import { createClient } from '@/lib/supabase/server';
import { NextRequest, NextResponse } from 'next/server';
import nodemailer from 'nodemailer';

// GET: list all subscribers
export async function GET(req: NextRequest) {
  const supabase = await createClient();
  const { data: { user } } = await supabase.auth.getUser();
  if (!user) return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });

  const { searchParams } = new URL(req.url);
  const status = searchParams.get('status') || 'all';
  const search = searchParams.get('search') || '';

  let query = supabase
    .from('newsletter_subscribers')
    .select('*')
    .order('subscribed_at', { ascending: false });

  if (status !== 'all') query = query.eq('status', status);
  if (search) query = query.ilike('email', `%${search}%`);

  const { data, error } = await query;
  if (error) return NextResponse.json({ error: error.message }, { status: 500 });

  return NextResponse.json({ subscribers: data || [] });
}

// DELETE: unsubscribe a subscriber
export async function DELETE(req: NextRequest) {
  const supabase = await createClient();
  const { data: { user } } = await supabase.auth.getUser();
  if (!user) return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });

  const { id } = await req.json();
  if (!id) return NextResponse.json({ error: 'ID required' }, { status: 400 });

  const { error } = await supabase
    .from('newsletter_subscribers')
    .update({ status: 'unsubscribed', unsubscribed_at: new Date().toISOString() })
    .eq('id', id);

  if (error) return NextResponse.json({ error: error.message }, { status: 500 });
  return NextResponse.json({ success: true });
}

// PATCH: bulk actions (bulk_unsubscribe, bulk_delete)
export async function PATCH(req: NextRequest) {
  const supabase = await createClient();
  const { data: { user } } = await supabase.auth.getUser();
  if (!user) return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });

  const { action, ids } = await req.json();
  if (!action || !Array.isArray(ids) || ids.length === 0) {
    return NextResponse.json({ error: 'action and ids[] required' }, { status: 400 });
  }

  if (action === 'bulk_unsubscribe') {
    const { error } = await supabase
      .from('newsletter_subscribers')
      .update({ status: 'unsubscribed', unsubscribed_at: new Date().toISOString() })
      .in('id', ids)
      .eq('status', 'active');
    if (error) return NextResponse.json({ error: error.message }, { status: 500 });
    return NextResponse.json({ success: true, count: ids.length });
  }

  if (action === 'bulk_delete') {
    const { error } = await supabase
      .from('newsletter_subscribers')
      .delete()
      .in('id', ids);
    if (error) return NextResponse.json({ error: error.message }, { status: 500 });
    return NextResponse.json({ success: true, count: ids.length });
  }

  return NextResponse.json({ error: 'Unknown action' }, { status: 400 });
}

// POST: send digest email to all active subscribers
export async function POST(req: NextRequest) {
  const supabase = await createClient();
  const { data: { user } } = await supabase.auth.getUser();
  if (!user) return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });

  const { subject, previewText, articles, customMessage } = await req.json();

  if (!subject) return NextResponse.json({ error: 'Subject is required' }, { status: 400 });
  if (!articles || articles.length === 0) {
    return NextResponse.json({ error: 'At least one article is required' }, { status: 400 });
  }

  const smtpHost = process.env.SMTP_HOST;
  const smtpPort = parseInt(process.env.SMTP_PORT || '587');
  const smtpUser = process.env.SMTP_USER;
  const smtpPass = process.env.SMTP_PASS;
  const fromEmail = process.env.SMTP_FROM_EMAIL || smtpUser;
  const fromName = process.env.SMTP_FROM_NAME || 'AV Beat';
  const siteUrl = process.env.NEXT_PUBLIC_SITE_URL || 'https://avbeat.com';

  if (!smtpHost || !smtpUser || !smtpPass) {
    return NextResponse.json({ error: 'SMTP credentials not configured' }, { status: 500 });
  }

