import { db } from '../db'

/**
 * Parse a full name string (Russian format: "Фамилия Имя [Отчество]")
 * into first_name, last_name, middle_name parts.
 */
function parseName(fullName: string): { firstName: string; lastName: string; middleName: string | null } {
  const parts = fullName.trim().split(/\s+/)
  if (parts.length === 1) {
    return { firstName: parts[0], lastName: '', middleName: null }
  }
  return {
    lastName:   parts[0],
    firstName:  parts[1],
    middleName: parts[2] ?? null,
  }
}

/**
 * Create or update a guest record based on booking data.
 * - Matches existing guest by email OR phone (same hotel)
 * - If found: updates name/phone/email if they were empty
 * - If not found: creates new guest record
 * Non-throwing: errors are swallowed so booking creation is never blocked.
 */
export async function upsertGuestFromBooking(params: {
  hotelId: string
  guestName: string
  guestEmail?: string | null
  guestPhone?: string | null
}): Promise<void> {
  try {
    const { hotelId, guestName, guestEmail, guestPhone } = params

    if (!guestName?.trim()) return

    // Build match conditions
    const conditions: string[] = []
    const matchParams: unknown[] = [hotelId]
    if (guestEmail?.trim()) {
      matchParams.push(guestEmail.toLowerCase().trim())
      conditions.push(`LOWER(email) = $${matchParams.length}`)
    }
    if (guestPhone?.trim()) {
      const cleanPhone = guestPhone.replace(/\D/g, '')
      if (cleanPhone.length >= 7) {
        matchParams.push(cleanPhone)
        conditions.push(`REGEXP_REPLACE(phone, '[^0-9]', '', 'g') = $${matchParams.length}`)
      }
    }

    if (conditions.length > 0) {
      // Check if guest already exists
      const { rows } = await db.query(
        `SELECT id, first_name, last_name, email, phone
           FROM guests
          WHERE hotel_id = $1 AND (${conditions.join(' OR ')})
          ORDER BY updated_at DESC
          LIMIT 1`,
        matchParams,
      )

      if (rows[0]) {
        // Guest exists — fill in any blank fields
        const updates: string[] = []
        const upParams: unknown[] = []
        const g = rows[0]

        if ((!g.email || g.email === '') && guestEmail?.trim()) {
          upParams.push(guestEmail.toLowerCase().trim())
          updates.push(`email = $${upParams.length}`)
        }
        if ((!g.phone || g.phone === '') && guestPhone?.trim()) {
          upParams.push(guestPhone.trim())
          updates.push(`phone = $${upParams.length}`)
        }
        if (updates.length > 0) {
          upParams.push(rows[0].id)
          await db.query(
            `UPDATE guests SET ${updates.join(', ')}, updated_at = NOW() WHERE id = $${upParams.length}`,
            upParams,
          )
        }
        return
      }
    }

    // No existing guest found — create new
    const { firstName, lastName, middleName } = parseName(guestName)
    await db.query(
      `INSERT INTO guests (hotel_id, first_name, last_name, middle_name, email, phone, loyalty_tier)
       VALUES ($1, $2, $3, $4, $5, $6, 'bronze')`,
      [
        hotelId,
        firstName,
        lastName,
        middleName,
        guestEmail?.toLowerCase().trim() ?? null,
        guestPhone?.trim() ?? null,
      ],
    )
  } catch {
    // Non-critical — never block booking creation
  }
}