/**
 * Email sending utility for the PieCed portal.
 *
 * Uses nodemailer with SMTP credentials from environment variables
 * (populated via ExternalSecret from OpenBao at pieced/portal/smtp).
 *
 * Env vars (from portal-smtp K8s secret):
 *   SMTP_HOST                  — e.g. smtp.gmail.com
 *   SMTP_PORT                  — e.g. 587 (default)
 *   SMTP_USER                  — e.g. noreply@pieced.ch
 *   SMTP_PASS                  — App Password
 *   SMTP_FROM                  — e.g. "PieCed <noreply@pieced.ch>"
 *   ADMIN_NOTIFICATION_EMAIL   — e.g. admin@pieced.ch (optional)
 */

import nodemailer from "nodemailer";

let _transporter: nodemailer.Transporter | null = null;

function getTransporter(): nodemailer.Transporter {
  if (!_transporter) {
    const host = process.env.SMTP_HOST;
    const user = process.env.SMTP_USER;
    const pass = process.env.SMTP_PASS;
    if (!host || !user || !pass) {
      throw new Error("SMTP_HOST, SMTP_USER, and SMTP_PASS must be set");
    }
    _transporter = nodemailer.createTransport({
      host,
      port: parseInt(process.env.SMTP_PORT || "587", 10),
      secure: process.env.SMTP_SECURE === "true",
      auth: { user, pass },
    });
  }
  return _transporter;
}

function getFrom(): string {
  return (
    process.env.SMTP_FROM ||
    `PieCed <${process.env.SMTP_USER}>`
  );
}

/**
 * Escape HTML entities to prevent injection in HTML emails.
 */
function escapeHtml(str: string): string {
  return str
    .replace(/&/g, "&amp;")
    .replace(/</g, "&lt;")
    .replace(/>/g, "&gt;")
    .replace(/"/g, "&quot;")
    .replace(/'/g, "&#39;");
}

export async function sendApprovalEmail(
  to: string,
  contactName: string,
  companyName: string
): Promise<void> {
  const safeName = escapeHtml(contactName);
  const safeCompany = escapeHtml(companyName);

  try {
    await getTransporter().sendMail({
      from: getFrom(),
      to,
      subject: `Your PieCed AI assistant is being set up — ${companyName}`,
      text: [
        `Hello ${contactName},`,
        "",
        `Great news! Your onboarding request for ${companyName} has been approved.`,
        "",
        "Your AI assistant instance is now being provisioned. This usually takes a few minutes.",
        "You can check the status in your dashboard at https://app.pieced.ch",
        "",
        "Once your instance is ready, you'll see it on your dashboard and can start configuring it.",
        "",
        "Best regards,",
        "PieCed IT",
      ].join("\n"),
      html: `
        <div style="font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif; max-width: 560px; margin: 0 auto; color: #e0e0e0; background: #1a1a1a; padding: 32px; border-radius: 12px;">
          <h2 style="color: #ffffff; margin-top: 0;">Your AI assistant is being set up</h2>
          <p>Hello ${safeName},</p>
          <p>Great news! Your onboarding request for <strong>${safeCompany}</strong> has been approved.</p>
          <p>Your AI assistant instance is now being provisioned. This usually takes a few minutes.</p>
          <p>
            <a href="https://app.pieced.ch" style="display: inline-block; padding: 10px 24px; background: #3b82f6; color: #ffffff; text-decoration: none; border-radius: 8px; font-weight: 500;">
              Go to Dashboard
            </a>
          </p>
          <p style="color: #888; font-size: 13px; margin-top: 24px;">
            Once your instance is ready, you'll see it on your dashboard and can start configuring it.
          </p>
          <hr style="border: none; border-top: 1px solid #333; margin: 24px 0;" />
          <p style="color: #666; font-size: 12px;">PieCed IT — Hosted on-premises in Switzerland</p>
        </div>
      `,
    });
  } catch (err) {
    console.error("Failed to send approval email:", err);
  }
}

export async function sendRejectionEmail(
  to: string,
  contactName: string,
  companyName: string,
  adminNotes?: string
): Promise<void> {
  const safeName = escapeHtml(contactName);
  const safeCompany = escapeHtml(companyName);
  const safeNotes = adminNotes ? escapeHtml(adminNotes) : "";

