }

    // ─── Public API ───────────────────────────────────────────────────────────

    public function send( string $to, string $template_key, array $vars = [] ): bool {
        $template = ADSD_RCC_DB::instance()->get_email_template( $template_key );

        if ( ! $template ) {
            $this->log_mail_error( $to, $template_key, 'Template not found.' );
            return false;
        }

        $vars    = array_merge( $this->default_vars(), $vars );
        $subject = $this->replace( $template->subject,          $vars );
        $heading = $this->replace( $template->heading,          $vars );
        $body    = $this->replace( $template->body,             $vars );
        $btn     = $this->replace( $template->button_text ?? '', $vars );
        $footer  = $this->replace( $template->footer ?? '',      $vars );
        $btn_url = $vars['{button_url}'] ?? '';

        $html = $this->render_html( $heading, $body, $btn, $btn_url, $footer );

        return $this->dispatch( $to, $subject, $html, $template_key );
    }

    public function send_raw( string $to, string $subject, string $html ): bool {
        return $this->dispatch( $to, $subject, $html, 'raw' );
    }

    public function get_last_error(): string {
        return $this->last_error;
    }

    // ─── Internal dispatch ────────────────────────────────────────────────────

    private function dispatch( string $to, string $subject, string $html, string $context ): bool {
        $this->last_error = '';

        // Guard: From Email must be configured
        $from = $this->from_email();
        if ( ! $from || ! is_email( $from ) ) {
            $this->last_error = __(
                'No valid From Email address configured. Go to Referral Rewards → Settings → Section 7 and set a From Email Address.',
                'adsd-referral-couponcore'
            );
            $this->log_mail_error( $to, $context, $this->last_error );
            return false;
        }

        add_action( 'wp_mail_failed',   [ $this, 'capture_mail_error' ] );
        add_filter( 'wp_mail_content_type', [ $this, 'html_content_type' ] );
        add_filter( 'wp_mail_from',     [ $this, 'filter_from_email' ] );
        add_filter( 'wp_mail_from_name', [ $this, 'filter_from_name' ] );

        $sent = wp_mail( $to, $subject, $html, $this->build_headers() );

        remove_filter( 'wp_mail_from_name', [ $this, 'filter_from_name' ] );
        remove_filter( 'wp_mail_from',     [ $this, 'filter_from_email' ] );
        remove_filter( 'wp_mail_content_type', [ $this, 'html_content_type' ] );
        remove_action( 'wp_mail_failed', [ $this, 'capture_mail_error' ] );

        if ( ! $sent ) {
            $this->log_mail_error( $to, $context, $this->last_error ?: 'wp_mail returned false.' );
        }

        return $sent;
    }

    // ─── WP filters ──────────────────────────────────────────────────────────

    public function html_content_type(): string  { return 'text/html'; }
    public function filter_from_email(): string   { return $this->from_email(); }
    public function filter_from_name(): string    { return $this->from_name(); }

    public function capture_mail_error( WP_Error $error ): void {
        $msgs = $error->get_error_messages();
        $this->last_error = implode( ' | ', $msgs );
    }

    // ─── Test email AJAX ──────────────────────────────────────────────────────

    public function ajax_send_test_email(): void {
        if ( ! current_user_can( 'manage_options' ) ||
             ! wp_verify_nonce( sanitize_text_field( wp_unslash( $_POST['nonce'] ?? '' ) ), 'adsd_rcc_admin_nonce' ) ) {
            wp_send_json_error( [ 'message' => __( 'Security check failed.', 'adsd-referral-couponcore' ) ] );
            return;
        }

        $to = sanitize_email( wp_unslash( $_POST['test_email'] ?? '' ) );
        if ( ! is_email( $to ) ) {
            wp_send_json_error( [ 'message' => __( 'Please enter a valid recipient email address.', 'adsd-referral-couponcore' ) ] );
            return;
        }

        $site    = get_bloginfo( 'name' );
        $from    = $this->from_email();
        $subject = sprintf( '[%s] ' . __( 'Test Email', 'adsd-referral-couponcore' ), $site );

        /* translators: %1$s: site name, %2$s: configured From email address */
        $body = sprintf(
            __( "Hi,

This is a test email from %1\$s.

