import nodemailer from 'nodemailer';
import type { Transporter } from 'nodemailer';
import { supabaseAdmin } from './supabase';

export interface SmtpConfig {
	host: string;
	port: number;
	secure: boolean;
	username: string;
	password: string;
	from_address: string;
	from_name: string;
}

export interface SendEmailOptions {
	to: string;
	subject: string;
	html: string;
	text?: string;
	recipientId?: string;
	recipientName?: string;
	templateKey?: string;
	emailType?: string;
	sentBy?: string;
}

/**
 * Get SMTP configuration from app_settings table, with fallback to environment variables
 * This allows welcome emails to work using the same SMTP as GoTrue when app_settings isn't configured
 */
export async function getSmtpConfig(): Promise<SmtpConfig | null> {
	// First try to get from app_settings
	const { data: settings } = await supabaseAdmin
		.from('app_settings')
		.select('setting_key, setting_value')
		.eq('category', 'email');

	const config: Record<string, string> = {};
	if (settings && settings.length > 0) {
		for (const s of settings) {
			// Parse the value - it might be JSON stringified or plain
			let value = s.setting_value;
			if (typeof value === 'string') {
				// Remove surrounding quotes if present
				value = value.replace(/^"|"$/g, '');
			}
			config[s.setting_key] = value as string;
		}
	}

	// Check if app_settings has valid SMTP config
	if (config.smtp_host && config.smtp_username && config.smtp_password) {
		return {
			host: config.smtp_host,
			port: parseInt(config.smtp_port || '587'),
			secure: config.smtp_secure === 'true' || parseInt(config.smtp_port || '587') === 465,
			username: config.smtp_username,
			password: config.smtp_password,
			from_address: config.smtp_from_address || 'noreply@monacousa.org',
			from_name: config.smtp_from_name || 'Monaco USA'
		};
	}

	// Fall back to environment variables (same as GoTrue SMTP settings)
	const envHost = process.env.SMTP_HOST || process.env.GOTRUE_SMTP_HOST;
	const envUser = process.env.SMTP_USER || process.env.GOTRUE_SMTP_USER;
	const envPass = process.env.SMTP_PASS || process.env.GOTRUE_SMTP_PASS;

	if (envHost && envUser && envPass) {
		const envPort = process.env.SMTP_PORT || process.env.GOTRUE_SMTP_PORT || '587';
		return {
			host: envHost,
			port: parseInt(envPort),
			secure: parseInt(envPort) === 465,
			username: envUser,
			password: envPass,
			from_address: process.env.SMTP_ADMIN_EMAIL || process.env.GOTRUE_SMTP_ADMIN_EMAIL || 'noreply@monacousa.org',
			from_name: process.env.SMTP_SENDER_NAME || process.env.GOTRUE_SMTP_SENDER_NAME || 'Monaco USA'
		};
	}

	return null;
}

/**
 * Create a nodemailer transporter with the configured SMTP settings
 */
export async function createTransporter(): Promise<Transporter | null> {
	const config = await getSmtpConfig();
	if (!config) {
		console.error('SMTP configuration not found or incomplete');
		return null;
	}

	return nodemailer.createTransport({
		host: config.host,
		port: config.port,
		secure: config.secure,
		auth: {
			user: config.username,
			pass: config.password
		}
	});
}

/**
 * Send an email using the configured SMTP settings
 */
export async function sendEmail(options: SendEmailOptions): Promise<{ success: boolean; error?: string; messageId?: string }> {
	const config = await getSmtpConfig();
	if (!config) {
		return { success: false, error: 'SMTP not configured. Please configure email settings first.' };
	}

	const transporter = await createTransporter();
	if (!transporter) {
		return { success: false, error: 'Failed to create email transporter' };
	}

	try {
		const result = await transporter.sendMail({
			from: `"${config.from_name}" <${config.from_address}>`,
			to: options.to,
			subject: options.subject,
			html: options.html,
			text: options.text || stripHtml(options.html)
		});

		// Log to email_logs table
		await supabaseAdmin.from('email_logs').insert({
			recipient_id: options.recipientId || null,
			recipient_email: options.to,
			recipient_name: options.recipientName || null,
			template_key: options.templateKey || null,
			subject: options.subject,
			email_type: options.emailType || 'manual',
			status: 'sent',
			provider: 'smtp',
			provider_message_id: result.messageId,
			sent_by: options.sentBy || null,
			sent_at: new Date().toISOString()
		});

		return { success: true, messageId: result.messageId };
	} catch (error) {
		const errorMessage = error instanceof Error ? error.message : 'Unknown error';
		console.error('Email send error:', error);

