import { openDB } from 'idb'

import type { DomainMatch } from './ncbiDomains'

const DB_NAME = 'jbrowse-msaview-domain-cache'
const STORE_NAME = 'domains'
const DB_VERSION = 1

interface CachedDomain {
  accession: string
  matches: DomainMatch[]
}

let dbPromise: ReturnType<typeof openDB> | undefined

function getDB() {
  dbPromise ??= openDB(DB_NAME, DB_VERSION, {
    upgrade(db) {
      if (!db.objectStoreNames.contains(STORE_NAME)) {
        db.createObjectStore(STORE_NAME, { keyPath: 'accession' })
      }
    },
  }).catch((e: unknown) => {
    dbPromise = undefined
    throw e
  })
  return dbPromise
}

export async function getCachedDomains(accessions: string[]) {
  const db = await getDB()
  const tx = db.transaction(STORE_NAME, 'readonly')
  const results = await Promise.all(
    accessions.map(
      accession => tx.store.get(accession) as Promise<CachedDomain | undefined>,
    ),
  )
  await tx.done
  return results
}

export async function saveDomains(entries: CachedDomain[]) {
  const db = await getDB()
  const tx = db.transaction(STORE_NAME, 'readwrite')
  for (const entry of entries) {
    await tx.store.put(entry)
  }
  await tx.done
}