import { env } from "@kk/env/server";
import nodemailer from "nodemailer";

// ---------------------------------------------------------------------------
// Transport
// ---------------------------------------------------------------------------

// Singleton transport — created once per module, reused across all email sends.
// Re-creating it on every call causes EventEmitter listener accumulation in
// long-lived Cloudflare Worker processes, triggering memory leak warnings.
let _transport: nodemailer.Transporter | null | undefined;

function getTransport(): nodemailer.Transporter | null {
	if (_transport !== undefined) return _transport;
	if (!env.SMTP_HOST || !env.SMTP_USER || !env.SMTP_PASS) {
		_transport = null;
		return null;
	}
	_transport = nodemailer.createTransport({
		host: env.SMTP_HOST,
		port: env.SMTP_PORT,
		secure: env.SMTP_PORT === 465,
		auth: {
			user: env.SMTP_USER,
			pass: env.SMTP_PASS,
		},
	});
	return _transport;
}

const from = env.SMTP_FROM ?? "Kunstenkamp <info@kunstenkamp.be>";
const baseUrl = env.BETTER_AUTH_URL ?? "https://kunstenkamp.be";

// ---------------------------------------------------------------------------
// Primitives
// ---------------------------------------------------------------------------

/** Format a cent amount as a Euro string, e.g. 500 → "€5", 550 → "€5,50". */
function formatEuro(cents: number): string {
	return `€${(cents / 100).toFixed(cents % 100 === 0 ? 0 : 2).replace(".", ",")}`;
}

/**
 * A shaded info box with a small uppercase label and a bold value.
 *
 * @example
 * infoBox("Jouw rol", "Optreden — Muziek")
 * infoBox("Inschrijvingen openen", "maandag 16 maart 2026 om 19:00")
 */
function infoBox(label: string, value: string): string {
	return `<table width="100%" cellpadding="0" cellspacing="0" style="background:rgba(255,255,255,0.08);border-radius:4px;margin:24px 0;">
  <tr>
    <td style="padding:20px 24px;">
      <p style="margin:0 0 8px;font-size:12px;color:rgba(255,255,255,0.5);text-transform:uppercase;letter-spacing:0.06em;">${label}</p>
      <p style="margin:0;font-size:18px;color:#ffffff;font-weight:600;">${value}</p>
    </td>
  </tr>
</table>`;
}

/**
 * A CTA button.
 *
 * - `"primary"` — white background, teal text (main action)
 * - `"secondary"` — translucent white background, white text (secondary action)
 */
function ctaButton(
	href: string,
	label: string,
	style: "primary" | "secondary" = "primary",
): string {
	const bg = style === "primary" ? "#ffffff" : "rgba(255,255,255,0.15)";
	const color = style === "primary" ? "#214e51" : "#ffffff";
	return `<table cellpadding="0" cellspacing="0">
  <tr>
    <td style="border-radius:2px;background:${bg};">
      <a href="${href}" style="display:inline-block;padding:14px 32px;font-size:16px;font-weight:600;color:${color};text-decoration:none;">
        ${label}
      </a>
    </td>
  </tr>
</table>`;
}

/**
 * A small muted link line rendered below a CTA button, e.g. "Of kopieer deze link: …"
 */
function ctaSubtext(text: string): string {
	return `<p style="margin:16px 0 0;font-size:13px;color:rgba(255,255,255,0.4);">${text}</p>`;
}

/**
 * A standard body paragraph (16 px, 85% white, 1.6 line-height).
 * Pass raw HTML as the content, e.g. include `<strong>` tags freely.
 */
function p(content: string): string {
	return `<p style="margin:0 0 16px;font-size:16px;color:rgba(255,255,255,0.85);line-height:1.6;">${content}</p>`;
}

/**
 * Payment summary box (drinkcard + gift + total).
 * Returns an empty string when both amounts are zero.
 */
function paymentSummaryBox(
	drinkCardCents: number,
	giftCents: number,
	heading = "Betaling",
): string {
	if (drinkCardCents === 0 && giftCents === 0) return "";
	const total = drinkCardCents + giftCents;
	return `<table width="100%" cellpadding="0" cellspacing="0" style="background:rgba(255,255,255,0.08);border-radius:4px;margin:16px 0;">
  <tr>
    <td style="padding:20px 24px;">
      <p style="margin:0 0 12px;font-size:12px;color:rgba(255,255,255,0.5);text-transform:uppercase;letter-spacing:0.06em;">${heading}</p>
      ${drinkCardCents > 0 ? `<p style="margin:0 0 8px;font-size:16px;color:rgba(255,255,255,0.85);line-height:1.5;">Drinkkaart: <span style="color:#ffffff;font-weight:500;">${formatEuro(drinkCardCents)}</span></p>` : ""}
      ${giftCents > 0 ? `<p style="margin:0 0 8px;font-size:16px;color:rgba(255,255,255,0.85);line-height:1.5;">Vrijwillige gift: <span style="color:#ffffff;font-weight:500;">${formatEuro(giftCents)}</span></p>` : ""}
      <p style="margin:16px 0 0;padding-top:12px;border-top:1px solid rgba(255,255,255,0.1);font-size:18px;color:#ffffff;font-weight:600;">Totaal: ${formatEuro(total)}</p>
    </td>
  </tr>
</table>`;
}