  try {
    const notesBlock = adminNotes
      ? `\nNote from our team:\n${adminNotes}\n`
      : "";
    const notesHtml = safeNotes
      ? `<div style="background: #2a2a2a; border-left: 3px solid #ef4444; padding: 12px 16px; border-radius: 6px; margin: 16px 0;">
           <p style="color: #ccc; font-size: 13px; margin: 0;"><strong>Note from our team:</strong></p>
           <p style="color: #aaa; font-size: 13px; margin: 8px 0 0 0;">${safeNotes}</p>
         </div>`
      : "";

    await getTransporter().sendMail({
      from: getFrom(),
      to,
      subject: `Update on your PieCed onboarding request — ${companyName}`,
      text: [
        `Hello ${contactName},`,
        "",
        `Thank you for your interest in PieCed IT. Unfortunately, we were unable to approve your onboarding request for ${companyName} at this time.`,
        notesBlock,
        "If you have questions or would like to discuss this further, please reply to this email.",
        "",
        "Best regards,",
        "PieCed IT",
      ].join("\n"),
      html: `
        <div style="font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif; max-width: 560px; margin: 0 auto; color: #e0e0e0; background: #1a1a1a; padding: 32px; border-radius: 12px;">
          <h2 style="color: #ffffff; margin-top: 0;">Update on your onboarding request</h2>
          <p>Hello ${safeName},</p>
          <p>Thank you for your interest in PieCed IT. Unfortunately, we were unable to approve your onboarding request for <strong>${safeCompany}</strong> at this time.</p>
          ${notesHtml}
          <p>If you have questions or would like to discuss this further, please reply to this email.</p>
          <hr style="border: none; border-top: 1px solid #333; margin: 24px 0;" />
          <p style="color: #666; font-size: 12px;">PieCed IT — Hosted on-premises in Switzerland</p>
        </div>
      `,
    });
  } catch (err) {
    console.error("Failed to send rejection email:", err);
  }
}

/**
 * Bug 37a: separate email for resume request approval. The tenant
 * already exists; the message is "we're un-suspending it" rather than
 * "we're provisioning a new instance". Avoids confusing the customer
 * with onboarding language for a tenant they already had.
 */
export async function sendResumeApprovalEmail(
  to: string,
  contactName: string,
  companyName: string
): Promise<void> {
  const safeName = escapeHtml(contactName);
  const safeCompany = escapeHtml(companyName);

  try {
    await getTransporter().sendMail({
      from: getFrom(),
      to,
      subject: `Your PieCed AI assistant has been reactivated — ${companyName}`,
      text: [
        `Hello ${contactName},`,
        "",
        `Good news — your reactivation request for ${companyName} has been approved.`,
        "",
        "Your AI assistant is being brought back online and should be ready in a few minutes.",
        "You can check the status in your dashboard at https://app.pieced.ch",
        "",
        "Best regards,",
        "PieCed IT",
      ].join("\n"),
      html: `
        <div style="font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif; max-width: 560px; margin: 0 auto; color: #e0e0e0; background: #1a1a1a; padding: 32px; border-radius: 12px;">
          <h2 style="color: #ffffff; margin-top: 0;">Your AI assistant has been reactivated</h2>
          <p>Hello ${safeName},</p>
          <p>Good news — your reactivation request for <strong>${safeCompany}</strong> has been approved.</p>
          <p>Your AI assistant is being brought back online and should be ready in a few minutes.</p>
          <p>
            <a href="https://app.pieced.ch" style="display: inline-block; padding: 10px 24px; background: #3b82f6; color: #ffffff; text-decoration: none; border-radius: 8px; font-weight: 500;">
              Go to Dashboard
            </a>
          </p>
          <hr style="border: none; border-top: 1px solid #333; margin: 24px 0;" />
          <p style="color: #666; font-size: 12px;">PieCed IT — Hosted on-premises in Switzerland</p>
        </div>
      `,
    });
  } catch (err) {
    console.error("Failed to send resume approval email:", err);
  }
}

