import { useCallback, useContext, useState } from 'react'
import { snapshot } from 'valtio'

import type { IStandaloneCodeEditor } from './SQLEditor.types'
import { useSQLEditorContext } from './SQLEditorContext'
import { createTabId, TabsStateContext } from '@/state/tabs'

/**
 * Owns the editor `onMount` handler (scroll-position restore + tracking) and the
 * mount counter that lets a diff request which arrived before the editor was
 * ready re-run once it is.
 */
export function useEditorMount({ id }: { id: string }) {
  const { scrollTopRef } = useSQLEditorContext()
  // The proxy store (stable reference), read non-reactively in onMount so the
  // callback identity doesn't churn on every tab-state change.
  const tabsState = useContext(TabsStateContext)

  // Bumped on every editor mount (including the keyed remount on snippet switch)
  // so a diff request that arrived before the editor was ready gets re-processed.
  const [editorMountCount, setEditorMountCount] = useState(0)

  const onMount = useCallback(
    (editor: IStandaloneCodeEditor) => {
      setEditorMountCount((count) => count + 1)

      const tabId = createTabId('sql', { id })
      const tabData = snapshot(tabsState).tabsMap[tabId]

      // [Joshen] Tiny timeout to give a bit of time for the content to load before scrolling
      setTimeout(() => {
        if (tabData?.metadata?.scrollTop) {
          editor.setScrollTop(tabData.metadata.scrollTop)
        }
      }, 20)
      editor.onDidScrollChange((e) => (scrollTopRef.current = e.scrollTop))
    },
    [id, scrollTopRef, tabsState]
  )

  return { onMount, editorMountCount }
}