import { determineEmojiSupportLevel } from './determineEmojiSupportLevel'
import { requestIdleCallback } from './requestIdleCallback.js'

// Check which emojis we know for sure aren't supported, based on Unicode version level
let promise
export const detectEmojiSupportLevel = () => {
  if (!promise) {
    // Delay so it can run while the IDB database is being created by the browser (on another thread).
    // This helps especially with first load – we want to start pre-populating the database on the main thread,
    // and then wait for IDB to commit everything, and while waiting we run this check.
    promise = new Promise(resolve => (
      requestIdleCallback(() => (
        resolve(determineEmojiSupportLevel()) // delay so ideally this can run while IDB is first populating
      ))
    ))

    /* istanbul ignore else */
    if (import.meta.env.MODE !== 'production') {
      promise.then(emojiSupportLevel => {
        console.log('emoji support level', emojiSupportLevel)
      })
    }
  }
  return promise
}
// determine which emojis containing ZWJ (zero width joiner) characters
// are supported (rendered as one glyph) rather than unsupported (rendered as two or more glyphs)
export const supportedZwjEmojis = new Map()