/**
 * Bug 37a: separate email for resume request rejection. Differs from
 * the onboarding rejection in two ways: it explicitly mentions the
 * tenant remains suspended, and it points the customer to the
 * 60-day retention window so they understand the deletion clock is
 * still ticking. The latter is important — a customer reading a
 * generic "request rejected" email might not realise their data is
 * still on a countdown.
 */
export async function sendResumeRejectionEmail(
  to: string,
  contactName: string,
  companyName: string,
  adminNotes?: string
): Promise<void> {
  const safeName = escapeHtml(contactName);
  const safeCompany = escapeHtml(companyName);
  const safeNotes = adminNotes ? escapeHtml(adminNotes) : "";

  try {
    const notesBlock = adminNotes
      ? `\nNote from our team:\n${adminNotes}\n`
      : "";
    const notesHtml = safeNotes
      ? `<div style="background: #2a2a2a; border-left: 3px solid #ef4444; padding: 12px 16px; border-radius: 6px; margin: 16px 0;">
           <p style="color: #ccc; font-size: 13px; margin: 0;"><strong>Note from our team:</strong></p>
           <p style="color: #aaa; font-size: 13px; margin: 8px 0 0 0;">${safeNotes}</p>
         </div>`
      : "";

    await getTransporter().sendMail({
      from: getFrom(),
      to,
      subject: `Update on your reactivation request — ${companyName}`,
      text: [
        `Hello ${contactName},`,
        "",
        `Thank you for your reactivation request for ${companyName}. Unfortunately, we were unable to approve it at this time.`,
        notesBlock,
        "Your tenant remains suspended. As a reminder, your data is preserved for 60 days from the original cancellation date, after which it will be permanently deleted. You can submit a new reactivation request at any time before then.",
        "",
        "If you have questions, please reply to this email.",
        "",
        "Best regards,",
        "PieCed IT",
      ].join("\n"),
      html: `
        <div style="font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif; max-width: 560px; margin: 0 auto; color: #e0e0e0; background: #1a1a1a; padding: 32px; border-radius: 12px;">
          <h2 style="color: #ffffff; margin-top: 0;">Update on your reactivation request</h2>
          <p>Hello ${safeName},</p>
          <p>Thank you for your reactivation request for <strong>${safeCompany}</strong>. Unfortunately, we were unable to approve it at this time.</p>
          ${notesHtml}
          <p>Your tenant remains suspended. As a reminder, your data is preserved for 60 days from the original cancellation date, after which it will be permanently deleted. You can submit a new reactivation request at any time before then.</p>
          <p>If you have questions, please reply to this email.</p>
          <hr style="border: none; border-top: 1px solid #333; margin: 24px 0;" />
          <p style="color: #666; font-size: 12px;">PieCed IT — Hosted on-premises in Switzerland</p>
        </div>
      `,
    });
  } catch (err) {
    console.error("Failed to send resume rejection email:", err);
  }
}

export async function sendAdminNotificationEmail(
  companyName: string,
  contactName: string,
  contactEmail: string
): Promise<void> {
  const adminEmail = process.env.ADMIN_NOTIFICATION_EMAIL;
  if (!adminEmail) return;

  const safeCompany = escapeHtml(companyName);
  const safeName = escapeHtml(contactName);
  const safeEmail = escapeHtml(contactEmail);