  // Fetch active subscribers
  const { data: subscribers, error: subError } = await supabase
    .from('newsletter_subscribers')
    .select('email')
    .eq('status', 'active');

  if (subError) return NextResponse.json({ error: subError.message }, { status: 500 });
  if (!subscribers || subscribers.length === 0) {
    return NextResponse.json({ error: 'No active subscribers found' }, { status: 400 });
  }

  const transporter = nodemailer.createTransport({
    host: smtpHost,
    port: smtpPort,
    secure: smtpPort === 465,
    auth: { user: smtpUser, pass: smtpPass },
  });

  // Build article HTML blocks
  const articlesHtml = articles
    .map(
      (a: { title: string; excerpt?: string; url?: string; image?: string; category?: string }) => `
      <div style="border-bottom:1px solid #DCE6F2;padding:20px 0;">
        ${a.category ? `<span style="color:#1D4ED8;font-size:11px;font-weight:bold;text-transform:uppercase;letter-spacing:1px;">${a.category}</span>` : ''}
        <h2 style="color:#e0e0e0;font-size:18px;margin:8px 0 6px;">
          ${a.url ? `<a href="${siteUrl}${a.url}" style="color:#e0e0e0;text-decoration:none;">${a.title}</a>` : a.title}
        </h2>
        ${a.excerpt ? `<p style="color:#888;font-size:14px;margin:0 0 10px;">${a.excerpt}</p>` : ''}
        ${a.url ? `<a href="${siteUrl}${a.url}" style="color:#1D4ED8;font-size:13px;text-decoration:none;">Read more →</a>` : ''}
      </div>
    `
    )
    .join('');

  const emailHtml = `
    <div style="background:#F8FAFC;padding:0;font-family:sans-serif;max-width:600px;margin:0 auto;">
      <!-- Header -->
      <div style="background:#111;border-bottom:2px solid #1D4ED8;padding:24px 32px;">
        <h1 style="color:#1D4ED8;font-size:22px;margin:0;font-weight:bold;">AV Beat</h1>
        <p style="color:#555;font-size:12px;margin:4px 0 0;">Pro AV, Display and Live Production Tech</p>
      </div>
      <!-- Body -->
      <div style="padding:32px;">
        ${previewText ? `<p style="color:#aaa;font-size:15px;margin:0 0 24px;">${previewText}</p>` : ''}
        ${customMessage ? `<div style="background:#FFFFFF;border-left:3px solid #1D4ED8;padding:16px;margin-bottom:24px;"><p style="color:#e0e0e0;font-size:14px;margin:0;">${customMessage}</p></div>` : ''}
        ${articlesHtml}
      </div>
      <!-- Footer -->
      <div style="background:#F8FAFC;padding:24px 32px;border-top:1px solid #DCE6F2;">
        <p style="color:#555;font-size:12px;margin:0;">You're receiving this because you subscribed at avbeat.com.</p>
        <p style="color:#555;font-size:12px;margin:8px 0 0;">
          <a href="${siteUrl}" style="color:#1D4ED8;">Visit AV Beat</a> · 
          <a href="${siteUrl}/unsubscribe?email={{email}}" style="color:#1D4ED8;">Unsubscribe</a>
        </p>
      </div>
    </div>
  `;

  // Send to all subscribers (batch with BCC or individual)
  const recipientEmails = subscribers.map((s) => s.email);
  let sent = 0;
  let failed = 0;

  // Send in batches of 50 to avoid rate limits
  const batchSize = 50;
  for (let i = 0; i < recipientEmails.length; i += batchSize) {
    const batch = recipientEmails.slice(i, i + batchSize);
    try {
      await transporter.sendMail({
        from: `"${fromName}" <${fromEmail}>`,
        bcc: batch,
        subject,
        html: emailHtml,
      });
      sent += batch.length;
    } catch (err) {
      console.error('Batch send error:', err);
      failed += batch.length;
    }
  }

  return NextResponse.json({ success: true, sent, failed, total: recipientEmails.length });
}