import nodemailer from 'nodemailer'
import { prisma } from './db'

export interface SmtpConfig {
  host: string
  port: number
  secure: boolean
  user: string
  pass: string
  fromName: string
  fromEmail: string
}

// Get SMTP settings from DB (SystemSetting table)
export async function getSmtpConfig(): Promise<SmtpConfig | null> {
  try {
    const settings = await (prisma as any).systemSetting.findMany({
      where: { category: 'smtp' },
    })
    if (!settings || settings.length === 0) return null

    const map: Record<string, string> = {}
    for (const s of settings) {
      map[s.key] = s.value
    }

    if (!map['smtp_host'] || !map['smtp_user']) return null

    return {
      host: map['smtp_host'],
      port: parseInt(map['smtp_port'] || '587'),
      secure: map['smtp_secure'] === 'true',
      user: map['smtp_user'],
      pass: map['smtp_pass'] || '',
      fromName: map['smtp_from_name'] || 'Lageplan',
      fromEmail: map['smtp_from_email'] || map['smtp_user'],
    }
  } catch {
    return null
  }
}

// Save SMTP settings to DB
export async function saveSmtpConfig(config: Partial<SmtpConfig>): Promise<void> {
  const entries: { key: string; value: string; isSecret: boolean }[] = []
  if (config.host !== undefined) entries.push({ key: 'smtp_host', value: config.host, isSecret: false })
  if (config.port !== undefined) entries.push({ key: 'smtp_port', value: String(config.port), isSecret: false })
  if (config.secure !== undefined) entries.push({ key: 'smtp_secure', value: String(config.secure), isSecret: false })
  if (config.user !== undefined) entries.push({ key: 'smtp_user', value: config.user, isSecret: false })
  if (config.pass !== undefined) entries.push({ key: 'smtp_pass', value: config.pass, isSecret: true })
  if (config.fromName !== undefined) entries.push({ key: 'smtp_from_name', value: config.fromName, isSecret: false })
  if (config.fromEmail !== undefined) entries.push({ key: 'smtp_from_email', value: config.fromEmail, isSecret: false })

  for (const entry of entries) {
    await (prisma as any).systemSetting.upsert({
      where: { key: entry.key },
      update: { value: entry.value, isSecret: entry.isSecret },
      create: { key: entry.key, value: entry.value, isSecret: entry.isSecret, category: 'smtp' },
    })
  }
}

// Create nodemailer transport from DB settings
async function createTransport() {
  const config = await getSmtpConfig()
  if (!config) throw new Error('SMTP nicht konfiguriert')

  return nodemailer.createTransport({
    host: config.host,
    port: config.port,
    secure: config.secure,
    auth: {
      user: config.user,
      pass: config.pass,
    },
    tls: {
      rejectUnauthorized: false,
    },
  })
}

// Send email
export async function sendEmail(to: string, subject: string, html: string): Promise<boolean> {
  try {
    const config = await getSmtpConfig()
    if (!config) throw new Error('SMTP nicht konfiguriert')
    const transport = await createTransport()

    await transport.sendMail({
      from: `"${config.fromName}" <${config.fromEmail}>`,
      to,
      subject,
      html,
    })
    return true
  } catch (error) {
    console.error('Email send error:', error)
    throw error
  }
}

// Test SMTP connection
export async function testSmtpConnection(): Promise<{ success: boolean; error?: string }> {
  try {
    const transport = await createTransport()
    await transport.verify()
    return { success: true }
  } catch (error) {
    return { success: false, error: error instanceof Error ? error.message : 'Verbindung fehlgeschlagen' }
  }
}