From address: %2\$s

If you received this, your email configuration is working correctly!", 'adsd-referral-couponcore' ),
            $site,
            $from
        );

        $html = $this->render_html(
            __( 'Test Email — Sending works!', 'adsd-referral-couponcore' ),
            $body,
            '',
            '',
            __( 'Sent by AD-SD Referral CouponCore EcoSystem', 'adsd-referral-couponcore' )
        );

        $sent = $this->send_raw( $to, $subject, $html );

        if ( $sent ) {
            wp_send_json_success( [
                'message' => sprintf(
                    /* translators: %s: email */
                    __( '✓ Test email sent to %s. Check your inbox (and spam folder).', 'adsd-referral-couponcore' ),
                    $to
                ),
            ] );
        } else {
            wp_send_json_error( [
                'message' => sprintf(
                    /* translators: %s: error */
                    __( '✗ Email failed. Error: %s', 'adsd-referral-couponcore' ),
                    $this->last_error ?: __( 'Unknown error — check your SMTP or server mail settings.', 'adsd-referral-couponcore' )
                ),
            ] );
        }
    }

    // ─── Private helpers ──────────────────────────────────────────────────────

    private function from_name(): string {
        $name = trim( (string) ADSD_RCC_Settings::instance()->get( 'mail_from_name', '' ) );
        return $name ?: get_bloginfo( 'name' );
    }

    private function from_email(): string {
        $email = sanitize_email( (string) ADSD_RCC_Settings::instance()->get( 'mail_from_email', '' ) );
        return is_email( $email ) ? $email : (string) get_option( 'admin_email' );
    }

    private function build_headers(): array {
        return [
            'Content-Type: text/html; charset=UTF-8',
            'MIME-Version: 1.0',
        ];
    }

    private function default_vars(): array {
        return [
            '{site_name}' => get_bloginfo( 'name' ),
            '{site_url}'  => home_url( '/' ),
        ];
    }

    private function replace( string $text, array $vars ): string {
        return str_replace( array_keys( $vars ), array_values( $vars ), $text );
    }

    private function log_mail_error( string $to, string $template, string $error ): void {
        ADSD_RCC_DB::instance()->log(
            'mail_error',
            null,
            null,
            "Failed [{$template}] to {$to}: {$error}",
            [ 'template' => $template, 'to' => $to, 'error' => $error ]
        );
    }

    // ─── HTML renderer ────────────────────────────────────────────────────────

    private function render_html(
        string $heading,
        string $body,
        string $btn_text,
        string $btn_url,
        string $footer
    ): string {

        // Safe HTML body — convert newlines then allow basic tags
        $body_html = wp_kses(
            wpautop( nl2br( $body ) ),
            [
                'p'      => [ 'style' => [] ],
                'br'     => [],
                'strong' => [],
                'b'      => [],
                'em'     => [],
                'i'      => [],
                'a'      => [ 'href' => [], 'style' => [] ],
                'span'   => [ 'style' => [] ],
                'code'   => [],
            ]
        );

        $btn_html = '';
        if ( $btn_text && $btn_url ) {
            $btn_html =
            '<div style="text-align:center;margin:32px 0 8px;">
              <a href="' . esc_url( $btn_url ) . '"
                 style="background:#2563eb;color:#ffffff !important;padding:14px 36px;
                        border-radius:8px;text-decoration:none;font-weight:700;
                        display:inline-block;font-size:16px;font-family:Arial,sans-serif;">'
                 . esc_html( $btn_text ) .
              '</a>
            </div>
            <p style="text-align:center;font-size:12px;color:#9ca3af;margin-top:8px;font-family:Arial,sans-serif;">
              ' . esc_html__( 'Button not working? Copy this link:', 'adsd-referral-couponcore' ) . '<br>
              <a href="' . esc_url( $btn_url ) . '" style="color:#2563eb;word-break:break-all;">' . esc_url( $btn_url ) . '</a>
            </p>';
        }

        $footer_html = $footer
            ? '<tr><td style="background:#f9fafb;padding:20px 40px;border-top:1px solid #e5e7eb;
                               color:#6b7280;font-size:12px;text-align:center;font-family:Arial,sans-serif;">' . esc_html( $footer ) . '</td></tr>'
            : '';

        $site_name = esc_html( get_bloginfo( 'name' ) );
        $heading_s = esc_html( $heading );

        return '<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width,initial-scale=1.0">
<title>' . $heading_s . '</title>
</head>
<body style="margin:0;padding:0;background:#f3f4f6;">
<table role="presentation" width="100%" cellpadding="0" cellspacing="0" border="0"
       style="background:#f3f4f6;padding:40px 16px;">
  <tr><td align="center">
  <table role="presentation" width="100%" cellpadding="0" cellspacing="0" border="0"
         style="max-width:600px;background:#ffffff;border-radius:12px;overflow:hidden;">
    <tr>
      <td style="background:#2563eb;padding:28px 40px;">
        <p style="margin:0;color:#fff;font-size:20px;font-weight:800;font-family:Arial,sans-serif;">' . $site_name . '</p>
      </td>
    </tr>
    <tr>
      <td style="padding:36px 40px;font-family:Arial,sans-serif;">
        <h2 style="margin:0 0 16px;color:#111827;font-size:20px;font-weight:700;">' . $heading_s . '</h2>
        <div style="color:#374151;font-size:15px;line-height:1.8;">' . $body_html . '</div>
        ' . $btn_html . '
      </td>
    </tr>
    ' . $footer_html . '
  </table>
  </td></tr>
</table>
</body>
</html>';
    }
}