// ---------------------------------------------------------------------------
// Layout shell
// ---------------------------------------------------------------------------

/**
 * Wraps content in the full Kunstenkamp email chrome:
 * outer grey background → teal card → header → body → footer.
 *
 * @param title       HTML `<title>` value
 * @param heading     Large white `<h1>` in the card header
 * @param bodyHtml    Everything between the header and the footer
 * @param footerLines Optional extra lines rendered above the default contact
 *                    line in the footer (e.g. unsubscribe notice). Pass an
 *                    array of plain strings or HTML snippets.
 * @param headerLabel Small uppercase label above the heading (default: "Kunstenkamp")
 */
function emailLayout({
	title,
	heading,
	bodyHtml,
	footerLines = [],
	headerLabel = "Kunstenkamp",
}: {
	title: string;
	heading: string;
	bodyHtml: string;
	footerLines?: string[];
	headerLabel?: string;
}): string {
	const extraFooter = footerLines
		.map((line) => `${line}<br/>`)
		.join("\n                ");

	return `<!DOCTYPE html>
<html lang="nl">
<head>
  <meta charset="UTF-8" />
  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
  <title>${title}</title>
</head>
<body style="margin:0;padding:0;background:#f4f4f5;font-family:sans-serif;">
  <table width="100%" cellpadding="0" cellspacing="0" style="background:#f4f4f5;padding:40px 0;">
    <tr>
      <td align="center">
        <table width="600" cellpadding="0" cellspacing="0" style="background:#214e51;border-radius:4px;overflow:hidden;">
          <!-- Header -->
          <tr>
            <td style="padding:40px 48px 32px;">
              <p style="margin:0;font-size:13px;color:rgba(255,255,255,0.5);letter-spacing:0.08em;text-transform:uppercase;">${headerLabel}</p>
              <h1 style="margin:12px 0 0;font-size:28px;color:#ffffff;font-weight:700;">${heading}</h1>
            </td>
          </tr>
          <!-- Body -->
          <tr>
            <td style="padding:0 48px 32px;">
              ${bodyHtml}
            </td>
          </tr>
          <!-- Footer -->
          <tr>
            <td style="padding:24px 48px;border-top:1px solid rgba(255,255,255,0.1);">
              <p style="margin:0;font-size:13px;color:rgba(255,255,255,0.4);line-height:1.6;">
                ${extraFooter}
                Vragen? Mail ons op <a href="mailto:info@kunstenkamp.be" style="color:rgba(255,255,255,0.6);">info@kunstenkamp.be</a><br/>
                Kunstenkamp vzw — Een initiatief voor en door kunstenaars.
              </p>
            </td>
          </tr>
        </table>
      </td>
    </tr>
  </table>
</body>
</html>`;
}

// ---------------------------------------------------------------------------
// Shared role / payment helpers
// ---------------------------------------------------------------------------

function roleLabel(wantsToPerform: boolean, artForm?: string | null): string {
	return wantsToPerform
		? `Optreden${artForm ? ` — ${artForm}` : ""}`
		: "Toeschouwer";
}

function toCents(
	drinkCardValue: number | undefined,
	giftAmount: number | undefined,
): { drinkCardCents: number; giftCents: number } {
	// drinkCardValue is stored in euros (e.g., 5); giftAmount in cents (e.g., 5000)
	return {
		drinkCardCents: (drinkCardValue ?? 0) * 100,
		giftCents: giftAmount ?? 0,
	};
}

