import {
  acceptCompletion,
  clearSnippet,
  closeCompletion,
  hasNextSnippetField,
  moveCompletionSelection,
  nextSnippetField,
  prevSnippetField,
  startCompletion,
} from '@codemirror/autocomplete'
import { Prec } from '@codemirror/state'
import { EditorView, keymap, KeyBinding } from '@codemirror/view'

import { CompletionItemKind } from 'vscode-languageserver-protocol'

export const CompletionItemKindMap = Object.fromEntries(
  Object.entries(CompletionItemKind).map(([key, value]) => [value, key])
) as Record<CompletionItemKind, string>

const lspAutocompleteKeymap: readonly KeyBinding[] = [
  { key: 'Ctrl-Space', run: startCompletion },
  {
    key: 'Escape',
    run: (view: EditorView): boolean => {
      if (clearSnippet(view)) return true

      return closeCompletion(view)
    },
  },
  { key: 'ArrowDown', run: moveCompletionSelection(true) },
  { key: 'ArrowUp', run: moveCompletionSelection(false) },
  { key: 'PageDown', run: moveCompletionSelection(true, 'page') },
  { key: 'PageUp', run: moveCompletionSelection(false, 'page') },
  { key: 'Enter', run: acceptCompletion },
  {
    key: 'Tab',
    run: (view: EditorView): boolean => {
      if (hasNextSnippetField(view.state)) {
        const result = nextSnippetField(view)
        return result
      }

      return acceptCompletion(view)
    },
    shift: prevSnippetField,
  },
]

export const lspAutocompleteKeymapExt = Prec.highest(
  keymap.of(lspAutocompleteKeymap)
)