import { Extension } from '@tiptap/core'
import { Plugin, PluginKey } from '@tiptap/pm/state'
import type { Transaction } from '@tiptap/pm/state'
import type { Node as PMNode } from '@tiptap/pm/model'

const BLOCK_TYPES = ['paragraph', 'heading', 'blockquote', 'bulletList', 'orderedList', 'taskList', 'codeBlock']

function assignMissingBlockIds(tr: Transaction, doc: PMNode) {
  let modified = false
  doc.descendants((node, pos) => {
    if (!BLOCK_TYPES.includes(node.type.name)) return
    if (node.attrs['data-id']) return

    tr.setNodeMarkup(pos, undefined, {
      ...node.attrs,
      'data-id': generateBlockId(),
    })
    modified = true
  })
  return modified
}

function generateBlockId(): string {
  if (typeof crypto !== 'undefined' && typeof crypto.randomUUID === 'function') {
    return crypto.randomUUID()
  }
  return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, (c) => {
    const r = (Math.random() * 16) | 0
    const v = c === 'x' ? r : (r & 0x3) | 0x8
    return v.toString(16)
  })
}

export const UniqueIdExtension = Extension.create({
  name: 'uniqueId',

  onCreate({ editor }) {
    const assign = () => {
      if (editor.isDestroyed) return
      const { tr, doc } = editor.state
      if (assignMissingBlockIds(tr, doc)) {
        editor.view.dispatch(tr)
      }
    }
    assign()
    requestAnimationFrame(assign)
  },

  addProseMirrorPlugins() {
    return [
      new Plugin({
        key: new PluginKey('uniqueId'),
        appendTransaction(transactions, _oldState, newState) {
          const hasDocChanged = transactions.some(t => t.docChanged)
          if (!hasDocChanged) return null

          const { tr, doc } = newState
          return assignMissingBlockIds(tr, doc) ? tr : null
        },
      }),
    ]
  },

  addGlobalAttributes() {
    return [
      {
        types: BLOCK_TYPES,
        attributes: {
          'data-id': {
            default: null,
            parseHTML: element => element.getAttribute('data-id'),
            renderHTML: attributes => {
              if (!attributes['data-id']) return {}
              return { 'data-id': attributes['data-id'] }
            },
          },
        },
      },
    ]
  },
})