// ---------------------------------------------------------------------------
// Email composers
// ---------------------------------------------------------------------------

function registrationConfirmationHtml(params: {
	firstName: string;
	manageUrl: string;
	signupUrl: string;
	wantsToPerform: boolean;
	artForm?: string | null;
	giftAmount?: number;
	drinkCardValue?: number;
}): string {
	const { drinkCardCents, giftCents } = toCents(
		params.drinkCardValue,
		params.giftAmount,
	);

	const body = [
		p(`Hoi ${params.firstName},`),
		p(
			`We hebben je inschrijving voor <strong style="color:#ffffff;">Open Mic Night — vrijdag 18 april 2026</strong> in goede orde ontvangen.`,
		),
		infoBox("Jouw rol", roleLabel(params.wantsToPerform, params.artForm)),
		paymentSummaryBox(drinkCardCents, giftCents),
		p(
			"Maak een account aan om je inschrijving te beheren en (voor bezoekers) je Drinkkaart te activeren.",
		),
		ctaButton(params.signupUrl, "Account aanmaken"),
		`<div style="margin-top:16px;"></div>`,
		p(
			"Wil je je gegevens later nog aanpassen of je inschrijving annuleren? Gebruik dan de knop hieronder. De link is uniek voor jou — deel hem niet.",
		),
		ctaButton(params.manageUrl, "Beheer mijn inschrijving", "secondary"),
		ctaSubtext(
			`Of kopieer deze link: <span style="color:rgba(255,255,255,0.6);">${params.manageUrl}</span>`,
		),
	].join("\n");

	return emailLayout({
		title: "Bevestiging inschrijving",
		heading: "Je inschrijving is bevestigd!",
		bodyHtml: body,
	});
}

function updateConfirmationHtml(params: {
	firstName: string;
	manageUrl: string;
	wantsToPerform: boolean;
	artForm?: string | null;
	giftAmount?: number;
	drinkCardValue?: number;
}): string {
	const { drinkCardCents, giftCents } = toCents(
		params.drinkCardValue,
		params.giftAmount,
	);

	const body = [
		p(`Hoi ${params.firstName},`),
		p(
			`Je inschrijving voor <strong style="color:#ffffff;">Open Mic Night — vrijdag 18 april 2026</strong> is succesvol bijgewerkt.`,
		),
		infoBox("Jouw rol", roleLabel(params.wantsToPerform, params.artForm)),
		paymentSummaryBox(drinkCardCents, giftCents),
		ctaButton(params.manageUrl, "Bekijk mijn inschrijving"),
	].join("\n");

	return emailLayout({
		title: "Inschrijving bijgewerkt",
		heading: "Inschrijving bijgewerkt",
		bodyHtml: body,
	});
}

function cancellationHtml(params: { firstName: string }): string {
	const body = [
		p(`Hoi ${params.firstName},`),
		p(
			`Je inschrijving voor <strong style="color:#ffffff;">Open Mic Night — vrijdag 18 april 2026</strong> is geannuleerd.`,
		),
		p(
			`Van gedachten veranderd? Je kunt je altijd opnieuw inschrijven via <a href="${baseUrl}/#registration" style="color:#ffffff;">kunstenkamp.be</a>.`,
		),
	].join("\n");

	return emailLayout({
		title: "Inschrijving geannuleerd",
		heading: "Inschrijving geannuleerd",
		bodyHtml: body,
	});
}

function reminder24hHtml(params: { firstName?: string | null }): string {
	const greeting = params.firstName ? `Hoi ${params.firstName},` : "Hoi!";
	const openDateStr = "maandag 16 maart 2026 om 19:00";
	const registrationUrl = `${baseUrl}/#registration`;

	const body = [
		p(greeting),
		p(
			`Morgen openen de inschrijvingen voor <strong style="color:#ffffff;">Open Mic Night — vrijdag 18 april 2026</strong>. Zet je wekker!`,
		),
		infoBox("Inschrijvingen openen", openDateStr),
		p("Wees er snel bij — de plaatsen zijn beperkt!"),
		ctaButton(registrationUrl, "Bekijk de pagina"),
		ctaSubtext(
			`Of ga naar: <span style="color:rgba(255,255,255,0.6);">${registrationUrl}</span>`,
		),
	].join("\n");

	return emailLayout({
		title: "Nog 24 uur — inschrijvingen openen morgen!",
		heading: "Nog 24 uur!",
		bodyHtml: body,
		footerLines: [
			"Je ontvangt dit bericht omdat je een herinnering hebt aangevraagd.",
		],
	});
}

function reminderHtml(params: { firstName?: string | null }): string {
	const greeting = params.firstName ? `Hoi ${params.firstName},` : "Hoi!";
	const openDateStr = "maandag 16 maart 2026 om 19:00";
	const registrationUrl = `${baseUrl}/#registration`;