		// Log failed attempt
		await supabaseAdmin.from('email_logs').insert({
			recipient_id: options.recipientId || null,
			recipient_email: options.to,
			recipient_name: options.recipientName || null,
			template_key: options.templateKey || null,
			subject: options.subject,
			email_type: options.emailType || 'manual',
			status: 'failed',
			provider: 'smtp',
			error_message: errorMessage,
			sent_by: options.sentBy || null
		});

		return { success: false, error: errorMessage };
	}
}

/**
 * Send a templated email with variable substitution
 * Templates should contain content only (no full HTML wrapper) - will be wrapped automatically
 */
export async function sendTemplatedEmail(
	templateKey: string,
	to: string,
	variables: Record<string, string>,
	options?: {
		recipientId?: string;
		recipientName?: string;
		sentBy?: string;
		baseUrl?: string;
	}
): Promise<{ success: boolean; error?: string; messageId?: string }> {
	// Fetch template from database
	const { data: template, error: templateError } = await supabaseAdmin
		.from('email_templates')
		.select('*')
		.eq('template_key', templateKey)
		.eq('is_active', true)
		.single();

	if (templateError || !template) {
		return { success: false, error: `Email template "${templateKey}" not found or inactive` };
	}

	// Get site URL for logo
	const baseUrl = options?.baseUrl || process.env.SITE_URL || 'https://monacousa.org';
	const logoUrl = `${baseUrl}/MONACOUSA-Flags_376x376.png`;

	// Add default variables
	const allVariables: Record<string, string> = {
		logo_url: logoUrl,
		site_url: baseUrl,
		...variables
	};

	// Replace variables in subject and body
	let subject = template.subject;
	let bodyContent = template.body_html;
	let text = template.body_text || '';

	for (const [key, value] of Object.entries(allVariables)) {
		const regex = new RegExp(`{{${key}}}`, 'g');
		subject = subject.replace(regex, value);
		bodyContent = bodyContent.replace(regex, value);
		text = text.replace(regex, value);
	}

	// Extract title from template or use subject
	// Look for title in template metadata or first h2 tag
	let emailTitle = template.email_title || subject;
	// Try to extract from first h2 in content
	const h2Match = bodyContent.match(/<h2[^>]*>([^<]+)<\/h2>/i);
	if (h2Match) {
		emailTitle = h2Match[1].replace(/{{[^}]+}}/g, '').trim();
	}

	// Check if template already has full HTML wrapper (legacy templates)
	const hasFullWrapper = bodyContent.includes('<!DOCTYPE') || bodyContent.includes('<html');

	let html: string;
	if (hasFullWrapper) {
		// Legacy template with full HTML - use as-is but inject background image
		// Replace old gradient-only background with new background image pattern
		html = bodyContent.replace(
			/<table role="presentation" width="100%" cellspacing="0" cellpadding="0" style="background: linear-gradient\([^)]+\); background-color: #0f172a;">/g,
			`<table role="presentation" width="100%" cellspacing="0" cellpadding="0" style="background-image: url('${EMAIL_BACKGROUND_IMAGE_URL}'); background-size: cover; background-position: center; background-color: #0f172a;">`
		);
	} else {
		// Content-only template - wrap with Monaco template
		html = wrapInMonacoTemplate({
			title: emailTitle,
			content: bodyContent,
			logoUrl
		});
	}

	return sendEmail({
		to,
		subject,
		html,
		text: text || undefined,
		recipientId: options?.recipientId,
		recipientName: options?.recipientName,
		templateKey,
		emailType: template.category,
		sentBy: options?.sentBy
	});
}

/**
 * Test SMTP connection and optionally send a test email
 */
export async function testSmtpConnection(
	sendTo?: string,
	sentBy?: string
): Promise<{ success: boolean; error?: string }> {
	const config = await getSmtpConfig();
	if (!config) {
		return { success: false, error: 'SMTP not configured. Please configure and save email settings first.' };
	}

	const transporter = await createTransporter();
	if (!transporter) {
		return { success: false, error: 'Failed to create email transporter' };
	}

	try {
		// Verify connection
		await transporter.verify();

		// If a recipient is provided, send a test email
		if (sendTo) {
			const testContent = `
              <p style="margin: 0 0 16px 0; color: #334155; line-height: 1.6;">This is a test email from your Monaco USA Portal.</p>
              <div style="background: #f0fdf4; border: 1px solid #bbf7d0; border-radius: 12px; padding: 20px; margin: 0 0 20px 0;">
                <p style="margin: 0 0 8px 0; color: #166534; font-size: 14px; font-weight: 600;">✓ Configuration Verified</p>
                <p style="margin: 0; color: #334155; font-size: 14px;">Your SMTP settings are working correctly!</p>
              </div>
              <p style="margin: 0; color: #64748b; font-size: 12px;">Sent at ${new Date().toLocaleString()}</p>`;

			const result = await sendEmail({
				to: sendTo,
				subject: 'Monaco USA Portal - SMTP Test Email',
				html: wrapInMonacoTemplate({
					title: 'SMTP Test Successful!',
					content: testContent
				}),
				emailType: 'test',
				sentBy
			});

			if (!result.success) {
				return { success: false, error: result.error };
			}
		}

		return { success: true };
	} catch (error) {
		const errorMessage = error instanceof Error ? error.message : 'Unknown error';
		console.error('SMTP test error:', error);
		return { success: false, error: `SMTP connection failed: ${errorMessage}` };
	}
}

