import { getDb } from '../db/client.js'

const sql = getDb()

export const createAnonymousCustomer = async ({ display_name, firebase_uid }) => {
  // Return existing customer if already linked to this Firebase UID
  const [existing] = await sql`
    SELECT id, display_name, is_anonymous, created_at
    FROM customers WHERE firebase_uid = ${firebase_uid}
  `
  if (existing) return existing

  const [customer] = await sql`
    INSERT INTO customers (display_name, is_anonymous, firebase_uid)
    VALUES (${display_name}, true, ${firebase_uid})
    RETURNING id, display_name, is_anonymous, created_at
  `
  return customer
}

export const linkCustomerAccount = async ({ customer_id, firebase_uid }) => {
  const [existing] = await sql`
    SELECT id, firebase_uid FROM customers WHERE id = ${customer_id}
  `
  if (!existing) throw Object.assign(new Error('Customer not found'), { code: 'NOT_FOUND', statusCode: 404 })
  if (existing.firebase_uid) throw Object.assign(new Error('Account already linked'), { code: 'ALREADY_REGISTERED', statusCode: 409 })

  // Also fetch phone from firebase_uid if exists in another customer record for uniqueness
  const [firebaseLinked] = await sql`
    SELECT id FROM customers WHERE firebase_uid = ${firebase_uid}
  `
  if (firebaseLinked) throw Object.assign(new Error('Account already linked'), { code: 'ALREADY_REGISTERED', statusCode: 409 })

  const [updated] = await sql`
    UPDATE customers
    SET firebase_uid = ${firebase_uid}, is_anonymous = false
    WHERE id = ${customer_id}
    RETURNING id, display_name, is_anonymous, phone, created_at
  `
  return updated
}

export const getCustomerByFirebaseUid = async (firebase_uid) => {
  const [customer] = await sql`
    SELECT id, display_name, is_anonymous, phone, created_at
    FROM customers
    WHERE firebase_uid = ${firebase_uid}
  `
  return customer
}

export const getOrCreateCustomer = async ({ firebase_uid, phone, display_name }) => {
  // Return existing customer if already linked to this Firebase UID
  const existing = await getCustomerByFirebaseUid(firebase_uid)
  if (existing) return existing

  // Check if a customer with this phone already exists (re-login with new Firebase UID)
  if (phone) {
    const [byPhone] = await sql`
      SELECT id, display_name, is_anonymous, phone, created_at
      FROM customers WHERE phone = ${phone}
    `
    if (byPhone) {
      // Link the new Firebase UID to the existing phone-based customer
      await sql`UPDATE customers SET firebase_uid = ${firebase_uid} WHERE id = ${byPhone.id}`
      return { ...byPhone, firebase_uid }
    }
  }

  // Auto-create a registered (non-anonymous) customer for phone/social login
  // display_name is null — user must set it on first login
  const [customer] = await sql`
    INSERT INTO customers (firebase_uid, phone, display_name, is_anonymous)
    VALUES (${firebase_uid}, ${phone || null}, ${display_name || null}, false)
    RETURNING id, display_name, is_anonymous, phone, created_at
  `
  return customer
}

export const updateCustomerDisplayName = async (customerId, displayName) => {
  const [customer] = await sql`
    UPDATE customers SET display_name = ${displayName}
    WHERE id = ${customerId}
    RETURNING id, display_name, is_anonymous, phone, created_at
  `
  return customer
}