  try {
    await getTransporter().sendMail({
      from: getFrom(),
      to: adminEmail,
      subject: `New onboarding request: ${companyName}`,
      text: [
        `A new onboarding request has been submitted.`,
        "",
        `Company: ${companyName}`,
        `Contact: ${contactName} (${contactEmail})`,
        "",
        `Review it at https://app.pieced.ch/admin`,
      ].join("\n"),
      html: `
        <div style="font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif; max-width: 560px; margin: 0 auto; color: #e0e0e0; background: #1a1a1a; padding: 32px; border-radius: 12px;">
          <h2 style="color: #ffffff; margin-top: 0;">New onboarding request</h2>
          <p>A new onboarding request has been submitted.</p>
          <table style="color: #ccc; font-size: 14px; margin: 16px 0;">
            <tr><td style="padding: 4px 12px 4px 0; color: #888;">Company:</td><td>${safeCompany}</td></tr>
            <tr><td style="padding: 4px 12px 4px 0; color: #888;">Contact:</td><td>${safeName} (${safeEmail})</td></tr>
          </table>
          <p>
            <a href="https://app.pieced.ch/admin" style="display: inline-block; padding: 10px 24px; background: #3b82f6; color: #ffffff; text-decoration: none; border-radius: 8px; font-weight: 500;">
              Review Request
            </a>
          </p>
          <hr style="border: none; border-top: 1px solid #333; margin: 24px 0;" />
          <p style="color: #666; font-size: 12px;">PieCed IT — Hosted on-premises in Switzerland</p>
        </div>
      `,
    });
  } catch (err) {
    console.error("Failed to send admin notification email:", err);
  }
}

// ---------------------------------------------------------------------------
// Feature 5: support ticket emails
// ---------------------------------------------------------------------------

/**
 * Email subject prefix that helps customers thread tickets in their
 * mail client. We don't have inbound email processing — replies via
 * email back to us go nowhere — but the prefix is still useful for
 * the customer's own organisation. The id is shortened to 8 chars
 * for human readability; collisions on the truncated form within a
 * single user's inbox are vanishingly unlikely.
 */
function ticketSubjectPrefix(ticketId: string): string {
  return `[PieCed Support #${ticketId.slice(0, 8)}]`;
}

const STATUS_LABELS_EN: Record<string, string> = {
  open: "Open",
  in_progress: "In progress",
  waiting_for_customer: "Waiting for your reply",
  resolved: "Resolved",
  reopened: "Reopened",
};

/**
 * Sent to the customer when they create a ticket — confirmation
 * that we received it and a copy of the ticket id for their records.
 */
export async function sendSupportTicketCreatedEmail(params: {
  to: string;
  contactName: string;
  ticketId: string;
  title: string;
}): Promise<void> {
  const safeName = escapeHtml(params.contactName);
  const safeTitle = escapeHtml(params.title);
  const shortId = params.ticketId.slice(0, 8);
  const subject = `${ticketSubjectPrefix(params.ticketId)} ${params.title}`;

  try {
    await getTransporter().sendMail({
      from: getFrom(),
      to: params.to,
      subject,
      text: [
        `Hello ${params.contactName},`,
        "",
        `We've received your support request "${params.title}" (reference #${shortId}).`,
        "",
        "Our team will review and respond as soon as possible. You can track the status and reply at https://app.pieced.ch/support.",
        "",
        "Best regards,",
        "PieCed IT",
      ].join("\n"),
      html: `
        <div style="font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif; max-width: 560px; margin: 0 auto; color: #e0e0e0; background: #1a1a1a; padding: 32px; border-radius: 12px;">
          <h2 style="color: #ffffff; margin-top: 0;">Support request received</h2>
          <p>Hello ${safeName},</p>
          <p>We've received your support request <strong>"${safeTitle}"</strong> (reference #${shortId}).</p>
          <p>Our team will review and respond as soon as possible.</p>
          <p>
            <a href="https://app.pieced.ch/support" style="display: inline-block; padding: 10px 24px; background: #3b82f6; color: #ffffff; text-decoration: none; border-radius: 8px; font-weight: 500;">
              View ticket
            </a>
          </p>
          <hr style="border: none; border-top: 1px solid #333; margin: 24px 0;" />
          <p style="color: #666; font-size: 12px;">PieCed IT — Hosted on-premises in Switzerland</p>
        </div>
      `,
    });
  } catch (err) {
    console.error("Failed to send support ticket creation email:", err);
  }
}

