import { Annotation, ChangeSet } from '@codemirror/state'
import type { NodeIndexResult } from '../automerge-markdown'
import type { Heads } from './heads'
import type { DocumentManager } from '../services/document-manager'
import { diffTextChanges } from './text-diff'

export type SaveStatus =
  | { state: 'idle' }
  | { state: 'saving' }
  | { state: 'saved' }
  | { state: 'error'; message: string }

export type DocumentId = Parameters<DocumentManager['readText']>[0]
export type LoadPhase = 'loading' | 'ready' | 'error' | 'disposed'
export type SubscriptionPhase = 'detached' | 'resolving' | 'attached'
export type SavePhase = 'idle' | 'pending-plain' | 'saving-plain' | 'queued-semantic' | 'saving-semantic' | 'saved' | 'error'

export interface SyncTextState {
  documentId: DocumentId
  heads: Heads
  content: string
  beforeContent?: string
  afterContent?: string
}

export interface DocumentSyncSnapshot {
  sessionId: number
  docUrl: DocumentId
  loadPhase: LoadPhase
  loadError: string | undefined
  content: string | undefined
  saveStatus: SaveStatus
  savePhase: SavePhase
  isConcurrentTabOpen: boolean
  localGeneration: number
  persistedGeneration: number
  boundViewGeneration: number
  subscriptionPhase: SubscriptionPhase
  saveAttemptCount: number
  lastSaveOutcome: 'accepted' | 'rejected' | null
  lastSaveOutcomeGeneration: number | null
  markdownNodeIndex: NodeIndexResult | null
  settledEditorText: string | undefined
  persistedMarkdown: string | undefined
  checkpoint: SyncTextState | null
  durableHeads: Heads
  materializedHeads: Heads
}

export const REMOTE_CHANGE_ANNOTATION: ReturnType<typeof Annotation.define<true>> = Annotation.define<true>()

export function projectionChange(oldText: string, newText: string): ChangeSet {
  return ChangeSet.of(diffTextChanges(oldText, newText), oldText.length)
}