import type { ResolvedPos } from '@prosekit/pm/model'
import { PluginKey, type EditorState, type Transaction } from '@prosekit/pm/state'

import type { AutocompleteRule } from './autocomplete-rule.ts'

export function defaultCanMatch({ state }: { state: EditorState }): boolean {
  const $pos = state.selection.$from
  return !isInsideCodeBlock($pos) && !isInsideCodeMark($pos)
}

function isInsideCodeBlock($pos: ResolvedPos): boolean {
  for (let d = $pos.depth; d > 0; d--) {
    if ($pos.node(d).type.spec.code) {
      return true
    }
  }
  return false
}

function isInsideCodeMark($pos: ResolvedPos): boolean {
  for (const mark of $pos.marks()) {
    if (mark.type.spec.code) {
      return true
    }
  }
  return false
}

/**
 * @internal
 */
export interface PredictionPluginMatching {
  rule: AutocompleteRule
  from: number
  to: number
  match: RegExpExecArray
}

/**
 * @internal
 */
export interface PredictionPluginState {
  /**
   * The matching positions that should be ignored.
   */
  ignores: Array<number>

  /**
   * The current active matching.
   */
  matching: PredictionPluginMatching | null
}

/**
 * @internal
 */
export type PredictionTransactionMeta = {
  type: 'enter'
  matching: PredictionPluginMatching
} | {
  type: 'leave'
}

export function getPluginState(state: EditorState): PredictionPluginState | undefined {
  return pluginKey.getState(state)
}

export function getTrMeta(tr: Transaction): PredictionTransactionMeta | undefined {
  return tr.getMeta(pluginKey) as PredictionTransactionMeta | undefined
}

export function setTrMeta(
  tr: Transaction,
  meta: PredictionTransactionMeta,
): Transaction {
  return tr.setMeta(pluginKey, meta)
}

export const pluginKey: PluginKey<PredictionPluginState> = new PluginKey<PredictionPluginState>('prosekit-autocomplete')