/**
 * Sent to the customer when an admin replies to one of their tickets.
 * Includes the body of the reply inline so the customer can read it
 * without clicking through (especially useful on mobile).
 */
export async function sendSupportTicketReplyEmail(params: {
  to: string;
  contactName: string;
  ticketId: string;
  title: string;
  authorName: string;
  body: string;
}): Promise<void> {
  const safeName = escapeHtml(params.contactName);
  const safeTitle = escapeHtml(params.title);
  const safeAuthor = escapeHtml(params.authorName);
  const safeBody = escapeHtml(params.body);
  const shortId = params.ticketId.slice(0, 8);
  const subject = `${ticketSubjectPrefix(params.ticketId)} Re: ${params.title}`;

  try {
    await getTransporter().sendMail({
      from: getFrom(),
      to: params.to,
      subject,
      text: [
        `Hello ${params.contactName},`,
        "",
        `${params.authorName} replied to your ticket "${params.title}" (#${shortId}):`,
        "",
        params.body,
        "",
        "Reply or follow up at https://app.pieced.ch/support.",
        "",
        "Best regards,",
        "PieCed IT",
      ].join("\n"),
      html: `
        <div style="font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif; max-width: 560px; margin: 0 auto; color: #e0e0e0; background: #1a1a1a; padding: 32px; border-radius: 12px;">
          <h2 style="color: #ffffff; margin-top: 0;">New reply on your ticket</h2>
          <p>Hello ${safeName},</p>
          <p><strong>${safeAuthor}</strong> replied to your ticket <strong>"${safeTitle}"</strong> (#${shortId}):</p>
          <div style="background: #2a2a2a; border-left: 3px solid #3b82f6; padding: 12px 16px; border-radius: 6px; margin: 16px 0; white-space: pre-wrap;">
            ${safeBody}
          </div>
          <p>
            <a href="https://app.pieced.ch/support" style="display: inline-block; padding: 10px 24px; background: #3b82f6; color: #ffffff; text-decoration: none; border-radius: 8px; font-weight: 500;">
              View ticket
            </a>
          </p>
          <hr style="border: none; border-top: 1px solid #333; margin: 24px 0;" />
          <p style="color: #666; font-size: 12px;">PieCed IT — Hosted on-premises in Switzerland</p>
        </div>
      `,
    });
  } catch (err) {
    console.error("Failed to send support ticket reply email:", err);
  }
}

/**
 * Sent to the customer when an admin changes status without a comment.
 * If the same admin action included a comment, they'd get the
 * reply email instead — caller decides which to send.
 */
export async function sendSupportTicketStatusEmail(params: {
  to: string;
  contactName: string;
  ticketId: string;
  title: string;
  newStatus: string;
}): Promise<void> {
  const safeName = escapeHtml(params.contactName);
  const safeTitle = escapeHtml(params.title);
  const statusLabel = STATUS_LABELS_EN[params.newStatus] ?? params.newStatus;
  const shortId = params.ticketId.slice(0, 8);
  const subject = `${ticketSubjectPrefix(params.ticketId)} Status: ${statusLabel}`;

  try {
    await getTransporter().sendMail({
      from: getFrom(),
      to: params.to,
      subject,
      text: [
        `Hello ${params.contactName},`,
        "",
        `The status of your ticket "${params.title}" (#${shortId}) has been updated to: ${statusLabel}.`,
        "",
        "View details and respond if needed at https://app.pieced.ch/support.",
        "",
        "Best regards,",
        "PieCed IT",
      ].join("\n"),
      html: `
        <div style="font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif; max-width: 560px; margin: 0 auto; color: #e0e0e0; background: #1a1a1a; padding: 32px; border-radius: 12px;">
          <h2 style="color: #ffffff; margin-top: 0;">Ticket status update</h2>
          <p>Hello ${safeName},</p>
          <p>The status of your ticket <strong>"${safeTitle}"</strong> (#${shortId}) has been updated to:</p>
          <p style="font-size: 18px; color: #3b82f6; font-weight: 600;">${escapeHtml(statusLabel)}</p>
          <p>
            <a href="https://app.pieced.ch/support" style="display: inline-block; padding: 10px 24px; background: #3b82f6; color: #ffffff; text-decoration: none; border-radius: 8px; font-weight: 500;">
              View ticket
            </a>
          </p>
          <hr style="border: none; border-top: 1px solid #333; margin: 24px 0;" />
          <p style="color: #666; font-size: 12px;">PieCed IT — Hosted on-premises in Switzerland</p>
        </div>
      `,
    });
  } catch (err) {
    console.error("Failed to send support ticket status email:", err);
  }
}