	const body = [
		p(greeting),
		p(
			`Over ongeveer <strong style="color:#ffffff;">1 uur</strong> openen de inschrijvingen voor <strong style="color:#ffffff;">Open Mic Night — vrijdag 18 april 2026</strong>.`,
		),
		infoBox("Inschrijvingen openen", openDateStr),
		p("Wees er snel bij — de plaatsen zijn beperkt!"),
		ctaButton(registrationUrl, "Schrijf je in"),
		ctaSubtext(
			`Of ga naar: <span style="color:rgba(255,255,255,0.6);">${registrationUrl}</span>`,
		),
	].join("\n");

	return emailLayout({
		title: "Nog 1 uur — inschrijvingen openen straks!",
		heading: "Nog 1 uur!",
		bodyHtml: body,
		footerLines: [
			"Je ontvangt dit bericht omdat je een herinnering hebt aangevraagd.",
		],
	});
}

function subscriptionConfirmationHtml(params: { email: string }): string {
	const openDateStr = "maandag 16 maart 2026 om 19:00";
	const registrationUrl = `${baseUrl}/#registration`;

	const body = [
		p(
			`We sturen een herinnering naar <strong style="color:#ffffff;">${params.email}</strong> wanneer de inschrijvingen openen.`,
		),
		infoBox("Inschrijvingen openen", openDateStr),
		p(
			"Je ontvangt twee herinneringen: één 24 uur van tevoren en één 1 uur voor de opening.",
		),
		p("Wees er snel bij — de plaatsen zijn beperkt!"),
		ctaButton(registrationUrl, "Bekijk de pagina"),
	].join("\n");

	return emailLayout({
		title: "Herinnering ingepland — Open Mic Night",
		heading: "Je herinnering is ingepland!",
		bodyHtml: body,
		footerLines: [
			"Je ontvangt dit bericht omdat je een herinnering hebt aangevraagd op kunstenkamp.be.",
		],
	});
}

function paymentReminderHtml(params: {
	firstName: string;
	accountUrl: string;
	manageUrl: string;
	drinkCardValue?: number;
	giftAmount?: number;
}): string {
	const { drinkCardCents, giftCents } = toCents(
		params.drinkCardValue,
		params.giftAmount,
	);
	const totalCents = drinkCardCents + giftCents;

	const amountLine =
		totalCents > 0
			? p(
					`Je betaling van <strong style="color:#ffffff;">${formatEuro(totalCents)}</strong> staat nog open. Log in op je account om te betalen.`,
				)
			: p("Je betaling staat nog open. Log in op je account om te betalen.");

	const body = [
		p(`Hoi ${params.firstName},`),
		p(
			`Je hebt je ingeschreven voor <strong style="color:#ffffff;">Open Mic Night — vrijdag 18 april 2026</strong>, maar we hebben nog geen betaling ontvangen.`,
		),
		amountLine,
		ctaButton(params.accountUrl, "Betaal nu"),
		ctaSubtext(
			`Je inschrijving beheren? <a href="${params.manageUrl}" style="color:rgba(255,255,255,0.6);">Klik hier</a>`,
		),
	].join("\n");

	return emailLayout({
		title: "Herinnering: betaling open",
		heading: "Betaling nog open",
		bodyHtml: body,
	});
}

function paymentConfirmationHtml(params: {
	firstName: string;
	manageUrl: string;
	drinkCardValue?: number;
	giftAmount?: number;
}): string {
	const { drinkCardCents, giftCents } = toCents(
		params.drinkCardValue,
		params.giftAmount,
	);

	const body = [
		p(`Hoi ${params.firstName},`),
		p(
			`We hebben je betaling voor <strong style="color:#ffffff;">Open Mic Night — vrijdag 18 april 2026</strong> in goede orde ontvangen. Tot dan!`,
		),
		paymentSummaryBox(drinkCardCents, giftCents, "Betaling ontvangen"),
		ctaButton(params.manageUrl, "Beheer mijn inschrijving", "secondary"),
	].join("\n");

	return emailLayout({
		title: "Betaling ontvangen",
		heading: "Betaling ontvangen!",
		bodyHtml: body,
	});
}

