// src/lib/monitor/mail-monitor.ts
import { ImapFlow } from 'imapflow'
import { simpleParser } from 'mailparser'
import * as cheerio from 'cheerio'
import type { EmailInfo, FaultInfo, MonitorConfig } from './types'

export class MailMonitor {
  private client: ImapFlow | null = null
  private retryCount = 0
  private readonly RETRY_DELAYS = [5_000, 15_000, 45_000]

  async connect(config: MonitorConfig['mail']): Promise<void> {
    this.client = new ImapFlow({
      host: config.imap_server,
      port: config.imap_port,
      secure: true,
      auth: { user: config.address, pass: config.password },
      logger: false,
      connectionTimeout: 15_000,
    })
    try {
      await this.client.connect()
      this.retryCount = 0
    } catch (e) {
      this.client = null
      throw e
    }
  }

  async disconnect(): Promise<void> {
    if (this.client) {
      try { await this.client.logout() } catch {}
      this.client = null
    }
  }

  isConnected(): boolean {
    return this.client !== null
  }

  async reconnect(config: MonitorConfig['mail']): Promise<void> {
    await this.disconnect()
    const delay = this.RETRY_DELAYS[Math.min(this.retryCount, this.RETRY_DELAYS.length - 1)]
    this.retryCount++
    await new Promise(r => setTimeout(r, delay))
    await this.connect(config)
  }

  async keepAlive(): Promise<boolean> {
    if (!this.client) return false
    try {
      await this.client.noop()
      return true
    } catch {
      this.client = null
      return false
    }
  }

  async fetchUnread(config: MonitorConfig): Promise<EmailInfo[]> {
    if (!this.client) return []
    const lock = await this.client.getMailboxLock('INBOX')
    try {
      // 搜索最近 7 天的邮件（避免遗漏昨天未处理的邮件），通过 processed_emails 表去重
      const since = new Date()
      since.setDate(since.getDate() - 7)
      const uids = await this.client.search({ since }, { uid: true })
      if (!uids || uids.length === 0) return []

      const emails: EmailInfo[] = []
      for (const uid of uids) {
        try {
          const msg = await this.client.fetchOne(uid, { source: true, uid: true }, { uid: true })
          if (!msg || !('source' in msg) || !(msg as any).source) continue
          const parsed = await simpleParser((msg as any).source as Buffer)
          const emailInfo: EmailInfo = {
            msg_id: parsed.messageId || String(uid),
            subject: parsed.subject || '',
            sender: parsed.from?.text || '',
            date: parsed.date?.toISOString() || '',
            html: parsed.html || null,
          }
          emails.push(emailInfo)
        } catch {}
      }
      return emails
    } finally {
      lock.release()
    }
  }

  filterEmail(email: EmailInfo, config: MonitorConfig['filter']): { pass: boolean; type: 'oem_diag' | 'oem_repair' | null } {
    // 主题关键词过滤
    const subjectMatch = config.subject_keywords.some(kw => email.subject.includes(kw))
    if (!subjectMatch) return { pass: false, type: null }
    // 发件人过滤
    if (!email.sender.includes(config.sender_email)) return { pass: false, type: null }
    // OEM 类型识别
    const repair = config.oem_repair_keywords
    const diag = config.oem_diag_keywords
    const isRepair = email.subject.includes(repair.base_keyword) && email.subject.includes(repair.type_keyword) && !email.subject.includes(repair.exclude_keyword)
    const isDiag = email.subject.includes(diag.base_keyword) && email.subject.includes(diag.type_keyword) && !email.subject.includes(diag.exclude_keyword)
    if (isRepair) return { pass: true, type: 'oem_repair' }
    if (isDiag) return { pass: true, type: 'oem_diag' }
    return { pass: false, type: null }
  }

  extractTable(html: string): string[][] | null {
    const $ = cheerio.load(html)
    const tables = $('table')
    if (tables.length === 0) return null
    let targetTable: any = null
    tables.each((_, table) => {
      if ($(table).text().includes('故障信息')) {
        targetTable = table
        return false
      }
    })
    if (!targetTable) targetTable = tables[0]!
    const rows: string[][] = []
    $(targetTable).find('tr').each((_, row) => {
      const cells: string[] = []
      $(row).find('th, td').each((_, cell) => {
        cells.push($(cell).text().trim())
      })
      if (cells.length > 0) rows.push(cells)
    })
    return rows.length > 0 ? rows : null
  }

  extractFaultInfo(html: string, tableData: string[][] | null): FaultInfo {
    const text = html.replace(/<[^>]+>/g, ' ').replace(/\s+/g, ' ')
    const patterns = {
      fault_time: [/故障(?:发生)?时间[：:\s]*(\d{4}-\d{2}-\d{2}\s+\d{2}:\d{2}:\d{2})/, /(\d{4}-\d{2}-\d{2}\s+\d{2}:\d{2}:\d{2})/],
      server_sn: [/服务器SN[：:\s]*([A-Za-z0-9]+)/, /SN[：:\s]*([A-Za-z0-9]+)/, /([A-Za-z0-9]{15,25})/],
      server_ip: [/服务器IP[：:\s]*(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})/, /IP[：:\s]*(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})/, /(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})/],
    }
    const result: FaultInfo = { fault_time: null, server_sn: null, server_ip: null, order_number: null, fault_detail: null }
    for (const [key, regexes] of Object.entries(patterns)) {
      for (const regex of regexes) {
        const match = text.match(regex)
        if (match) { result[key as keyof FaultInfo] = match[1] as never; break }
      }
    }
    // 从主题提取工单号
    const orderMatch = html.match(/【服务器故障单】(\d+),/)
    if (orderMatch) result.order_number = orderMatch[1]
    // 从表格提取故障详情
    if (tableData) {
      for (const row of tableData) {
        const idx = row.findIndex(cell => cell.includes('故障信息'))
        if (idx >= 0 && idx + 1 < row.length) {
          result.fault_detail = row[idx + 1]
          break
        }
      }
    }
    return result
  }

  extractOrderNumber(subject: string): string | null {
    const match = subject.match(/【服务器故障单】(\d+),/)
    return match?.[1] ?? null
  }
}