import type { Priority } from '@prosekit/core'
import { union, withPriority, type PlainExtension, type Union } from '@prosekit/core'
import type * as Y from 'yjs'

import { defineYjsCommands, type YjsCommandsExtension } from './yjs-commands.ts'
import { defineYjsCursorPlugin, type YjsCursorPluginOptions } from './yjs-cursor-plugin.ts'
import { defineYjsKeymap } from './yjs-keymap.ts'
import { defineYjsSyncPlugin, type YjsSyncPluginOptions } from './yjs-sync-plugin.ts'
import type { Awareness } from './yjs-types.ts'
import { defineYjsUndoPlugin, type YjsUndoPluginOptions } from './yjs-undo-plugin.ts'

export interface YjsOptions {
  /**
   * The Yjs instance handles the state of shared data.
   */
  doc: Y.Doc

  /**
   * The Awareness instance.
   */
  awareness: Awareness

  /**
   * The Yjs XmlFragment to use. If not provided,
   * `doc.getXmlFragment('prosemirror')` will be used.
   */
  fragment?: Y.XmlFragment

  /**
   * Options for `y-prosemirror`'s `ySyncPlugin`.
   */
  sync?: YjsSyncPluginOptions

  /**
   * Options for the `y-prosemirror`'s `yUndoPlugin`.
   */
  undo?: YjsUndoPluginOptions

  /**
   * Options for `y-prosemirror`'s `yCursorPlugin`.
   */
  cursor?: YjsCursorPluginOptions
}

/**
 * @internal
 */
export type YjsExtension = Union<[YjsCommandsExtension, PlainExtension]>

export function defineYjs(options: YjsOptions): YjsExtension {
  const { doc, awareness, sync, undo, cursor } = options
  const fragment = options.fragment ?? doc.getXmlFragment('prosemirror')

  return withPriority(
    union([
      defineYjsKeymap(),
      defineYjsCommands(),
      defineYjsCursorPlugin({ ...cursor, awareness }),
      defineYjsUndoPlugin({ ...undo }),
      defineYjsSyncPlugin({ ...sync, fragment }),
    ]),
    3 satisfies typeof Priority.high,
  )
}