// ---------------------------------------------------------------------------
// Public send functions
// ---------------------------------------------------------------------------

export async function sendConfirmationEmail(params: {
	to: string;
	firstName: string;
	managementToken: string;
	wantsToPerform: boolean;
	artForm?: string | null;
	giftAmount?: number;
	drinkCardValue?: number;
	/** Pre-filled signup URL, e.g. /login?signup=1&email=…&next=/account */
	signupUrl?: string;
}) {
	const transport = getTransport();
	if (!transport) {
		console.warn("SMTP not configured — skipping confirmation email");
		return;
	}
	const manageUrl = `${baseUrl}/manage/${params.managementToken}`;
	const signupUrl =
		params.signupUrl ??
		`${baseUrl}/login?signup=1&email=${encodeURIComponent(params.to)}&next=/account`;
	await transport.sendMail({
		from,
		to: params.to,
		subject: "Bevestiging inschrijving — Open Mic Night",
		html: registrationConfirmationHtml({
			firstName: params.firstName,
			manageUrl,
			signupUrl,
			wantsToPerform: params.wantsToPerform,
			artForm: params.artForm,
			giftAmount: params.giftAmount,
			drinkCardValue: params.drinkCardValue,
		}),
	});
}

export async function sendUpdateEmail(params: {
	to: string;
	firstName: string;
	managementToken: string;
	wantsToPerform: boolean;
	artForm?: string | null;
	giftAmount?: number;
	drinkCardValue?: number;
}) {
	const transport = getTransport();
	if (!transport) {
		console.warn("SMTP not configured — skipping update email");
		return;
	}
	const manageUrl = `${baseUrl}/manage/${params.managementToken}`;
	await transport.sendMail({
		from,
		to: params.to,
		subject: "Inschrijving bijgewerkt — Open Mic Night",
		html: updateConfirmationHtml({
			firstName: params.firstName,
			manageUrl,
			wantsToPerform: params.wantsToPerform,
			artForm: params.artForm,
			giftAmount: params.giftAmount,
			drinkCardValue: params.drinkCardValue,
		}),
	});
}

export async function sendCancellationEmail(params: {
	to: string;
	firstName: string;
}) {
	const transport = getTransport();
	if (!transport) {
		console.warn("SMTP not configured — skipping cancellation email");
		return;
	}
	await transport.sendMail({
		from,
		to: params.to,
		subject: "Inschrijving geannuleerd — Open Mic Night",
		html: cancellationHtml({ firstName: params.firstName }),
	});
}

export async function sendSubscriptionConfirmationEmail(params: {
	to: string;
}) {
	const transport = getTransport();
	if (!transport) {
		console.warn(
			"SMTP not configured — skipping subscription confirmation email",
		);
		return;
	}
	await transport.sendMail({
		from,
		to: params.to,
		subject: "Herinnering ingepland — Open Mic Night",
		html: subscriptionConfirmationHtml({ email: params.to }),
	});
}

export async function sendReminder24hEmail(params: {
	to: string;
	firstName?: string | null;
}) {
	const transport = getTransport();
	if (!transport) {
		console.warn("SMTP not configured — skipping 24h reminder email");
		return;
	}
	await transport.sendMail({
		from,
		to: params.to,
		subject: "Nog 24 uur — inschrijvingen openen morgen!",
		html: reminder24hHtml({ firstName: params.firstName }),
	});
}

export async function sendReminderEmail(params: {
	to: string;
	firstName?: string | null;
}) {
	const transport = getTransport();
	if (!transport) {
		console.warn("SMTP not configured — skipping reminder email");
		return;
	}
	await transport.sendMail({
		from,
		to: params.to,
		subject: "Nog 1 uur — inschrijvingen openen straks!",
		html: reminderHtml({ firstName: params.firstName }),
	});
}

export async function sendPaymentReminderEmail(params: {
	to: string;
	firstName: string;
	managementToken: string;
	drinkCardValue?: number;
	giftAmount?: number;
}) {
	const transport = getTransport();
	if (!transport) {
		console.warn("SMTP not configured — skipping payment reminder email");
		return;
	}
	const accountUrl = `${baseUrl}/account`;
	const manageUrl = `${baseUrl}/manage/${params.managementToken}`;
	await transport.sendMail({
		from,
		to: params.to,
		subject: "Herinnering: betaling open — Open Mic Night",
		html: paymentReminderHtml({
			firstName: params.firstName,
			accountUrl,
			manageUrl,
			drinkCardValue: params.drinkCardValue,
			giftAmount: params.giftAmount,
		}),
	});
}

export async function sendPaymentConfirmationEmail(params: {
	to: string;
	firstName: string;
	managementToken: string;
	drinkCardValue?: number;
	giftAmount?: number;
}) {
	const transport = getTransport();
	if (!transport) {
		console.warn("SMTP not configured — skipping payment confirmation email");
		return;
	}
	const manageUrl = `${baseUrl}/manage/${params.managementToken}`;
	await transport.sendMail({
		from,
		to: params.to,
		subject: "Betaling ontvangen — Open Mic Night",
		html: paymentConfirmationHtml({
			firstName: params.firstName,
			manageUrl,
			drinkCardValue: params.drinkCardValue,
			giftAmount: params.giftAmount,
		}),
	});
}