/**
 * Notify the platform admin distribution list of a new ticket OR a
 * customer reply. Mirror of sendAdminNotificationEmail's pattern —
 * uses the same ADMIN_NOTIFICATION_EMAIL env var.
 *
 * Two trigger reasons supported:
 *  - 'created'  → new ticket from a customer
 *  - 'replied'  → customer replied to existing ticket (we want admin
 *                 visibility, e.g. to know the ticket needs another
 *                 round of attention)
 */
export async function sendSupportAdminNotificationEmail(params: {
  reason: "created" | "replied";
  ticketId: string;
  title: string;
  contactName: string;
  contactEmail: string;
  body?: string; // The new message content (description on create, comment body on reply)
  category?: string;
}): Promise<void> {
  const adminEmail = process.env.ADMIN_NOTIFICATION_EMAIL;
  if (!adminEmail) {
    console.warn(
      "ADMIN_NOTIFICATION_EMAIL not set; skipping admin support notification"
    );
    return;
  }
  const safeContact = escapeHtml(params.contactName);
  const safeContactEmail = escapeHtml(params.contactEmail);
  const safeTitle = escapeHtml(params.title);
  const safeBody = params.body ? escapeHtml(params.body) : "";
  const shortId = params.ticketId.slice(0, 8);

  const subjectVerb = params.reason === "created" ? "New" : "Reply on";
  const subject = `${ticketSubjectPrefix(params.ticketId)} ${subjectVerb}: ${params.title}`;

  const headlineHtml =
    params.reason === "created"
      ? `<h2 style="color: #ffffff; margin-top: 0;">New support ticket</h2>`
      : `<h2 style="color: #ffffff; margin-top: 0;">Customer replied on ticket</h2>`;

  try {
    await getTransporter().sendMail({
      from: getFrom(),
      to: adminEmail,
      subject,
      text: [
        params.reason === "created"
          ? "A new support ticket was opened:"
          : "A customer replied to a support ticket:",
        "",
        `From:     ${params.contactName} <${params.contactEmail}>`,
        `Ticket:   ${params.title} (#${shortId})`,
        params.category ? `Category: ${params.category}` : "",
        "",
        params.body ? "Message:" : "",
        params.body ?? "",
        "",
        `View at https://app.pieced.ch/support/${params.ticketId}`,
      ]
        .filter((s) => s !== "")
        .join("\n"),
      html: `
        <div style="font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif; max-width: 560px; margin: 0 auto; color: #e0e0e0; background: #1a1a1a; padding: 32px; border-radius: 12px;">
          ${headlineHtml}
          <table style="width:100%; font-size: 13px; color: #aaa; margin-bottom: 16px;">
            <tr><td style="padding: 4px 0; width: 100px;">From</td><td style="padding: 4px 0; color: #fff;">${safeContact} &lt;${safeContactEmail}&gt;</td></tr>
            <tr><td style="padding: 4px 0;">Title</td><td style="padding: 4px 0; color: #fff;">${safeTitle} <span style="color: #666;">(#${shortId})</span></td></tr>
            ${params.category ? `<tr><td style="padding: 4px 0;">Category</td><td style="padding: 4px 0; color: #fff;">${escapeHtml(params.category)}</td></tr>` : ""}
          </table>
          ${
            params.body
              ? `<div style="background: #2a2a2a; border-left: 3px solid #3b82f6; padding: 12px 16px; border-radius: 6px; margin: 16px 0; white-space: pre-wrap;">${safeBody}</div>`
              : ""
          }
          <p>
            <a href="https://app.pieced.ch/support/${params.ticketId}" style="display: inline-block; padding: 10px 24px; background: #3b82f6; color: #ffffff; text-decoration: none; border-radius: 8px; font-weight: 500;">
              Open in admin queue
            </a>
          </p>
          <hr style="border: none; border-top: 1px solid #333; margin: 24px 0;" />
          <p style="color: #666; font-size: 12px;">PieCed IT — Admin notification</p>
        </div>
      `,
    });
  } catch (err) {
    console.error("Failed to send admin support notification:", err);
  }
}