import type { AgentEvent } from './api'

const DB_NAME = 'smart-factory-agent'
const STORE_NAME = 'events'

function openDatabase() {
  return new Promise<IDBDatabase>((resolve, reject) => {
    const request = indexedDB.open(DB_NAME, 1)
    request.onupgradeneeded = () => {
      const store = request.result.createObjectStore(STORE_NAME, { keyPath: ['projectId', 'id'] })
      store.createIndex('projectId', 'projectId')
    }
    request.onsuccess = () => resolve(request.result)
    request.onerror = () => reject(request.error)
  })
}

export async function readCachedEvents(projectId: string): Promise<AgentEvent[]> {
  const database = await openDatabase()
  return new Promise((resolve, reject) => {
    const transaction = database.transaction(STORE_NAME, 'readonly')
    const request = transaction.objectStore(STORE_NAME).index('projectId').getAll(projectId)
    request.onsuccess = () => resolve((request.result as AgentEvent[]).sort((a, b) => a.id - b.id))
    request.onerror = () => reject(request.error)
    transaction.oncomplete = () => database.close()
  })
}

export async function cacheEvents(events: AgentEvent[]) {
  if (!events.length) return
  const database = await openDatabase()
  await new Promise<void>((resolve, reject) => {
    const transaction = database.transaction(STORE_NAME, 'readwrite')
    const store = transaction.objectStore(STORE_NAME)
    for (const event of events) store.put(event)
    transaction.oncomplete = () => resolve()
    transaction.onerror = () => reject(transaction.error)
  })
  database.close()
}

export async function deleteCachedEvents(projectId: string) {
  const database = await openDatabase()
  await new Promise<void>((resolve, reject) => {
    const transaction = database.transaction(STORE_NAME, 'readwrite')
    const request = transaction.objectStore(STORE_NAME).index('projectId').openCursor(IDBKeyRange.only(projectId))
    request.onsuccess = () => {
      const cursor = request.result
      if (!cursor) return
      cursor.delete()
      cursor.continue()
    }
    transaction.oncomplete = () => resolve()
    transaction.onerror = () => reject(transaction.error)
  })
  database.close()
}