// S3-hosted background image URL matching login screen
const EMAIL_BACKGROUND_IMAGE_URL = 'https://s3.monacousa.org/public/monaco_high_res.jpg';

/**
 * Wrap email content in Monaco-branded template
 * This creates a consistent look matching the login page styling with background image
 */
export function wrapInMonacoTemplate(options: {
	title: string;
	content: string;
	logoUrl?: string;
	backgroundImageUrl?: string;
}): string {
	const baseUrl = process.env.SITE_URL || 'http://localhost:7453';
	const logoUrl = options.logoUrl || `${baseUrl}/MONACOUSA-Flags_376x376.png`;
	const bgImageUrl = options.backgroundImageUrl || EMAIL_BACKGROUND_IMAGE_URL;

	return `<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <!--[if mso]>
  <style type="text/css">
    body, table, td { font-family: Arial, sans-serif !important; }
  </style>
  <![endif]-->
</head>
<body style="margin: 0; padding: 0; font-family: Arial, sans-serif; background-color: #0f172a;">
  <!--[if gte mso 9]>
  <v:background xmlns:v="urn:schemas-microsoft-com:vml" fill="t">
    <v:fill type="tile" src="${bgImageUrl}" color="#0f172a"/>
  </v:background>
  <![endif]-->
  <table role="presentation" width="100%" cellspacing="0" cellpadding="0" style="background-image: url('${bgImageUrl}'); background-size: cover; background-position: center; background-color: #0f172a;">
    <tr>
      <td>
        <!-- Gradient overlay matching login screen: from-slate-900/80 via-slate-900/60 to-monaco-900/70 -->
        <div style="background: linear-gradient(135deg, rgba(15, 23, 42, 0.8) 0%, rgba(15, 23, 42, 0.6) 50%, rgba(127, 29, 29, 0.7) 100%);">
          <table role="presentation" width="100%" cellspacing="0" cellpadding="0">
            <tr>
              <td align="center" style="padding: 40px 20px;">
                <!-- Logo Section -->
                <table role="presentation" width="100%" cellspacing="0" cellpadding="0" style="max-width: 480px;">
                  <tr>
                    <td align="center" style="padding-bottom: 30px;">
                      <div style="background: rgba(255, 255, 255, 0.95); border-radius: 16px; padding: 12px; display: inline-block; box-shadow: 0 10px 40px rgba(0, 0, 0, 0.3);">
                        <img src="${logoUrl}" alt="Monaco USA" width="80" height="80" style="display: block; border-radius: 8px;">
                      </div>
                      <h1 style="margin: 16px 0 4px 0; font-size: 24px; font-weight: bold; color: #ffffff; text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);">Monaco <span style="color: #fca5a5;">USA</span></h1>
                      <p style="margin: 0; font-size: 14px; color: rgba(255, 255, 255, 0.8);">Americans in Monaco</p>
                    </td>
                  </tr>
                </table>

                <!-- Main Content Card -->
                <table role="presentation" cellspacing="0" cellpadding="0" style="max-width: 480px; width: 100%; background: #ffffff; border-radius: 16px; box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);">
                  <tr>
                    <td style="padding: 40px;">
                      <h2 style="margin: 0 0 20px 0; color: #CE1126; font-size: 24px; text-align: center;">${options.title}</h2>
                      <div style="text-align: left;">${options.content}</div>
                    </td>
                  </tr>
                </table>

                <!-- Footer -->
                <table role="presentation" width="100%" cellspacing="0" cellpadding="0" style="max-width: 480px;">
                  <tr>
                    <td align="center" style="padding-top: 24px;">
                      <p style="margin: 0; font-size: 12px; color: rgba(255, 255, 255, 0.5);">&copy; 2026 Monaco USA. All rights reserved.</p>
                    </td>
                  </tr>
                </table>
              </td>
            </tr>
          </table>
        </div>
      </td>
    </tr>
  </table>
</body>
</html>`;
}

/**
 * Strip HTML tags from a string to create plain text version
 */
function stripHtml(html: string): string {
	return html
		.replace(/<[^>]*>/g, '')
		.replace(/&nbsp;/g, ' ')
		.replace(/&amp;/g, '&')
		.replace(/&lt;/g, '<')
		.replace(/&gt;/g, '>')
		.replace(/&quot;/g, '"')
		.replace(/&#39;/g, "'")
		.replace(/\s+/g, ' ')
		.trim();
}